Old Ottawa East

District Energy System Proposal

Fall 2013

Created By: Carleton Engineering Students For: Sustainable Living Ottawa East

Report Produced By: Nathan Bosscher, Antoine Fillion, Mehsen Kassem, Ahmed Omar (Project Management) Nick Brown, Andrew K, Sean, Ed (Buildings & Distribution) Mitch, Nik, Kuba, Roberto (Centralized Energy) Matt Mickkelsen, Hunho, Zain, Brendan(Distributed Energy) Arian, Omar, Michael, Kevin (Cooling technologies) Joseph, Paige, Kailey, Sam(Seasonal Thermal Storage) Joel, Kathleen, Aly (Short-term Thermal Storage) David,Chris, Matt Doel (GSHP)

Special Thanks To: Michael Wiggin and Stephen Pope

Notes: References are formatted as [a#.#.#] and indexed as such in the respective appendix, glossary and reference section of this report. Please forward any questions to Nathan Bosscher ([email protected])

Table of Contents

1.0 Introduction: 2.0 Buildings 2.0.1 Introduction 2.1 Heating, Cooling and Power Loads [Andrew Kovala] 2.1.1 Heating Loads 2.1.2 Section Cooling Loads 2.1.3: Power Loads 2.1.4: Total Loads for OOE ILDA 2.2: Water Temperature, Flow Rate, Heat Transfer Stations, and Steam vs. Liquid Water [Sean Romano] 2.2.1: Water Temperature and Flow Rate 2.2.2: Heat Transfer Stations 2.2.3: Liquid Water versus Steam 2.3 Analysis of Wall Mounted Panel Heaters & Baseboard Heaters [Nicholas Brown] 2.3.1 Operating Temperature 2.3.2 Wall Mounted Panel and Baseboard Heaters 2.3.2.1 Space Requirements of Baseboard Heaters and Wall Mounted Panel Heaters 2.3.2.2 Thermal Efficiency of Hydronic Wall Mounted Panel Heaters and Baseboard Heaters 2.3.3 Cost Analysis For Wall Mounted Space Heaters 3.0 Production 3.0.1 Introduction [Antoine] 3.0.1 Natural Gas Boilers [Antoine] 3.0.2 Biomass Boilers [Antoine] 3.0.3 Solar Panels [Antoine] 3.0.4 Ground Source Heat Pumps [Antoine] 3.0.5 Recommendations [Antoine] 3.1 Distributed Solar Energy 3.1.1 Introduction 3.1.2 Solar Photovoltaics 3.1.3 Comparing Solar Panel Systems 3.1.4 Flat Mounting System (FMS): Flat Roof Solar Mounting Systems 3.1.5 Titled Mounting System (TMS): Fixed Tilt Solar Racking System 3.1.6 Auto Tilting Solar panels: Single-Axis Solar Tracking System 3.1.7 Recommended Arrangement 3.1.8 Power Generation 3.1.9 The Optimum Material for the Solar Panels 3.1.10 The Specific Solar Panel Model 3.1.11 The Angle and Placement of Panels to Maximize Energy Generation 3.1.12 The Number of Panels that could be Installed 3.1.13 The Average Solar Radiation Levels in Ottawa 3.1.14 Determining energy production 3.1.15 Selling the Generated Energy 3.1.16 Government Incentives 3.1.17 Feed-In Tariff (FIT) Program 3.1.18 Net Metering 3.1.19 Recommendation for Selling the Generated Energy 3.1.20 Electrical Storage 3.1.21 Comparing Types of Batteries 3.1.22 Selecting the Specific Battery Model 3.1.23 Sizing the Battery 3.1.24 Recommendation for Locally Storing Power 3.1.25 Maintenance 3.1.26 Solar Thermal Energy Generation 3.1.27 Solar Collectors 3.1.28 Flat Plate Collectors 3.1.29 Evacuated Tube collectors 3.1.30 Solar Thermal Systems 3.1.31 Thermosiphon (Passive) Systems 3.1.32 Active Indirect Systems 3.2 Centralized Energy System 3.2.1 Introduction 3.2.2 Biomass Boiler [Mitchell Liddy] 3.2.2.1 Introduction 3.2.2.2 - Thermal Energy Output 3.2.2.3 Maintenance Requirments and Cost 3.2.2.4 Capital Cost 3.2.2.4 - Type of Biomass [Roberto Ionescu] 3.2.2.5 - Costs of Wood Biomass [Roberto Ionescu] 3.2.2.6 - Energy Densities of Wood Biomass [Roberto Ionescu] 3.2.3 Natural Gas Boilers 3.2.3.1 Introduction 3.2.3.2 Heating Demand for Old Ottawa [Nik] 3.2.3.3-Natural Gas Boiler Specifications [Nik] 3.2.3.4 Capital Cost of Natural Gas Boilers [Nik] 3.2.3.5 Environmental Impact of Natural Gas [Kuba] 3.2.3.6 Cost of Natural Gas [Kuba] 3.2.3.7 The Future of Natural Gas [Kuba] 3.3 Ground Source Heat Pumps 3.3.1.0 Introduction [David Gallacher] 3.3.1.1 Ground water 3.3.1.2 Surface Water 3.3.1.3 Benefits 3.3.1.4 Costs 3.3.1.5 Conclusion 3.3.2.0 Introduction [Matthew Doel] 3.3.2.1 Design & Function 3.3.2.1.1 Materials used 3.3.2.1.2 Alternative Water Heating Function 3.3.2.2 Vertical Systems 3.3.2.3 Horizontal Systems 3.3.3.3 Maintenance 3.3.2.5 Feasibility for Old Ottawa East development 3.3.3.0 Complementary Systems and Seasonal Use for a Ground Source Heat Pumps (GSHP) [Christopher Morency] 3.3.3.2 Natural Gas Coupling 3.3.3.3 Solar Panel Coupling 3.3.3.3 Seasonal Possibilities 3.3.3.5 Conclusion 3.4 Cooling Technologies 3.4.1 Cooling Loads in Ottawa (Kevin Skea) 3.4.1.1 Months 3.4.1.2 Hourly loads 3.4.1.3 Amount of cooling 3.4.1.4 Cost without district system 3.4.2.1 Vapor-compression chillers vs. absorption chillers 3.4.2.2 Types of compressors in electric chillers 3.4.2.3 Operating costs of district chillers vs. single air conditioning units 3.4.3.1 Supply and Return Temperatures for the District Cooling System (Arian Rayegani) 3.4.3.4 Understanding District Cooling Systems 3.4.3.3 Findings Regarding Supply and Return Conditions 3.4.3.3.1 Supply temperature 3.4.3.3.2 Return Temperature 3.4.3.3.3 Flow Rate 3.4.4.1 Home insulation: Introduction 3.4.4.2 The Building Envelope 3.4.4.3 How Does Heat Flow? 3.4.4.4 Areas of the building envelope that could be insulated 3.4.4.5 Ceiling and Walls Insulation 3.4.4.6 Windows 3.4.4.7 Conclusion 3.5 Conclusion [Ahmed Omar] 3.5.1 Natural gas: 3.5.2 Biomass: 3.5.3 Solar Panels 3.5.4 Ground Source Heat Pumps: 3.5 Conclusion: 4.0 Storage 4.0.1 Storage Introduction - Mohssen Kassem 4.0.2 Background 4.0.3 Seasonal Energy Storage 4.0.4 Short Term Energy Storage 4.0.5 Overall Energy Storage Systems Distribution 4.1 Short Term Thermal Storage 4.1.1 COLD STORAGE SYSTEMS - Joel Prakash 4.1.1.1 What cold storage systems are 4.1.1.2 Phases in a cold storage system 4.1.1.3. Benefits that a cold storage system could provide 4.1.1.4 Mediums used for cold storage systems: 4.1.1.5 Choosing between chilled water and ice storage: 4.1.1.6 Materials used for the storage tank: 4.1.1.7 Layout of cold storage systems with chillers 4.1.1.8 Control strategies for cold storage systems: 4.1.1.9 Conclusion 4.1.2 Thermal Storage Tanks - Aly Rasmy 4.1.2.1 Why water is used as a storage medium 4.1.2.2 How a thermal storage tank work 4.1.2.3 Why thermal tanks are used 4.1.2.4 Relation of heating load with heating demand 4.1.2.5 Tank capacity 4.1.2.6 Cost effectiveness 4.1.2.7 Properties of the tank 4.1.2.8 Overall size and cost results of the tank 4.1.3 Thermal Mass Storage – Kathleen Rozman 4.1.3.1 Overview of thermal mass storage 4.1.3.2 Methods to facilitate thermal mass storage 4.1.3.3 Benefits of the thermal mass storage systems 4.2 Seasonal Thermal Energy Storage 4.2.0 Introduction: 4.2.0.1 Background 4.2.0.2 Seasonal Energy Storage 4.2.0.3 Short Term Energy Storage 4.2.0.3 Overall Energy Storage Systems Distribution 4.2.0.4 Conclusion and Recommendations 4.2.1 Introduction 4.2.2 Aquifer Thermal Energy Storage System (ATES) [Kailey De Silva] 4.2.2.1 Usage in a District Energy System 4.2.2.2 How It Works 4.2.2.2.1 Aquifer Thermal Energy Storage System 4.2.2.2.2 Heat Exchangers 4.2.2.2.3 Heat pumps 4.2.2.3 Approximate Costs of Aquifer Thermal Storage 4.2.2.4 Installation in Old Ottawa East 4.2.2.5 Alternative Means of Implementing ATES in Old Ottawa East 4.2.2.6 Aquifer Thermal Storage System Research Conclusion 4.2.3 Borehole Thermal Energy Storage (BTES) [Samantha Champagne] 4.2.3.1 Understanding Borehole Thermal Energy Storage 4.2.3.2 Storage Medium and Heat Capacity 4.2.3.3 Compatibility with Old Ottawa East Institutional Lands Development 4.2.3.3.1 Thermal Conductivity 4.2.3.3.2 Groundwater Flow 4.2.3.4 Installation Cost of Borehole Thermal Energy Storage System 4.2.3.5 Conclusion 4.2.4 Environmental Comparison of BTES and ATES [Paige Waldock] 4.2.4.1 Environmental Aspects of Borehole and Aquifer Systems 4.2.4.2 Environmental Considerations on Implementation in Ottawa 4.2.4.3 Environmental Comparison Research Conclusion 4.2.5 Operational Temperature Limits and Energy Capacity [Joseph Botros] 4.2.5.1 Energy Demand Estimates 4.2.5.2 Operational Temperature Limits 4.2.5.3 Required System Thermal Energy Capacity 4.2.5.4 Insulation Materials 4.2.5.4.1 Perlite Vacuum Super-insulation 4.2.5.4.2 Conventional Materials for Insulation 4.2.5.4.3 Comparing Materials 4.2.5.4.4 Insulation Recommendation 4.2.5.5 Energy and Insulation Research Conclusion 4.2.6 Conclusion 5.0 Modeling 5.1 Site and Energy Production: 5.2 Modeling: 5.3 Conclusion: 6.0 Conclusion

1.0 Introduction:

The current development of the institutional lands in Old Ottawa East brings about the possibility for great innovations which can in turn bring many improvements. A few months ago, the class of CCDP 2100 V proposed the concept of a district energy system for the area and started the research on its possibility. The way it would work is by creating heat within the area which is then sent to the various buildings to be consumed. There are however many methods to do this which is why this report will be divided in sections relating to main topics such as: Buildings (Section 2), Production (Section 3), Storage (Section 4) and Modeling (Section 5). The Buildings sections will discuss the needs for Old Ottawa East and the means to distribute the heat as efficiently as possible. Production is divided further in two groups: Distributed (Section 3.1) and Centralized (Section 3.2) which will each elaborate on the possible energy facilities that would produce the heat. The possibility of storing any excess energy for later use will also be split in two with short term storage (Section 4.1) and seasonal storage (Section 4.2). A Modeling section has been added afterwards to compare the information that was found and to draw some conclusions of the results. This report sets out to research the feasibility of a district energy system which would supply the heating needs of Old Ottawa East. It is therefore important to note that the results are to be used only for associations with the specified area and are by no means representative of other locations.

2.0 Buildings

2.0.1 Introduction Our team has been researching components of buildings and distribution, as part of a larger team effort to research a district energy system for the Old Ottawa East institutional development lands. This report contains research on heating, cooling and power loads (Section 2.1), water temperature, flow rate, heat transfer stations, and hot water vs steam (Section 2.2), and a comparison of baseboard and wall panel heaters (Section 2.3).

2.1 Heating, Cooling and Power Loads [Andrew Kovala] For a district energy system to coordinate the power requirements for each of the buildings, the main power or heat source has to be sufficient for all of the buildings. Also, the heating and cooling loads for the buildings and help determine the flow rate through the underground water distribution pipes [r2.1.1]. The power loads help indicate the overall power requirements in the area and also how much power is available for other systems to work sufficiently [r2.1.1]. Other groups can rely on this information to make their calculations based on how much electrical power, heating power, or cooling power is available [r2.1.1]. Table 1[a2.1.1] shows all of the loads in kWh per year for a 4 storey multi-unit residential building [MURB]. These values are used because in Old Ottawa Easts Institutional lands Development area (OOE ILDA), a 4 storey MURB is the type of residential buildings in OOE [r2.1.3]. The power requirements for heating, service water, cooling and the total power requirements for the 4 storey MURB had to be converted to kWh/m^2.

2.1.1 Heating Loads For heating, it was calculated by adding the service water loads (hot water for heating/taps etc) to the heating loads (appliances such as baseboard heaters or wall heaters) to get the total heating loads for the 4 storey MURB. Then the heating loads for the 4 storey MURB were divided by the total floor area of the 4 storey MURB the get the total heating loads in kWh/m^2 per year, as seen in the sample calculation[a2.1.1.1].

This value was concluded to be 80 kWh/m^2 a year. There were also commercial heating loads to account for, since a commercial building or floor uses a different amount of energy. As seen in table 2 [a2.1.1], the heating and service water values are different. Using the calculations[a2.1.1.2], it was concluded that the overall commercial heating loads for a commercial building to be 89.5 kWh/m^2.

2.1.2 Section Cooling Loads In regards to the cooling loads, these included the kWh of cooling and the kWh for the fans. After adding these two values for a 4 storey residential MURB and dividing them by the total floor area, the residential cooling loads per meter squared were calculated to be 68.9 kWh/m^2. For the commercial cooling loads, the fans and the cooling water were also added together, and divided by the total floor area. This value was calculated to be 22.3 kWh/m^2.

2.1.3: Power Loads For the total electrical loads per meter squared, figure one and figure two had already calculated them [r2.1.2]. They were 210 kWh/m^2 for residential buildings and 191 kWh/m^2 for commercial buildings.

2.1.4: Total Loads for OOE ILDA Using the table 2.1.3 [r2.1.2], I was able to find the total floor area for commercial and residential buildings, which were, respectively, 3570 m^2 and 137,786 m^2. I could multiply the floor area by the kWh per m^2 for heating and cooling loads to achieve the total loads for each of cooling, heating and the total electrical loads, as seen in the formula below.

(Loads in kWh/m^2)(total area of buildings in m^2) = annual loads per year in kWh (2)

Using this formula for the heating loads, the commercial and the residential loads had to be calculated separately, then added up. To find the total annual loads, we used the calculations [a2.1.4.1].

We then found the total heating load for OOE ILDA, which was 1,134,239 kWh per year. Using equation 2[a2.1.4.1], the cooling and power loads could be calculated for OOE ILDA also. The total cooling loads were calculated to be 9,573,066 kWh per year. For the total power loads, the total power required for each system was added up and divided by the total floor area, and then the value obtained was multiplied by the total floor area of OOE ILDA [a2.1.3], which was discovered to be 29,616,930 kWh per year. These values are important to the district energy system project because they give maximum values for the other teams to use [r2.1.1]. The energy consumption for heating, cooling and total electrical loads should not exceed these values, or energy will be wasted [r2.1.1]. The goal is to save as much energy as possible, and consuming as little energy as possible is the only way to do it. These values give a good starting point for systems such as heaters, chillers and other appliances to aim for in their energy consumption. Also, these are yearly loads. For cooling in the winter, there are very few appliances which require it, so these loads apply mostly to the cold months. For heating, space heaters are rarely required so the only heating loads needed will be the service water loads for showers, dishwashers, and other appliances requiring hot water.

2.2: Water Temperature, Flow Rate, Heat Transfer Stations, and Steam vs. Liquid Water [Sean Romano] 2.2.1: Water Temperature and Flow Rate

The DES should be created to include heating domestic hot water in addition to providing thermal energy to heat the buildings, which is the water used to wash your dishes, shower, and to wash your clothes, among other things. This would be beneficial primarily for larger buildings as it would allow them to completely remove their boiler assemblies and replace them with a few heat transfer stations, allowing for reduced maintenance and installation costs. If we are to include the capacity to heat domestic hot water, the district energy system (DES) would need to maintain a temperature of at least 85 degrees Celsius in the supply pipes year round otherwise there will not be sufficiently high temperature hot water in the buildings[r2.2.1]. These temperatures could vary to as high as 105 degrees Celsius during the winter to ensure enough heat is supplied to the buildings. This temperature is possible without the water boiling due to the pressure on the system that is used to create flow, as a pressure difference is a force difference and causes acceleration and thus movement of the fluid, and the chemicals (like phosphates, and acetic acid) added to the supply loop, which is the loop that is heated by the DES and supplied to the buildings on the network. Return temperature, or the temperature the water returns at after distributing most of its thermal energy to the internal system for individual buildings, is also very important. As the difference between the supplied and returned temperatures indicates how much thermal energy has been transferred. A lower return temperature means that more heat has been transferred to the buildings on the DES which increases efficiency, as a higher portion of supplied heat is utilized with a higher temperature difference [a2.2.1.1] Expected return temperatures are about 40 degrees lower than supplied temperatures. Using the known expected temperature drop, which is 40 degrees, and the formula [a2.2.1.2] we can calculate that the required flow rate is an average of 7.7 litres per second in order to provide enough heat to the buildings on the network assuming return temperatures of 40 degrees lower[r2.2.2]

2.2.2: Heat Transfer Stations Heat transfer stations[a2.2.2.1] are units that go between the supply piping, and the buildings internal hot water network. Heat transfer stations are desirable as they provide an interface for heat transfer between the DES and the buildings on it without mixing of mediums, as can be seen in figure 2. This facilitates the use of additives on the supply side, while allowing the water on the consumer/building end to be pure. These additives would be chemicals to reduce corrosion (Examples of chemicals which would reduce corrosion: Phosphates, Silicates and Calcium) , and raise the boiling point (Examples of chemicals which would raise boiling point: Acetic Acid, Phenol)[r2.2.4]. This allows for increased temperature of the supplied water when required, and decreased maintenance. Which should lead to lower costs, compared to a open loop using pure water. The use of pure water on the building side is beneficial because it allows for easier and cheaper replacement in case of a leak, in addition to being safer in case of a leak. It also allows for the water to be used (As in showering, washing dishes) without impacting the supply loop.

2.2.3: Liquid Water versus Steam Hot water is a desirable heat transfer medium, or fluid used to carry thermal energy for our purposes. This is primarily due to the fact when dealing with hot water you can avoid phase changes, or changes between liquid water and water vapor (steam). As these changes would increase costs by requiring additional pumps since you cannot pump steam with a pump designed for water and vice versa.[r2.2.5] This means you will need to install pumps for each state, liquid and gas, if you were to use steam as once you remove most of the thermal energy it will return to being liquid water. This will increase the expense on electricity to pump it throughout the lifecycle of the system, and increase installation costs. In addition, in a new installation intended to work with hot water, boilers can operate at lower combustion temperatures, which increases efficiency[r2.2.6]. Since all of the heaters will be new installations at central locations, hot water will be preferable because of these reasons despite steam being a faster transferring medium. It‟s faster transferring due to the general greater difference in temperature between it, and what the thermal energy is being transferred to as compared to hot water as steam can be much higher temperature than 100 degrees Celsius, whereas liquid water can only be heated to slightly over, depending on pressure and a few other conditions. In other words, the temperature difference between 200+ degree steam and what the energy is being transferred to, is generally much larger than the difference between ~100 degree water, and the same target, this will generally lead to steam transferring heat energy faster.

2.3 Analysis of Wall Mounted Panel Heaters & Baseboard Heaters [Nicholas Brown] One of the questions of this project was whether baseboard heaters or wall mounted panel heaters should be used to heat the rooms in the ILDA. Research was focused on electronic panel heater devices for efficiency rather than hydronic panel heaters since there is more information available and there is no difference between hydronic and electrical heaters in terms of effectiveness at heating a room. Heat dispersion is the same for each device whether it is supplied with thermal energy from electricity or from heated water. The operating temperature of each device will be discussed in section 2.3.2.1, the space requirements of each will be covered in section 2.3.2.2, the efficiency of heat transfer will be the topic of 2.3.2.3 and there will be a cost analysis in section 2.3.3.

2.3.1 Operating Temperature The operating temperature of baseboard heaters is higher than operating temperatures of wall mounted space heaters. Wall mounted space heaters require an operating temperature of 38 to 82 degrees Celsius [r2.3.1]. Baseboard heaters require an operating temperature as high as 93 degrees Celsius [r2.3.2]. Having a lower operating temperature means that less energy is required to reach the maximum heat output will occur.

2.3.2 Wall Mounted Panel and Baseboard Heaters 2.3.2.1 Space Requirements of Baseboard Heaters and Wall Mounted Panel Heaters Baseboard heaters require much more space to operate than wall mounted panel heaters. Baseboards can span 4.5 feet to 8 feet (1.2 to 2.4m) across the length of a wall and you are not supposed to place furniture nearby, reducing the working space in the room. Wall mounted panel heaters of equivalent power usage are approximately a foot and a half wide by two feet tall [r2.3.3]. These devices are much less cumbersome than the baseboards since there is only a foot and a half of wall space which furniture should not be placed near compared to a full 8 feet of wall space. Wall mounted panel heaters take up less space than baseboards while performing at the same level and effectiveness.

2.3.2.2 Thermal Efficiency of Hydronic Wall Mounted Panel Heaters and Baseboard Heaters Wall mounted panel heaters require less space and operating temperatures because they have more surface area due to their design. Hydronic panel heaters have a square shape with hot water pipes running through two metallic panels making the most use out of the small amount of space it takes up see figure 2.3.4. Panel heaters also have the option of having a small integrated fan to force the air over its components. This drastically increases the heat transfer rate of the system since more air is passing over hot elements in the panel heater. Baseboards are designed with one long, straight pipe with radiator fins attached to it, increasing its surface area, see Figure 2.3.3. Although the increased surface area of the fins improves the heat transfer rate to the air, it is still not as efficient as the panel heater. Looking at all these factors, it is obvious that panel heaters are much more effective at heat transfer than baseboard heaters.

The heat transfer rates were calculated through use of Fourier‟s law of heat conduction, [r2.3.6], Newton‟s law of law of cooling, [r2.3.7], and the convective and conductive heat transfer coefficients found in table 2.3.1 and 2.3.2. Conduction is the transfer of heat through a material or from one solid material to another. Convection is the transfer of heat from a solid to a fluid, in this case air. [a2.3.1][a2.3.2]

Baseboard heaters work by pumping heated water through copper pipes which run along the bottom of the wall. Attached to these fluid-filled pipes are radiator fins[a2.3.3] to increase heat transfer to the air. This is due to the surface area being increased, allowing more air to be heated. If the fins are made from 3” 3.25” (0.076m 0.086m respectively) sheets of aluminum [r2.3.9] then by Fourier‟s equation of conduction and values above from table 2.3.1, the conductive heat transfer of a baseboard heater is calculated to be 4322W. Through use of table 2.3.2 and Newton‟s law of cooling, the convection heat transfer rate is calculated to be 551W. When looking at wall mounted panel heaters, the dimensions are different but the equations are the same. Through this process and knowing that the panels are 23.25” by 15.5” (0.59m 0.39m respectively) [r2.3.12], these equations can be used again to calculate the conductive and convective heat transfer rates: 4411W and 2931W respectively. Although the conductive heat transfer rates are similar, the convective rates are quite different. Since the panel heater[a2.3.4] has a larger surface area and uses forced air convection, the panel heater has a much greater rate of convection than the baseboard heater making it ideal for the ILDA. 2.3.3 Cost Analysis For Wall Mounted Space Heaters When looking at wall mounted space heaters, research was done on electric space heaters since there is more information readily available. The means by which the space heater gains its thermal energy does not matter; the only factor needing to be considered are their performance of heat transfer. All calculations performed for this section of the report are under the assumption that energy consumed for heat transfer will be the same for electric and hydronic heating devices. It is estimated that 39.4 Watts of energy will be consumed by every square meter of space [r2.3.13] for wall mounted space heaters [r2.3.14]. Knowing that there is a total of 133616 m2 of floor space in the ILDA buildings and that there is an average of approximately 348 m2/floor [r2.3.15], the Watts per square meter and amount of floor space can be multiplied together to calculate the amount of energy consumed for space heating; 5259.126 kilowatts (total space) and 13.696 kilowatts/floor respectively. If we assume each room is approximately 30m2 then we have an energy usage of 1.18 kilowatts/room. Assuming that the panel heaters will be in use throughout the day and the night, the average cost of energy is 9.55 cents per kilowatt hour in Ontario [r2.3.16]. When taking this number in conjunction with the energy required for the system, we see that it would cost $329 to heat each room and $1,466,000 to heat the system each winter (assuming 4 month period of peak load). Refer to table 2.3.3 for a summary of findings. The cost of a hydronic panel heater of the size analyzed is approximately $200 [r2.3.17], and the cost of a hydronic baseboard heater is $135 [r2.3.18]. Since the panel heater is so much more efficient at heat transfer, if it is used not as much energy will be used to heat the buildings. This means that money will be saved each year of operation, making the panel heater the more financially enticing option.[a2.3.5]

3.0 Production

3.0.0 Introduction [Antoine]

3.0.1 Natural Gas Boilers [Antoine] Natural gas boilers are a convenient source of heating as they can be turned on and off easily. The proposed boilers are three Vitomax 100-LW which can produce from 0.65 to 6.0 MW [2] and a single Vitomax 200-WS for 1.75 to 11.63 MW [2]. Four boilers would ensure a steady cycle for maintenance since at any given time; the regular energy demand can be satisfied with the larger boiler along with a smaller one. Therefore two smaller boilers can be shut down for maintenance while the other two keep performing or the three small boilers can all be functioning while the larger one gets maintained. The cost for natural gas is currently around 16.20 $/MWh [3], though the price for gas is expected to increase, and 10,500,000$ for all four boilers.

3.0.2 Biomass Boilers [Antoine] Biomass boilers operate by burning biological matter such as wood in order to heat water which is then used to distribute heat. They were found to be a reliable source of thermal energy as a large variety of fuels such as wood chips, pellets, coal and even sometimes garbage could be used to heat the district. The most cost effective fuel was found to be dried wood chips standing at a rate of 10.58$/MWh [4,5,6] which is due to the large supply of wood found in North America. The proposed variety of boiler has an output capacity of 8 MW [3] which is enough to supply approximately 36-40% of the peak load and would cost 6,400,000$ [3]. As for maintenance, the biomass burners and boilers need to be cleaned and monitored on a regular basis. Depending on the exact boiler this will include removing ash every month, sweeping the chimney and flu, lubricating the fuel loading system along with regular visual reviews [7]. Though most of these can be done while the system is functioning, there still needs to be an annual shutdown period which disables the boiler for a certain amount of time. This is a period of time where the boiler is shut off in order to replace parts and clean the system. This improves overall performance and safety though it decreases the amount of time the boiler may function.

3.0.3 Solar Panels [Antoine] With global warming becoming an increasingly important issue, renewable energy sources such as solar have become more common. The heat of the sun can be captured with thermal solar panels. These panels are heated by the sun and heat water which is then sent to the building to be used. There are many types of panels which use different absorption methods that can create both electricity and heat. For Old Ottawa East, the proposed panel would be the evacuated tube panels 30 Tube Solar Collectors [8] which will allow for 3358 panels to be installed. The cost for all the panels would be estimated at a capital cost of 3,861,000$. Since solar panels only need the sun to create energy, every MWh produced can be used to pay for the solar system. On average, the entire system will create around 0.6 MW [8] of thermal energy, though it will produce more during the summer than in the winter. When it comes to maintenance, rain will remove any dust or cobwebs that may start to appear on the panels. The only necessity therefore is to keep the panels clear of anything that prevents the panels from receiving sunlight such as snow or leaves.

3.0.4 Ground Source Heat Pumps [Antoine] Ground source heat pumps are systems that draw heat from the ground or, more commonly, from bodies of water. Since the pumps that extract heat do not work as well in grounds that are high in clay such as that of Old of Ottawa East, the focus was brought to water pumps. There are two types of heat pumps that use water to obtain heat which vary according to where the source of water is located. The first type uses an open water source such as a lake or a deep river though Old Ottawa East however only has the river near it which is not deep enough for the system to function properly. The second kind of water heat pump requires an underground water source which unfortunately the target area does not have. The ground source heat pumps therefore have been determined as an unlikely possibility for the district energy system.

3.0.5 Recommendations [Antoine] Thus far, having reviewed the four possible energy facilities considered for the area, some conclusions can be drawn. Since the peak load stands at an estimated 22 MW [3], Biomass boilers could supply a large amount of the heat needed for the district since it can produce up to 8 MW [3] which represents around 36-40% of the maximum load. The boilers also supply the energy at a lower cost than natural gas at 10.58$/MWh [4,5,6]. For additional peak needs, natural gas boilers would work well since they can be turned on or off for the times they are needed and can provide a large quantity of heating energy. Natural gas is also more expensive currently standing at 16.20$/MWh [3] but the high amounts of heat it can produce make it a good fit for the peak loads the biomass boilers can fully supply. As for solar panels, they are still a possibility however they rely heavily on the weather which make them a riskier choice for big projects such as Old Ottawa East. In conclusion, it was determined that the combination of biomass and natural gas are a reliable and cost efficient combination for the planned district energy system.

3.1 Distributed Solar Energy 3.1.1 Introduction To contribute to the model for a district energy system(DES) [g3.1.1] for the institutional lands of Old Ottawa East, our research team studied methods of generating solar energy [g3.1.2]. We focused on two types of solar energy: solar electric power, and solar thermal. 3.1.2 Solar Photovoltaics Solar panels use photovoltaic [g3.1.3] technology to convert the sun‟s rays into power [r3.1.1, p.21]. This photoelectric effect works because the solar panel is made up of a positive layer and negative layer. This is achieved by doping silicon with phosphorus for the negative layer (phosphorus has an extra electron that silicon does not require), and doping silicon with boron for the positive layer (boron has only three electrons; one short of the four required to fill silicon‟s valence shell). When the photons from the solar radiation [g3.1.4] come in contact with the negative layer, they knock the extra electron out of the outer valence shell, which then flows through the “hole” of the missing electron in the positive layer. This induces an electric field, and the electrons flow from the negative layer through the positive layer and into the circuit [a3.1.1].

3.1.3 Comparing Solar Panel Systems There are 3 main types of Solar Photovoltaic (PV) solar absorption systems: 3.1.4 The flat mounting system 3.1.5 The titled mounting system 3.1.6 The auto tilting system

3.1.4 Flat Mounting System (FMS): Flat Roof Solar Mounting Systems The flat mounting system is one type of solar absorption system [r3.1.2]. FMS is simple to install, does not take up a lot of area once installed, and it costs the least amount of money compared to the other two systems. For a 1000 kW system, FMS costs $33,000 less than tilted mounting system and $1,350,200 less than auto tilting systems [a3.1.2]. However, the efficiency of solar energy absorption is much lower than in the other two systems, because it does not face the sun directly at peak time and it can get damaged easily from hail and rainstorms. [a3.1.3]

3.1.5 Titled Mounting System (TMS): Fixed Tilt Solar Racking System When a tilted mounting system[a3.1.4] is installed, the panel is set at a fixed angle [r3.1.4]. The common angle of the tilted panels is 45°, which is the average angle for maximizing sun absorption for each month. TMS costs $33,000 more than FMS to be installed. However, it costs $1,317,200 less than auto tilting system and it absorbs more solar energy than FMS because it can be set at the best angle which absorbs the most energy at peak time(see Sect 3.1.11 for angle calculation).

3.1.6 Auto Tilting Solar panels: Single-Axis Solar Tracking System Auto tilting solar panels[a3.1.5] automatically find the best angle to absorb the most solar energy throughout the day. But its installation cost is higher than for the other two systems. In the auto tilting system, an algorithm automatically receives information from the system's light sensor and changes the angle of the solar panels to absorb the most solar energy.

3.1.7 Recommended Arrangement One of our key findings is that the auto tilting system, though expensive to install, is the most efficient absorber of solar energy. The next best option would be to use a tilted mounting system, which, while it is less efficient than the auto tilting system, is still effective and costs less to install. For this project, it is recommended to use a tilted mounting system because it is a more reliable option and would require less maintenance; there are no moving parts that could result in mechanical failure [g3.1.5].

3.1.8 Power Generation Before calculating the amount of power that can be generated from solar radiation, there are many factors we must first consider. We must know: The optimum material for the solar panels The specific solar panel model The angle and placement of panels to maximize energy generation The number of panels that could be installed The average solar radiation levels in Ottawa

3.1.9 The Optimum Material for the Solar Panels When selecting an appropriate material, we considered the two most common silicon structures used in solar panel fabrication – monocrystalline and polycrystalline [r3.1.6]. Polycrystalline is made by solidifying molten crystal, while monocrystalline is synthesized to mimic naturally occurring silicon; which is a more expensive process. The monocrystalline is a better choice for this project because it has a greater efficiency due to its larger area of exposed crystals[a3.1.6] allowing it to be more space efficient and have a higher maximum power rating[g3.1.6].

3.1.10 The Specific Solar Panel Model The monocrystalline model that was selected for this project is the Heliene HEE300M72 [r3.1.8]. The 0.936 m by 1.872 m panel contains seventy-two 156 mm by 156 mm solar cells. It has a power rating of 300 watts and 16.1% module efficiency at peak power. The panels are manufactured in Sault Ste Marie, Ontario, which avoids the hassles of ordering out of province. They cost $309.00 CAD. The panels are FIT [g3.1.7] and compliant; a government incentive program which will be discussed further in Section 3.1.16. Heliene is a reputable company, which we feel will remain an enterprise long enough to satisfy their 10-year product warranty and a 25-year power guarantee.

3.1.11 The Angle and Placement of Panels to Maximize Energy Generation When installing solar panels, we must consider that they should always face south in the northern hemisphere. The winter season has the least sun, so it is important to make the most of it. To maximize absorption, the panel should be adjusted so that it points directly at the sun at noon because that is when solar energy has the shortest path through the atmosphere, which makes the energy more intense at that time of day. [a3.1.7][a3.1.8]

For summer (June 21), one can simply multiply the latitude of Ottawa (45 degrees) by 0.9, then add 25 degrees (moving toward the horizontal) in order to achieve the optimal panel angle, [r- 3.1.10] because in June the sun rises higher than in any other month. Every following month until December 21, one can subtract 7.2 degrees; for example, in July we add 17.2 degrees. Once December 21 is past, one should ideally add 7.2 degrees per month until June 21. These calculations can be found in [a3.1.9]. In accordance with the calculations below, the best angle for maximum absorption on December 21 is gained by multiplying Ottawa's latitude by 0.9, then subtracting 18 degrees (moving toward the vertical). The reason for multiplying by 0.9 (in summer as in winter) is that the sun has the shortest path through the atmosphere between 12 and 2 pm, which means that between 12 and 2 pm solar panels can absorb the most energy. [a3.1.10] shows a table of the best angle for each month.

3.1.12 The Number of Panels that could be Installed To get the number of panels that could be installed on the rooftops of the OOE buildings (excluding St.Paul‟s university and other existing buildings), we needed to calculate the shadow cast by the panels to figure out how far the panels should be placed from one another [a3.1.11]. This is important to consider as shadows on the face of another panel would hinder their effectiveness. We selected 22° as the angle of sunlight to account for the lowest angle at peak time in winter. The total number of panels was calculated to be 3358.

3.1.13 The Average Solar Radiation Levels in Ottawa Ottawa receives a yearly average solar radiation of 4.33 kWh/m2/day[r3.1.11]. Table 5 in [a3.1.12] illustrates the solar radiation levels in Ottawa for each month over the course of a year. Ottawa receives the most sunlight during the winter and summer months, peaking during June at an average of 5.53 kWh/m2/day.

3.1.14 Determining energy production Given the 3358 panels rated for 300 watts each, the total DC [g3.1.8]power rating on the system was found to be 1007.4 kW(determined by multiplying 3358 panels by 300 watts). However, this value is only useful for calculating the amount of DC power the system can produce. Since AC [g3.1.9] power is required, a DC to AC derate factor(the efficiency of converting from DC to AC) of 77% was assumed in order to calculate the AC power [r3.1.11]. The AC power rating was found to be 775.7 kW. Using this in combination with the solar radiation Ottawa receives, the annual amount of energy that could be produced by the system is 1.17481 GWh. When comparing this to the predicted annual electrical load of the institutional lands of Old Ottawa East of 29.61693 GWh provided by Team 2 (Buildings Group), it becomes evident that this solar panel system would only offset the energy required by the area. Despite this, it is still essential to research energy storage options, as the additional price of storing the energy will be a factor in determining whether offsetting the electrical load with solar powers is an effective option, which will be discussed in section 3.1.24. To contrast this approach, we researched how effective it would be to sell the electricity generated back to the power grid through the government incentive programs.

3.1.15 Selling the Generated Energy There are several programs put into place that this project could be eligible for. The following approach will demonstrate how much money could be made if all the electricity generated were sold back to the grid.

3.1.16 Government Incentives The government incentives include two programs: A. Feed-In Tariff (FIT) Program (i) Application Process (ii) FIT price schedule (iii) Incentives for peak production

B. Net Metering Program (i) Option A (ii) Option B

3.1.17 Feed-In Tariff (FIT) Program The Ontario Feed-in Tariff (FIT) program allows homeowners, business owners and private developers to generate renewable energy and sell it to the province at a guaranteed price for a fixed contract term [r3.1.12].This program is a Government of Ontario program which is carried out by the Ontario Power Authority (OPA) [g3.1.10]. (i)Application Process [a3.1.13] summarizes the key steps in the FIT Program application process and indicates the OPA‟s targets for completing the key stages of application review summary of which is given below: 1. Application is submitted online via the FIT website. 2. Application is reviewed by OPA, if eligible; it‟s ranked according to priority. 3. OPA checks for the Distribution Availability Test (DAT) [g3.1.11] and a Transmission Availability Test (TAT) [g3.1.12]. 4. If the above tests are passed, contracts are issued by the OPA. (ii) FIT Price Schedule The [a3.1.14] shows the price of selling solar energy back to the grid. The prices are given in Canadian Dollar Value per Kilo Watt Hour. For instance, it shows 32.9 cents per Kilo Watt Hour for projects greater than 100 Kilo Watt Hour. So, if 1 Kilo Watt Hour of energy is produced and sold (without consuming any of that energy) to the grid, the OPA will pay 32.9 cents for that much energy.

(iii) Incentives for Peak Production Payments are 35% higher (than the prices given in [a3.1.14] from 11am-7pm on business days and 10% less (than the prices given in [a3.1.14]) during off peak hours [r3.1.15]. This means projects will earn the FIT price (As shown in [a3.1.14]) multiplied by: 0.9 for off peak periods 1.35 for peak periods While calculating the money that can be generated by the solar PV, an average of 1.35 and 0.9 is taken, which equals 1.125.[a3.1.15]

3.1.18 Net Metering There are two types of metering arrangements that can be used: (i) Option A In this configuration, the utility charges you for the net consumption of electricity, if the electricity produced is more than the consumption, then the meter will run backwards to provide you with a credit. As shown in [a3.1.16], the Photovoltaic panels are connect to an inverter, the energy produced by the PV panel is DC and energy that can be used by the end user is AC, the invertor converts the energy from DC to AC for use which goes in the breaker panel i.e. in the houses where appliances can be plugged in to use the electricity. The breaker panel is connected to a meter to measure the usage and then to the grid. The advantage of using this option is it is useful in isolated areas away from the grid. The disadvantages with this configuration include poor quality of power and lack of power safety (ii) Option B In this option as shown in [a3.1.17] below, PV panels are connected to the inverter to convert the DC to AC similar to what is explained in Option A. The inverter is then connected to an export meter to measure the electricity to be sold to the grid, and electricity is directly taken from the grid through an import meter to measure the electricity consumed Electricity produced by the photovoltaic system is measured with a second utility meter. In this metering configuration, the utility pays the homeowner a different rate of electricity that is generated than what is taken from the grid. The advantages of using this option are good quality of power and power safety. The disadvantage with this option is the additional cost for a second meter.

3.1.19 Recommendation for Selling the Generated Energy After a careful assessment of all possibilities in the DES, it is evident that the FIT Program is profitable in the long run and should be implemented in Old Ottawa East District energy system. Also, Net Metering option B is appropriate for this project because of the benefits. It will take us approximately four years to break-even [a3.1.18] with the cost of installation . After the four years, this solar PV system will offset 1191.30 CAD per day [a3.1.15]. So, instead of paying $7302.80 CAD/day[a3.1.15], we will pay $6111.50 CAD per day for electricity from the grid. 3.1.20 Electrical Storage The following approach will evaluate the effectiveness of storing all the generated electricity for local usage. When selecting a storage option, three general storage methods were considered: electrical, mechanical, and chemical storage [r3.1.1 p. 61]. Electrical storage is not recommended as they would involve capacitors [g3.1.13], which discharge quickly, and inductors [g3.1.14], which do not have a large storage capacity. As for mechanical storage, a flywheel is more suitable for short-term storage, and storing potential energy by elevating water requires a tall structure to be built, which can be expensive. Chemical storage appears to be the best option as it can store energy for longer periods. While electrolysis [g3.1.15] could be used, electrochemical storage is recommended as it is the most common chemical storage method. In order to determine an appropriate chemical storage system, we had to accomplish the following:

3.1.21 Comparing Types of Batteries In order to select the type of battery, the pros and cons were compared for various battery types, including Lead Sulphide, Nickel Cadmium, Nickel Hydride, Lithium-Ion, and Nickel Iron [r3.1.1, p.70-72 ]. The battery that was selected for this project is the Lead Sulphide battery. This is due to its high energy efficiency, varying size and capacities, and long lifetime. Also, we can oversize the batteries to compensate for their lower depth of discharge [g3.1.16], as well as ensure that the battery is constantly at use to avoid sulfation [g3.1.17] [r3.1.1, p. 67, 70-72].

3.1.22 Selecting the Specific Battery Model The specific battery we selected is the AGM Sealed Discover EV-Series. This battery is virtually maintenance free due to its valve regulation. It can also withstand a broad temperature range, which allows it to be reliable even in the winter[r3.1.17].

3.1.23 Sizing the Battery Four factors were considered when selecting the size of battery: the amount of energy needed to be stored, the depth of discharge of the battery, the lowest exposed ambient temperature, and the system voltage[r3.1.18]. According to the calculations presented in [a3.1.18], a minimum of 1122.295 Ah is the required capacity for each rooftop. Therefore, nineteen 1170 Ah AGM Sealed Batteries are required for the system, costing $14 321.

3.1.24 Recommendation for Locally Storing Power Given the cost of the batteries being $14 321 and the cost of installation (panel cost included) being $1 705 000 [r3.1.29], the total cost of the system including storage was found to be $1 1 th 719 321. Since the power generation was found to be roughly /29 of the required electrical energy of the institutional lands, it is recommended to use the stored electrical energy during Ottawa hydro‟s peak hours (see diagram in [a3.1.15]) in order to maximize savings. If these recommendations are followed, the payback period on the solar panels will be approximately 11.8 years (see calculations in [a3.1.18]). Afterwards, the system it will generate around $400 per day in electricity savings.

3.1.25 Maintenance Very little maintenance is required once the solar panels have been installed. About once a year, the panels should be cleaned off to remove bird droppings and dirt. During this time, the frames of the panels should be inspected to ensure they have not corroded, and the wires should also be checked to ensure small animals have not chewed them. However, using a non- corrosive material for the frame [r3.1.1, p.115] and “squirrel guards” [r3.1.19] are steps that should be taken to prevent such damage.

3.1.26 Solar Thermal Energy Generation Modern solar thermal installations have two main aspects to them; the solar collector and the thermal system a diagram of this system is shown in [a3.1.19] The solar collector is the panel on the roof that collects solar radiation converting it into thermal energy. The solar thermal system is the system that carries the heated water or glycol to hot water storage tanks to be used by the consumer.

3.1.27 Solar Collectors This Section will look at the potential use of two different types of solar thermal collectors: glazed flat plate collectors and evacuated tube collectors [r3.1.20].

3.1.28 Flat Plate Collectors Flat plate collectors are made from a tube or array of tubes encased in an insulated panel that has a glazing on one side of it allowing light to enter. A cross sectional view of flat plate collectors can be seen [a3.1.20] Flat plate collectors are the more economical choice of solar thermal collector. The disadvantages of these collectors are that they are not as effective at collecting heat at low incident angles [g3.1.18]compared to other collectors. The diagram[a3.1.19] shows the comparison of collector areas at different angles. These collectors also have a risk of freeze damage if not drained in the winter at night. A possible flat plate solar collector is the S32A-P by Thermo Dynamics Limited [r3.1.23]. Using this brand of flat plate collectors approximately 2,519 collectors could be installed on the roofs of the new buildings providing a possible 1,700.1 Mwh of thermal Energy a year. The Approximate cost per collector would be 1,000 Canadian dollars [r3.1.23]. The total approximate cost of all the collectors would be about 2,519,000 Canadian dollars. This solar collector installation on average would save 41,306 dollars a year on heating. These numbers were found using the calculations in [a3.1.21].

3.1.29 Evacuated Tube collectors Evacuated tube collectors are freeze resistant and can collect more heat at low incident angles than flat plate collectors. Evacuated tube collectors are made by surrounding long metal tubes in a vacuum sealed glass encasement as shown in the image [a3.1.22]. The near vacuum created between tube and the ambient air [g3.1.9] allows for minimal of the collected heat to be lost as well it protects the collector from freeze damage. The brand of evacuated solar collector that we are considering is the 30 Tube Solar Collector from Latitude 51 Solar [r3.1.25]. Approximately 1 400 of these collectors could be installed on the roofs of the new buildings in the OOE institutional lands development. The Approximate cost per collector would be $1 150 CAD [r3.1.25]. The total cost of collectors would cost approximately $1 610 000 CAD. This installation could generate approximately 2 220.12 MWh of thermal energy a year. The installation of this system would save $35 966 per year. The calculations for these parameters can be found in [3.1.23].

3.1.30 Solar Thermal Systems A thermal system is a system which transfers the thermal energy from the collectors to the consumer, in this case the district energy system [r3.1.26]. There are different types of solar thermal systems from simple Thermosiphon systems to more complex active indirect systems [g3.1.20].

3.1.31 Thermosiphon (Passive) Systems Thermosiphon systems are low maintenance and require no moving parts [r3.1.26]. Thermosiphon or passive systems are designed so that the storage tank is above the solar collector as shown [a3.1.24]. This allows the system to make use of the phenomenon that heat rises. These systems are good since they have a very low risk of mechanical failure as long as the temperature remains above freezing; otherwise the system would have to be drained because there would be a risk of freeze damage.

3.1.32 Active Indirect Systems If the user wants to run the solar thermal system year round, they can use an active indirect system as shown as seen in the image [a3.1.25]. In these systems, the heat exchange fluid is forced through the collectors and into a heat exchange coil in the building in order to heat a hot water tank. The advantage of this type of system is that it is more freeze resistant and allows for the hot water to be stored inside of the building.

3.2 Centralized Energy System

3.2.1 Introduction Group three is researching plans for a Centralized Energy System (CES). A CES a community- wide development that amalgamates the heating for multiple homes in the area into one central plant. This plant heats water and distributes it to the homes to be used for radiation heating [r3.2.2] and will operate on a mix of biomass fuel and natural gas burning boilers, 15MW from Natural Gas and 8MW from Biomass Boilers [r3.2.2].

3.2.2 Biomass Boiler [Mitchell Liddy] 3.2.2.1 Introduction This section will outline the feasibility of implementing a biomass boiler as one of the primary sources of thermal energy. In the this section you will find the optimal thermal energy output of the biomass boiler, the cost to buy, run and maintain, and what types of fuel can be used.

3.2.2.2 - Thermal Energy Output The Biomass Boiler should be designed to meet the requirements of 85% of the annual thermal energy and 40% of the peak load because operating near design capacity increases efficiency, capital cost remain lower, Biomass use will be maximized and fossil fuel use minimized [r3.2.3]. The Old Ottawa East development area requires 33600 MWh of thermal energy per year to meet hot water and heating requirements [r3.2.4]. During the winter months, the thermal energy load will be at its peak load of 22 MW for roughly a non continuous duration of 2240 Hrs. Producing 85% of annual thermal energy will result in 28460 MWh of thermal energy, and operating at a peak load of 40% will produce 8 MW of peak thermal energy. The remainder of annual thermal energy and peak load will be produced by the natural gas boilers. Below is a graph showing the thermal energy load and for how long it is at a certain load. 100% being the peak thermal energy load of 22 MW. The biomass boiler can produce all the energy up to its 40% peak load of 8 MW. The total area under the curve below 40% is equal to the annual thermal energy output of the biomass boiler, 85% of annual thermal energy load or 28460 MWh. When the load is small, roughly for a duration of 2000 hours, the biomass boiler can be shut down and the natural gas boilers can pick up the small remaining load[a3.2.3].

3.2.2.3 Maintenance Requirments and Cost Maintenance varies upon type of Biomass Boiler and the environment it is exposed to. During the summer months when the heating load is low, the Biomass Boiler can be shut down for a full inspection and to replace any parts past their life cycle. While the boiler is operational, routine maintenance can be performed by one of the two staff members running both the Biomass and Natural Gas Boiler [r3.2.4]. Routine maintenance includes monthly ash removal [r3.2.6], quarterly chimney and flue sweeping [r3.2.7], weekly visual inspection and lubrication. Failure to perform routine maintenance can result in low efficiency and fire hazards [r3.2.1]

.

3.2.2.4 Capital Cost Biomass Boilers are an expensive heating source due to their high capital cost. The cost roughly $800 00 per MW, so for the required boiler with an output of 8 MW, it will cost around $6 400 000 [r3.2.4]. The cost is quite high due to the infrastructure that will be required to support the Biomass Boiler. Infrastructure includes a loading dock for the fuel, forklift and an area for the boiler, with other minor things needed as well.

3.2.2.4 - Type of Biomass [Roberto Ionescu] We feel that wood biomass is the most viable source biomass fuel source for the following reasons. Firstly, wood is readily available in Ontario, where the forest industry is worth over $11 billion [r3.2.8]. Additionally, logging operations generally leave behind 25-30% of the biomass as logging residues that could be burned to create energy [r3.2.9]. In fact, every year in the Pacific Northwest, logging operations leave behind enough residue to provide 150% of the electricity for the Pacific Northwest [r3.2.10]. To varying degrees, this occurs globally, making waste wood a plentiful source of energy. Secondly, using wood for energy is friendly to the environment, especially in Ontario. For example, only 0.5% of Ontario‟s trees are harvested annually [r3.2.11]. Additionally, forestry in Ontario is regulated by the Crown Forest Sustainability Act and forest companies are audited every 5 years to ensure sustainable practices [r3.2.12]. Burning wood for energy is also less harmful to the atmosphere than burning fossil fuels, such as natural gas, because the burning of wood releases carbon into the atmosphere that is then reabsorbed when new trees grow [r3.2.9]. This means that the carbon is essentially recycled and acts similarly to a tree‟s natural life cycle of absorbing carbon during growth and expelling it during decay. For these reasons, wood is the best choice for a biomass fuel.

3.2.2.5 - Costs of Wood Biomass [Roberto Ionescu] There are many different forms of wood biomass to investigate, such as cordwood, wood chips and pellets. Most of our findings are based on reports from Pennsylvania State University [r3.2.13, r-3.2.14] in Pennsylvania, USA, but this information is only used for comparison. With that being said, in our research we have found that dried wood chips are the best choice of wood biomass. After factoring in transport costs and boiler inefficiencies, the two forms of wood chips, dried and green wood chips, are by far the least expensive, as seen in table 2 [a3.2.4] with cordwood costing 2.34 times as much, and pellets costing 3.29 times as much. Wood chips from Townsend Lumber Inc, a lumber mill in Southern Ontario, cost around $10.97 per MWh [r3.2.15], making it even cheaper than natural gas which costs $16.20 per MWh (see section 3.2.2.2). Therefore, with wood chips fuelling the biomass boilers, the cost of the woodchips for one year would be about $312 000.

3.2.2.6 - Energy Densities of Wood Biomass [Roberto Ionescu] Energy density is important because biomass will be brought to the boiler site by truck, potentially causing a disturbance for the residents. It is more desirable to use dried wood chips because they are more energy dense than green wood chips, so fewer trucks would be needed for the same amount of energy. For the peak load of 8 MW (see section 3.2.1.1) occurring throughout the winter, 192 MWh of thermal energy would be produced each day. To produce that amount, 107 m3 of dried wood chips would be needed every day, or if green wood chips were used, 143 m3 would be needed. For comparison, a typical 53-foot trailer has an internal volume of about 110m3 [r3.2.16]. This means that the minimum disturbance possible would be one large truck or two smaller trucks of dried wood chips per day. Between the higher energy density and low cost, dried wood chips seem to be the best choice for a source of biomass energy.

3.2.3 Natural Gas Boilers

3.2.3.1 Introduction This section will outline the plans for natural gas boilers to be installed. Its sections are the specifications of the boilers that are to be purchased, the cost to install these boilers as well as to run them and the environmental impact, cost and future of natural gas use.

3.2.3.2 Heating Demand for Old Ottawa [Nik] The Old Ottawa East Development will require a peak of 22MW of heat power during the winter, the time of highest heating demand [r3.2.17]. This is to be split up with up to 8MW being supplied by Biomass and up to 15MW being supplied by natural gas. The Centralized Energy System must be prepared to meet this load at all times, even when one boiler may not be in working condition and to allow regular maintenance in all boilers.

3.2.3.3-Natural Gas Boiler Specifications [Nik] This summarizes the findings for real natural gas boilers to fit the needs of the development, including the number and size of each boiler to be used. These boilers are all real boilers currently in production.

Based on the needs for heat production outlined in section 3.2.3.1 we have concluded that the boiler configuration that would work the best is to have three small (between five and ten MW) and one large (more than ten MW) boilers. This configuration allows the system to easily meet the peak demand when any one of the boilers is shut down. This means that the configuration will work under all reasonable conditions. Boilers can be cycled through use and maintenance using the cycle shown in [a3.2.1] and specific boilers currently in production can be seen in [a3.2.2].

3.2.3.4 Capital Cost of Natural Gas Boilers [Nik] As natural gas boilers are one of the most common forms of heating, the capital cost is relatively low so that companies can compete for customers. The average cost per megawatt for natural gas boilers is $350,000, and so, purchasing there 6MW boilers and one 12MW boiler results in a capital cost of approximately $10,500,000 [r3.2.17]. This is a large capital cost, however, coming with it is the security of always being able to continually provide heat.

3.2.3.5 Environmental Impact of Natural Gas [Kuba] Natural gas is an abundant and secure source of energy with lower environmental impacts than coal or oil [r3.2.18]. Natural gas is also the most environmentally friendly fossil fuel for the production of energy. Due to the complex molecular makeup of oil and coal, more harmful pollutants are released from their emissions when they are combusted, than the emission of natural gas[a3.2.5]. Natural gas is mostly made up of methane, which releases water vapour and carbon dioxide after complete combustion. These two molecules are what we breathe out after taking in oxygen, chemicals that are not harmful to our bodies.

As seen in the table [a3.2.5], oil and coal release higher levels of nitrogen oxide and sulfur dioxide compared to natural gas [r3.2.18]. Natural gas also releases virtually no particulate matter as a result of complete combustion compared to the amount released by oil and coal. Particulate matter contributes to smog in the atmosphere. Pollutants emitted from fossil fuels have raised many environmental concerns. Using natural gas due to its lower environmental impact can help address some of these environmental concerns. The biggest concern is the amount of carbon dioxide in the air. Carbon dioxide traps heat, and having too much of it in the atmosphere means the global temperature will continue to rise. Using natural gas is a good option for the production of energy because it has the lowest carbon dioxide emissions per kilowatt-hour produced[a3.2.5].

Even though natural gas is the most environmentally friendly in terms of the release of chemicals compared to the other fossil fuels, the methods of extraction of natural gas have raised environmental questions. Natural gas is extracted using the method of fracking. Fracking involves blasting large amounts of water, sand and chemicals at high pressures beneath the ground to free up natural gas. A normal well can be fracked up to 14 times and can use between 10-70 million liters of water. Fracking has been linked to contaminated water in Alaska and Pennsylvania as well as small earthquakes in Arkansas. The Canadian Association of Petroleum Producers has said that in order for these claims to be true the chemicals would have to seep up through over 2 kilometers of rock to contaminate water [r3.2.20].

3.2.3.6 Cost of Natural Gas [Kuba] As per Michael Wiggin‟s excel spreadsheets, the cost of natural gas is $4.50 /GJ which is roughly $16.20 per megawatt hour [r3.2.17]. It has been estimated that the required load in Old Ottawa East would be 6300 MWh which would come out to an annual cost of approximately $102,060. This cost is purely based on the price of natural gas, it does not include the cost of transportation to the boilers, nor the maintenance cost of the boiler .

3.2.3.7 The Future of Natural Gas [Kuba] Due to the abundance of natural gas scientists feel that it will certainly be relied on heavily in the future [r3.2.18]. With respect to the environment and cost it will be an ideal choice for heating the buildings and making the buildings heating efficient [r3.2.19]. Higher efficiency is what we strive for and implementing it in OOE would lead to highly energy efficient community. According to the Canadian Gas Association natural gas will be used in combination with other renewable sources of energy such as biomass, wind and solar energy to provide energy for communities in Canada. Due to the fact that sources of energy such as solar and wind provide intermittent energy, natural gas will be used as a cost-effective support for other sources of energy.

With the environmental friendliness and abundance of natural gas, it will continue to play an important role in meeting energy demands in the future [r3.2.20]. The only thing that could stop natural gas playing an important role in the future is if policy changes are made in regards to how natural gas is extracted. As we pointed out in section 3.2.3.5, fracking has raised many environmental issues and there have been constant protests against fracking [r3.2.22]. If these protests keep on occurring, we feel like the government will step in and try to make a change to how natural gas is extracted.

3.3 Ground Source Heat Pumps Our team researched ground source heat pumps for an OOE development. Section 3.3.1 contains information on water source heat pumps, section 3.3.2 contains information on horizontal and vertical systems and section 3.3.3 contains information on coupling ground source heat pumps with other systems and the seasonal usage of them.

3.3.1.0 Introduction [David Gallacher]

The topic I researched was the feasibility of a Water source heat pump in OOEDES and the advantages and disadvantages of such a system. There are two different types of water source heat pumps, the first is a open source which uses ground water as the heat exchange medium, and a closed source which uses a coil of fluid submersed in a surface water source , such as a pond or a lake[3.3.1.1].

3.3.1.1 Ground water A ground water type heat pump works by pumping water from a natural ground water source such as an aquifer which is either a stagnant underground reservoir or an underground river . The water is pumped from the ground through a well and is run through a heat exchanger which either extracts the heat from the water or outputs heat into the water, which is then put back into the aquifer through an injection well. The geology of the OOEDES is very typical to this area of Canada[3.3.1.2], where in there is a layer of soil, which is followed by hard clay for several meters[3.3.1.2]. This layer is typically followed by the rock of the Canadian shield. For a ground water pump to work , there must be a naturally occurring aquifer (either stagnant or flowing) ,there is a lack of any natural occurring aquifer of sufficient size in the OOE [3.3.1.2], therefore removing the option of a ground water source heat pump. The ground water heat pump varies from a aquifer thermal storage system significantly in application, although the technology is very similar. Both systems use a two well system into an aquifer , the difference in application is that where a ground water heat pump system uses the naturally cooler water temperatures as a medium for cooling in most cases, and an aquifer thermal storage system deposits residual heat from the environment into the aquifer where it is to be extracted by a heat pump.

3.3.1.2 Surface Water The closed source style of pump is a surface water heat pump, which is very similar to a traditional ground source heat pump where in the interior system is the same , the difference being that instead of the ground needing to be excavated and pipes laid , a surface water system takes advantage of a surface water source where a coil of piping is submerged. The source has to be at least 30 feet deep for the pump not to have any serious effects of the temperature of the source and therefore effecting the environment[3.3.1.3]. A main difference between a surface water pump and a ground source is that the surface water pump is much more effective during the summer than the winter , due to freezing of the water source , there is little to no heat to be extracted from near freezing water and this removes the effectiveness of a water source pump in the winter months. This however has a reverse effect for cooling during the summer months , where in a cool water source is a much more effective medium for cooling because water has a much higher heat capacity than the ground [3.3.1.4].The heat exchanger for a water source pump is very similar to that of a ground source , the only difference being in a ground source pump which uses water as the medium instead of an antifreeze or refrigerant. The heat exchanger works by pumping the heat exchange medium through a refrigerant filled primary heat exchanger, this causes the refrigerant to boil to a low temperature vapour , which is then sent to a condenser which increases the temperature further , this is then passed through a coil in which the house air is blown over and heated. This causes the refrigerant to reduce in temperature where it is then passed through an expansion valve and further reduced so that it can repeat the cycle . For cooling the flow is reversed and the refrigerant picks up heat from the air and deposits this into the ground or water source[3.3.1.5].

3.3.1.3 Benefits A water source heat pump is a more effective type of pump because the heat transfer with water is much faster and more effective than with the earth, however the water source pumps can have a more harmful affect on the environment since it is in direct contact with wildlife. Most ground source heat pumps have a coefficient of performance of 3-4[3.3.1.3] , which is to say that there is an output of 3 units of heat or cooling for every 1 unit of electricity used. In specific conditions such as a location with an exceptionally large aquifer or water source pump there can be a coefficient of performance of up to 6. The environmental benefits of any type of ground source heat pump are significant with a single residential unit resulting in an average of 3-5 thousand KgCO2 reduced in emissions per year depending on which type of system that was previously used[3.3.1.6]. There are very few environmental impacts from the use of water source heat pumps , the few that there are is the risk of a fluid leak in the surface water variety , however this can be avoided by using water as the medium of heat transfer. The ground water pump has the risk of damaging the water table by either introducing too much heat into the aquifer , which could in turn run off into a lake and harm the ecosystems present , or it could do the reverse by taking too much from the water[3.3.1.3].

3.3.1.4 Costs The water source heat pump system for a single unit costs varying from 15-25 thousand dollars for the interior component of the system[2.6.6]. Costs for a water source system loop system varies greatly depending on whether it is a closed or an open system and on the environment in which it is to be installed. While costs for the system are high when compared to traditional heating/cooling systems , there are several grants available in Canada and in Ontario for installing a ground source heat pump. These grants combined with the fact that the system pays for its self in its longevity and lack of maintenance as well as the fact that the interior system needs only be replaced every 15 years and the exterior component once every 50 years[3.3.1.7].

3.3.1.5 Conclusion The conditions in the OOE are not favourable for either style of water source pump due to the shallowness(less than 10m) of the only surface water source ( Rideau River) and the absence of any natural aquifers which can be accessed through a well[3.3.1.2]. Due to this it is not feasible to install a water source style system as part of the OOEDES, however a horizontal or vertical ground source heat pump would be much better suited to the geological environment.

3.3.2.0 Introduction [Matthew Doel] Efficiency is all about making the most out of something. Life is only present on our earth because of the powerful energy emitted from the sun that both heats our world to survivable temperatures, and allows our plants to grow. But are we using the suns energy efficiently? The energy of the sun can be harnessed by using solar power, but it is impossible to cover the earth with solar panels. Some of the sun's thermal energy goes directly into the ground, heating the land under our feet globally. There is a way we can use this thermal energy, which is naturally stored in the ground; Ground Source Heat Pumps. The earth itself acts as a natural insulator and therefore at a certain depth which varies from region to region there exists an underground deposit of constant temperature worldwide, year-round. Even in seasonal climates there exists a constant temperature cooler than the air in the summer, and warmer than the air in the winter. For Ottawa this region exists at 5-6m deep with a constant temperature of approximately 10ºC [3.3.2.1]. Ground Source Heat Pumps (hereby referred to as GSHP's) aim to take advantage of this constant temperature by “pumping” it into the house in the winter, and by “pumping” hot air out of the house and into the ground in the summer. GSHP's were first conceptualized by Lord Kelvin in 1852 [3.3.2.2]. Since then there have been many optimizations and designs of GSHP's, my aim is to research specifically horizontal and vertical closed loop GSHP's and the latest technologies which these GSHP's employ. I will be considering horizontal and vertical closed loop GSHP's as an option for a district energy system in the Old Ottawa East development and discussing the viability of such a system.

3.3.2.1 Design & Function Closed loop GSHP's use a closed loop design (so termed because no liquid enters or leaves the system-the loop is closed) powered by electricity that uses a refrigeration cycle to upgrade low grade heat from the ground to useable heat for space or water heating in the house. The system consists of three simple components and corresponding cycles. The components are: the liquid exchange medium, heat pump unit, and the air delivery system. This system provides heat by cycling antifreeze through horizontal or vertical loops of heat conductive material (commonly high density polyethylene) buried in the ground. As heat flows from hot to cold the grounds heat is naturally absorbed by the antifreeze solution and pumped into the house. The warm heating fluid flows into the heat pump in the house where it passes through a heat exchanger. The heat exchanger contains refrigerant which is heated to vapour by the warm antifreeze, then compressed into gas to increase its temperature. Air is then blown across a condenser coil containing the hot gas to be heated and distributed throughout the building. [3.3.2.3] The same cycle is used in reverse when cooling is needed. Hot air is taken from the house and pumped into the ground where the heat is transferred into the ground, the cool antifreeze then flows back into the house to start the cycle again. GSHP's boast a CoP (coefficient of performance) of 3-4 [3.3.3.3] meaning that for every unit of electricity put it you get 3-4 units of heat out. [a3.3.1]

3.3.2.1.1 Materials used GSHP's use antifreeze in the ground loop to prevent the liquid from freezing when its heat is exchanged to the refrigerant. There are several possible antifreeze options based on the temperatures being operated at and the environmental code for toxicity in the region in question. Two viable options for the Old Ottawa East development are: Calcium chloride (where corrosion needs to be taken into account and thus all components other than the tubes in contact with the liquid must be brass), and Propylene Glycol[3.3.2.5]. High Density Polyethylene pipe is used for its flexibility and low temperature impact resistance [3.3.2.6]. 3.3.2.1.2 Alternative Water Heating Function An auxiliary desuperheater can be installed with the GSHP that is essentially another heat exchange medium at the condenser which transfers excess heat from the condenser to a pipe with water that is transported to the home's storage water heater tank. During the summer when there is a lot of excess heat nearly all of the home's water can be heated using a GSHP. [3.3.2.7]

3.3.2.2 Vertical Systems Vertical systems use U-shaped tubes in vertical bore holes in the ground to collect heat from the ground[a3.3.2]. The boreholes are generally 30-100 m deep [3.3.2.9] depending on cost of installation (depth of hole, digging costs, tube cost) and heating/cooling capacity needed for the building. Vertical systems are capable of putting out 1 ton of heating/cooling capacity per 75 m length of borehole. [3.3.2.9] Vertical systems are much more expensive to install due to drilling costs (between 20-50k per home) than horizontal systems but are slightly more efficient.

3.3.2.3 Horizontal Systems Horizontal systems use loops of pipe installed horizontally, cross a large area generally 1-2m deep [a3.3.2]. Horizontal systems are cheaper to install than vertical due to the smaller trench (between 10-20k per home). Horizontal systems provide 1 ton of capacity per 150m of pipe. [3.3.2.9] PROS/CONS

3.3.3.3 Maintenance In a study conducted by the government of Canada analyzing 200 vertical closed loop GSHP's over 15 years the maintenance cost was $0 [3.3.2.10]. GSHP's are known to last 25+ years without maintenance for the inside components and 50+ years for the in-ground components. [3.3.2.10]

3.3.2.5 Feasibility for Old Ottawa East development The factors that affect the feasibility for a GSHP district energy system in OOE are: ground type, emissions, and cost. First of all the ground type must be taken into account to deduce if either a horizontal or vertical GSHP is viable. Because the constant temperature area is 5-6m deep in Ottawa the cost for installation of a horizontal GSHP would be much higher than the average horizontal system, as 5-6m deep trenches would have to be dug across wide expanses of the entire development. This leaves vertical pumps as a more feasible option. Something to note is that GSHP district energy systems are an extremely new technology and only a few exist in the world. Therefore it is hard to anticipate costs and capacity. However, one such system that is comparable to a hypothetical OOE system is the Richard Stockton College district GSHP system. The Richard Stockton College system consists of 400 boreholes dug to 130m. It cost 5.1 million dollars to install and provides 1741 tons of heating and cooling. It heats and cools 5 buildings. [http://www.cleanenergyactionproject.com/CleanEnergyActionProject/Geothermal_Technologies _Case_Studies_files/Richard%20Stockton%20College%20District%20Geothermal%20System. pdf]. On top of the fact that OOE is primarily clay which would add to drilling cost, a fairly substantial installation cost is apparent. Obviously this amount is not enough to eat the proposed 22 buildings in OOE and therefore if a GSHP were to be used it would most likely be in conjunction with another heat source which will be discussed in section 3. A GSHP system would be extremely environmentally friendly as the only emissions come from electricity production which in Ontario is primarily from nuclear sources and is therefore safe for the environment. So ultimately, the ground conditions are not favourable for either horizontal or vertical systems and therefore installation would be extremely costly. Due to the heating capacity required for the development a GSHP system would not be able to heat the entire development alone and thus another heating source would be required which will be discussed in section 3.

3.3.3.0 Complementary Systems and Seasonal Use [Christopher Morency] This section will cover what other heating and cooling systems a GSHP can be used in concert with to provide the most energy and cost efficient sustainable system. Based on the research completed for this project, there are two viable systems to couple with the GSHP. The most rational systems for coupling with a GSHP in the OOE community would be either a natural gas system and/or solar panels. Below in sections 4.1 and 4.2 the coupling is explained.

3.3.3.2 Natural Gas Coupling Natural gas systems are very efficient systems that can be used for heating and cooling needs. A natural gas system coupled with a GSHP would be possible and effective. [3.3.3.1] The GSHP could be used to provide the majority of the power while the natural gas would make up for the rest. [3.3.3.2] The most cost efficient way to do this would be to have the GSHP built to 60% of the total capacity needed for peak seasons as 90% of the time the energy needed would be less than 60% of the total capacity. [3.3.3.3] This system would mean less piping would be needed and the GSHP would be able to run for the vast majority of the time saving the consumer money with a low operating cost. From the figure 3.3.3.1, using a 60 to 40 percent ratio, the cost of the equipment for the system would be 25.6% less. [3.3.3.3] Taking the extra cost of the gas into account, the annual cost would increase by approximately 3.3%. This would mean the net cost of the 2 systems would be approximately 23% lower. Using this method would decrease the tax incentives as well making the system about 3% more expensive. [3.3.3.5] If the natural gas were to be coupled with the GSHP, the total operating and equipment cost of the system would be approximately 20% lower[a3.3.4]. This would make a suitable and cost effective choice for the OOE community.

3.3.3.3 Solar Panel Coupling For a GSHP one could use a conventional solar photovoltaic system which takes the energy from the sun and turns it directly into electricity or a solar thermal system which warms a refrigerant in the solar panel which would be the same as that used in the GSHP. [3.3.3.6] Solar thermal panels are great systems that are environmentally friendly and efficient with GSHP. These solar panels gather the heat from the sun and warm up the heating substance underneath them. This makes it possible for them to cut the amount of piping needed for the ground source heat pump and having one meter of these panels per 27 meters of piping decreases the cost of the system by 4%. [3.3.3.7] They will also increase the efficiency of the system making them essential. The other option is the solar photovoltaic panels. Since the GSHP needs electricity to run, this makes these solar panels a perfect match for a self- sustainable heating and/or cooling system. [3.3.3.8] The solar panels would also be beneficial to the electricity supply of the community as they would also be capable of providing surplus electricity during non-peak heating and cooling hours. This coupling of GSHP and solar panels is a cost effective way (over the long run) to provide heating and/or cooling needs to the community.

3.3.3.3 Seasonal Possibilities A GSHP can be used for heating and/or cooling depending on which part of the year it may be. Assuming this system is used, it would be best to have it run for all heating and cooling needs. In normal systems, as the GSHP heats the community during the winter, it extracts heat from the ground. This, in turn, leads to the ground having a lower temperature for the remainder of the winter. When the system is needed for heating, the ground would already be colder from the heat extracted during the summer that it would be much more efficient for depositing heat into the ground. The exact same phenomena would happen during the summer, except the ground would be warmer. [3.3.3.2] With the OOE community, the soil type would not retain the heat keeping a steady temperature for most of the year. This has an advantage as the system would not need to do more work at the end of the seasons to warm or cool the facilities. Already having a system in place, there would be no need to have an entirely different system for one half of the year especially when it is more efficient to use for both heating and cooling. [3.3.3.3] It would frankly be a waste of money. To conclude, the GSHP would be most effective if it were used throughout the entire year.

3.3.3.5 Conclusion The GSHP would be able to work on its own, but with the aid of other heating and cooling methods, would make a more cost efficient system. If the GSHP were to be used, it would be best to pair it with both a natural gas boiler and solar thermal panels.

3.4 Cooling Technologies As part of the CCDP 2100-V class the cooling team has conducted research on the most effective cooling method for the Institutional Development Lands in Old Ottawa East (OOE) community. This section of the report will cover cooling demands and months of cooling for the OOE community, the cost of running chillers compared to traditional air conditioning units, the optimal temperature of the water that runs to the homes, and effective ways to insulate the homes to save costs.

3.4.1 Cooling Loads in Ottawa (Kevin Skea) We will be discussing the amount of cooling that is required for the Institutional lands development area in Old Ottawa East. Building sizes can be seen in the layout of the area [A – 3.4.1.4]. Building K is an existing building so it will not require cooling and the calculated cooling for the building will not be included in the total. This report will cover months that require cooling, hourly cooling loads, the amount of cooling, and the cost without a district cooling system.

3.4.1.1 Months The months that require cooling throughout the year are generally May to September. There may be days during October or April that require cooling, however there are very few days. The temperature peaks in the middle of July [A – 3.4.1.1][r – 3.4.1.3], causing the largest demand for air conditioning. During these days that are very hot, people may want to use a larger amount of cooling. They will still be able to do this with a central cooling system because while part of the community may want extra cooling, other community members may choose to save money and use less than the expected amount of cooling. So the people that want extra cooling are able to get the excess from other people using less cooling.

3.4.1.2 Hourly loads During the summer, the cooling loads follow the temperature outside. They start low in the morning, start to climb around 7:00 am, peak at about 4:00 pm, than start to drop at 5:30 pm [A – 3.4.1.6].

3.4.1.3 Amount of cooling The amount of cooling required for the ILDA was determined using the size of each building and the average size of the units in the buildings [A – 3.4.1.3][r – 3.4.1.1]. A table of the average amount of cooling per square foot, which was converted to cooling per square meter [A – 3.4.1.2][r – 3.4.1.2] was then used to calculate the tons of cooling [g – 3.4.1.1] that each unit will require, where a unit is a single condo or a townhouse. The amount of cooling was also calculated for commercial spaces in the buildings and the extra spaces, such as hallways. All of these cooling loads were then added to get the total amount of cooling that each building will require. The total cooling for each building was then added up to get the total amount of cooling that the community will require [A – 3.4.1.2]. It was found that most of the condominiums required 1.5 tons of cooling, while the townhouses required 2.5 tons or 3.8 tons, depending on the size of the house[A – 3.4.1.2]. While the townhouses require significantly more cooling then the condominiums, the efficiency of the space used for the town houses is much greater because the condominiums use public hallways which is extra space [r – 3.4.1.1]. This results in extra cooling for the hallways and extra spaces in the condos. This extra cooling, while being less than the amount of cooling for all of the units in the building, is still much larger than the townhouses, with extra cooling needs of up to 22.8 tons for a single building [A – 3.4.1.2]. It was found that the total amount of cooling required for the entire community is 2294 tons of cooling [A – 3.4.1.2]. This is the required capacity for the district air conditioning system.

3.4.1.4 Cost without district system On average, one unit requires 1.58 tons of cooling. The average SEER [g – 3.4.1.3] rating for air conditioners is 13.66 [5]. It was calculated that this air conditioner would use 1.39 kwh per 1 hour of use [A – 3.4.1.7]. Using the cost of electricity for Ottawa [r – 3.4.1.6], it was found that running at full capacity for a full day, the air conditioner would cost $3.16. However air conditioners do not need to run 24 hours a day. In July, the air conditioner would only need to run for about 7 hours a day which was calculated from the cooling degree days [A – 3.4.1.1] [g – 3.4.1.2]. As seen in [A – 3.4.1.6], the air conditioner would run from about 1:00pm to about 8:00pm. This would cost about $1 a day.

3.4.2.1 Vapor-compression chillers vs. absorption chillers The purpose of this section is to compare two commonly used chilling processes. Using the proper type of chiller can reduce energy consumption and running costs, in addition of being environmentally friendly. Chillers can operate by different refrigeration processes; the most commonly used are vapor-compression processes and absorption processes. Vapor- compression refrigeration cycles are used from fridges, to personal air conditioners, and large scale chillers. They work by passing a compressed liquid through a radiator, called the condenser, cooling the liquid[r – 3.4.2.1]. Once the liquid has been cooled, it is expanded via an expansion valve. This results in the liquid becoming a cool gas. The cool gas passes through yet another radiator through which a warm air current passes. This current is cooled by the cool vapor while the vapor warms up. The vapor is then passed through a compressor to bring it back to the liquid form and restarts the cycle[r – 3.4.2.2]. The compressor in a vapor compressor chiller requires power, usually delivered as electric power, hence the term electric chiller. An absorption cycle on the other hand does not require a large compressor to operate, therefore it does not consume as much electricity as an electric chiller. It does however require a constant heat source. This is because an absorption chiller depends on a thermo chemical process to obtain a higher pressure. The heat is provided by either waste heat from other units in the building (like water heaters) or from a natural gas burner integrated in the chiller[r – 3.4.2.3]. Absorption chillers tend to be less efficient than electric chillers, but may turn out to be less expensive thanks to their ability to make use of unused heat as seen in the following section. Antares Groupe Inc., a clean energy solution firm, has put together an approximation of both the cost of an absorption chiller and of an electric chiller in the same scenario. Assuming a system of 100 tons in a north-eastern climate, like Ottawa, and electric prices of 7 cents per kilowatt- hour and gas prices of 5 dollars per MMbtu, the results are shown in [a3.4.2] and [a3.4.3]. As we can see in [a3.4.2], to use each chiller for 116,000 ton-hr/year would cost 5700 dollars for an electric chiller whereas an absorption chiller would cost more than twice as much. These figures do not include the cost of maintenance, which is higher for an absorption chiller[r – 3.4.2.4]. [a3.4.3] represents a yearly running cost on the x-axis, versus natural gas costs on the y-axis. The red dotted lines represent the cost of running a 100 ton chiller at certain average electricity costs. Using data from Ontario Energy Board, we get that the average price for natural gas is 3.68 dollars per MMbtu[r – 3.4.2.5] as well as 8.3 cents per kilowatt-hour for electricity[r – 3.4.2.6]. In figure 1 we see that an electric chiller would cost near to 6500 dollars per year to operate, whereas an absorption chiller would cost, again, twice as much. Also, according to the National Energy Board of Canada, the price of gas is anticipated to rise due to the depletion of fossil fuels[r – 3.4.2.7]. Absorption chillers are therefore not an effective solution for the OOEILD.

3.4.2.2 Types of compressors in electric chillers Electric chillers can come with many different types of compressors, each with their own advantages and disadvantages. Choosing the proper type of compressor for the desired application can reduce the unnecessary energy consumption, consequently reducing operating costs. The first kind of commonly used compressor is known as a reciprocating compressor [a3.4.4], where a piston is driven by an electric motor. The piston has the job to push the fluid into an open valve, pressurizing it[8]. These compressors are usually loud and produce vibrations, making them not suitable for quiet neighbourhoods. Centrifugal compressors[a3.4.5] are widely used in chillers[r – 3.4.2.9]. Air is pushed along the side of the compressor casing due to the turning blades. Since the air has nowhere to go, it is forced at a high pressure into the exhaust. In general, these compressors require less maintenance than other type of compressors, and are quiet and produce minimal vibrations[r – 3.4.2.10]. A screw compressor[a3.4.5] utilises two screws. As they turn in opposite directions, fluid is forced up the grooves into a channel, pressurizing it. These are better suited in low temperature conditions, a property not needed for the Ottawa region. Scroll compressors[a3.4.7] make use of two interlaced coils, one still and another rotating. As the coil rotates, fluid is forced down the grove formed by the two coils and exits via the exhaust[r – 3.4.2.11]. These compressors are recent in the industry, are quiet and efficient but are limited to compressors of 60 tons. Enercom Inc., an energy and power software developer, has published a chart comparing these different types of compressors[a3.4.8]. This [a3.4.8] displays the average power consumption of certain chillers in function of 1000W per ton of cooling, as well as the cooling power of each. Reciprocating compressors are the least efficient of all four types of compressor, however they are capable of operating at low cooling output (three tons). However they have become redundant with the introduction of scroll compressors, which can operate at the same power, but are more efficient as well as quiet. Since scroll compressors are limited to 60 tons, centrifugal of screw compressors are the only options for the OODEILD. Since the OODEILD will require near to 100 tons of cooling, either centrifugal or screw compressors are adequate. However, centrifugal compressors have proven to be more reliable than screw compressors. Therefore a centrifugal compressor would be the most adequate for the OODEILD[r – 3.4.2.12].

3.4.2.3 Operating costs of district chillers vs. single air conditioning units Running costs are an important factor when choosing a air conditioning system and avoid useless energy expenses. Using chiller efficiencies provided by the North Carolina Energy Office[r – 3.4.2.13], as well as single air conditioner power consumption from a typical Carrier air conditioner unit[r – 3.4.2.14], our team was able to calculate the average running cost for each system. From Table 3, we see that the total power consumption would be of 1398 kW for the sum of the chillers compared to 1852 kW required to operate single air conditioning units[r – 3.4.2.15]. Assuming an average operating time of 10 hours per day and an average electricity price of 10 C/kWh, the running cost is of $1398 for the chillers and $1852 for the single air conditioning units. This represents an average saving of $454 per day. Chillers are therefore the better option compared to single unit air conditioners.

3.4.3.1 Supply and Return Temperatures for the District Cooling System (Arian Rayegani) This section of the report will cover the recommended supply temperature (section 3.4.3.1), return temperature (section 3.4.3.4) and flow rate (section 3.4.3.3) to optimise the efficiency of the chillers and to reduce cost to the developers and homeowners.

3.4.3.4 Understanding District Cooling Systems A district cooling system provides cooling to the residential and commercial areas through the following procedure. First cold water is run to the homes via underground pipes. Then the cold water passes through a heat exchanger (like a radiator). Once the cold water has passed through the radiator it has warmed up and is sent back to the chillers where it will be cooled once more. See [a3.4.9] for the schematic of cold water as it moves through the district cooling system.

3.4.3.3 Findings Regarding Supply and Return Conditions 3.4.3.3.1 Supply temperature An ideal supply temperature for a district cooling system is 4°C [R- 3.4.3.1]. This is because it is at this temperature where water is the densest [R- 3.4.3.4]. Refer to [A- 3.4.3.1] for a chart comparing water density and water temperature. When water has the highest density it can be pumped through the district cooling system at the highest efficiency. This is because more mass can be pumped per volume than at a lower density. In addition 4°C is an adequate temperature to provide effective cooling and it is not so cold that it will cause freezing in the underground pipes, which can cause major damage to the chillers and pipes. 3.4.3.3.2 Return Temperature To achieve a large Coefficient of Performance (COP) it is recommended that the return temperature be 13°C [R- 3.4.3.1]. This is because the greater the difference between the supply and return temperature, the more energy can be absorbed by the water for the same amount of volume of water being pumped through the system [R- 3.4.3.3]. However this is only true to an extent. If the return temperature were even greater, for example 20°C, then the cooling system would be effective between 4°C and 13°C, but very ineffective from 13°C to 20°C. This is because at this point the water is close to the temperature of the surrounding air and therefore the water will need more time in the heat transfer pipes to absorb the surrounding heat. This means a longer set of pipes will be needed in each building so the water can absorb heat for a longer period of time. By increasing the piping, a greater overall cost will be placed on the cooling system with no significant efficiency gains. 3.4.3.3.3 Flow Rate To achieve the above supply and return temperatures it is also recommended that the flow rate of 12.95L/min/ton be used [R- 3.4.3.1]. For example, for the OOE community a total of 2294 tons of cooling is needed for a hot summer day (Refer to section 3.4.1.3 for more information about loads). Therefore the flow rate of the entire chilled water system should be 29707.3 L/min.

3.4.4.1 Home insulation: Introduction Having efficient cooling system means that you are producing energy efficiently, but In order to have an efficient system the end consumer has to be using the energy provided effectively. One of the ways this could be done is by using insulation, preventing energy from escaping the envelope of the building. By reducing the amount of energy being wasted to the exterior of the building we can reduce the amount of cooling load that is required to be supplied.

3.4.4.2 The Building Envelope The building envelope is the shell of the building, which comprises the basement, walls, and floor (i.e. the foundation), the above-grade walls, the roof, windows and doors. The envelope separates the indoor environment from the weather outside. To maintain the indoor environment, the envelope must control the flow of heat, air and moisture from the inside to the outdoors [1,p.10].

3.4.4.3 How Does Heat Flow? Heat flows in three distinct ways, which are conduction, convection, and radiation [2,p.88]. Heat is flowing across this wall in these three ways like you see in [a3.4.10]. Radiation is the process of heat transfer in the form of microwaves, this occurs when you have warm object emitting heat like in [a3.4.10] the two men are radiating. Convection is the heat flow due to the movement of air, when current of air is created hot and cold air will mix and they will try to cancel out the excess heat to reach equilibrium. Conduction is the movement of energy through an object like the wall that is been created by radiation and convection on the surface of that wall.

3.4.4.4 Areas of the building envelope that could be insulated The Envelope can be categorized into five areas and each one has different heat loss because of the structure and the exposure to the weather. Those categories are listed in [a3.4.11] and [a3.4.12].

3.4.4.5 Ceiling and Walls Insulation To insulate the ceilings and walls we can use spray foam to fill the attic and spaces between the walls. We recommend using closed cell foam to fill the attic, which is more effective then regular open-cell foam [6]. The difference between closed-cell foam and open-cell foam is that the closed cell is more condensed. This is because the cells of the foam are tiny and are closed packed. The physical properties of the two foams are listed in [a3.4.13]. In the table [a3.4.13] you can see that as the density increases the RSI value for insulation, and also shows that closed cell foam have low vapor permeability. The downside of using closed-cell foam is it is expensive compared to other insulation available in the market. But it needs no maintenance [9].

3.4.4.6 Windows Double or triple pane windows can be used to improve insulating a house. The space between two glass panes is called profile, which contains vacuum or sometimes filled with inert gas as can be seen in [a3.3.14]. Having vacuum or inert gas between the glass panes will reduce heat transfer, because of the lack of media for heat to travel through.

3.4.4.7 Conclusion Having good insulation is important and it is essential in every home, it is the simplest to save energy and money in the long run. You can buy a system that provides cooling very effectively and efficiently, but that would be expensive and would require annual maintenance. While on the other hand installing a better insulation for your home will save you money and energy in the long run. As insulation will require no or very little maintenance.

3.5 Conclusion [Ahmed Omar]

The following section discusses the advantages and disadvantages of the four energy sources listed above.

3.5.1 Natural gas: Natural gas is one of the cleanest energy sources as it produces only 0.076kg of annual gas emissions [1]. For this reason, natural gas is the most environmentally friendly fossil fuel for the production of energy. The cost of natural gas is $4.50 /GJ which is roughly $16.20 per megawatt hour.[2] The required load for the Old East Ottawa is estimated to be 6300 MWh[3]. This comes to an annual cost of approximately $102,060. However, the capital cost comes to approximately $10,500,000 which is very expensive, but it comes with the security of always having heat being provided to the Old Ottawa East area[2]. This cost is based on the price of natural gas, it does not include the cost of transportation to the boilers, nor the maintenance cost of the boiler .

Natural gas has the lowest CO2 emissions among the fossil fuels and coal. Although it releases carbon dioxide and water vapour after combustion, the amount is too and not harmful to human. However, the method of extracting natural gas brings up concerns. The method used to extract the natural gas is fracking and this might cause earthquakes. This problem can be avoided by drilling the wells at least 2 km to avoid sweeping of the chemicals[4].With respect to the environment and cost; natural gas can be used in conjunction with other sources of energy.

3.5.2 Biomass: Wood biomass was found to be the most efficient and valuable of biomass fuel, as it is readily available in Ontario. The wood industry in Ontario is over $11 billion worth and it is harvested responsibly and it is a sustainable source of energy [5]. The research was made into different types of pellets and wood chips, the dried wood chips are the least expensive and it comes with a cost of $10.97 per MWh and a capital cost of $6.4 million [6,7]. This makes it cheaper than natural gas and this why biomass is the energy source the Old Ottawa East will rely on.

The annual cost was found to be $312,000 for 28,460 MWh, operating at 85% of annual thermal energy and 40% peak load [8]. This will increase efficiency, capital cost will remain lower and the biomass use is maximized and fossil fuel usage will be minimized. The environmental impact of biomass is too low, since all the trees that are being cut down for biomass, are being grown again.

3.5.3 Solar Panels Solar is a renewable source of energy. The technology is used in harvesting solar energy and makes it useable. The photovoltaic technology used by the solar panels to convert the sun‟s ray to power. The assumed numbers of solar panels to be used in the building of the Old Ottawa East are 3358 panels. The cost is 0 MWh, as solar is known as the free energy source, it only uses the sunlight to produce energy. The amount of energy will vary according to the weather. However the panels must stay clear of leaves or snow to allow the panel to receive the sunlight.

3.5.4 Ground Source Heat Pumps: Ground source heat pumps system is used to get heat from ground or water. It takes the advantage of the moderate temperatures in the ground to eliminate burning harmful fossil fuels and reduces operational costs of heating and cooling of houses. However, water pumps are found to be more useful in the Old Ottawa East area, because the ground cannot be dug enough to install the system as there is clay and it will prevent the system from working properly. A water-water or water-air heat pump to be used that raises the heat collected to useful temperatures, but the nearest water source to the area isn‟t deep enough for the system to be installed and to work properly.

3.5 Conclusion: The four energy sources were reviewed and we came into conclusion that the biomass will be used as the main source of energy, as it produces a lot of energy[2,7]. IT comes with a cost of 10.97, which makes it even cheaper than the natural gas that comes with $16.20. Working at 85% of annual thermal energy and 40% peak load, it will cover most of the demand of energy in the Old Ottawa East area. Natural gas can be used in conjunction with the biomass as it can be turned on and off easily and it produces a lot of energy too. We cannot rely on the solar panels, because weather plays an important factor in their production of energy, which makes it riskier to build in the Old Ottawa East area. In conclusion, it was determined that the combination of biomass and natural gas will be most cost efficient.

4.0 Storage 4.0.1 Storage Introduction - Mohssen Kassem I have put together this report regarding the Old Ottawa East District energy project for seasonal and short term thermal energy storage systems [a1.0.1]. Our main goal is to find the best method of energy storage in order to regulate the supply and demand on seasonal or daily basis. In order to create the most effective energy storage system, we had to research about the capital cost, maintenance expenses, fuel consumption and payback period [g1.0.1] of every system. The BTES [g1.0.2], ATES [g1.0.3], chilled water systems, ice storage systems and thermal energy storage tanks are the systems we will research about. In addition to that, we will research about the effect of every system on the environment and surrounding communities.

4.0.2 Background The role of the seasonal energy storage is to regulate the supply and demand of energy along a two-phased time period. In the summer, the thermal energy stored from the winter will be used to for the district cooling. However, the thermal energy stored from the summer will be used to provide heat in the winter [r4.0.2]. On the other hand the short term energy storage is supposed to regulate the supply of energy on a daily bases. For example, the solar energy stored in during the day will be stored and kept for later use at night. Since the energy stored will only be used when the supply of energy does not meet the demand, the community will be not be using it constantly. Therefore, our team has to determine the base load (the minimum amount of energy that will be continuously supplied). Upon that, the seasonal and short term energy stored will be supplied when the base load [g2.0.1] does not meet the minimum amount of energy needed on daily/seasonal basis.

4.0.3 Seasonal Energy Storage Regarding the seasonal energy storage, we narrowed down our choices to two energy systems. The first system is the BTES high stores thermal energy underground. The thermal energy can be collected whenever it is available and be used whenever needed. This system -reduces peak demand, energy consumption and CO2 emissions. For example, the thermal energy from solar heat collectors will be stored during sunny days to be used during the winter for heating purposes. Also, the natural cold of winter air can be stored for summertime air conditioning [r4.0.2]. However, the cost of this system can vary depending on local ground conditions, required depth of boreholes, and amount and type of insulation used. In our case, the installation of the borehole will cost around $4.5-5 Million [r4.0.1], in addition to the expenses of installing the supporting piping systems to each building. Our second choice that we are considering is the ATES, which has a cheap initial cost and is expected to have a 5 year payback period.

4.0.4 Short Term Energy Storage Regarding the short term energy storage systems, our main systems were chilled water systems, ice storage systems and thermal energy storage tanks. These systems will be able to store thermal energy on a daily basis. The chilled water systems can use existing chillers and acts like a double duty, providing water in case of fire. On the other hand, the Ice storage systems require less space and can provide colder air to the buildings [ref3.0.2]. However, it requires more energy to operate in order to keep the temperatures low inside the storage facilities. Therefore we need better insulation and piping systems to maximize the amount of thermal energy [ref3.0.1]. Regarding the initial capital costs and maintenance expenses, our team did not have access to this type of information. Therefore, we will recommend the most effective system based on different factors, such as its advantages and disadvantages on the community.

4.0.5 Overall Energy Storage Systems Distribution The thermal energy collected by the solar energy collectors will be transferred through the piping systems and will be stored in the short term energy storage tanks[a1.0.2]. These tanks will store the thermal energy whenever the sun is available and will supply it whenever it is needed. The thermal energy stored (In addition to the thermal energy produced by the boilers) will be transferred back to the buildings and other facilities for later use. Since the storage tanks are not perfectly efficient, almost 2-5% [ref3.0.1] of the energy stored will be lost. In addition to that, 15% of the thermal energy will be lost while being transferred through the pipes from/to storage systems [r4.0.1]. Therefore, 90-95% of the heat coming into short term storage is delivered to the community. The initial cost required to install these systems was not available to our team. The community will not consume all the energy stored from the short term energy storage tanks. This will result in an excess of thermal energy that will not be used. Therefore, the excess heat from the short term energy storage tanks will be sent to the BTES system. Like the short term energy storage tanks, the BTES system is not a perfect system since 55% of this energy will be lost to the ground surrounding it. Due to the thermal energy loses in the pipings , almost 40% of the energy stored will be delivered to the short term storage tanks and supplied whenever needed. The BTES system required an initial capital of $4-5 million CAD in addition to additional expenses to install the required systems in the buildings to successfully transport the thermal energy [r4.0.2].

4.0 Conclusion and Recommendations

The seasonal/short term energy storage systems are able to effectively reduce the difference between the supply and demand. However, buying the energy storage systems (such as the boreholes) will be expensive since it needs requires more than $5 million to be installed. Our team decided not to use the BTES since the initial investment of $4-5 million is not worth the money that will be saved by using this storage system. Therefore, the community will only use the short term energy storage tanks to store energy.

4.1 Short Term Thermal Storage Short-term thermal storage allows us to store surplus thermal energy, which would otherwise be wasted. This energy can then be used for future uses, whenever the need arises. Short-term thermal storage uses heat-energy collected by day, to be used at night or cooled water at night to be used by day. We have divided the topic of short-term thermal storage into three aspects: Cold Storage systems, the concept of Thermal Mass and Thermal Storage Tanks. Joel Prakash will be focusing on Cold Storage Systems, Aly Rasmy will focus on Thermal Storage Tanks and Kathleen Rozman will focus on the concept of Thermal Mass.

4.1.1 COLD STORAGE SYSTEMS - Joel Prakash This part of the report will look at cold storage systems and the technologies that they use, such as, chilled water systems and ice storage systems, which will be explained later on in Section 4.1.1.4, for the Old Ottawa East District Energy System (OOE DES). A chiller is a facility which houses a large refrigeration unit which cools water when its passed through the unit. There will be 21 chillers that will be used with a single Cold Storage System, (see Section 4.1.1.8). Together these will provide cooling to the entire OOE district system. This part of the report includes the following content: What Cold Storage Systems are (covered in Section 4.1.1.1); Phases in a Cold Storage Systems (covered in Section 4.1.1.2); Benefits that a Cold Storage System could provide (covered in Section 4.1.1.3); Mediums used for Cold Storage System (covered in Section 4.1.1.4); Materials used for the storage tank (covered in Section 4.1.1.5); Choosing between Chilled water and Ice Storage (covered in Section 4.1.1.5); Materials used for a Cold Storage Tank (covered in Section 4.1.1.6); Layout of Cold Storage Systems with the chillers (covered in Section 4.1.1.7) and Control strategies for Cold Storage Systems (covered in Section 4.1.1.8)

4.1.1.1 What cold storage systems are

Cold storage Systems are systems where ice/chilled water are produced by the chillers when electricity rates are low (usually at night), stored in tanks and can then be brought out for cooling the building later on (usually during the day time). This is beneficial because during hours when the electricity rates are high, the chiller can be shut off and instead the cooling required can be met by bringing out the stored ice/chilled water, which was stored beforehand [4.1.1].

4.1.1.2 Phases in a cold storage system

The Cold Storage Systems have two phases: Night time and Day time. Most of the production and storage of ice/chilled water happens during the night, while during the day the ice/chilled water is brought out and used for cooling. These two phases form a cycle over a 24hr daily period. Night time Water is cooled by chillers at night. This is done when electricity rates are low (off-peak hours) and stored in tanks [4.1.1]. Day time The cooled water/ice that was stored during the night, will now be brought out for air conditioning during the hot hours of the day or when electricity rates are high (on-peak costs) [4.1.1]. Cold Storage Systems avoid on-peak electric costs and thus save money on electric bills.

4.1.1.3. Benefits that a cold storage system could provide

Cold Storage Systems provide mainly three benefits: Load Shifting, Lower Capital Outlays and Efficiency in operation as explained below

Load shifting A chiller is usually set up in order to work for a certain number of hours in a day. Instead of having all of these hours during the day time, a part of it can instead be shifted to run during the night. This is called „Load Shifting‟. This helps in lowering operating costs of the chiller by saving money on electric bills and avoiding high electric charges during the day [4.1.1]. Lower capital outlays A chiller that uses a Cold Storage System is always smaller than one that uses a Chilled Water System. Thus a lot of money can be saved in installing a smaller chiller plant, due to less material needed for the storage tank [4.1.1].

Efficiency in operation The chillers with Cold Storage Systems, typically operate at night, when the outdoor air temperatures are cooler than the day. This allows the chiller to cool water more efficiently, thus improving the overall efficiency of the chiller due to the chiller being able to produce lower temperature chilled water/ice more easily [4.1.1].

4.1.1.4 Mediums used for cold storage systems:

The two main mediums Cold Storage Systems are Chilled water and Ice as explained below Chilled water storage In this case, the medium used for Chilled Water System is simply chilled water. So, the chiller chills water, which is then stored in a storage tank. This water can then be brought out later on for cooling [4.1.1]. Ice storage In this case, instead of using chilled water as the medium, ice is used. Now, additional equipment is required to convert the chilled water supplied by the chiller to ice. This ice is then stored in storage tanks. When cooling is required the ice is melted and turned into chilled water and supplied for air conditioning through pipes leading to the building [4.1.1]. While, it is true that ice is being stored and kept in this type of system, we also have to use a refrigerant in order to produce the ice. The refrigerant or the medium that makes this cooling possible is glycol. This substance is usually used due to its low freezing temperatures. In order to explain this entire process more thoroughly we have chosen EVAPCO‟s „Ice on Coils‟ system, which is a good example of an ice storage system. The “Ice on Coils‟ system (see Figure 1), has two modes of operation: ice build and melt-out This is very similar to the night time/day time phases of Cold Storage, which was explained earlier in section 4.1.1.2. This process is explained in detail below [4.1.2].

Ice build The glycol chillers [a4.1.1], are operational only during the off-peak hours. During this time they produce low temperature glycol, which is then circulated through the glycol pump through tubes of the thermal storage coils, as seen in [a4.1.2], indicated by the blue pipe which goes into the Cold Storage Tank. The cold glycol then passes through the coils in the Cold Storage Tank, which removes heat from the water in the tank (see Figure 1). This causes the water to freeze in the tank. This tank can be made up of concrete or steel and can be placed either underground or above ground. The next phase that occurs would be the melt-out as explained below [a4.1.2]. Melt-out During the melt-out phase, the glycol chiller remains off. Due to this the water that passes through the glycol chiller would be warm enough to melt the ice in the Cold Storage Tank water. This warm water is indicated by the red pipe that goes into the Cold Storage Tank (shown in Figure 1). Due to this, some of the ice is melted and forms an ice-water slurry which is passed through the „heat exchanger‟. At the same time, more water that arrives from the building is passed into the heat exchanger. This water is then cooled by the ice-water slurry in the heat exchanger and then finally sent to the „Building Air Handler‟, which supplies this chilled water throughout building and provides cooling [a4.1.2].

4.1.1.5 Choosing between chilled water and ice storage:

Both of these systems have advantages and disadvantages. There will be situations where one type of system would work over the other. A few of the advantages and disadvantages of Chilled water and Ice is summarized below in [a4.1.2]. [a4.1.3] shows the differences between chilled water and ice based on their storage temperature and volume occupied. 4.1.1.6 Materials used for the storage tank:

Two of the most common materials that can be used for the Cold Storage Tank would be steel or concrete whose advantages and disadvantages areas shown below in [a4.1.4] 4.1.1.7 Layout of cold storage systems with chillers

[a4.1.5] shows that 21 chillers (structures shown in red) will be connected to one central Cold Storage Tank (structure shown in blue). Each of the chillers will supply cooling to their designated building, while storing either ice or chilled water during off-peak hours in the Cold Storage Tank. While, each of the 21 chillers are of different sizes, they will all be setup based on a single configuration. They will all operate at the same time and at the same capacity. 4.1.1.8 Control strategies for cold storage systems: Control strategies for cold storage systems are often classified into three major categories: Full Storage, Partial Storage and Demand Limiting [4.1.1]. The three categories are shown in [a4.1.6-8]. Each of these figures represents a graph having a 24hr time period. In each of the following three graphs the day period will be at middle of the graph and the night period will be on the extreme ends of the graph. We shall first explain about a Full Storage configuration as shown below. Full storage Full Storage systems as shown in figure 3 below, is a system where the chiller has to operate at 100% of its capacity, and it meets the entire cooling load [g – 4.1.1.8] at the off-peak hours (night time), when the electric costs are low [4.1.4]. Cooling load is the total amount of energy required to fulfill all the cooling requirements for the entire day. The chiller has to meet this cooling load each day without fail. But, we can set at what times and at how much capacity it can run, during that day. Due to this, we can set up the chiller with the Cold Storage System so that we get the lowest cost, but still meet the cooling load for that day. .The solid line in [a4.1.6] represents the cooling load to be met on that day. The chiller works at night creating ice and storing it, which is indicated by the striped region. The white region under the solid line shows that the chiller meets the load directly, that is, it supplies chilled water for cooling as soon as it produces it and unlike the shaded region does not store the ice for a later time. During the day, the chiller remains off as shown in the gray portion of the graph. But the chiller still meets the cooling load during this time by using the ice which is stored at night (shaded portion). Full Storage captures the greatest savings possible by shifting most of the electric demand from hours that have high electric cost rates (on-peak hours) to hours that have low electric cost rates (off-peak hours) [4.1.4]. Partial storage The other two control strategies both come under Partial Storage. They are Load Leveling and Demand Leveling [4.1.4]. These are both types of partial storage systems. Partial Storage Systems in general meet part of the cooling load from storage during the off-peak hours and the rest of it comes directly from the chiller during the on-peak electric hours. The two different configurations of partial storage are Load Leveling and Demand Leveling are explained in more detail in sections below Partial storage – load leveling Load Leveling makes the chiller run for 24 hours a day [4.1.4]. The dotted line in [a4.1.7] above, indicates the output of the chiller, that is, the amount of energy the chiller consumes in order to produce cooling. The solid line, which forms a parabola as shown in [a4.1.7] above is the cooling load demand, or the total energy needed for cooling on that day. When the cooling load demand (solid line) is less than the output of the chiller (dotted line) as shown in the shaded region, ice/chilled water storage takes place. When the cooling load demand (solid line) exceeds the output of the chiller (dotted line), the medium (ice/chilled water) is discharged from the tank and used to satisfy the cooling load demands. Load Leveling thus minimizes the size and cost of the chiller and its storage components, but has higher electricity costs than full storage. Partial storage – demand limiting Partial Storage-Demand Limiting as shown in [a4.1.8], falls in between Full Storage [a4.1.6] and Partial Storage-load Leveling [a4.1.7], where the chiller operation (white area) is reduced, but not eliminated during the on-peak period [4.1.4]. Thus the size and costs of the chiller, the storage tank and electric cost tend to fall between Full Storage and Partial Storage-Load Leveling options [4.1.4]. The chiller output (dotted line) can be adjusted in the on-peak region (middle of the [a4.1.7]) and this allows for easy adjustments to the configuration of the thermal energy system. Thus this system would be the most flexible out of the three and can have two different configurations for the summer and winter.

4.1.1.9 Conclusion For the Old Ottawa East District Cooling System, the overall cost for an Ice Storage System would be cheaper than a Chilled Water system due to the Ice Storage System having fewer workers and a more compact system than chilled water. A concrete tank would be suitable as it is cheaper than a steel tank and can be integrated with the building foundation easily as seen in [a4.1.4]. Partial Storage-Demand Limiting would be a suitable control strategy for the cold storage system as it offers the maximum flexibility and can be easily configured for any situation.

4.1.2 Thermal Storage Tanks - Aly Rasmy This section of the report addresses hot water thermal storage tanks1, which allows excess thermal energy to be collected for later use. Thermal storage is receiving renewed attention as a means of reduction of fossil use and taking advantage of excess solar heat energy production during the day to meet the heating demands of buildings across the whole day [4.1.19]. Our objective is to reduce the need for fossil fuels for heating as they produce greenhouse gases. The first Section on thermal storage tanks below explains why water is used in the tank (4.1.2.1) and then the next Section covers how the tank works (4.1.2.2), followed by a Section discussing the advantages of a thermal storage tank (4.1.2.3). The following Section addresses the relationship between heating demand and heating production across different seasons (4.1.2.4). Sections 4.1.2.5 and 4.1.2.6 cover the tank capacity calculation and the cost effectiveness respectively. Lastly, Sections 4.1.2.7 and 4.1.2.8 cover the properties of the tank and summary of the overall size and cost of the tank.

4.1.2.1 Why water is used as a storage medium

1 These tanks are powered by solar energy. Water is an ideal material in which to store heat in a thermal storage tank because it is low in cost, non-toxic and has a high specific heat capacity [g-4.1.2.1]. Specific heat capacity refers to the amount of energy it takes to increase the temperature of one gram of a substance by 1oC degree [4.1.7]. So if the heat capacity of water is high then this means it takes more energy to heat up than other materials, which is a good thing as this means it can store more energy. For cooling, water gives off more energy than other substances when the temperature is decreased by 1oC degree, which is also a good thing as this means that water does not decrease in temperature easily.

4.1.2.2 How a thermal storage tank work

[a4.1.9] below shows a representation of a thermal storage tank system. Heat is radiated [g- 4.1.2.2] from the sun onto the solar collectors. Following the principle of conservation of energy [g-4.1.2.2], energy is converted from light energy to thermal energy, which will heat the water coming from the bottom of the tank and provide it to the top of the tank [4.1.9], [4.1.10]. This thermal energy can be stored for use when the sun is not shining. When solar energy is not available from the collectors or the storage tank and heat energy is required, then boilers could be used to supply the consumers‟ heating needs. Hot water is accumulated at the top of the tank due to convection (hot water tends to rise and cold water sinks) [g-4.1.2.2]. Thermal stratification [g-4.1.2.2] implies the existence of temperature layers within a water storage, whereby the hot and cold water layers appear to be separated by an invisible sheet of water. This is because of a large difference in density between the hot and cold parts of the tank. Stratification is achieved through the elimination of mixing during storage, which means that the effectiveness with which the energy can be used will be improved if it is supplied to the load at the temperature it was collected rather than at a lower mixed storage temperature [4.1.19]. When hot water supply is needed, water is taken from the top of the tank through the pipes to the buildings. After the buildings use the thermal energy in the water, the water is then taken to the bottom of the tank via pipes [4.1.18]. 4.1.2.3 Why thermal tanks are used

Solar thermal systems exhibit in general high efficiency levels when it comes to solar heating applications [4.1.8]. In combination with their moderate life cycle costs they can offer a good return on investment at short repayment periods. Depending on environmental conditions and competing fuel prices repayment of initial investment may be expected within as little as the first five years. Solar collectors used for heating are a mature technology offering a high-energy contribution at a very low operating cost [4.1.18]. Moreover, solar systems can easily store thermal energy by use of storage tanks and use it when it is required without interference from immediate environmental conditions, for example overnight or during cloudy periods. Furthermore, thermal tanks use solar energy when available to displace the natural gas used by boilers. As boilers are harmful to the environment because they produce greenhouse gases

4.1.2.4 Relation of heating load with heating demand

In order to calculate the amount of thermal energy needed to be stored in a thermal tank for a short term (daily cycle), the relationship of a daily thermal energy demand (consumption) with a daily solar thermal production (produced by the solar panels) has to be studied for different months. [a4.1.10-12] are only for illustrative purposes; they show graphs of the rate at which thermal energy (kW or mj/hr) is produced or used against time (hour) across a 24-hour period for different seasons (spring or fall day– explained in section “Average spring or fall day” below, peak winter day– explained in section “Peak winter day” below, peak summer day– explained in section “Peak summer day” below). There are two separate curves on each graph; the energy demand curve (red) and the solar energy production curve (blue). The purpose of storage is to store excess thermal energy when energy production is much higher than energy demand (yellow). This energy stored will later be used during period the day when energy demand is higher than energy production (area in green) [4.1.17].

Average spring or fall day (shoulder seasons) [a4.1.10] shows an average spring day trend, where the amount of excess thermal energy produced by solar collectors (yellow region) is greater than amount of the energy demand on off peak hours (green region) [4.1.17]. Therefore, the tank will meet all energy requirements without needing the use of boilers. Peak winter day [a4.1.11] below shows peak winter day trend, where the amount of thermal energy production at the peak of the day is lower than the demand as winter requires a lot of heat and not enough sunlight available [4.1.17]. Therefore, not enough thermal energy will be stored in the tank (yellow) and this means that the tank will not meet all the thermal energy demand across the day (green). Therefore, another source of energy must be supplied to heat up the water in the tank as solar is not available. This is when boilers have to be used to meet the demand. Peak summer day [a4.1.12] shows peak summer day trend. As shown in the graph below, thermal energy production (blue curve) is always greater than thermal energy demand (red curve) during the day [4.1.17]. Since there is no point in storing more than is required during the night using short term storage, then there may be a case for using seasonal storage as is done at Drake‟s Landing (Okotoks, Alberta) [4.1.18]. This means that the summer season is when the tank would not be needed as the heat production throughout the 24-hour period meets the demand without the need to store any for later use. 4.1.2.5 Tank capacity

The volume of the tank is calculated by [a4.1.13-14]. [a4.1.13] was used to calculate the mass of water that will store the amount of heat energy required [4.1.17]. After plugging in all the given values into Equations [a4.1.13-14], the final volume of the tank is 560 m3.

4.1.2.6 Cost effectiveness

[a4.1.15] was used to calculate the amount of unused solar heat energy produced (wasted). For [a4.1.15], solar heat potentially wasted if there was no storage is 1174.81 MWhrs/year (provided by Solar team production curves compared to the annual hot water demand (buildings team)). The effective use of the storage tank volume might be about 70% (suggested by M.Wiggin). This means that after un-useful space is accounted for (some space between hotter and cooler water zones and space for dispersion piping) then about 70% of the total tank volume can be considered as useful [4.1.18]. Therefore, the solar heat potentially wasted is 822.367 MWhrs/year.

Equation [a4.1.16] below was used to calculate the cost of the thermal storage tank. The cost of storage is the price of the tank per unit volume (80 $/m3) multiplied by the total volume of the tank (560 m3). Therefore, the cost of the storage tank is $44,815. Using the values calculated in [a4.1.15-16], we used [a4.1.17] to calculate the total cost of energy saved. The cost of energy saved or made useful is the cost of the storage tank ($44,815) divided by the amount of energy saved and made useful (822.367 MWhrs/year). Therefore, the total cost of energy saved is $54.5 per MWhrs/year. 4.1.2.7 Properties of the tank

The tank will be used for daily storage, so the period of storage time is short and the tank will be well insulated. Therefore, the thermal energy losses will be low because a low amount of heat in the tank will escape to the surroundings in this short cycle (daily cycle) [4.1.18][4.1.19]. In this case a metallic vertical tank will be used. Vertical tanks are generally preferred in comparison to the horizontally mounted ones because of the requirement of the latter to resist beam bending and buckling action. Also, for smaller sized tanks fiberglass or plastic tanks may be suitable. For insulation, polyurethane foam can be used up to 120oC and it is the common insulation employed.

4.1.2.8 Overall size and cost results of the tank

Based on rough unit costs from Chicago Bridge and Iron Company (CBI), the cost for the tank and the interface2 would be in the order of price per volume cubed multiplied by the volume of the tank plus any special site preparation costs. This assumes a tank cost of about $44,815 [4.1.20] plus an allowance of $40,000 (suggested by M.Wiggin) for the interface with the system.

4.1.3 Thermal Mass Storage – Kathleen Rozman

2 The interface is required because the system pressure is typically higher than the storage tank pressure, which is at atmospheric pressure [4.1.20]. 2 4.1.3.1 Overview of thermal mass storage

This section of the report will cover an overview of thermal mass storage, the engineering principle behind the storage system and appropriate materials to be used in the storage system. Converting solar energy to thermal energy is a method of using sustainable and renewable energy [4.1.26]. Refer to [a4.1.18]. In order to convert this solar energy, a storage unit with attached solar collectors is needed. Thermal mass storage is a process where this concept is applied. Solar energy is radiated onto solar collectors where the energy is then passed through a storage system. The energy is distributed into a home/building. This process produces thermal energy for it to be distributed at the time it is needed. The process involves the concept of the engineering principle of thermal mass. Choosing an appropriate material All material contains a thermal mass. This is where the heat is held within the substance [4.1.22]. The heat that is stored in a substance is generated by burning fuel or through radiation from the sun. The heat is slowly released back into the surroundings. The amount of heat stored and heat released into the surroundings from a substance depends on its density. We can use Equation [a4.1.19] to calculate the density of a material. Equation [a4.1.19] gives the proportional ratio of density (ρ) Mass and volume are directly proportional meaning as the value of density increase, the value of mass increases whereas the value of volume decreases. In order to obtain a great density, the value of mass must be large and the value of volume must be small. In order to effectively store and distribute heat by using the concept of Thermal mass for a building, there must be a combination of heat capacity and density in the storage material [4.1.22]. In order to choose an appropriate material, there are 2 key factors to consider, the density and the heat capacity of a material. Table [4.1.20] below shows that air has a higher heat capacity than concrete and concrete has a higher density than air. Concrete holds 2.086 (MJ/m3K) heat per volume, whereas air holds 0.0012 (MJ/m3K) heat per volume. Air contains a heat capacity of 1.0035 (J/gK) whereas concrete contains a heat capacity of 0.88 (J/gK). The rock pebbles have a fairly high density of 1600 (kg/m3) and concrete has a fairly high density of 2371 (kg/m3). Therefore, the two materials chosen to be implemented in the storage systems are rock pebbles and concrete. These materials contain a high value of heat per volume and density can store more thermal mass. There are two methods of Thermal Mass storage that use these materials: Air-based storage and storage walls. 4.1.3.2 Methods to facilitate thermal mass storage

This section of the report will cover two different methods that facilitate thermal mass storage. It will include the process and general parameters of the two systems. Method 1: Packed-bed storage Packed-bed storage is a technology that is a form of air-based storage. It is an insulated container filled with loosely packed rock pebbles through which air is circulated to produce natural or forced convection [g-4.1.3.2] that heats a building [4.1.23]. Refer to Table [a4.1.21] for general parameters of the packed-bed storage system. There are three modes that the Packed-bed storage technology can be in: charging, discharging and auxiliary.

The charging mode The charging mode of the Packed- bed storage method is shown in [a4.1.22]. First, sunlight is collected in the solar collector [4.1.23]. This solar energy is passed through a damper [g- 4.1.3.2]. The hot air is distributed to the packed rocks. As a result the rock bed is heated. The hottest air remains at the top of the rock bed while the cooler air returns to the solar collector to be heated and to start the process once again. Discharging mode The Discharging mode of the packed-bed storage method is shown in [a4.1.23]. This mode is where there is no solar energy available to be collected in the solar collector, however, there is a need to heat the building [4.1.23]. In this case, hot air that was stored from the charging mode explained above is drawn from the top of the packed-bed. This hot air is passed through the auxiliary heater, which will be described later in this section, and distributed through the house. The cooler air is returned to the bottom of the bed where it will be distribute to the solar collector to be heated when there is solar energy available. Auxiliary mode The auxiliary mode of the packed-bed storage is shown in [a4.1.24]. This mode is where there is both cases are occurring at the same time – there is solar energy available for the solar collector and there is a demand for heat [4.1.23]. Hot air from the solar collector is led directly into the house, as opposed to storing it in the packed-bed. The cooler air from the house is led back to the solar collector to be heated. The auxiliary heater shown in [a4.1.11] is a separate heating unit that ensures the air is at its desired temperature, in case the collector or storage unit is not meeting the load demands. Method 2: Trombe walls The Trombe wall technology is a passive solar building design and is a form of storage wall [4.1.24]. The Trombe wall system is shown in [a4.1.25]. The wall is a sun-faced oriented wall built out of concrete containing a black painted absorber, insulated glazing (glass). The insulated glazing is installed a few inches away from the concrete. Throughout the day while the sun is shining, solar energy is absorbed through the glass and warms the concrete located in the interior surface (area in between the glazing and black absorber). The solar energy is encased in the interior surface until there is no sunlight. The Thermal energy that is stored is distributed out towards the upper portion of the concrete wall through the ventilation system where it is diffused into the interior of the home. Refer to [a4.1.26] for general parameters of a Trombe wall.

4.1.3.3 Benefits of the thermal mass storage systems This section of the report will cover the benefits of the thermal mass storage systems, in terms of financial, economic and efficiency means. Benefits of packed-bed storage The process of this system does not involve any chemical reactions that could potentially be harmful to the environment. The material used within the storage unit, pebble rocks, is non- combustible and inexpensive. The typical size of pebble rock ranges from 1cm to 5cm [4.1.26]. There is great contact time between the air flow and the packed-bed, refer back to Table 5. This ensures good heat transfer from the rock bed to the home [4.1.32]. While the system is in charging mode there is low-heat loss through the pebble bed. This is because the pebble rocks are packed closely to ensure there is no presence of cool air entering the voids of the packed- bed. This advantage to the packed-bed storage system leads to the fact that the system does not require much insulation around the system and also does not sustain any corrosion or freezing problems [4.1.32]. Financially, the packed-bed storage system is quite inexpensive. In order to save money, it is in our best interest to maximize the net income, which is the difference between the economic value of heat stored and two cost factors [4.1.33]. The two cost facts consist of the capital equipment costs and operating costs. The operating cost entails the pumping costs of the circulating air contained in the packed-bed storage system. This pumping cost depends on the pressure drop through the bed, which varies in different situations. Therefore, the investment cost for the air blower constitutes to approximately 30$ / year. The equipment cost of the column is separated into annual payments. For one year of operation, the cost of the cylindrical column is $1.00 / m2. However, this technology contains limits because it is a method of short-term thermal storage. The load peaks are based off 24 hours versus the load peaks that are based off a month‟s time, meaning this type of solar energy is a time-dependent energy resource [4.1.23]. Benefits of the trombe wall Financially, the installation of a trombe wall is inexpensive; however, the costs that will be saved throughout the duration of the seasons will be more substantial. The approximated cost of the installation of the concrete wall is $734.00 and installation of the glazing window would be approximately $912.00 [4.1.24]. Overall, the cost of the installation of a Trombe would be $1700, including labour. The Trombe wall does not involve monthly cost for maintenance or usage costs. Environmentally, there is no fossil fuel use, unlike a standard heating system such as a furnace. The Trombe wall reduces usage of central heating systems and distributes a natural and constant radiant heat through the duration of the day. This passive solar collector is a form of sustainable energy, due to the use of the sun‟s energy to distribute heat to a specified area. This form of passive solar heating does not attribute to much heat loss during the night. The Trombe wall is contained in a small real estate that requires no maintenance. However, the trombe wall is contained in a large surface area which helps heat the room evenly [4.1.34]. The Trombe wall heating system takes up to 8-10 hours to reach the interior space of the building [4.1.35]. This ensures that the interior of the building remains at a comfortable temperature during the day and receives a slow even heating for hours after the sun sets. The Trombe wall contains upper and lower wall vents (refer to [a4.1.22]). Similar to the packed- bed storage system, these vent placements allow convention currents [4.1.35]. This is because the warm air exits out of the upper vent, and the cool air enters from the lower event, facilitating natural convection. Therefore, these vents prevent reverse convection [g-4.1.3.3] currents that would occur during the night which would cool the interior space of the home. The ventilation system in the Trombe wall method also allows the occupants of the building control instantaneous heating. 4.2 Seasonal Thermal Energy Storage 4.2.0 Introduction: I have put together this report regarding the Old Ottawa East District energy project for seasonal and short term thermal energy storage systems [a1.0.1]. Our main goal is to find the best method of energy storage in order to regulate the supply and demand on seasonal or daily basis. In order to create the most effective energy storage system, we had to research about the capital cost, maintenance expenses, fuel consumption and payback period [g1.0.1] of every system. The BTES [g1.0.2], ATES [g1.0.3], chilled water systems, ice storage systems and thermal energy storage tanks are the systems we will research about. In addition to that, we will research about the effect of every system on the environment and surrounding communities. 4.2.0.1 Background The role of the seasonal energy storage is to regulate the supply and demand of energy along a two-phased time period. In the summer, the thermal energy stored from the winter will be used to for the district cooling. However, the thermal energy stored from the summer will be used to provide heat in the winter [r4.2.0.2]. On the other hand the short term energy storage is supposed to regulate the supply of energy on a daily bases. For example, the solar energy stored in during the day will be stored and kept for later use at night. Since the energy stored will only be used when the supply of energy does not meet the demand, the community will be not be using it constantly. Therefore, our team has to determine the base load (the minimum amount of energy that will be continuously supplied). Upon that, the seasonal and short term energy stored will be supplied when the base load [g2.0.1] does not meet the minimum amount of energy needed on daily/seasonal basis. 4.2.0.2 Seasonal Energy Storage Regarding the seasonal energy storage, we narrowed down our choices to two energy systems. The first system is the BTES system which stores thermal energy underground.This system - reduces peak demand, energy consumption and CO2 emissions. The thermal energy can be collected whenever it is available and be used whenever needed. For example, the thermal energy from solar heat collectors will be stored during sunny days to be used during the winter for heating purposes. Also, the natural cold of winter air can be stored for summertime air conditioning [r4.2.0.2]. However, the cost of this system can vary depending on local ground conditions, required depth of boreholes, and amount and type of insulation used. In our case, the installation of the borehole will cost around $4.5-5 Million [r4.2.0.1], in addition to the expenses of installing the supporting piping systems to each building. Our second choice that we are considering is the ATES, which has a cheap initial cost and is expected to have a 5 year payback period.

4.2.0.3 Short Term Energy Storage Regarding the short term energy storage systems, our main systems were chilled water systems, ice storage systems and thermal energy storage tanks. These systems will be able to store thermal energy on a daily basis. The chilled water systems can use existing chillers and acts like a double duty, providing water in case of fire. On the other hand, the Ice storage systems require less space and can provide colder air to the buildings [r4.3.0.2]. However, it requires more energy to operate in order to keep the temperatures low inside the storage facilities. Therefore we need better insulation and piping systems to maximize the amount of thermal energy [r4.3.0.1]. Regarding the initial capital costs and maintenance expenses, our team did not have access to this type of information. Therefore, we will recommend the most effective system based on different factors, such as its advantages and disadvantages on the community.

4.2.0.3 Overall Energy Storage Systems Distribution The thermal energy collected by the solar energy collectors will be transferred through the piping systems and will be stored in the short term energy storage tanks[a1.0.2]. These tanks will store the thermal energy whenever the sun is available and will supply it whenever it is needed. The thermal energy stored (In addition to the thermal energy produced by the boilers) will be transferred back to the buildings and other facilities for later use. Since the storage tanks are not perfectly efficient, almost 2-5% [r4.3.0.1] of the energy stored will be lost. In addition to that, 15% of the thermal energy will be lost while being transferred through the pipes from/to storage systems [r4.2.0.1]. Therefore, 90-95% of the heat coming into short term storage is delivered to the community. The initial cost required to install these systems was not available to our team. The community will not consume all the energy stored from the short term energy storage tanks. This will result in an excess of thermal energy that will not be used. Therefore, the excess heat from the short term energy storage tanks will be sent to the BTES system. Like the short term energy storage tanks, the BTES system is not a perfect system since 55% of this energy will be lost to the ground surrounding it. Due to the thermal energy loses in the pipings , almost 40% of the energy stored will be delivered to the short term storage tanks and supplied whenever needed. The BTES system required an initial capital of $4-5 million CAD in addition to additional expenses to install the required systems in the buildings to successfully transport the thermal energy [r4.2.0.2].

4.2.0.4 Conclusion and Recommendations The seasonal/short term energy storage systems are able to effectively reduce the difference between the supply and demand. However, buying the energy storage systems (such as the boreholes) will be expensive since it needs requires more than $5 million to be installed. Our team decided not to use the BTES since the initial investment of $4-5 million is not worth the money that will be saved by using these storage system. Therefore, the community will not store energy in the short term or long term energy storage systems. A more detailed model about the overall energy combination is discussed in the modeling part of our team report.

4.2.1 Introduction Seasonal Thermal Energy Storage is a method in which excess thermal energy is collected from sources such as solar panels, and then stored in the ground for later, long-term, use. This is relevant to the Old Ottawa East institutional lands community because excess energy will be produced by the proposed district energy system, and seasonal thermal energy storage could provide a use for this excess energy. This report is divided into four main sections: aquifer thermal energy storage systems (Section 2.0), borehole thermal energy storage systems (Section 3.0), the environmental implications of seasonal thermal energy storage and a comparison of the two systems (Section 4.0), and an analysis of the energy required to be stored in the system, insulation methods and operational temperature limits (Section 5.0). This report will conclude with a recommendation based on these findings.

4.2.2 Aquifer Thermal Energy Storage System (ATES) [Kailey De Silva] This section of the report will be focusing on the technical aspects of an aquifer thermal energy storage system and whether this system will be a viable option for the Institutional Land Area of Old Ottawa East. This section will include information on the role of aquifer thermal storage systems in a district energy system (Section 2.1), how an aquifer thermal energy storage systems work (Section 2.2), approximated costs of building an aquifer thermal energy storage system (Section 2.3), whether aquifer thermal energy storage could be installed in the Institutional Land Area of Old Ottawa East (Section 2.4), as well as other ways to implement aquifer thermal energy storage systems in Old Ottawa East (Section 2.5). 4.2.2.1 Usage in a District Energy System Waste thermal energy generated by other systems, such as the heat generated by air conditioning systems and extra heat generated by the centralized energy system (biomass or natural gas generator), and excess cooling energy can be stored in an aquifer thermal energy storage system to be used later throughout the year [a4.2.1]. As shown in a presentation by Underground Energy LLC. Aquifer thermal energy storage systems are very efficient as they are able to recover up to 70% of the energy that is stored within them. The systems also have a coefficient of performance that varies between 8 to 20 and an efficiency of 68%, classifying it as an efficient thermal storage system. Using an aquifer thermal storage system as part of a district energy system can potentially allow the community to save up to 60 to 80% of the electricity used for cooling, which would potentially reduce the electricity needed by the community at the seasonal peak by 80- 90%. For heating, the aquifer thermal energy storage system can potentially allow the community to save 20-30% on energy. Greater energy savings can be achieved depending on the project specifics, such as location and resource availability.

4.2.2.2 How It Works This section will be explain how an aquifer thermal energy storage system works. This section will include how an aquifer thermal energy storage system is able to store thermal energy and circulated it to the building (Section 2.2.1). This section will also explain how the components of an aquifer thermal storage system work. These components including heat exchangers (Section 2.2.2) and heat pumps (Section 2.2.3).

4.2.2.2.1 Aquifer Thermal Energy Storage System Aquifer thermal energy storage systems are seasonal energy storage systems that store thermal energy in natural aquifers, located underground. This energy can then be taken from the aquifer to be used to heat or cool buildings throughout the year. The ATES system discussed in this report uses a stagnant aquifer, rather than on which flows.

An aquifer is an underground deposit of water that is able to flow through a layer of permeable soil and can be formed naturally around rivers, lakes and other bodies of water [a4.2.2]. Thermal energy can be stored in this underground water in the form of heat. The more thermal energy that is transferred into the aquifer the warmer the ground water gets. The heat from the ground water can then be circulated through buildings, heating them. The same process applies for cooling, when cold water is used. In an aquifer thermal energy system thermal energy for both heating and cooling is stored in the groundwater [a4.2.2]. The thermal energy used for cooling is stored at one end of the aquifer, called the cold store since the groundwater at this end of the aquifer [a4.2.1]. The thermal energy used for heating is stored in the groundwater at the opposite end of the aquifer, called the warm store since the groundwater at this end of the aquifer is warmer [a4.2.2]. It is important that the warm store and the cold store remain separated. This will ensure that the warm water stays warm and can be used for heating, while the cold water stays cold and can can be used for cooling.

The groundwater from the thermal energy stores is pumped up thermal wells into a heat exchanger located above ground [a4.2.2]. The heat exchangers transfers the thermal energy to a fluid called brine which will them be passed through a heat pump [a4.2.4]. Brine is usually a mixture of water and alcohol or glycol. This mixture ensures that the brine does not freeze when receiving thermal energy from the cold store. Brine is used as a mediator fluid, receiving thermal energy from the groundwater and then transferring it to a refrigerant which will be used to heat and cool the buildings [a4.2.2].

In the summer the aquifer thermal energy storage system can be used for cooling, by circulating thermal energy from the cold store [a4.2.2]. After the cooled refrigerant has been used to cool the building it will have absorbed heat from the building, warming it. The resulting heat can then be deposited in the warm store to be used for heating in the winter [a4.2.2].

In the winter thermal energy will be transferred from the warm store to the building, using both the heat exchanger and the heat pump. Once this energy has been released into the building as heating the resulting cool thermal energy can then deposited in the cold store for cooling in the summer [a4.2.3]. This circulation of energy is important to maintaining the balance of the system. Balance is important since over storage of thermal energy in the cold or warm store can cause mixing of the two stores. This can also occur if the stores are located too close together.

4.2.2.2.2 Heat Exchangers Heat Exchangers are devices that exchange thermal energy in the form of heat from one fluid to another without allowing the two fluids to mix. In an aquifer thermal storage system heat exchangers are used to transfer heat from the ground water from the aquifer to the brine [a4.2.5]. This is done by passing the groundwater around small pipes of brine [a4.2.2]. As heated ground water comes in contact with the pipe containing the brine the ground water heats the pipes. The pipes, which are now heated, heat the brine that is flowing through them. The heated brine is then transferred to the heat pump. 4.2.2.2.3 Heat pumps Heat pumps are sometimes necessary when providing heating from an aquifer thermal energy storage system [r4.2.4]. They are required when the temperature required for heating buildings or the district heating system is higher than the storage temperature. In a heat pump thermal energy is transferred from brine to a liquid refrigerant the same way energy is transferred in heat exchangers, without the fluids mixing. The refrigerant is then evaporated into a vapour due to the heat provided by the brine. The heat pump then compresses this vapour into a high temperature liquid, condensing it.

The energy expelled by compressing the vapour is then passed through the building to provide heating by releasing the heat into the air. Once the liquid has cooled it is then reduced in pressure, returning the refrigerant to its original state, and the process repeats.

4.2.2.3 Approximate Costs of Aquifer Thermal Storage The cost of building an aquifer thermal energy storage system varies per project [r4.2.7]. To give an idea of the cost the values given in the Aquifer Thermal Energy Cold Storage System at Richard Stockton College, an American report, was used as a reference. The total costs taken from this project is $2 600 000. This is an estimated value, which includes the approximate cost of the following system components and building processes. The cost of the wells is about $360 000 to $653 800 per well and $40 000 per well house. Depending on the system more than two wells may be required, the project this site references uses six wells. All the components of the well cost approximately $320 000. Well piping will cost about $93 000, electric service well control cables cost about $194 000 and the controls and frequency controllers cost about $120 000. Other fees include insurance, around $3 600, depending on the location of the site, mobilization and demobilization, costing $120 000, prints, signage, inspection and code review costing approximately $8 400, $13 000, $41 000 and $23 000 respectively.

4.2.2.4 Installation in Old Ottawa East The soil in Old Ottawa East is 60% clay, 26% sand, 9% lime, and 5% till [r4.2.8]. Since the soil in Old Ottawa East is mostly clay, which is (water cannot pass through it) the chance of there being a natural aquifer is very low. Due to the sizable amounts of sand and lime it may be possible that an aquifer exist deeper underground as 22% of the soil 5m below ground level has a medium permeability and 10% of the soil 5m below ground level has a high permeability. It would require expert evaluation to determine if a natural aquifer exists so other options in terms of thermal storage may have to be considered. 4.2.2.5 Alternative Means of Implementing ATES in Old Ottawa East Since the likelihood of there being a natural aquifer in the Institutional Lands Area of Old Ottawa East is low alternative solutions can be found to incorporate aquifer thermal energy storage system in the district energy system. One solution is to use an existing aquifer that is close by [r4.2.9]. This would require a land survey to determine if there is a suitable aquifer around. The system can then transfer the stored energy to the community, rather than being located within the community. Another option would be to use a man-made aquifer. This would require building a storage area underground which would be used hold the water, rather than an aquifer. These systems do not have to reach the same underground depth as a natural aquifer but they do need to be insulated.

4.2.2.6 Aquifer Thermal Storage System Research Conclusion To conclude, aquifer thermal energy storage systems are effective additions to district energy systems in terms of storing thermal energy to be used seasonally for both heating and cooling. However due the known soil conditions of the Old Ottawa East area it is unlikely that an aquifer will exist. Therefore implementing this seasonal storage system using a natural aquifer may not be possible. To confirm the presence or location of a natural aquifer a professional survey of the land would be necessary. Though other alternative solutions exist within the field of aquifer thermal energy storage, which are more expensive, it might be beneficial to entertain other seasonal storage systems for this project.

4.2.3 Borehole Thermal Energy Storage (BTES) [Samantha Champagne] This section will review, from a technical perspective, whether borehole thermal energy storage is a viable choice of seasonal thermal energy storage for the Old Ottawa East (OOE) institutional lands development. The following subsections will discuss: borehole thermal energy storage (BTES) (Section 3.1), thermal energy storage mediums for a BTES system (Section 3.2), the compatibility of borehole thermal energy storage with the Old Ottawa East institutional lands development (Section 3.3), and the relative installation costs of a BTES system to provide space and water heating for homes and buildings in the OOE institutional lands development community (Section 3.4). This section will conclude with a recommendation based on these findings.

4.2.3.1 Understanding Borehole Thermal Energy Storage Borehole thermal energy storage (BTES) is a system that takes excess thermal energy, such as waste heat generated by a centralized energy system (as mentioned previously in Section 2.1), and stores it within the ground for later use by using a system of boreholes [r4.2.10]. A borehole is a large underground well drilled 30-200 meters into the ground, with a long „U‟ shaped pipe running through it [a4.2.6]. A carrier fluid, a fluid that is heated and used to move heat around the BTES, passes through this “U” shaped pipe and then flows through a series of pipes which connect to other boreholes within a borehole field ( a series of connected boreholes, [a4.2.7]. As the carrier fluid moves through the system of pipes, it transfers heat into the ground to be stored. The carrier fluid is usually water, or water mixed with glycol or alcohol to prevent freezing during the winter months.

Once the pipe is installed into the borehole, the hole is filled with grouting material. A layer of insulation is then placed over the borehole to prevent heat loss. A system of closely placed boreholes (a borehole field) is connected to an energy center. An energy center is the building in which the carrier fluid is heated. The energy center is then connected to houses and buildings through a piping system [r4.2.13]. BTESs are easily expandable, and allow for additional boreholes to be added to the borehole field to enable greater thermal energy storage.

In the summer, excess energy is used to heat the carrier fluid in the energy center [r4.2.13]. This excess heat comes from unused energy from the district energy system, as there is a lower demand for energy during the summer months. The heated carrier fluid is pumped into the ground, flowing first through the center of the borehole field, then towards the outer boundaries at which temperature is lower [r4.2.14] [a4.2.8]. During this process the carrier fluid transfers thermal energy into the ground. When it reaches the outer boundary the carrier fluid is cooled, and then it is cycled back to the energy center to be reheated. The process then repeats.

During the winter months, the opposite occurs [a4.2.9]. Cool carrier fluid is pumped to the edge of the borehole field and flows towards the center of the borehole field. During this process the thermal energy stored in the ground is transferred into the carrier fluid which causes the carrier fluid to become heated [r4.2.14]. The heated carrier fluid is then pumped to the energy center which distributes the heated carrier fluid to buildings in the community through a system of pipes as part of the district energy system [r4.2.10].

4.2.3.2 Storage Medium and Heat Capacity The amount of heat that can be stored by BTES is limited by the specific heat capacity of the material in which the heat is being stored, and the carrier fluid [r4.2.10]. Specific heat capacity is the amount of heat per unit of mass needed to heat a substance by one degree Celsius [r4.2.17]. A greater specific heat capacity means greater heat storage. There are many different storage mediums used in boreholes: groundwater, bentonite, molten salt, quartz sand, and thermally enhanced grouts [r4.2.10]. A comparison of two of these storage mediums can be found in Table [a4.2.1] . Out of these choices, water is often the most effective option, as it is the least expensive and has a high specific heat capacity: 4190 J/ kg °C. Molten salt has a lower specific heat capacity than water, but it is useful in cases where heat must be stored at very hot temperatures (over 100°C) above which water would become steam [r4.2.17]. For the OOE Institutional lands development, however, the storage temperature in the boreholes would have a maximum range from 4°C to 90°C, and would have an ideal range of 27°C to 60°C, which will be discussed in greater detail in Section 5.1.2. Within this range, water would be the most effective thermal energy storage medium.

4.2.3.3 Compatibility with Old Ottawa East Institutional Lands Development For a BTES to be installed, the proposed ground must be drillable and should consist mainly of soil and rock [r4.2.18]. These parameters would have to be consistent up to a depth range of 30 to 60 meters deep, which is a common and cost-effective depth range in which a high level of thermal energy storage can be achieved.

As stated in Section 4.2.4, the geology of the Old Ottawa East institutional lands consists mainly of clay (60%), sand (26%) and some limestone (9%) [r4.2.8] [a4.2.10]. This is not an ideal ground type for thermal energy storage. A BTES can still potentially be installed, but due to the incompatibility of the ground type, the costs may increase significantly. Additionally, the system would have lower storage capabilities than predicted due to lower thermal energy capacity and greater thermal energy losses. 3

3 The geology of the OOE institutional lands development would require a full geological survey going down depths of approximately 50 meters if the installation of borehole thermal energy storage were to be seriously considered. The ground types in this report were based on studies done on the geology at a relatively small depth

There are two major considerations when determining the compatibility of a ground type with BTES: thermal conductivity and groundwater flow. The following subsections will compare the thermal conductivity and groundwater flow found in the OOE institutional lands development to the ideal conditions for BTES.

4.2.3.3.1 Thermal Conductivity Thermal conductivity is the ability of a material to conduct (transfer) thermal energy [r4.2.17]. A medium thermal conductivity is desirable for borehole thermal energy storage. Medium thermal conductivity is high enough to allow thermal energy to flow easily between the borehole and the ground for storage, but is still low enough to prevent large losses of thermal energy at the outer boundaries of the borehole field [r4.2.19]. The thermal conductivity of an ideal ground (containing mainly rock and soil) is greater than the thermal conductivity of the ground in the Old Ottawa East Institutional lands development, which comprises mainly of clay and sand [a4.2.2]. The low thermal conductivities of clay and sand would cause the thermal energy in the carrier fluid to transfer less easily from the boreholes into the ground for storage [r4.2.17]. For this reason, a larger system would need to be installed to meet thermal energy storage needs.

4.2.3.3.2 Groundwater Flow Groundwater flow is another important factor in considering the efficiency of a borehole thermal energy system. Little to no groundwater flow is ideal around a borehole field because flowing groundwater would transfer the heat being stored in the ground outward, away from the thermal energy storage system and into the surrounding environment. This would create losses in thermal energy and consequently less energy would be accessible for use by the district energy system [r4.2.18]. The ground in the Old Ottawa East institutional lands development has a very low permeability which results in little groundwater and is ideal for a borehole thermal energy system [a4.2.11][r4.2.8].

4.2.3.4 Installation Cost of Borehole Thermal Energy Storage System Many factors influence the cost of BTES; variables such as size, efficiency, and frequency of use of the system have a large impact on costing. This makes cost estimations ineffective because there is such a large range in cost for different applications of the technology [r4.2.20].

BTES systems typically have a thermal energy storage capacity of 15-30 kWh/ m3 [r4.2.10]. For the storage of energy ranging from 10 to 50 MWh required for the proposed district energy system, a BTES of approximately 3333 m3 would be required (assuming a thermal energy

(several meters). For the purpose of this report, it was assumed that the ground types would remain constant as depth increases.

3 storage capacity on the lowest end of the spectrum due to the non-ideal ground type and the low thermal conductivity of the ground in the OOE institutional lands development). Based on figures from the construction of the borehole thermal energy storage system in the Drake‟s Landing Solar Community in Okotoks Alberta [r4.2.13], the cost of replicating the borehole thermal energy system in the OOE institutional lands development would be approximately 4 million dollars for the design, modelling, and building of the system. The BTES system would consist of 144 boreholes 35 meters in depth with a diameter 155mm. It would cost an additional $12 400 dollars/home or small building for the connection to the district loop as well as energy efficient upgrades in the buildings. Additional costs would have to be taken into consideration due to complications that may occur due to the incompatibility of the ground type. After an initial period of 3 years in which the borehole field would become fully heated, the borehole thermal energy system would ideally provide over 90% of space and domestic hot water heating.

4.2.3.5 Conclusion Borehole thermal energy storage is not a viable thermal energy storage system for the Old Ottawa East Institutional lands development. The system is a new technology which has not yet been fully studied or optimized, and this technology comes at a high installation cost. Additionally, the incompatibility of the ground type would cause complications in the construction and functioning of the BTES system resulting in high additional costs and lower thermal energy storage.

4.2.4 Environmental Comparison of BTES and ATES [Paige Waldock] This section of the report will be focusing on the aquifer and borehole thermal energy storage and comparing their environmental considerations, in regards to the Ottawa area. It will include the sections Environmental Aspects of Borehole and Aquifer Systems and Environmental Considerations on Implementation in Ottawa. These sections will give an overview on what types of concerns or benefits each of the systems would have for the environment and how those concerns would directly impact the Ottawa area. This section will conclude with a brief conclusion comparing the findings of the two systems. 4.2.4.1 Environmental Aspects of Borehole and Aquifer Systems To fully understand the environmental impacts of the borehole and aquifer systems their coefficient of performance (COP) values must be compared. COP is the ratio between the amounts of heat moved by the system to the units of energy used by the system [r4.2.21]. This means that the higher the COP value the more effective the system is. As the COP increases it shows that the system uses less energy to move the same amount of heat [r4.2.21]. Overall, this shows that if a system has a higher COP value it uses less energy and thus produces fewer emissions. Aquifer systems have a COP value that usual ranges from 8-20 while the borehole system has a COP that ranges from 4-7 [r4.2.22]. This shows that the aquifer system needs less energy in order to run. It should be kept in mind that the COP value is the effectiveness of the system and does not reflect on how much heat can be stored and used.

Another environmental aspect that could be considered is the physical size of the system. The larger the system the greater the direct impact it has on its surrounding area and uses a greater amount of refined materials, or materials that have gone through the refining process to remove undesirable particles [r4.2.23]. The refined material itself is not hazardous, but many of the process to produce and manufacture these materials can have a negative environmental impact. Aquifer systems only need two wells to function [r4.2.22]. One well is used to store energy and the other is used to extract energy. The borehole system needs numerous drilled wells in order to function. The wells are drilled into the ground and are used to move the heat from the ground to the buildings. With the need for more wells to function correctly, the borehole system is more intrusive to its surrounding landscape.

The aquifer system is integrated into the groundwater meaning water contamination is a possibility [r4.2.22]. The risk of chemical contamination of the water table arises if the system was to malfunction and heat contamination to surrounding lakes or rivers is a possibility, as well. Heat contamination occurs when so much heat is put into water that the temperature of lakes or rivers begin to rise [r4.2.24]. This poses a threat to the creatures that might live in that water. As the temperature of water increases the ability for it to hold oxygen decreases [a4.2.12]. [a4.2.12] shows that with an increase in the temperature of the water the oxygen that is present decreases. With a reduction of the amount of oxygen in the water the fish are unable to breath and can die. This change can also introduce other species of aquatic life into the environment and alter the biodiversity of the ecosystem.

4.2.4.2 Environmental Considerations on Implementation in Ottawa Implementing a seasonal thermal storage system into Ottawa would mean that the amount of energy, provided by an outside source, would decrease. The community would be using more energy that they have produced and stored through the district thermal energy system. In terms of the Ottawa area, most of the energy comes from nuclear power plants making up about 56% of the energy used in Ontario [r4.2.26]. While there is still a large debate about the benefits and impacts of nuclear energy it is a relatively clean source when compared to fossil fuels or coal. This means that reducing the energy does not have as great an effect on the environmental aspect in Ottawa, as it would on other parts of Canada that rely on energy produced from natural gas, coal, or oil. Images [a4.2.13] and [a4.2.14] compare Ontario‟s reliance on different aspects of energy production to Canada as a whole. Thermal energy storage would still reduce the amount of money spent of electricity as the community would already have some stored. It is important to understand that the thermal energy storage units do not decrease the amount of energy used by a community. The storage units save thermal energy produced in the summer for the winter. The houses still use the same amount of energy to heat their homes, it is just energy that they already have access to.

4.2.4.3 Environmental Comparison Research Conclusion Of the two systems the aquifer has a higher COP value and a smaller physical impact on its surrounding environment. In regards to a cleaner and environmentally friendlier system the aquifer would be the better choice. The aquifer system also has the added benefit of being the less expensive of the two options with a lower initial cost than the borehole system. The aquifer system, however, needs a natural aquifer to be present in the ground, which makes the borehole system the more flexible option in terms of its location. From a solely environmental aspect, the aquifer thermal energy systems boasts of having better statistics, but it also poses a larger threat of contamination. This should also be considered when comparing the two systems.

4.2.5 Operational Temperature Limits and Energy Capacity [Joseph Botros] This section of the report provides information regarding the temperature limits of both Seasonal Thermal Energy Storage systems, and the required thermal energy to be provided to the institutional lands development in Old Ottawa East, by these systems. Section 5.1 contains energy demand estimates leading to the calculation of the amount of energy required from the Seasonal Thermal Energy Storage system, in Section 5.2. Section 5.3 contains the operational temperature limit findings for each system and the reasoning behind those limits. In Section 5.4, insulation options to maintain temperature limits and a recommendation of the most suitable insulation material. A conclusion is found in Section 5.5

4.2.5.1 Energy Demand Estimates The institutional lands development community needs thermal energy for heating and cooling needs, and Seasonal Thermal Energy Storage is an option to provide some of the required thermal energy. To find how much thermal energy is needed from the Seasonal Energy Storage system, the total energy demand of the community is estimated and then part of the maximum energy demand is taken, which will be the capacity of the system. This is the thermal energy which will be provided, when needed, at peak times. First, the community energy demands are obtained, then the capacity of the system is calculated. The demand is: · 490 kWh at minimum [r4.2.31] · 690 kWh on average [r4.2.32] · 1600 kWh at most (peak) [r4.2.35] All three numbers above are in terms of per household and per month, and they come from taking the average Ontario energy demands and then scaling down to the approximate population of the institutional lands development community [r4.2.33]. Depending on the time and season, the usage of this energy will vary. 40% of the energy demand is used for heating and cooling. Therefore, the thermal energy to be stored is between 10 MWh minimum and 50 MWh maximum, per year [r4.2.33].

4.2.5.2 Operational Temperature Limits It is essential that the temperature of the water flowing through the systems is within the operational temperature limits to prevent freezing and boiling of water while in the system. This would prevent possible damage, such as leaks, cracks and explosions. These limits are shown in [a4.2.3]. Before considering insulation options, the temperature limits of each system were found, to have a better idea of which insulating material to recommend. The reason why the lower operational temperature limits of each system are different is due to the nature of how each system operates. An aquifer contains water so the minimum temperature limit is lower to allow for lower aquifer temperatures, yet to not pump frozen water out of the aquifer. A borehole uses liquid to transfer energy, and the minimum temperature limit is higher to allow for more thermal transfer.

4.2.5.3 Required System Thermal Energy Capacity From Section 5.1, the thermal energy required for storage is, at maximum, 50 MWh. By using the heat capacity equation [r4.2.36] and by using the required thermal energy, heat retention property of water, and change in temperature at 30 ºC, the required volume of water to store the required energy is:

● 400 L with a 30 ºC temperature increase in the water [r4.2.36] ● Equivalent to 0.40 m3 of physical volume Please see the [a4.2.20] for the calculation of that value, at the end of this section of the report. That volume of water is to be stored by the storage and energy center units to hold the required thermal energy from seasonal storage.

4.2.5.4 Insulation Materials We researched three materials for heat retention, called insulating materials, to determine an optimal material to keep the system temperature within operational temperature limits. Perlite vacuum insulation [r4.2.37], spray foam insulation and fiberglass insulation [r4.2.38] are the three researched materials. A recommendation has been made for the material with optimal heat retention performance while minimizing cost.

As can be seen in [a4.2.13], insulation works by reducing thermal energy loss by preventing low temperature from affecting the higher temperature inside the storage unit and preventing the heat inside from escaping.

4.2.5.4.1 Perlite Vacuum Super-insulation An insulating material has been developed which uses a material called perlite, which is volcanic dust [r4.2.37]. This material is coupled with vacuum insulation methods to prevent 95% of heat loss from the system. However, the cost of this insulation method is $560 per m2 of insulated area and, for the 200 m2 to 400 m2 required, the cost is approximately $560,000 to $1,100,000 in Canadian dollars.

4.2.5.4.2 Conventional Materials for Insulation Conventional materials, such as fiberglass and spray foam, costs $5 per m2 to $10 per m2, for a total cost of $50,000 to $200,000 [r4.2.38]. These materials are effective in reducing heat loss from storage containers, and are a sound alternative to the more expensive method, using perlite in a vacuum insulation method.

4.2.5.4.3 Comparing Materials Perlite, spray foam and fiberglass, can be compared by checking their R-Values. These values measure the effectiveness of the material per unit length of thickness; the higher the „R-value‟ the more effective the material in preventing heat loss. The „R-values‟ for the three particular materials are:

1. Perlite Vacuum: Rperlite = 3.52 [r4.2.39]

2. Spray Foam: Rsprayfoam = 1.46 [r4.2.40] 3. Fiberglass: Rfibreglass = 0.88 [r4.2.40] The perlite vacuum insulation is two and a half times more effective than spray foam and spray foam is twice as effective as fiberglass.

4.2.5.4.4 Insulation Recommendation Perlite vacuum would be the most effective and optimal method of insulation but it is 3 to 5 times more costly. Spray foam and fiberglass are good insulators, but heat loss will be 2 to 5 times greater than with perlite vacuum insulation. However, for most performance and least cost, the optimal choice would be spray foam, being twice as effective as fiberglass, and costing $10.76 per m2 [r4.2.38], for a total cost of $200,000 at most. Perlite insulation is not conventional for this project, due to high costs, and is considered for research and possibility purposes only.

4.2.5.5 Energy and Insulation Research Conclusion In conclusion, the thermal energy capacity of the system is required to be 50 MWh which can be stored in 400 L of water with a temperature difference of 30 ºC. The operational temperature limits are between 10 ºC and 90 ºC for both systems, and the recommended insulating material is spray foam, costing at most $200,000 Canadian dollars.

4.2.6 Conclusion Due to the known soil conditions of the Old Ottawa East area it is unlikely that an aquifer will exist in order to implement this seasonal storage system using a natural aquifer. To confirm the presence or location of a natural aquifer a professional survey of the land would be necessary. It was determined that borehole thermal energy storage would not be an optimal thermal energy storage system for the lands development due to the ground type and the high initial cost of the system. Unless an aquifer was found into the Old Ottawa East institutional lands development site, the better of the two systems to be installed would be the borehole thermal energy system. Due to its more flexible nature, this system would still be able to function in the clay ground type but with greater thermal energy loss. It was also noted that, with low coal and natural gases electricity production for Ottawa, the actual environmental effects would be limited. It was determined that if a seasonal thermal energy system were to be installed in the Old Ottawa East institutional lands development, the thermal energy capacity of the system would be 50 MWh as required by the district energy system. This energy would be stored in storage units able to handle temperatures between 4 ºC and 90 ºC, and would be more efficiently kept within these limits by spray foam insulation.

5.0 Modeling [Nathan Bosscher] 5.1 Site and Energy Production: The Old Ottawa East site[a5.0.1] is relatively undeveloped which gives a wide playing field for a district energy system. The site will contain living spaces in the form of town houses, condos and an old age home. There also will be a small amount of commercial space.

To produce heating, cooling and electricity for all the buildings on this site we have two options. First, we can have a centralized energy source[g5.0.1] (e.g. natural gas boiler) which is distributed out to all the buildings. This is a good idea since larger sources are more cost effective and easier to maintain. Second, we can have distributed energy (e.g. solar) . This is helpful since distribution is less of a problem and each building is more self reliant. For this application however, it would be most cost effective and reliable to have a central energy unit. This will be expanded on the modeling section.

Currently there are three production methods available to us for this site. Natural gas, biomass and solar. Natural gas has been used with great success and is very easy to start up at a moments notice to compensate for a new load. Our research found it to be quite expensive to build, but relatively cheap to run with medium level of emissions. It is also very simple to use, just hook up to the gas line and perform regular maintenance. Biomass, is simply, burning organic waste to boil water to run a turbine[g5.0.2]. It is a good option since it is not overly expensive to build and uses up waste that we would have to pay to get rid of. It does however require more work in running. Maintenance is slightly more intensive than natural gas and it is a relatively new technology, but it has been used with great success in Great Britain and other European countries. Finally solar is a very expensive option. It produces relatively little and has an very large capital cost. Also it is not reliable since it requires sun and seems to be more of a science project than a good source of energy.

All three of these sources can be used in a combined heat and power system which allows the exhaust steam/hot water from the electric turbines to be used to heat homes. In most cases this converts a 25% efficient system into a 40-60% efficient system. The heat to electricity ratio can carry the heating load well, and any additional heating requirements can be met by simply over producing electricity and selling to the grid or skipping the turbine and using the boiler to directly heat the system.

5.2 Modeling: In order to produce a working model of the requirements of the Old Ottawa East community, there are several factors to consider. First, we do not have electricity data for the site, so a prediction must be made. To make the best prediction with the information I was given, I took IESO‟s[ref5.0.1] data for electricity usage in Ontario for the last 10 years and used a series of periodic sum of squares fitting. From this I had a function of time for electricity usage for all of Ontario. Next, I took the building specs given and found the electricity usage based on NRCAN‟s[ref5.0.2] usage data. From the electricity usage I factored out heating and cooling loads using NRCAN‟s heating and cooling data. With the site yearly usage, I scaled my Ontario electricity usage function to the site size. Using this new function of site electricity usage over time, I could find the peak, average and base loads. These values are very important in choosing the energy sources and production sizes later in this section.

Heating and cooling usage can be hand waved as lots of cooling in the summer and a similar or greater amount of heating in the winter. For a more accurate prediction, I took degree heating[g5.0.1] and cooling days from Environment Canada[ref5.0.3] for the last 10 years and fitted a gaussian curve[g5.0.2] to it. Using NRCAN‟s heating and cooling usage per heating/cooling degree, I was able to create a function for the heating and cooling loads on the site.

Choosing a production configuration[g5.0.3] requires several considerations. First, costs of everything from capital/installation to operating and maintenance on a yearly basis or every x amount of hours. To test this, I simply run the configuration through the electricity and heating usage function. Note that heating is only considered with it exceeds the heat to electricity ratio since else it can be considered free. Finally emissions were considered with a weighting of 3:2 (cost:emissions). Computing emissions is as simple as taking the total yearly production multiplied by the average emissions per MW of the energy production configuration.

5.3 Conclusion: Taking everything discussed in modeling and energy production into consideration, I produced several possible configurations. Running tests on configurations of all natural gas, all biomass or a mixture of both resulted in the best result being[a5.0.3] 7x3MW biomass boilers with 2 x 4MW natural gas reciprocal production units for heating. Electricity production is similar, with 6x3MW natural gas and 6x6MW biomass units. Cooling on the other hand can only fulfilled with natural gas. For cooling I would recommend 3x15MW units. These scenarios work well because in electricity and heating biomass boilers can do the bulk of the production and the natural gas can kick in when there is greater demand or in case of unit failure or maintenance.

6.0 Conclusion The OOE project is an opportunity to build a community that is energy efficient and eco-friendly. The objective of this project was to build a sustainable community while preserving the different landmarks around the area and making the least amount of damage to the surrounding communities. After conducting detailed researches about different sectors of this project, the management team determined the most effective energy combination that should be used. Biomass and natural gas will produce the required amount of energy needed by the community for cooling, heating and electricity whenever it is needed. This scenario provides the OOE community with a better energy system that is expandable and can undergo further development to meet future needs.

Appendices Appendix 2.1

2.1.1 Residential loads [2.1.1]

4-Storey MURB

System - Gas Heat & SWH NECB 2011

Lighting (kWh) 62,185

Misc Equipment (kWh) 116,974

Heating (kWh) 167,684

Cooling (kWh) 46,862

Pump (kWh) 11,045

Fans (kWh) 169,363

Service Water (kWh) 83,564

TOTAL (kWh) 657,677

TOTAL (kWh/m2) 210

Total Floor Area (m2) 3136

2.1.1.1 ((Service water)+(heating power))/(Total Floor Area) = Total Heating loads per year in kWh/m^2 ((167,684kWh)+(83,564kWh))/(3136m^2)= 80kWh/m^2 per year

2.1.1.2 : Commercial Loads [r2.1.1]

STAND ALONE RETAIL System - Gas Heat & SWH NECB 2011

Lighting (kWh) 143,288

Misc Equipment (kWh) 19,650

Heating (kWh) 194,435

Cooling (kWh) 17,086

Fans (kWh) 52,447

Service Water (kWh) 11,310

TOTAL (kWh) 438,216

TOTAL (kWh/m2) 191

Area (m2) 2299

2.1.1.2 ((11,310 kWk)+(194,345kWh))/2299m^2 = 89.5kWh/m^2

2.1.4.1 Residential: (80 kWh/m^2/year)(137,786 m^2) = 11,022,880 kWh /year Commercial: (89.5 kWh/m^2/year)(3570 m^2) = 319,515 kWh /year Total: (11,022,880 kWh) + (319,151 kWh) = total annual loads per year in kWh 2.1.3: Building square footage [r2.1.2]

Appendix 2.2

2.2.1.1 As q=K*A*ΔT Where: K=A transfer constant (1) A=Area q=Heat flow ΔT=Difference in temperature

2.2.1.2 Q=c*m*ΔT Where: m=D*V (2) D=Density of water (1 000 kg/m^3) V=Volume c=specific heat 4.186 kJ/kg° C 11342395KWh/year Q=Required thermal energy

2.2.2.1: Illustration of concept behind heat transfer station [r2.2.3]

Appendix 2.3

2.3.1: Baseboard heater [r2.3.4]

2.3.2 Wall mounted panel heater [r2.3.5]

2.3.1: Conductive Heat Transfer Coefficients [r2.3.6]

Water Copper Air Aluminum k (W/m*K) 0.56 401 0.024 205

2.3.2: Convective Heat Transfer Coefficients [r2.3.7]

Water in copper Forced Air Free Air Aluminum pipe to air h (W/m2*K) 13.1 200 25 25

2.3.3: Radiator fins [r2.3.10]

2.3.4: Piping in a panel heater [r2.3.11]

2.3.5: Summary of Research Results

Total Per Room

Floor Space (m2) 131176 30

Energy usage (kW at peak 5 259.126 1.18 load)

Cost of heating ($/winter at 1 466 000 329 peak load) [Assuming 4 months]

Appendix 3.1

3.1.1 Demonstration of the electron traveling from the negative layer to the positive layer; inducing an electric field and current [1, p.22]

3.1.2: Pricing of Solar Absorption Systems

3.1.3 Flat roof solar mounting systems [r-3.1.3]

3.1.4 Fixed tilt solar racking system [r-3.1.4]

3.1.5 Single-axis solar tracking system [r-3.1.5]

3.1.6: A comparison of the microscopic surface area of the crystals of both the monocrystalline and polycrystalline silicon structures[r-3.1.7]

3.1.7 Sun path for each season [r-3.1.9]

3.1.8 The latitude and longitude of Ottawa [r-3.1.10]

3.1.9 Tilt Calculations

3.1.10 Best angle for each month [r-3.1.31]

3.1.11 Calculation of number of panels

3.1.12: Ottawa‟s daily average solar radiation per metre square for each month of the year [r- 3.1.11]

3.1.13 Application process [r-3.1.13]

3.1.14 Feed-In Tariff Price Schedule [r-3.1.14]

3.1.15 Energy produced by solar cells(annual): 1.17481 GWhr which equals 11174810 KWhr. Energy produced by solar panels per day(average): 1174810/(365 days) = 3218.6575 KWhr The money to be made every day : => Average peak rate * Price of selling solar electricity * Energy produced per day =>1.125*32.9*3218.6575 => 119130.55 cents or $1191.30 CAD per day[Refer to Table t-3.1.2 and Section 3.1.17(iii)]

Cost of Installation : Cost of solar panels + Cost of installation of solar panels => (309 CAD * 3358) + (198 CAD(approx)*3358) (Refer to sections 3.1.10 and 3.1.14) => 1,705,000 CAD(approx.) [r-3.1.29] Time taken to recover the cost of solar PV system = 1,705,000/ (1191.30*365) = 4 years (approx) Buying Electricity from the grid:

Energy required from the grid for the total DES(annual) : 29616930 KWhr Energy required from the grid for the total DES(per day): 29616930/365 = 81142.3 KWhr Cost of buying electricity : 9cents/KWhr (average) (refer to the diagram below) Cost of buying the electricity required every day(average)= 81142.3*9cents = $7302.80 CAD

[r-3.1.32]

3.1.16 Configuration of net metering [r-3.1.16]

3.1.17 Alternate configuration of net metering [r-3.1.16]

3.1.18 Calculations for battery size and cost

Energy/day/rooftop= (Total Electrical Energy/year * 1 year/365 days)/19 rooftops = 1.17481GWh/365/19 = 169.40303 kWh * 1000 Wh/1 kWh = 169403.03 Wh Minimum Storage Capacity = ((169403.03 Wh * 2 days)/0.8 depth of discharge * 1.59)/600V = 1122.295 Ah Note: 2 days was selected to oversize the battery in order to hold enough charge for an extra day. 1.59 was a tabulated value determined by the lowest ambient temperature of Ottawa[18], [33] Price of Batteries = 19 batteries * $749 = $14231 Total Price = Cost of Installation + Cost of Batteries = $1705000 + $14321 = $1719321 Total Daily Savings = (Amount of Energy Generated Per Year/365 Days in a Year)* Price of Energy = (1174810 kWh/365 days) * $0.124/kWh = $399.11 Payback Time = Total Price / (Total Daily Savings * 365 Days in a Year ) = $1719321 / ($399.11 * 365 days) = 11.8 years

3.1.19 Comparison of Flat Plate Collectors and Evacuated Tube Collectors at Different Angles [r3.1.22]

3.1.20 Flat Plate Collectors

3.1.21 Calculating Return on Flat Plate Collectors

3.1.22 Evacuated Tube Collector [r3.1.24]

3.1.23 Calculating Return on Evacuated Tube Collectors

3.1.24 Passive Thermosiphon System [r3.1.27]

3.1.25 [r3.1.26]

Appendix 3.2 3.2.1 Boiler Configurations which still allow 15MW output In this infographic, Boilers 1,2, and 3 are small, and 4 is large, as defined in section 3.2.3.3

:

:

:

:

3.2.2 Specific Boilers Currently in Production

Boiler Name Power Range (MW) Quantity Boiler number(s) in above Infographic

Vitomax 100-LW 0.65-6.0(small) 3 1-3

Vitomax 200-WS 1.75-11.63(large) 1 4

Ref: The Viessman Group. “Oil/gas boilers for medium and high output” Internet: http://www.viessmann.com/com/content/dam/internet- global/pdf_documents/com/brochures_englisch/pr- oil_gas_boilers_for_medium_and_high_output.pdf, Nov. 2012 [October 2, 2013]

3.2.3 Graph #1: Annual District Heating Load Duration Curve [r3.2.5]

3.2.4 Costs and energy densities, relative to dried wood chips [r3.2.14, r-3.2.15]

Fuel Cost per unit energy Energy Density Max. Daily Volume

Switchgrass pellets 3.47 1.28 0.78

Hardwood pellets 3.29 1.35 0.74

Dried wood chips 1 (20.59 $/MWh) 1 (2.24 MWh/m3) 1 (80.5 m3)

Green wood chips 1.002 0.75 1.33

Cordwood 2.34 0.70 1.90

3.2.5 Fossil Fuel Emissions [1, modified] Fossil Fuel Emission Levels (kg per MWh of energy Input)

Pollutant Natural Gas Oil Coal

Carbon Dioxide 181.083405 253.826311 321.926053

Carbon Monoxide 6.19089E-02 5.10748E-02 0.321926

Nitrogen Oxides 0.14239 0.693379 0.707309

Sulfur Oxide 1.54772E-03 1.736543 4.010146

Particulates 1.0834E-02 0.130009 4.246948

Mercury 0 1.0834E-05 2.47635E-05

Appendix 3.3

3.3.1 depicting the refrigeration cycle that GSHP's use to transfer heat from the ground to the house[3.3.2.3]

3.3.2 Depicting horizontal and vertical GSHP's. [3.3.2.8]

3.3.4 Comparing costs of a natural gas furnace to a GSHP [4]

Appendix 3.4 3.4.1.1 Cooling degree days [r – 3.4.1.3]

3.4.1.2 Amount of cooling needed

Building Cooling/uni Number of Residential Commercia Extra Total Code t Units Cooling l Cooling Cooling Cooling (tons) (tons) (tons) (hallways) (tons) (tons)

A 1.5 70 105 18.8 13.7 137.5

B1 2.5 14 35 0 0 35

B2 2.5 14 35 0 0 35

C1 1.5 30 45 0 7.5 52.5

C2 1.5 44 66 0 10.4 76.4

C3 1.5 44 66 0 10.4 76.4

D1 1.5 63 94.5 18.8 11.8 125.1 E1 1.5 110 165 0 22.8 187.8

F1 1.5 91 136.5 0 18.7 155.2

F2 1.5 95 142.5 0 19 161.5

G1 1.5 105 157.5 0 21.3 178.8

G2 1.5 102 153 0 20.4 173.4

H1 – H5 1.75 181 316.75 0 45.2 362

H6 1.75 27 47.25 0 6.7 53.95

J1 3.8 6 22.8 0 0 22.8

J2 3.8 6 22.8 0 0 22.8

J3 3.8 6 22.8 0 0 22.8

J4 3.8 6 22.8 0 0 22.8

K 1 175 175 0 41.4 216.4

L 1 65 65 0 15.5 80.5

D2 1.5 63 94.5 18.8 11.4 124.7

E2 1.5 110 165 0 22.3 187.3

TOTAL COOLING FOR ENTIRE AREA (TONS): 2294 3.4.1.3 Building sizes [r – 3.4.1.1]

3.4.1.4 Building layout [r – 3.4.1.1]

3.4.1.5 Amount of cooling per m2 [r – 3.4.1.2] (converted)

Area To Be Cooled (m2) Capacity Needed (tons) 9 up to 14 0.4

14 up to 23 0.5

23 up to 28 0.6

28 up to 32.5 0.66

32.5 up to 37 0.75

37 up to 42 0.8

42 up to 51 1

51 up to 65 1.2

65 up to 93 1.5

93 up to 111.6 1.75

111.6 up to 130.2 1.9

130.2 up to 139.5 2

139.5 up to 186 2.5

186 up to 232.5 2.8

3.4.1.6 Daily temperature [r – 3.4.1.7]

3.4.1.7 Calculations [r – 3.4.1.8] 1.58 ton x (12 000 Btu/ton)/ (13.66 Btu/watt) x (1 kilowatt/1000 watt) x 1 hour = 1.39 kwh

3.4.3 [A- 3.4.3.1] Density of water with respect to Temperature [R- 3.4.3.6]

3.4.1: Vapor-Compression Cycle [r – 3.2.2.1]

3.4.2: Running Costs[r – 3.2.2.4]

3.4.3 Annual Costs[r – 3.2.2.4]

3.4.4 Reciprocating Compressor[r – 3.2.2.8]

3.4.5 Centrifugal Compressor[r – 3.2.2.8]

3.4.6 Screw compressor[r – 3.2.2.8]

3.4.7 Scroll compressor[r – 3.2.2.8]

3.4.8: Compressor efficiency[r – 3.2.2.12]

Compressor Type Compressor kW/Ton Sizes (Tons)

Reciprocating 1.0 - 1.3 3 - 450

Centrifugal 0.7 - 0.9 80 - 1300 Screw 0.7 - 1.2 45 - 380

Scroll up to 1.2 up to 60

3.4.9 Schematic of cold water moving through a district cooling center

3.4.10: Heat conduction diagram [3]

3.4.11: Common areas to be insulated [4]

Area Percentage of heat Type of insulation Recommended loss (%) that could be used minimum insulation value (RSI)

Ceilings 10% Spray Foam 8.8

Walls 12% - 14% Board Foam 4.2

Floor 15% - 18% Board Foam 5.5

Windows 18% - 20% Double or triple -- pane windows

*Infiltration4 35% Foam or Draught- -- proofing

*Infiltration is not a category in specific you can have infiltration within walls windows and even floor it occurs when you have air leakage where cold and hot air can pass through which would cause heat loss

4

3.4.12: Areas of a building that can be insulated [5]

3.4.13: Properties of Open Cell and Closed cell foam. [7]

Parameter Open Cell Closed cell

RSI -value Good (RSI = 0.62) Great (RSI = 1+)

Density Low, 8 kg/m3 Medium, 32 kg/m3

PERM rating High (bad) Low (good)

Air Barrier Yes-at full wall thickness Yes Absorbs Water Yes No

Misc Good sound barrier Great racking/shear strength

3.4.14: Double pane glass [8]

Appendix 4.0 4.0.1 Team 1 Project Proposal: See CULearn

Appendix 4.1

4.1.1: Evapco‟s „ice on coils‟ [4.1.2].

4.1.2: Advantages and disadvantages of chilled water/ice storage [4.1.1].

TYPES OF ADVANTAGES DISADVANTAGES STORAGE

CHILLED The chilled water from chillers A storage system that uses WATER can directly be put into the chilled water will require 5 STORAGE storage tank, without installing times more capacity than an additional equipment. ice storage system.

Water in the storage tank can Less thermal energy per be used for fire protection. kilogram than ice storage, since chilled water is used instead. Chilled water systems becomes cheaper than ice storage systems in applications that require more than 10,000 Needs a lot of work force for ton-hours of cooling. maintenance. This increases the maintenance costs.

ICE Even though it is more Requires more additional STORAGE complex and needs additional equipment as it has to equipment, compared to a convert chilled water system, the overall system still takes up The chilled water supplied less space. This is mainly due by the chillers into ice to be to the greater amount of heat stored in the tanks. This the ice absorbs when it makes it more complex. changes its state, that is, solid to liquid compared to water. This is know as latent heat of fusion.

It consumes more energy It provides colder air to the than a chilled water system building and also provides

greater efficiency to the chiller due the greater latent heat of fusion of ice.

4.1.3: Storage temperature, return temperature and volume of ice/chilled water storage [4.1.1].

Storage Volume Storage Return medium (feet3/ ton-hour) temperature temperature (degrees C) (degrees C)

Chilled 10.7-21 3.89 – 6.67 5 – 7.78 water

Ice 2.4-3.3 32 34-36

4.1.4: Advantages and disadvantages of steel/concrete storage tanks [4.1.1]. TANK MATERIAL ADVANTAGES DISADVANTAGES

STEEL TANKS This tank is typically made More expensive than from galvanized sheet concrete tanks. steel and can be used to hold several millions of gallons.

Can withstand higher pressure of water/ice and more sturdy.

CONCRETE These tanks can be pre- TANKS cast and are more economical in sizes of one million gallons or more, than a steel tank.

Cast-in-place tanks can often be integrated with However, these Cast-in- building foundations to place tanks are less sturdy reduce costs. than their steel tank counterparts.

4.1.5: 21 chillers will be connected with 1 central cold storage unit [4.1.5].

4.1.6: Full storage [4.1.4]

4.1.7: Partial Storage – load leveling [4.1.4].

4.1.8: Partial storage – demand limiting [4.1.4]

4.1.9: Thermal storage tank system [4.1.Aly Rasmy]

4.1.10: Heat energy demand and production relationship for spring [4.1.Aly Rasmy]

4.1.11: Heat energy demand and production relationship for winter [4.1.Aly Rasmy]

4.1.12: Heat energy demand and production relationship for summer [4.1.Aly Rasmy]

4.1.13 Eq. 1 M= Q / (C x DeltaT) [4.1.15] M = mass of water (grams (g)). Q = quantity of heat (joules (J)). This is the amount of heat that can usefully be stored to meet off-peak needs. 79200000000 J (provided by team 1). DeltaT = change in temperature (ºC). Hot water will be stored at the system supply temperature – say 95C and will have water returned at about 60C with a storage temperature difference of 35°C. C = specific heat capacity (J/g.ºC). It is Constant number for water 4.186 J/(g. °C).

Using the mass calculated in Equation 1, we used Equation 2 to calculate the volume of the tank.

4.1.14 Eq. 2 Volume= Mass/Density [4.1.16] Volume= volume in m3. Mass = mass in grams. Calculated above with Equation 1 Density= Density of water at 90°C in (g/m^3). It is a Constant number for water 965 000 (g/m^3) [4.1.11].

4.1.15 Eq. 3 Solar heat potentially wasted = (1174.81 MWhrs/year) x 0.7 [4.1.17]

4.1.16 Eq. 4 Cost of storage tank = price of tank per m3 x volume of the tank [4.1.17]

4.1.17 Eq.5 Cost of energy saved= Cost of storage tank ÷ Amount of energy saved [4.1.17]

4.1.18: Thermal Mass Storage [4.1.KR]

4.1.19 Eq. 6 ρ = M [4.1.28] V Where ρ is density, M is the mass and V is the volume.

4.l.20: Heat Capacity, Density and Heat per Volume in Common Materials [4.1.22]

Heat Heat per Density Material Capacity volume (kg/m3 ) (J/gK) (MJ/m3K)

Water 4.18 1000 4.18

Gypsum 1.09 1602 1.746

Air 1.0035 1.204 0.0012

Concrete 0.88 2371 2.086

Brick 0.84 2301 2.018

Limestone 0.84 2611 2.193

Basalt 0.84 3011 2.529

Sand (dry) 0.835 1602 1.337

Soil 0.80 1522 1.217

Granite 0.79 2691 2.125

Rock Pebbles 0.88 1600 1410

4.1.21: General Parameters of a packed-bed storage system [4.1.32]

Column diameter 1.2 m

Collection time 8 hours

Column Length 13.7 m

Particle Diameter 0.08 m Mass flowrate 0.95 kg/sec

4.1.22: Charging mode of Packed-bed storage [4.1.23]

Figure 4.1.23: Discharging mode of Packed-bed storage [4.1.23]

4.1.24: Auxiliary mode of Packed-bed storage [4.1.23]

4.1.25: Diagram of a Trombe Wall [4.1.24]

4.1.26: General Parameters of a Trombe wall. [4.1.25]

Wall Height 2.47 m Wall Width 1.34 m

Concrete wall thickness 0.15 m

Distance between the surface of the glazing 0.03 m wall and massive wall

Surface of concrete wall vent 0.09m2

Vertical distance between two vents 2.15 m

Temperature of specified area 19° C

Appendix 4.2

4.2.1: ATES warm and cold stores [4.2.3, modified by Kailey De Silva]

4.2.2: Aquifer Thermal Energy Storage System providing cooling [4.2.1]

4.2.3: Aquifer Thermal Energy Storage System providing Heating [4.2.1]

4.2.4: Heat Exchanger [4.2.5, modified by Kailey De Silva]

4.2.5: Heat Pump [4.2.6, modified by Kailey De Silva]

4.2.6: Side View of a Borehole [4.2.11]

4.2.7: Aerial view of Borehole Field demonstrating the movement of heated carrier fluid through the piping system [4.2.12]

4.2.8: Borehole Thermal Energy Storage in the Summer [4.2.15]

4.2.9: Borehole Thermal Energy Storage in the Winter [4.2.16]

4.2.1: Specific Heat Capacities and Temperature Range for Storage Mediums

Material Specific Heat Capacity (J/kg °C) Temperature Range (°C) [4.2.17] [4.2.17]

Water 4190 0-100

Molten salt 1560 142-540

(50% KNO3 - 40% NaNO2 - 7% NaNO3 (by weight))

4.2.10: Old Ottawa East Institutional Lands Ground Type [4.2.8, Graph by Samantha Champagne]

4.2.11: Hydrologic Soil Type in Old Ottawa East Institutional Lands [4.2.8, Graph by Samantha Champagne]

4.2.2: Thermal Conductivity of Ground Materials

Material Thermal Conductivity W/ (m ● K) [4.2.17]

Ideal Conditions Rock (solid) 2.00 -7 .00

Sand (moist) 0.25 – 2.00

Actual Conditions Clay (dry to moist) 0.15 – 1.80

Sand (moist) 0.25 – 2.00

4.2.12: Oxygen Content to Temperature graph [4.2.25]

4.2.13: Graph explaining the division of energy production in Ontario (2012) [4.2.27]

4.2.14: Graph depicting the division of Energy production sources in Canada [4.2.28]

4.2.3: Operational temperature limits for aquifer and borehole based systems

System Minimum (ºC) Maximum (ºC)

Aquifer 4 [4.2.34] 90 [4.2.34]

Borehol 10 [4.2.35] 90 [4.2.35] e

4.2.15: A diagram showing how insulation works. Only some of the heat (shown as the arrow rays) escapes the wall, with insulation in between each side of the wall [4.2.39].

4.2.20

Where „E‟ is the energy required, „m‟ is the mass, „C‟ is the heat capacity of water, „V‟ is the volume, „p‟ is the density of water, and „ΔT‟ is the change in temperature. All values can be seen in the equation. Mass is density multiplied by volume, and the volume is solved.

Appendix 5.0 5.0.1 Team 1 Project Proposal: See CULearn or Prof Lisa Meyer, Carleton University, Ottawa, ON

5.0.2

5.0.3 Summary - Next Page Detail - Pages following summary

modelingResultsDetail.pdf

Glossaries 3.1 Glossary

3.1.1 District Energy District energy systems (DES) centralize the production of heating or System (DES) cooling for a neighbourhood or community [r-3.1.35].

3.1.2 Solar Energy Converting the sun's energy into heat and electricity [r-3.1.40].

3.1.3 Photovoltaic (PV) Solar energy systems that create energy from the direct conversion of solar radiation to electricity [r-3.1.40].

3.1.4 Solar Radiation Sunlight.

3.1.5 Mechanical A change in property of a machine or part of a machine that makes it Failure not able to perform its intended function.[ r-3.1.38]

3.1.6 Power Rating The amount of power a device is said to be able to generate.

3.1.7 Feed-In-Tariff A policy mechanism designed to accelerate investment in renewable (FIT) energy technologies. It achieves this by offering lonterm contracts to renewable energy producers, typically based on the cost of generation of each technology. [r-3.1.37]

3.1.8 Direct Current The type of electrical current that most electronics require; inefficient (DC) for travelling distances (see AC).

3.1.9 Alternating The type of electrical current used to travel across electrical wires; Current (AC) the current supplied to your house.

3.1.10 Ontario Power The Ontario Power Authority (OPA) is an independent, non-profit Authority (OPA) corporation established through the Electricity Restructuring Act, 2004 (Bill 100). Licensed by the Ontario Energy Board, it reports to the Ontario legislature through Ontario's Ministry of Energy. [r- 3.1.39]

3.1.11 Distribution In the distribution availability test, applications will be assessed in Availability Test sequential order based on the established priority ranking [r-3.1.34] (DAT)

3.1.12 Transmission The transmission availability test will be performed by the OPA to Availability Test determine if there is connection availability on the transmission (TAT) system to connect your renewable energy project. [r-3.1.41]

3.1.13 Capacitors An electrical element used in circuits that stores charge into an electric field between two conductive plates.

3.1.14 Inductors An electrical element consisting of a conductive coil which stores charge into the magnetic field found inside the coil. 3.1.15 Electrolysis The act of using electricity to break down water into hydrogen and oxygen gas and storing it to be burned.

3.1.16 Depth of The percentage of battery capacity a battery is said to be able to Discharge discharge to without losing its overall capacity.

3.1.17 Sulfation The chemical process of large lead sulfate crystals being created inside the battery; creates an obstruction to an essential part of the battery required for charging [r-3.1.1, p.67].

3.1.18 Incident Angles The angle at which the sunlight hits the solar collectors.

3.1.19 Ambient Air The air around the outside of the solar thermal collector.

3.1.20 Active Indirect A system that moves the heated water in solar thermal collectors to Systems the hot water storage tanks.

3.2 Glossary Cordwood: wood that has been cut into uniform lengths, as commonly used for firewood. Energy Density: the amount of energy contained in a certain volume of a material. Green wood chips: Wood chips with a high moisture content, above 30-40%. Non continuous duration: occurring in scattered and irregular or unpredictable instances, all the instances will add up to 2240 hours. [r-3-2-21] Wood pellets: A form of wood fuel made from compacted sawdust.

3.4 Glossary 3.4.1.1 Ton of cooling A ton of cooling is the amount of energy released from one ton of ice melting in one day [8].

3.4.1.2 Cooling A cooling degree day is the number of degrees that the average Degree Day temperature for a day is over 10o C [4].

3.4.1.3 SEER A rating for the efficiency of an air conditioner. It is the total cooling output for a year over the total energy input for a year [8].

3.4.2 Glossary Radiator: Heat exchanger, used to cool or heat a liquid[1]. Expansion Valve: Valve used to control the pressure at which a liquid is transferred[1]. MMbtu: One million btu. ton-hr/year: Amount of tons of cooling used every hour, during the course of a year.

3.4.3 Glossary Heat exchanger: A device that is used to transfer thermal energy (heat) from one medium to another [R- 3.4.3.5]. Coefficient of Performance (COP): Is a ratio between the amount of the work done by the system over the amount of energy put into the system [R- 3.4.3.4]. 3.4.4 Glossary Conduction: Heat can be transferred directly from one part of an object to another part

Convection: The movement of air or a fluid such as water can transfer heat. In an uninsulated wall space, for instance, air picks up heat from the warm side of the wall and then circulates to the cold wall, where it loses the heat. The mixing of warm and cold air also transfers some heat. Cold convection currents are often misinterpreted as air leaks around windows.

Radiation: Any object will radiate heat in the same way as the sun or a fire does. When standing in front of a cold window, you radiate heat to the window and so you feel cold, even though the room temperature may be high.

RSI is matric unit used to measure the effectiveness of insulation

4.0 Glossary

4.0.1 Payback Period: Period of time required to recoup the funds expended in an investment.

4.0.2 BTES: Borehole Thermal Energy Storage system.

4.0.3 ATES: Aquifer Thermal Energy Storage system.

4.0.1 Base Load: Minimum amount of power that must be made available.

4.1 Glossary 4.1.2.2 Conservation of Energy cannot be created nor destroyed, it changes from Energy one form to the other [7].

4.1.2.2 Convection The circulation of liquid or gas due to particle density. It states that hot liquid/gas tends to rise and cold liquid/gas sinks [7].

4.1.1.8 Cooling load Cooling load is the amount of energy needed for cooling demand/Cooling load during a certain time period. [2]

4.1.1.5 Cooling-ton A cooling-ton [g - 4.1.1.5] or simply ton, is defined as the energy needed to melt 1 ton of ice at 0o C, in a day (24hrs) [3]. 1 ton = 12,000 Btu/hr or 3.517 kW

4.1.3.2 Damper Device that controls direction of the air (air blower) [23]

4.1.3.2 Forced Convection The air is forced to flow in a tube by external means, such as a fan [31]

4.1.3.2 Natural Convection Refers to the collective movement of gases, in this case air, through buoyancy (exchange of mass, energy and momentum between systems) [31]

4.1.2.2 Radiation The transport of energy inform of electromagnetic waves without touching the hot object [7].

4.2 Glossary 4.2.1.0.1 Payback Period: Period of time required to recoup the funds expended in an investment. 4.2.1.0.2 BTES: Borehole Thermal Energy Storage system. 4.2.1.0.3 ATES: Aquifer Thermal Energy Storage system. 4.2.2.0.1 Base Load: Minimum amount of power that must be made available.

Aquifer: An underground layer of permeable rock that allows for groundwater to pass through it [44]

Aquifer Thermal Energy Storage: heat storage that uses natural aquifers, bodies of water, in the ground to store heat energy for later use. It pumps heat into the ground that is then transferred to the water, later when the energy is needed the heat is extracted from the water and pumped back out of the ground [45]

Borehole: A borehole is essentially a well that is drilled deep into the ground and which is inserted with a long plastic pipe with a rounded bottom and then filled with highly thermal conductive grouting [46]

Borehole Thermal Energy Storage: Large underground structures that consist of many groupings of boreholes. Water is heated and then cycled through a field of boreholes, which systematically transfer the heat from the water into the surrounding soil and rock to be stored for later use [46] 5.0 Glossary

5.0.1 system modeling A math or logic that defines the way a group of units work together.

5.0.2 energy production Methods for generating an energy resource (ie. heating, electricity options or cooling)

5.0.1 centralized A method of generating energy that involves all or most of the energy source production being done in one location

5.0.2 turbine A large fan type implement that harnesses fast moving air or combustible materials to produce electricity.

5.0.1 Degree heating The number of degrees over the course of a day below 10C (where days you would need to use heating)

5.0.2 gaussian curve A curve in the shape of a rounded off mountain. http://hyperphysics.phy-astr.gsu.edu/hbase/math/immath/gauds.gif

5.0.3 production A unique set of energy producing units that work together to configuration produce energy.

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References 4.0 4.0.1 Borehole Field in the The Drake Landing Solar Community, [Online] 2013 http://www.hme.ca/presentations/Drake_Landing_Solar_Community-- AAPT.pdf (Accessed 1 December 2013)

4.0.2 Borehole Thermal Energy Storage (BTES), [Online] 2013 http://www.dlsc.ca/borehole.htm (Accessed 1 December 2013)

4.0.1 Michael Wiggin, Short Term Energy Storage Tanks, Carleton University, Ottawa (November 27 2013)

[Online] 2013 https://culearn.carleton.ca/moodle/mod/forum/discuss.php?d=52783#p122866 (Accessed 4 December 2013)

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4.2.2.0.1 Borehole Field in the The Drake Landing Solar Community, [Online] 2013 http://www.hme.ca/presentations/Drake_Landing_Solar_Community-- AAPT.pdf (Accessed 1 December 2013)

4.2.2.0.2 Borehole Thermal Energy Storage (BTES), [Online] 2013 http://www.dlsc.ca/borehole.htm (Accessed 1 December 2013)

4.2.3.0.1 Michael Wiggin, Short Term Energy Storage Tanks, Carleton University, Ottawa (November 27 2013)

4.2.3.0.2 Research notes#4, [Online] 2013 https://culearn.carleton.ca/moodle/mod/forum/discuss.php?d=52783#p122866 (Accessed 4 December 2013)

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