EVALUATION OF ENERGY PERFORMANCE
AND COST OF DIFFERENT
ENERGY SAVING SOLUTIONS
IN RESIDENTIAL BUILDINGS OF CHINA
Yang Xuan
Master of Science Thesis Stockholm 2007
Yang Xuan
EVALUATION OF ENERGY PERFORMANCE AND COST OF DIFFERENT ENERGY SAVING SOLUTIONS IN RESIDENTIAL BUILDINGS OF CHINA
Supervisor and Examiner: Lennart Nilson, Industrial Ecology, KTH
Master of Science Thesis
STOCKHOLM 2007
PRESENTED AT INDUSTRIAL ECOLOGY ROYAL INSTITUTE OF TECHNOLOGY
TRITA-IM 2007:29 ISSN 1402-7615
Industrial Ecology, Royal Institute of Technology www.ima.kth.se Abstract
This report reviewed Chinese building energy and related codes, directives and guidelines and compared them with Swedish ones. It also provides general information on residential buildings in China (area, height, layout, etc) and describes building envelope insulation status and market there (window, exterior walls and roof) and energy related characteristics (heating, heating fee system, cooling and ventilation).
This report is targeted towards governmental organizations in Wuhai city in Inner Mongolia of China since this thesis is project (Sino-Swe project) based research and Wuhai city is the place where the project is being carried out. A one week trip to Wuhai city was done during the research time and information concerning aspects such as market, energy saving status and residents’ attitudes were collected through interviews, organized meetings and on-site investigation.
Data collected from national level and Wuhai city are combined to support simulation of energy performance of a model building in Wuhai. Two tools are employed to calculate energy consumption. One is Dest, developed by Institute of Building Environment and Building Services, Tsinghua University, Beijing, China and has been used in various prestige large structures such as State Grand Theatre. The second one is Standardized Method, proposed by Heating, ventilation and air conditioning design code. It is a traditional and simple energy calculation method and can be realized by Excel. Nowadays, instead of directly using it, its calculation concepts and steps are integrated into different commercial calculation softwares but in a more complex way.
Different envelope types, heating methods, ventilation systems are evaluated and building energy consumption for heating and corresponding initial investment and operation cost are calculated. Then life cycle cost methodology is applied to compare different alternatives and those alternatives, according to their payback time, are located into different categories. From the calculation the following figure is obtained and suggestions are made.
Heat recovery ventilator Heat pump Thermal valves Triple glazing Mineral wool insulation 100 EPS wall insulation, 150 EPS roof insulation,
5 year 10 year
Payback time categories of products
I
Acknowledgements
The end of my thesis I would like to thank all those people who made this thesis possible and an enjoyable experience for me.
First of all I wish to express my sincere gratitude to my supervisor Mrs Anna Jarnehammar from Swedish Environmental Research Institute (IVL), for allowing me to work with IVL in their special Sino-Swe project, guiding me through the project from the beginning until the end and helping me whenever I was in need.
Many thanks are due to my supervisor Lennart Nilson from KTH for introducing me to IVL and providing me many advices on my thesis work.
I am very grateful to the members of IVL for their support and suggestions on my thesis work, especially to Iverfeldt Åke, Kildsgaard Ivana, Huang Bokai, Erlandsson Martin, Lindfors Lars- Gunnar, Lundberg Hans.
I also appreciate all the assistances and information provided to me by a number of Chinese contacts working in different sectors.
Last but least, I acknowledge the financial support given to me by IVL for completion of this thesis.
II III Terminologies
Infiltration: the unintentional and uncontrolled flow of air into/out of a building through leaks in the building envelope caused by pressures induced by weather and ventilation equipment operation.
Ventilation: intentional and, ideally, controlled flow air into/out of building via either mechanical or natural ventilation system.
COP: the abbreviation of the coefficient of performance. The COP of a heat pump is the ratio of the output heat to the supplied work or COP=Q/W, where Q is the useful heat supplied by heat pump and W is the energy consumed by the heat pump.
U value: thermal conductivity. It is defined as the quantity of heat, Q, transmitted in time t through a thickness L, in a direction normal to a surface of area A, due to a temperature difference T, under steady state conditions and when the heat transfer is dependent only on the temperature gradient. the calculation formula seen as below:
R: The R-value is a measure of thermal resistance. R-values can be calculated from thermal conductivity, U, and the thickness of the material, t: R = t/U
EPS insulation: expanded Polystyrene insulation
XPS insulation: extruded polystyrene foam insulation yuan: Chinese currency unit. 100 SEK approximately equals to 108 yuan
IV V Table of Contents
Abstract ...... I Acknowledgements ...... II Terminologies...... IV Table of Contents...... VI 1 Introduction...... 1 1.1 Map ...... 1 1.2 Background ...... 1 1.3 Purpose and objectives...... 2 1.4 Scope and Limitations ...... 2 1.5 Frame of reference...... 2 2. Methodology...... 3 2.1 Literature review...... 3 2.2 On-site survey...... 3 2.3 Calculation & Simulation ...... 3 2.3.1 Life cycle cost ...... 3 2.3.2 Energy calculation tools ...... 5 2.3.2.1 DeST...... 5 2.3.2.2 Standardized Method...... 5 3 Regulations description: ...... 7 3.1 Overview...... 7 3.2 Comparison between Thermal standards...... 8 3.2.1 Indoor environment...... 8 3.2.2 Thermal insulation...... 8 3.2.3 Heating, air-conditioning and ventilation...... 10 4 Residential buildings in China ...... 11 4.1 General Description ...... 11 4.2 Insulation ...... 12 4.2.1 Window...... 12 4.2.2 Exterior walls ...... 13 4.2.3 Roof...... 14 4.3 Energy related characteristics ...... 15 4.3.1 Heating ...... 15 4.3.2 Heating fee system ...... 16 4.3.3 Cooling& Ventilation ...... 16 4.4 Conclusion...... 18 5. Wuhai Status...... 19 5.1 Market description...... 19 5.2 Current Situation...... 19 5.3 Development...... 20 5.4 Residents’ attitudes...... 20 5.5 Conclusion...... 21 6 Calculation Strategy...... 23 7 Simulation...... 25 7.1 Building description...... 25 7.2 Climate condition...... 25 7.3 Heating method ...... 26 7.4 Envelope type ...... 28 7.5 Thermostatic radiator valves ...... 30 7.6 Heat Recovery Ventilation System ...... 30 7.7 Heating fee system ...... 31 7.7 Discount& inflation rate ...... 32 8 Calculation...... 33 8.1 Basic settings...... 33 8.2 NPV calculation ...... 36 8.3 Sensitivity analysis...... 38 9 Conclusions and suggestions...... 39 Appendix 1:...... 40
VI Calculation steps of standardized method ...... 41 Appendix 2...... 42 Loan interest rate...... 42 Reference ...... 43 Presentation Document …………………………………………………………………………… 46
VII Residential buildings energy performance of China
1 Introduction
1.1 Map
Figure 1 Map of China and Wuhai (Source: Economist)
1.2 Background
An energy saving trend can be easily observed in the construction sector in China. Since 2005, the sector takes up more than 30% of total energy use all over the nation. 1
Not only are existing regulations paid more attention to, but also new ones are published or adjustments are made on the old ones in order to fit for the new situation. As to technical part, some outdated methods and energy wasting materials are forbidden while new alternatives are introduced and encouraged to use during the construction process. According to the announcement by Construction Ministry of China, in the next five years, the new buildings should save 50% of energy compared with the current ones. 2
As to energy saving issue, the western China should be paid great attention to because of its cold climate and rapid construction rate. The development campaign of the western regions has greatly promoted the economic situation of those less developed areas. Efforts have been mainly put to increase GDP; however, the environment related issues are not being paid the same attention.
Wuhai is a good case to study since its development model is a typical one followed by many cities in western China. Wuhai is located in southwest of Inner Mongolia Autonomous region, with 1754 square kilometres and 450,000 population, governing three administrative districts of Haibowan, Wuda and Hainan. Built on the exploitation of natural resources, it is a typical newly emerging industrial city in North West China.
In recent years, Wuhai has been developing very fast and the population is expected to increase from 450,000 in 2006 to 530,000 in 2008 and to 700,000 in 2020. The good economic performance and population growth make real estate development rocket into sky. The construction work can be seen everywhere in Wuhai and according to 11th 5 years plan (2006- 2010), 60,000 new apartments will be provided and 1.7 million m2 existing building area or 30,000 apartments in Wuhai have to be reconstructed to meet the estimated demand. 3 Even if part of them were built with energy efficiency technology, a lot of energy could be saved.
1 Residential buildings energy performance of China
However, whether the goal of energy saving society can be met is still unclear. For the building sector the use of energy saving technology must be stressed even more and the used technology needs to be much better than average building technology.
Technology transfer which is robust, affordable and high performing is a necessary development. All good examples from the building sector needs to be used. Sweden and Inner Mongolia with similar climate conditions could be a fruitful combination and a good choice because of long cooperation relationship. 1.3 Purpose and objectives
The objectives of this study are to:
investigate Chinese regulations and the current status of residential buildings in China.
investigate the current situation of Wuhai.
analyze the roles of government, developer and households (owner) in the decision making process concerning energy saving market in China.
evaluate energy performance and cost of different envelopes and heating methods.
identify barriers of introducing Swedish experiences and give suggestions.
1.4 Scope and limitations The thesis concentrates on 4 factors which impact building energy consumption and cost most; they are building energy regulations, building energy consumption efficiency (insulation quality, energy saving devices), heating methods, heating fee system. The focus is on the current status of China and some Swedish experiences are used as references. To Wuhai, simulation is made to evaluate the energy performance of residential buildings for different envelope types and life cycle cost (LCC) method is used to assess the economic benefits of different building components under the local climate condition.
This report does not include evaluations on software and methods. Cooling need is not included.
1.5 Frame of reference
Wuhai became the focus of this field study since it is the location where the Sustainable City (SUCI) project is being carried out by IVL Swedish Environmental Research Institute (IVL). The initiators are familiar with the region and have an established local contact network. One of the main aims of the proposed “SUCI” project is to establish a sustainable technology and environmental training centre, transfer Swedish experiences and knowledge in sustainable construction and promote the local awareness of sustainable development. Evaluating the energy performance and cost is necessary to pass direct messages to local people. This thesis serves as part of the project. Since Wuhai is representative of other industry cities in western China, the findings and recommendations should also be suitable for other parts of western China.
2 Residential buildings energy performance of China
2. Methodology
2.1 Literature review
Building regulations and standards, residential buildings insulation status of China, and the energy market are carefully investigated. The information and data are mainly from the authoritative up-to-date internet resource and contacts in governmental and research organizations, products manufacture companies, construction companies and real estate development companies.
2.2 On-site survey
(1) Investigation on current building energy saving and heating source situation in Wuhai (2) Collect response from contacts in the government. (3) Collect response from developer in charge of development of Sino-Sweden project area (Binhe new district) (4) Collect possible industry cooperation materials.
The trip in Wuhai was from Nov 12th until 17th, in total 5 days and most of contacts in Wuhai were met.
2.3 Calculation & Simulation
2. 3.1 Life cycle cost
LCC analysis is an economic method for evaluating a project or project alternatives over a designated study period. The method entails computing the LCC for alternative building designs or system specifications having the same purpose and then comparing them to determine which has the lowest LCC over the study period.4
There have already been some researches about how to use LCC to evaluate energy system and building envelope. Arif Ileri’s analyses illustrate the dependency of the life cycle costs on fuel and heating system types, building size and location, inflation and interest rates.5 Afif Hasan provided a systematic approach for optimization of insulation material thickness based on life cycle cost analysis.6 Katsunori Nagano presented a detailed LCC analysis of a heat pump.7
The steps those researches are following are similar to each other and can be a summarized into the categories below4:
Identify objectives, alternatives, and constraints. Establish basic assumptions for the analysis Compile cost data Compute the LCC for each alternative Compare LCCs of each alternative to determine the one with the minimum LCC Make final decision, based on LCC results.
Payback method with compensation for money changing value over time or the net present value method is adopted in those researches. In this report, the net present value accompanied with payback method is chosen here, because normally investors want to know not only how much they can gain in a certain period, but also the payback time for the initial investment.
3 Residential buildings energy performance of China
The net present value method (NPV) uses a discount rate to discount the value of money over a period of time. The discount rate has to be determined and here real discount rate is used, which takes consideration of price inflation. It is defined by Equation 1: 1 i r n 1 (1) n 1 In Where: I=the rate of price inflation. It can be general price inflation rate or rate for electricity, fuel, depending on objectives.
i =the rate of return on the next best available use of funds. Here it is defined as the annual interest an individual will get if he or she has money in the bank.
n =year n. I and i can be different in different years, leading to different r.
Then the net present value of the cost which occurs in the year n can be defined by Equation 2
C NPV n (2) n (1rr12 )(1 )...(1 rn ) Where:
C =cost that occurs in the year n.
If it is assumed that the defined discount rate is constant, Equation (2) can be expressed as Equation (3)
C NPV n (3) n (1rconstan t )
To arrive at the total net present value for one kind of cost, the costs for all years during the life span have to be added together, as in Equation 4. Here, it is assumed that the discount rates are constant. CC C NPV C 12 ... n (4) 0 2 n (1rrconstan t ) (1 cons tan t ) (1 r cons tan t )
Then the following formula can be used to calculate the total life cycle cost during a certain period: LCC L M E S (5) where: L = initial capital cost M =maintenance cost E = energy cost S= scrap value
Then two comparison procedures can be made. The first is to find the least NPV: compare the NPVs of all the alternative methods, then set the order of NPVs and finally choose the one with least NPV. The second one is to subtract the NPV of baseline from NPV of alternative ones and find the time point when NPV reaches zero. The year that time point indicates is the payback time.
During calculation, interest rate, quality of the product and life span are paid attention to. The table 1 shows the main aspects considered in this paper.
4 Residential buildings energy performance of China
District heating Energy source Heat pump Exterior wall Initial cost Envelope Window Roof Thermostatic radiator valves & meter Heat recovery ventilation system Operation cost Energy cost, wages, management fee, etc Heating fee Heating fee system Table 1 Aspects of LCC
2.3.2 Energy calculation tools
Two simulation tools have been used, for the reason that the results are more reassuring if these are proved by different means. The computational program, Dest designed by Tsinghua Univ., is detailed both in modelling and input as well as the hourly calculations and is made for estimation of heating loss and heat design load (kW/m2) during winter period. The other one, which is compiled by Excel, is based on a standardised calculation procedure proposed by Ministry of Construction to predict heat design load of residential buildings. Here the calculation results of heat load will be compared.
With these two models, annual energy requirement in residential buildings is calculated and the main aim for this part is to see the potential in reduction of energy requirements in buildings by choice of different buildings materials and methods.
2. 3.2.1 Dest
Dest is developed by Institute of Building Environment and Building Services, Tsinghua University, Beijing, China. The process of Dest developing started in early of 1990s, and has lasted more than 10 years. It has been widely used in China for various prestige large structures such as State Grand Theatre and the State Swimming Centre8.
The structure of Dest is shown in Fig. 2. Each part of Dest stands for a module with specific function served in specific design stage. The figure of man with wide arrow stands for a manual input by user9.
Figure 2 Dest program structure The program calculates all thermal gains in the form of solar heat, heat given off by people, equipment, lighting, e., as well as the power demands and energy consumption for all components of heating, cooling and ventilation for each zone. Now there are five versions in Dest family and the one used in this report is Dest-h for residential buildings.
2.3.2.2 Standardized Method
5 Residential buildings energy performance of China
Following the steps proposed by Heating, ventilation and air conditioning design code (2003), an excel program has been compiled (refer to excel sheet) and the heat loading during heating period is calculated. Then with the results, the types of pipes and radiators will be defined and cost will be calculated but in this report this part are not presented because changes on envelopes and heating systems don’t lead to big changes of pipes layout.
Only two most important sources for heat loss here are considered for the sake of simplification and reality. Usually these two sources are only ones to be included in the calculation process when engineers do the heating load estimation for the normal residential buildings. They are: Heat loss through the envelope, Heat loss through infiltration. The effects of cold bridge, orientation, solar radiation, wind. ect are taken into account by using correction factors selected according to the code. The calculation steps can refer to Appendix 1.10
6 Residential buildings energy performance of China
3 Regulations description: 3.1 Overview
Compared with Swedish building regulations, the one in China is a quite complicated system, including many different formats and types, from national energy laws, regional codes to department regulations. Many of the regulations and laws in China are administrative rules and regulatory documents, which are issued by the departments under the State Council. As to building energy and related codes, it is the Ministry of Construction of the People’s Republic of China that is responsible for issuing and publication.
The residential energy code (JGJ 26-95) emphasizes on thermal insulation to reduce heating energy, and its trial version (first released in 1986) has been implemented in a few cities in China, including Beijing and Tianjin. Since the residential sector in China is one of the key consumers for energy and many buildings are still using poor thermal insulation and low-efficiency heating method, much of the attention for energy efficiency is put on residential buildings. The present target is to achieve 50% energy savings by 2010 compared with the consumption of typical Chinese residential buildings (“base buildings” referring to table 2)11 designed in 1980–1981. (20% from thermal insulation and 30% from building systems and management).
Component Material K-value Heat loss (%) (w/k.m2) Exterior wall Solid brick(370mm) 1.57 25.6 Exterior window Single glazed 6.4 23.7 Roof Flat hollow concrete 1.26 8.6 Stairwell wall Brick or concrete 1.83 10.8 Interior door Wood 2.91 2.8 floor Reinforced concrete 0.3 2.3 Balcony door Plate steel 6.4 3.0 Infiltration* 23.2 * infiltration: different from mechanical ventilation, infiltration occurs partly owing to the low airtightness quality of windows, doors, ect. Table 2 Base building characteristic Five years later based on the climate differences among regional zones, two specific codes are developed, which are Design Standard for Energy Efficiency of Residential Buildings in Hot Summer and Chilly Winter Zone (JGJ 134-2001) and Design Standards for Energy efficiency of residential Buildings in Hot Summer and Warm Winter Zone(JGJ 75-2003). Then the residential energy code (JGJ 26-95) becomes mainly for cold north regions. Wuhai belongs to cold north regions, thus the residential energy code is used in this report.
Recently, a draft of Design Standard for Energy Efficiency of Residential Buildings has been published by Ministry of Construction for suggestions. This draft is for the whole nation and contains more detailed and stricter energy consumption requirements and more scientifical methods for evaluation of building thermal quality. Possibly it will be put into effect in 2007 and the aim is to reduce the energy consumption by 65% in the future. 12
There are also some other building design codes which might affect energy efficiency. A list of them is given below and they include codes for thermal design and other building service systems13. (See table 3)
Related building codes Date implemented Thermal design code for civil building GB 50176-93 October 1993 Design code for residential buildings. GB50096-1999 June 1999 Heating, ventilation and air conditioning design code GBJ 19-87 August 1988 Lighting design code for civil building. GBJ 133-90 March 1991 Code of electrical design of civil buildings, JGJ/T 16-92 August 1993 Table 3 Related building codes
7 Residential buildings energy performance of China
3.2 Comparison between Thermal standards 3.2.1 Indoor environment
For the consideration of thermal comfort and air quality, the inside design conditions should be fulfilled in China as follows. Winter conditions: bedroom, living room: 16-18eC air exchange rate: 0.5 time /h Summer conditions: bedroom, living room: 26-28 eC air exchange rate: 1.0 time /h
In Sweden, it is required that ventilation for housing should be 0.5 air change / hour + 50% heat recovery of ventilation air. The major reason leading to this difference is that in China the heat recovery system is not common in residential buildings. 14
The recommendations given in the Swedish National Board of Building Regulations (BBR) concerning indoor temperature is that lowest operative temperature in the occupied zone will be 18eC in habitable rooms and surface temperature of the floor in the occupied zone of a room will be not less than 16eC and no more than 27eC. Concerning this aspect, Chinese regulations are similar to Swedish ones. The general practice is to design the buildings in Sweden with an operative temperature of at least 20eC.
3.2.2 Thermal insulation
Compared with U value requirements in Sweden, the situation is far more complicated in China. Currently, the whole nation is divided into five climate regions (see figure 3) and the three codes are used, requiring different envelop thermal qualities for each region. In the near future, when the new Design Standard for Energy Efficiency of Residential Buildings comes into effect, eleven climate regions division may be used instead of five, and for each region separate requirements are made.
Then in one region, the U values set for the specified envelope can also be different. For example, the U values requirements for window depend on the area ratio of window to wall: the bigger the ratio is, the smaller the value. The reason to make such complicated system, explained by Ministry of Construction, is that it is not economic to make warmer zones follow the same standards of cold zones considering the higher cost of better insulation materials and China’s economic situation; that detailed standards are more easily implemented in China than the general ones.
Figure 3 Divisions of climate regions
8 Residential buildings energy performance of China
When we compare the strictest Chinese thermal regulations in the coldest regions with the Swedish ones, the big gap between two countries can be easily found (see table 4).
window Outer wall Outer roof floor slab outer door Similar climate (W/m2.K) 3.2 0.5 0.5 0.5 2.0 strictest(w/m2.k) 1.7 0.33 0.33 0.28 1.5 BBR* U values(w/m2.k) 1.3 0.18 0.13 0.15 1.3 * In Sweden, for buildings with an area below 100 m2 the regulations are based on details instead of a certain average demand. 0.5w/m2.k is the highest U-value in average of all components for the building envelope. Table 4 Comparison between U values
Besides limitations on U values of different components, both countries have also developed their own building regulations which are more oriented to energy demand. The annual energy demand for South Sweden is 110 kWh/m2 (A temp) and for North Sweden 130 kWh/m2 on condition that heated area’s temperature is above 10eC. As to China, specific heating energy demands are given according to areas and most are around 20 w/m2. However, it is difficult to compare figures from these two countries because energy demand given out by Sweden also includes water heating energy consumption while in China, most residential buildings don’t provide hot water and figures only focus on space heating. Further, even with both countries’ figures which include all energy use types, the living habits of people and weather conditions of two countries vary a lot and could lead to big differences in total energy use. For example, Chinese have to or prefer to heat tap water before drinking and Swedes drink cold tap water directly. Thus, compared with energy demand comparison, U value comparison and comparisons in specific fields are preferred.
In 2000, EU was working on establishing the Danish Thermal Building code, identical to the Swedish prior 1978, to be a minimum directive for EU member countries15 16(see table 5). When applying the model building regulation in Denmark in each member state, energy consumptions of most of EU countries except Sweden decreased dramatically (see figure 4). From this we can notice that Swedish codes are even the strictest among EU members. Also it is believed that proposed minimum directive for EU member countries is a very applicable minimum goal for developing countries.15
Components Principles Base insulation of 10 to 20 cm special mineral wool protected Base insulation by ventilated base and humidity barrier. Wall insulation Wall insulation is corresponding to 10 cm mineral wool. Ceiling or roof insulation is corresponding to 20 cm of mineral Ceiling insulation wool. The general recommendation is to use glasses of different thicknesses. This will improve acoustic insulation. As thermal Window standards. insulation the largest benefit from double or tri-glass windows is coming from the higher surface temperature on the inner glass, not necessarily the modest gain in insulation value. Table 5 Proposed minimum directive
Figure 4: Energy consumption in Member States according to their existing national building regulations compared to the Danish model regulation adjusted for climatic differences16
9 Residential buildings energy performance of China
In reality, China is making efforts on implementing its own standards. However, because of improper management and inefficient market mechanism, after ten years of publication of the Residential Energy Code (JGJ 26-95), according to Ministry of Construction, still 95% of existing buildings and more than 80% of newly built buildings don’t fulfill those requirements.
3.2.3 Heating, air-conditioning and ventilation
In China, there is no single regulation covering all the fields of heating, air conditioning and ventilation, neither is there a single regulation covering just one field. It is similar for both Sweden and China while in Sweden, the heating, cooling and ventilation related regulations or recommendations are distributed into different functional chapters of Building Regulations BBR, such as chapters of Mechanical Resistance and Stability, Safety in case of Fire, etc. This makes it quite difficult to compare them one by one. Instead, several Chinese codes and basic information concerning those fields are listed below and can be referred to for further research.
Heating
For central heating, required by the newest national code, temperature control and heat allocation measures should be designed for each family. Heating system and other energy conservation designs should be in compliance with revised version of Thermal design code for civil building GB 50176-93.
Cooling
For Central air conditioning system design, it should be in compliance with Energy conservation design standard on building envelope and air conditioning for tourist hotels (GB 50189-93).
Ventilation
For ventilation, kitchen and bathroom are required to have mechanical ventilation equipment to get rid of exhausted air with bad smell and possible harmful i According to Indoor air quality standards, air exchange rate should guarantee that the minimum amount of fresh air for each person in the room is 30 m3/h.
No mandatory requirements on heat recovery systems can be found; neither can any regulation that includes the concept of heat recovery systems be found.
There are no specific requirements on energy performance of devices and operation units. When separate air adjuster is used for air conditioning and heating, the EER (Energy Efficiency Rating) and performance coefficients of it should be in compliance with related national standards. When central heating and air conditioning are adopted, the performance coefficients of operation units should be in compliance with current national regulations such as Thermal design code for civil building, Design code for residential buildings, Heating, ventilation and air conditioning design code, ect.
10 Residential buildings energy performance of China
4 Residential buildings in China 4.1 General Description
According to the statistics provided by Ministry of Construction, by the end of year 2005, the total area of residential buildings in cities andd towns is 10.77 billion sq m2.17 Also it is estimated that the area of residential buildings will increase by 1 billion per year during the next 15 years and by the end of 2020, 15 billion m2 more dwellings will be built.18
Various forms of residential buildings exist in China. In cities, low rise buildings are rare, at least not as common as in Sweden due to the high density of population. Generally, multi- floor residential building (four to six floors), middle high rise residential building (seven to nine) and High rise residential buildings (10 floors or more) are normal. Due to the rapid economic growth and raise of living standards in recent years, the amount of independent villa buildings has been increasing in the suburb and towns.
There are two types of building layouts which can be seen everywhere in China and are still used independently or with combination. They are slab layout and point layout. The former is mainly for low rise and multi-floor buildings and the latter high rise buildings. Under these two types, six frequently used layouts are listed below (see figure 5)
Figure 5 Layout of residential buildings Each apartment unit is comprised of one or more rooms. Normally, one unit is for one family and the members in the family can include as much as four generations. The family life also varies due to the differences in living habit, culture and natural environment. However, we can say that family life revolves around three centres, which are living room, bedroom and kitchen. There is one phenomenon quite different from Sweden concerning the layout of living room and kitchen. In China, during usage time kitchen is usually an enclosed space only connecting outer environment by ventilation fans while in Sweden, kitchen and living room often share the same environment. This is because the traditional way of Chinese cooking generates much more oil smoke pollution than that of Sweden and the smoke with unpleasant cooking smell could fill the whole living room quickly even with effective ventilation.
The average construction area per unit varies in different parts of China. Usually, for south part the units range from 100 to 120 m2; for north-east part, from 80 to 100 m2; North cold districts, from 70 to 80 m2. Recently, to control the sky rising price of dwellings and reduce energy consumption, a new national regulation on usage area of dwellings is issued. 19It
11 Residential buildings energy performance of China
announces that from June 1, 2006, 70% of units or more of the newly planned residential buildings should have usage area lower than 90 m2/unit, which means construction area would not be more than 110m2/unit. (Normally, the difference between usage area and construction area is about 20m2/unit.). In Sweden there is no limit for the construction area per unit.
For the height, the height of dwellings should not be lower than 2.8 m2. The net height of living room, bedroom should not be lower than 2.4m, kitchen and bathroom not lower than 2.2m and store room not lower than 2m. 4.2 Insulation 4.2.1 Window
Aluminium and PVC are mostly used window frame materials in China. In total, the frames made of these two materials takes approximate 90% of market share. As to aluminium frames, only 20% are thermally broken ones, which are used for insulating glass windows. (See figure 6)
Market share of glasses Aluminium frame market
$OXPLQLXP 3ODVWLF RWKHUV 7KHUPDOO\EURNHQ 1RUPDOIUDPH
Figure 6 Market shares of different windows
According to Chinese National Centre of Quality Supervision and Test of Building, U value of single window with frame of PVC is around 4.7W/ (m2·K) while U value of double glazing with frame of PVC ranges from 2.4 to 2.7. U value of single glazing with metal frame is about 6.4 (W/m2·K) and double glazing 4.1 W/ (m2·K). U value of ordinary heat broke aluminium frame with double glazing is above 3.1W/ (m2·K). Due to high price, Low-E or tri-glazing are not common in the residential buildings. A more detailed list of U values of different types of windows can be seen in table 6. The insulation quality of Swedish brand windows are better, for double glazing, standard U value is 2.2 w/m2.k and triple glazing, 1.3 w/m2.k.
Glazing Area ration of U value Frame materials Air thickness(mm) frame to glazing (w/m2.k) Single _ 20-30% 6.4 Aluminium 12 20-30% 3.9 Double 16 20-30% 3.7 Single _ 30-40% 4.7 PVC 12 30-40% 2.7 Double 16 30-40% 2.6 PVC Low-E _ _ 1.9 Table 6 U values of different windows In 2004, Chinese Ministry of Construction issued a note for window technology saying that double glazing with aluminium or PVC frame should be promoted and the traditional low quality windows be limited or forbidden. Then in 2006, 10 window manufacture companies are recommended by Ministry of Construction and the U values of the windows from these companies can be as low as 1.7 W/m2·K.
Currently, in glass market, transparent glass for single window still takes approximately 80% of the share because it can be hundreds of SEK cheaper than other good quality ones. The amount of insulating glass is increasing very fast, by 40% per year due to increasing demand caused by stricter regulations and inspection. For the single year of 2005 more than 60 million
12 Residential buildings energy performance of China
sq m2 insulating glass were produced and it is predicted that the increasing rate could reach as high as 70% from 2007.20
4.2.2 Exterior walls
The currently built residential buildings usually have an external wall of a composite structure and external insulation. The basic layer can be stones, concrete or bricks and two types of insulation materials are polystyrene board and polystyrene foaming granule. The common way of constructing a composite wall is to attach the insulation material on the outer surface of substrate, in most cases, bricks and put mortar with mesh on it.
Polystyrene board and polystyrene foaming granule can be used for both reconstruction projects and newly buildings. Several corresponding technical codes have been published to regulate the way to use these two types of materials. In 2004, Ministry of Construction issued a note to promote four insulation systems with use of these two materials. (See figure 7)
(1) (2) (3) (4) Figure 7 External wall structures
(1)EPS board with thin mortar 1—bricks 2—adhesive 3—EPS board 4—Glass Fiber Net 5—Thin layer insulation system layer 6—Decorated Coatings 7—Anchors (2)EPS granule insulation 1—bricks 2—Mortar Interface 3—EPS foaming granule 4—anti- system crack mortar layer 5—Glass Fiber mesh 6—Decorated layer (3) Cast-in-place with mesh 1—concrete exterior wall 2—EPS single side steel mesh board 3— insulation system Mortar 4—steel mesh 5—decorated layer 6—#6 steel bar (4) Cast-in-place without mesh 1—concrete exterior wall 2—EPS board 3—Anchors 4—anti-cracking insulation system mortar layer 5—decorated layer Table 7 External wall structure
In the market, thousands of companies are supplying those two types of insulation materials and similar ones, such as XPS. The prices can vary a lot for quality difference. Products from STO (German), DRIVIT (the USA) are sold with higher price and shares in the market are increasing for the higher quality requirement. Some Chinese companies also have their own patents and produce good quality materials but with lower price and also take a good share. In 2006 March, a list of around 20 companies is published by Ministry of Construction and distributed to the governments, construction companies of different levels. The technology and materials supplied by those companies would be considered first as the request of Ministry of Construction. 21
However, even with those available products and compulsory regulations, though a lot of good projects can be seen, the real situation is not that positive. In places where the supervision is not so strict, the cheap materials with low insulation quality are often selected by constructors for sake of profits and these materials can only keep their quality for a short time but enough to pass the official inspection. They dominate the market.
Chinese Energy Conservation Research Institute has been carrying out a national investigation about external thermal insulating render systems and 23 questions are proposed to the people in the construction sector.22The answers that have been collected show two most ironic features are “what have been reported is not same as what have been done” and “what
13 Residential buildings energy performance of China
have been done is not same what should be done”. Inefficient management, unreasonable regulations and low quality constructor are within ranks to blame for.
Figure 8 Aerated concrete wall In some place single material wall also gets attention. In the market the usually selected sing material product is aerated concrete. The wall of aerated concrete doesn't need extra insulation layer because of its good thermal quality. With the same insulation requirements, the cost of aerated concrete wall is lower than that of composite wall.
4.2.3 Roof
Flat roof is the common form used in China while sloped roof is increasing in popularity because of better waterproof and insulation quality. For example, in Shanghai, a huge reconstruction project had changed more than 170 thousand flat roofs into sloped ones by 2004.24However, mostly, the sloped roof is not same as titled roof or attic but more like another insulation layer on the flat one. It doesn’t increase the usage area of the building but only improve the appearance, water proof and thermal qualities.
Flat roof sloped roof Figure 9 Flat and slope roofs The traditional way to insulate the roof is to use cement-expanded perlite as insulation material and cover it with a waterproof layer.25 Due to the low insulation quality of the cement-expanded perlite when it absorbs the water and the development of other alternative materials, cement-expanded perlite has been abandoned in Roof Construction Technology Regulations GB 50345-2004. Now there are two types of roof insulation layers: board material insulation layer and cast-in-place insulation layer. The normally used materials are listed below26:
Mineral wool PE board Board insulation layer EPS board XPS board Asphalt expanded perlite board Cast-in-place insulation layer Asphalt expanded perlite Cast in place XPS Figure 10 Insulation material list The new way of External Thermal Insulation is now gradually accepted and used many times in big projects. It uses polystyrene board as insulation layer, covered by the protection layer mainly consisted of concrete. Also, compared with traditional method, the insulation layer is placed right above the waterproof layer instead of being below it.
14 Residential buildings energy performance of China
The overall R values of different types of roofs range from 0.5m2K/W to 2 m2K/W and the U values depend on the types and thickness of insulation layer. Normally, in cold area, U value should be lower than 0.8w/m2.k according to regulations. 4.3 Energy related characteristics 4.3.1 Heating
There are several main ways for the heating. One is district heating, which can be in forms of municipal district heating or local district heating. Also it is the most common way of heating in China. Usually, in areas where the municipal duct system can not reach, the local community will build a small station to supply heat. Water is heated by a central boiler or other heat providers and distributed to each house by municipal ductwork or local ductwork. Then the heat is transferred to the air by radiators, which may be mounted on walls or buried in the floor to give under-floor heating, in a way of convection.
The possible heat providers can be: Hydronic boilers They are used in generating heat typically for residential uses. The hydronic boiler operates by way of heating water/fluid to a preset temperature and circulating that fluid throughout the home typically by way of radiators, baseboard heaters or through the floors. The fluid can be heated by any means....gas, wood, fuel oil, etc, while in most parts of China, coal is the usual choice. Combined heat and power Combined heat and power (Cogeneration or CHP) is used where electricity and heat are needed and there is a condition to design such system. It uses a heat engine or a power station to simultaneously generate both electricity and useful heat.Thermal power plants and heat engines in general, do not convert all of their available energy into electricity, with the excess being wasted as excess heat.
By capturing the excess heat, CHP allows a more total use of energy than conventional generation, potentially reaching an efficiency of 70%, compared with approximately 35% for the conventional plants. CHP is most efficient when the heat can be used on site or very close to it. Overall efficiency is reduced when the heat must be transported over longer distances. Heat pumps Two types of heat pumps for homes are air-coupled and ground-coupled heat pumps, the former ones don’t work well once outside temperatures fall below around -5 or -10°C. For a ground-coupled heat pump, in heating mode, it draws heat from the ground or groundwater, which below a depth of about eight feet is at a relatively constant temperature year around, so its COP (coefficient of performance) is often higher, on average, than for an air-coupled heat pump. The tradeoff for this improved performance is that a ground-coupled heat pump is usually more complicated due to the need for wells or buried coils, and thus is also usually much more expensive to install than an air-coupled heat pump.
Heat pump is rarely used and most existing projects are built for demonstrations. But there may be a great change in the future. A survey carried out in 2005 shows that in Beijing a group of companies which can provide heat pump technology, products and service has formed and there were more than 20 system integration companies holding ground coupled technology27. Also, Shengyang, the capital city of Liaoning province, located in the very cold region, now is acting as a racial reformer. Now it has 3.5 million m2 areas getting heat from water source or ground source heat pump and as proposed by government all the new buildings should apply heat pump technology, which means another 10 million m2 area will be added by the end of 200728. But there is one thing to mention that many investigations
15 Residential buildings energy performance of China
have proved that the geological conditions of Shengyang are quite suitable for heat pumps. The geological conditions of China vary a lot, so before a promotion is carried out, a thorough feasibility study is needed.
4.3.2 Heating fee system
Currently the heating fee in cities is charged only according to heating area. Also for years, urban residents, who are working in state-owned enterprises or government organizations, lived in apartments belonging to companies or institutions. Those companies or institutions paid residents’ home heating fee during winter heating period.
Major reforms since the 1990s gradually ruled out further welfare housing distribution and work units started selling the property rights of residential homes to staff members, but until recently companies or institutions have still paid most of the heating bill. When enterprises meet financial problems and can no longer afford to cover heating fee for staff, the residents are refusing to pay and still regard heat as the company’s responsibility. Then it leads to the deterioration of heating provider services without fees and make even more people reluctant to pay.
This old heating fee system is seen as one of the main obstacles for implementation of energy saving policies and the government is so eager to change it. The Ministry of Construction have issued a note urging all the companies to stop free heating and the published codes require installing temperature-control and metering equipments. Also houses are not allowed to be built if not using parallel double-pipe annd current buildings will be reconstructed to fulfil the new requirements. A quite tight time schedule for the transformation has been published by Ministry of Construction recently (see table 8).
Time scale Expectations Before 2006 Heating Season Part of Government office buildings should be reconstructed Before 2008 Heating Season All the government office buildings should be reconstructed 2006-2010 ( 11th Five Year’s Plan) Reconstruction proportion of the existing buildings Big cities: 35%; Middle cities: 25%; Small cities: 15%; 2006-2010 ( 11th Five Year’s Plan All the newly built buildings Table 8 Time Schedule
In reality, until end of 2006, energy monitoring and adjusting devices can not be found in already built buildings, neither in the newly built ones even though the issued codes require new ones to do so. The state-owned heating providers still monopolize the market and a competitive heating market has not been established. In some trial projects, the great efforts don’t pay off. For example, in one residential community in Beijing, after the new system was implemented, the heating fee doubled and the residents refused to pay. The manager of heating company pointed that there were too many problems to overcome and the main ones are unclear heating fee standards, bad envelope insulation quality, heavy reconstruction work and technical problems of devices.
4.3.3 Cooling& Ventilation
Cooling
Now separate air conditioner for each apartment is quite a common way for residents to cool down the room during the hot summer. Fans together with natural ventilation are also a frequently used method in warm summer places or people who can’t afford conditioner.
16 Residential buildings energy performance of China
Air conditioner mechanical fan natural ventilation
Ventilation
As to residents’ behaviour, according to the survey by Tsinghua Univ., the households will turn on the air conditioner when the indoor temperature reaches a certain point (tolerance temperature). When the air conditioner is on, the indoor temperature will be kept at a low degree. Also, the survey shows that in the transitional seasons and summer, households are willing to ventilate the room by opening windows and doors, especially during night to improve the indoor thermal environment. Only when the outdoor temperature goes to an uncomfortable level, the households will close the windows and doors and run the air conditioner.
No special pipe network for ventilation can be found in low rise or middle rise residential buildings. Opening windows and infiltration are the main methods to exchange air with outdoor environment. Small mechanical fans or devices are usually installed in the wall connected with open air in the toilet and kitchen by owners to speed up the air exchange rate during the usage time. In some big cities, to attract buyers and achieve higher profits, developers also install central cooling and ventilation system in high rise residential buildings. But it is not common over the nation.
Figure 11 Ventilation fan
Heat recovery ventilation started to get attention when illness known as SARS (Severe Acute Respiratory Syndrome) spread in China during the year of 2003. In 2004, estimated by Tsinghua Tongfang Co., the second biggest heat recovery ventilator manufacturer in China, the market capacity for heat recovery ventilators reached several hundred million SEK and was developing at an amazing speed. But compared with 10 billion market demand on central ventilation system products each year, heat recovery ventilation only takes a quite small share and has great potential. The 2008 Beijing Olympic Game has also paved the way for wider acceptance of heat recovery ventilation concept. In 2008, only the hotels, public buildings which pass the Green Standards can serve the Olympic Game participants and visitors. Green Standards include the requirements on fresh air, energy saving and indoor air quality, which can be all met by heat recovery ventilation system.
17 Residential buildings energy performance of China
In the market, there are several dozens of companies which supply heat recovery ventilators. The most famous domestic ones are Huandu, Tsinghua Tongfang and the products of Huandu are developed based on Japanese technologies. The international companies are mainly from Japan, including Panasonic, Toshiba and Mitsubishi.
Normally, 70% of heat in the exhaust air can be recovered.
4.4 Conclusion
Several years ago, there was little concern about energy saving and few followed the requirements of national regulations. But all of a sudden, energy saving along with environmental protection has been becoming one of several prioritized issues on government’s agenda and various standards, notes and directives are being issued and sent out by corresponding governmental departments to regulate the chaotic market and promote environmentally friendly products within the building sector.
Most of time, those new standards, notes and directives, of which the concepts and requirements stand quite ahead of the real situation, are more like compulsory plans without guidance and help for the developers and construction companies. For example, heating fee system, it is demanded in national code that heating fee should be charged according to heating consumption but not area. However, few know how to do it but the one who first succeeds will dominate the market. The principle also works for other newly released regulations.
For the moment the market is a trial and error with a lot of different ways to fulfill the new regulations. In general, we can see energy saving market of China is now coming to a transitional period.
18 Residential buildings energy performance of China
5. Wuhai Status 5.1 Market description
Average income for citizens is 15000 yuan per year according to statistical figure. For most of normal people, the average income is around 10000 yuan per year. For unemployed workers with government aid the income is from 200 to 400 yuan per month. Compared with Swedes’ income level, the one in Wuhai is quite lower. Also, it indicates the importance of localization.
The price of apartments in Haibowan district has been increasing a lot in recent years, from average 1050 yuan/m2 in 2003 to 1800 yuan/ m2 in 2006. One of the main reasons is the increasing cost of land. Usually, the government sells land to developers through bidding process. But bidding could be “fake bidding” in which only developers with relationship can get the information released by government. Then the cost for land is low. Now due to more transparent trading market and regulated process, the bidding procedure becomes more complicate and cost of land increases.
One very interesting phenomenon is that residential flats are sold very fast though with the factors of high price and low population. The possible reason can be people from other two districts, Hainan and Wuda, are starting to buy apartments in Haibowan for better environmental quality and better education opportunities for their children.
Based on the data provided by the developer, to achieve 50% energy saving target, 70 to 90 yuan/m2 extra cost, which takes around 10% of total construction cost, will be spent. For a flat of 120 m2, it means around 10000 yuan more will be spent.
5.2 Current Situation
Currently the way of insulation for wall is to use 370 mm thick bricks as basic layer then put 60 mm ESP on. The thickness of insulation layer for roof is 100 mm. Mineral wool was used before but is not common now. The reason might be this material is not used in a proper way so the insulation quality was not as good as it could be. Instead, it is tied around district heating pipes for insulation.
The window is double glazing with aluminium frame. The window area at balcony is large because the residents like to have enough sunshine. The quality of window is under doubt and by experience windows can’t keep their quality after two years of usage.
Attics are not common in Wuhai. There may be two reasons. One reason is the local residents are not used to the attic heights. The other one is in Wuhai, the sunshine is quite strong, especially during summer. It would make the indoor temperature of attic rise to a quite uncomfortable degree.
In the newly built buildings, thermostatic radiator valves are installed and the space is left for the monitor devices. Two kinds of valves can be found in the market, one is cheaper mechanic valve, around 20 yuan each. The other type is IC card valve, 100 yuan each and the maintenance fee is high. The old buildings now are waiting for pipe reconstruction and device installation, the cost of which is around 20 yuan/m2 (construction area) and may be shared by three parties, residents, companies and government.
The real energy performance of buildings is unknown. Whether the buildings meet the standards is judged by a government institution with help of one calculation software, which follows the steps of Standardize methods. .
19 Residential buildings energy performance of China
In Haibowan district, where more than 90% of boilers are abandoned , the heating source is cogeneration29.The heating companies, which are owned or sponsored by the government, pay the price of 8.6 yuan/GJ to buy surplus heat from a local power plant that is managed directly by the province not Wuhai city. The high temperature steam from the power plant is supplied to the district heating company by pipes, and through heat exchange devices then water on the other side gets heat from steam and the temperature of it can raise to 115 degrees. The average is 100 degree. Then the high temperature water flows to the residential district and go through the secondary heat exchange station and the return water temperature is around 60 to 70 degrees.
Hot tap water is not provided by heating companies because if so the cost will be as high as 6.7 yuan/ton while the price for cold tap water is 1.12 yuan/ton. Also hot water passing through galvanized pipes may contain harmful chemicals. Thus the residents use individual electrical devices or solar energy.
The heating price is decided by the Price Bureau, not by the market. The current heating fee is 9.54 yuan/m2. The heating companies are all running in the red, average 3 yuan loss/m2. One heating company I visited lost more than 10 million yuan per year. The budget gap is filled by the government and other nation-owned companies through compensation.
5.3 Development
Wuhai started to fulfil the target of 50% energy saving in building sector from 2006 and before that, there was no action. The newly built public buildings in Binhe new district meet the 50% energy saving target according to the software used by local officer for evaluation.
According to 11th 5 years plan (2006-2010), 1.7 million m2 existing building area or 30 thousand buildings in Wuhai have to be reconstructed. It means that on the exterior wall an insulation layer will added and the single glazing window will be changed to double glazing ones. The financial source is under discussion but possibly shared by government and residents.
In 2007, the covered allowances to consumers are turned into open allowance. That means the government and the companies will not finance heating companies directly. Instead, the residents will get compensation directly, around 300 yuan/cap. year and the heating price will be adjusted to a level where heating companies can at least cover the cost. It is suggested that the heating fee after adjustment should be around 12 yuan/m2.
In Binhe new district, all the land has been sold out. Now all the completed projects or the ones under construction are the government’s. The developers for commercial and residential buildings are holding wait-and-see attitude and one of the reasons is who develops first will bear more infrastructure cost and market risk. However, they have to start development within two years because land held more than two years without development will be taken back by the government.
As to heating, 10 sub heat exchange stations will be built, 10.7 miles primary pipe and 3.6 miles secondary pipe will be installed30. The heating source is cogeneration.
5.4 Residents’ attitudes
From the interviews with governmental officers and local residents, the residents or consumers don’t pay much attention on energy performance of the buildings. What they care most about are the location, layout and orientation. So the developers don’t have any incentives to further improve the quality of insulation beyond compulsory requirements because good energy performance doesn’t lead to good price in the market.
20 Residential buildings energy performance of China
They are very sensitive to the price fluctuation of public goods, especially the old generation who went through planned economy period. Some residents are reluctant to pay the heating fee bill.
Residents are not confident about the quality of domestically-made brand products while they also complain about the high price of foreign products.
5.5 Conclusion
Though several steps behind, Wuhai is following central government’s policy quite tightly. Reconstruction work, new allowance policy, new buildings with insulation layer all show Wuhai government’s endeavor to meet national standards in next five year plan.
But if they want to do more instead of barely meeting standards is another issue.
21 Residential buildings energy performance of China
22 Residential buildings energy performance of China
6 Calculation Strategy
A lot of researches have been done to provide concepts and statistical consequences for the economic evaluation of a system or product and LCC is the one usually used. Most of the times, the calculation results will prove that more investment at the beginning, after a certain time, the reduction on water, electricity and heating bills due to better performance will finally write a positive figure on the budget sheet. This is a good approach to show the benefit of high performance goods.
However, those calculation results might have little impact on final decisions if the audience group is not identified or if we imposed our so called good ideas without enough or right communication.
Thus, to the first “if”, for heating and residential building energy saving market, government is seen as the real decision maker because the heating fee system made by government and the funding from government to heating companies or residents directly determine the benefits and wiliness of developers and consumers (see table 9). Plus, Energy saving activities are policy oriented instead of market driven, so the aim of this calculation is to let government know how much they could save on the budget through implementation of energy saving technologies. For example, implementations of those energy saving methods will reduce heating companies’ needs for governmental funding and thus release government’s financial pressure. Furthermore, from the point view of government, heating fee system will only put impact on the benefits allocated to heating companies and residents, but not on the costs to society. Thus, in this report, though heating fee system is listed as an important issue to discuss, it doesn’t have direct relationship with the calculation results.
Stakeholders Function& Power Aim Government Set up the rules for actors Fulfill the mission set by central Supervision on actors government Absolute authority Increase financial income and reduce Ability to intervene the market with debt. governmental orders Minimize costs to society Pursue political and economic achievements Heating Government owned welfare Supply heating company company Developer Develop houses under the rules Invest less money for higher profits Consumers Buy or not Spend less money for higher quality house Table 9 description of different stakeholders As to second “if”, good communication, we can set some limitations on our action plan based on local people’s ideas. Here are some notes: first, according to Steven Zhou, who have stayed in China for a long time as the China-branch manager of a Swedish company of heat exchanger, the payback time of higher price products should not exceed 5 years at most otherwise it would be quite difficult to convince consumers to buy or government to agree; plus, the energy prices can not be known after 5 years in such a dynamic market; second, to Wuhai, as said above, what they are trying to do is to fulfill the targets of 50% energy saving and currently they have available technologies and methods though quality can be questioned. Therefore, as far as it is concerned, in this report, we choose methods aiming at 50% energy saving standard as the benchmark for the comparison, though the investigation shows that more than 90% residential buildings don’t fulfill this requirement. The reason lies on that choices now are made between methods of 50% energy saving and other alternatives. Also, instead of giving scenario analysis of 20 or 30 years, 5 and 10 years are set as points for all the decisions. It would be best if payback time stays within 5 years and the products with payback time from 5 to 10 year can be proposed. If the cash flow on the calculation sheet is
23 Residential buildings energy performance of China
shorten the payback time or just quit if there is no solid relation network or other special added values. So basically, the products can be divided into three categories. (See figure 12)
Proposed as the second
Best best alternative Redesign or quit
5 year 10 year Figure 12 payback time categories of products
24 Residential buildings energy performance of China
7 Simulation 7.1 Building description
For the estimations carried out in this paper, a model building was considered, as illustrated in Fig. 13. Also, we assume the building is located in Wuhai city in Inner Mongolia of China, where SUCI project is being carried out. The building comprises 5 floors with 2 apartments, 1 unheated stairway. Here the building height is chosen as five floors because the energy performances of middle floors (from third floor to the last third one) are similar thus third floor can represent all the middle ones.31
Each apartment contains one living room, one kitchen, two bath rooms, three bed rooms and a balcony, which is a typical apartment layout in China. The usage area of each apartment is 86 m2, less than 90 m2 according to the newly published regulations. The total area of each floor is approximately 200 m2, including walls and stairways. Each storey has 10 windows, 8 are facing north, and 2 are facing south. Area ratio of window to wall ranges from 20 to 25%. The balcony doors are facing south. The orientation here is not a variable but fixed.
Figure 13 layout of residential building
7.2 Climate condition
Wuhai city has an extreme continental climate with cold winters and warm summers, and it is also extremely dry. Based on statistics from the last 5 years, average annual temperature is +9 C. The average monthly temperature is listed in figure 2.
Month 1 2 3 4 5 6 7 8 9 10 11 12 Average -10 -5 1 12 14 18 25 28 20 18 4 -7 temperatureeC Table 10 average monthly temperature The period of lowest temperature is about 20 days. The period of high temperature with a cooling need is about 20-40 days but active cooling is not needed. The heating season is theoretically 6 months (October 15 to April 15), but in practise it is between November 1 and April 1. Due to lack of hourly weather data and similar location of Wuhai as Yinchuan city, here settings for Yinchuan city are used (see figure 14). When data are available in future, settings will be changed in accordance with Wuhai’s climate conditions.
25 Residential buildings energy performance of China
'DLO\7HPSHUDWXUH
ć˅
'U\EXOEWHPSHUDWXUH
GDLO\DYHUDJHWHPSHUDWXUHV ć GDLO\KLJKHVWWHPSHUDWXUH ć GDLO\ORZHVWWHPSHUDWXUH ć
Figure 14 climate data (Source: Dest data base32) Here we can easily see that during most of the time in winter, the outside temperature is lower than -5 degree or even -10 degree. Thus, air coupled pump may not be a good choice concerning the current technology level and possible cost.
Here three heating methods are discussed and will be evaluated in the calculation.
7.3 Heating method
Based on investigation of Wuhai and the discussion above, three heating methods are presented.
Cogeneration: As mentioned above, for cogeneration, the heat is the byproduct generated through the process of electricity production. So it is inappropriate to judge the performance of CHP as a heating source with the same standards as others. When there is a condition for the construction of a CHP, maybe it is the best available technology for the local area. The experiences from Netherlands also show the great potential of CHPs as a clean source for both electricity and heat.33
In Wuhai’s case, the CHP is located just 2 miles away from Haibowan district and the heating companies buy surplus heat from the CHP at price of 8.6 yuan/GJ, which is quite low compared that in other Chinese cities, and then transfer it to the residential buildings by the media of water. As said before, CHP is most efficient when the heat can be used on site or very close to it. Plus, the fuel for the CHP is coal, which is abundant and cheap in Wuhai. In one word, in Haibowan district, where district heating system can cover, CHP’s role can’t be challenged in current situation. But there is some possible space for the further improvement. One is energy efficiency such as burning efficiency of coal. Another one is pollution control such as the dust and CO2 emitted through the burning process.
Figure 15 CO2 emissions of different methods
What is more, feasibility of using household garbage as fuel can also be investigated. The figure 15 shows CO2 emissions of CHP with biomass that is negative because it transfer the energy stored in the “natural waste” to heat and electricity and the reduced CO2 emissions can be traded as “Certified Emissions Reductions (CERS)” in the world market according to
26 Residential buildings energy performance of China
Kyoto Protocol. Now the price for CERS is around 9 US dollars/ ton and it could greatly encourage the local CHP Company.
In Sweden, more than 40% of municipal waste is processed by combustion and can be quite a good example for China.34 But there are some things that need to be known before action, when the topic touches waste management. First, usually the calorific value of municipal solid waste has a positive linear relationship with the development levels of cities and Wuhai, as a less developed city, the situation there is not that optimistic. Second, the initial and running cost might be too high for Wuhai and there lacks corresponding preferential policy as most European countries have. Also the emissions from burning waste have bad impact and need to be reduced by using better technology for cleaning the air emission. An overall feasibility analysis is needed.
Hydronic boilers& Heat pump In places where the CHP is situated too far away, the boiler and heat pumps are alternatives if we assume that the geological conditions are suitable for the application of heat pumps. Actually in Wuhai, even though the detailed information concerning groundwater resource data is not available, there is a possibility to use water coupled heat pump in parts of the area because of large storage of groundwater. There are more than 700 water wells in Wuhai and the average density of well is 1.2 well/square kilometres.35 There is also a possibility to use the existing wells as the heat pump wells instead of digging new ones.
So a comparison is needed to decide which one is better.
Hydronic boilers The initial investment of boilers with coal is around 100 yuan/m2. The running expenses, according to the local heating company, are around 13.5 yuan/m2 and it depends on factors such as local weather conditions, coal price and local wages level, ect.
A table is listed:
No. Items Price Amount 1 Coal, water, and electricity fee 13.5 yuan/m2 2 Management fee(wages) 700 yuan/cap. month 2 3 allowances for repairs and maintenance 1.8% initial investment Company management fee 2.5% (1 Total cost 1+2+3+4 Table 11 operation cost of hydronic boilers Here we assume that the running expenses correlates with heat consumption. Then we can get the following formula: current running expenses running expenses heat consumption (6) current heat consumption Where current running expenses are 13 yuan/m2 and current heat consumption is from the calculation. Heat pump The cost for the wells and pump stations are approximately 1000 yuan/m.well.36 So the groundwater level is one of the key factors affecting the total cost. Because there is no heat pump project in Wuhai, so the data from a heat pump project located in Tianjin city is chosen as a reference. The initial investment is assumed to be 250 yuan/m2, including wells, heat pumps and pipes. 37
27 Residential buildings energy performance of China
The system is designed for both heating and cooling. The documents from Wuhai government show that in part of Wuhai, the depths of existing wells ranges from 100 to 300 m.38 180 m is chosen as the average depth for the calculation. Then the calculation show that wells takes around 20% of initial investment of 250 yuan/m2. Here we should notice this percentage is not fixed, depending on the local geological conditions, well depths and types. The literature shows that this percentage can be as high as 45%.39 This also tells us that the decision should be made case by case.
Because of dual functions of heating and cooling, we choose 60% of initial investment, which is 150 yuan/m2, as the initial investment for heating system part considering relatively short cooling period. It is in accordance with the experiences from Shenyang heat pump projects, of which the initial investment is roughly 140 yuan/m2 (only for heating part).40
Figure 16 Heat pump operation chart The operation cost consists of energy cost, management fee, allowances for repairs and maintenance. For energy cost, because of recharge well system, water fee can be avoided and main cost is electricity cost. Here we assume the electricity fee is calculated with the following formula:
Electricity fee= heat consumption/COP electricity price (7) Here we assume COP =3
A table is made as below to show the detailed operation cost information.
No. Items Price Amount See formula 1 Electricity fee 0.37 yuan/ kWh above 2 Management fee(wages) 700 yuan/cap.month 1 3 allowances for repairs and maintenance 1.8% initial investment Company management fee 2.5% (1 Total cost 1+2+3+4+5 Table 12 Operation cost of heat pump
7.4 Envelope type
As mentioned above, the Chinese market of insulation products is going to a new phase. Also there are many new products available, which are more environmentally friendly. Nevertheless, most part of the market is still occupied by conventional products and a lot of promotion work need to be done. Here Table 13 summarises the most used exterior wall types, their main thermo-physical properties and the total cost. Then table 14 lists cost of different wall materials. Table 16 gives U values and cost of windows and roofs.
28 Residential buildings energy performance of China
Thickness Thermal conductivity Conductance U Total cost Wall type (mm) (w/m.k) (W/m2.k) (yuan/m2) Wall 1 390 1.57 40 Clay brick 370 0.814 Plaster 20 0.814 Wall 2 470 0.518 145 Clay brick 370 0.814 Plaster 20 0.814 Expanded polystyrene 60 0.041 (EPS) Plaster 20 0.814 Wall 3 320 0.57 145 porous brick 240 Plaster 20 0.814 Expanded polystyrene 0.041 (EPS) 60 Plaster 20 0.814 Wall 4 320 0.7 135 porous brick 240 Plaster 20 0.814 Expanded polystyrene 0.06 granule 60 Plaster 20 0.814 Wall 5 340 0.609 75 Plaster 20 0.814 Aerated concrete 300 0.209 block41 Plaster 20 0.814 Table 13 U values and cost of wall types
The wall conductance U for a typical wall that includes a layer of insulation is given by the total thermal resistance as follows, 1 URiRRR[]win0 (8) where Ri and Ro are the inside and outside air thermal resistance; Rw is thermal resistance of a composite wall, excluding the Ri , and Rin ; Rin is thermal resistance of the insulation layer. The calculation of U values is done by the software of Dest.
Component type Materilas type Cost Aerated concrete 45-48 yuan/m2 Clay brick(37cm) 35 yuan/m2 Basic layer Hollow clay brick(37cm) 35 yuan/m2 Exterior wall(1) Concret bricks (240) 35 yuan/ m2 Expanded polystyrene (EPS) (60mm) 85-130 yuan/ m2 Insulation Expanded polystyrene granule (60mm) 100 yuan/ m2 layer Extruded polystyrene (XPS) (40mm) 95-148 yuan/ m2 Mineral board (100m) 30-40 yuan/m2 Table 14 Component type of exterior wall (1) The price of insulation layer includes the cost of insulation material, mortar, decorated layer and construction cost. (2) yuan/m2: m2 indicates surface area of layers.
Wall 1 is commonly used during 80s, 90s and the main target for the conversion work. Wall 2, 3, 4 are promoted by the government and normally used and wall 5 is also a good alternative. There are also many other choices, depending on the climatic conditions of the site, the building geometry and access to materials. However, in this report, the focus is not to find
29 Residential buildings energy performance of China
which is best among those but to present the current average situation. Thus, the average U values and cost of Wall 2,3,4,5 are calculated and seen as the representative. (Here we assume that these four methods take the same amount of market share). (See table 15)
Conductance U Total cost Wall type Thickness(mm) 2 (W/m .k) (yuan/m2) *the heat capacity of materials is R wall 363 0.6 125 not considered here. Table 15 Average U values and cost
Envelope Type U value Cost Window(1) Single glazing window 4.7 150-250 yuan/ m2 Double glazing window with PVC frame 2.7-3.1 210-350 yuan/ m2 Double glazing with heat broke aluminium frame 2.7-3.1 400-800 yuan/m2 Flat roof or slope roof N/V 250-350 yuan/ m2 Roof (2) Slope roof with attic N/V +1000 yuan/m2 Table 16 Types of windows and roofs (1) The prices of windows, even of some type, can vary a lot. Here the selection of prices is based on construction material price list of Baotou. The brands are Fenglv and Hailuo. (2) The cost of flat roof is not available now. However, based on experience from reconstruction project, we assume that the sloop roof is 300 yuan/m2 or 1000 yuan/m2 higher than flat roof. Because of residents’ habits, the effects of attic roof are not discussed in this report.
7.5 Thermostatic radiator valves
A thermostatic radiator valve (TRV) is located at the top or bottom of a radiator. After the installation of thermostatic radiator valves, the residents can set up the desired room temperatures in advance (automatic) or turn the knob afterwards (mechanical) and the TRV controls the temperature of a room by regulating the flow of hot water to the radiator. It avoids overheating problem and also allows residents to set a low indoor temperature when they are absent from rooms. Thus the energy consumption will be reduced.
Figure 17 Thermostatic radiator valves According to the materials provided by Danfoss, one Danish valve manufacture company, their demonstration project in Shenyang shows that the indoor temperature fluctuates within 2 degrees and total energy consumption decreased by 30% during the two years’ operation of automatic valves; that payback time for the cost of 15/m2 is about 5 years for both TRVs and thermal meters.
In the calculation, the simulation after installation of TRV is realized by the setting of temperature range in Dest.
7.6 Heat Recovery Ventilation System
Typically, a HRV is able to recover 70 to 80 percent of the heat from the exhaust air and transfer it to the incoming air. This dramatically reduces the energy needed to heat outdoor air to a comfortable temperature. The market price is around 2000 yuan/unit, including installation fee.
30 Residential buildings energy performance of China
In the calculation part, we assume that the airtighness of envelopes reaches a level that the ventilation is mainly realized by heat recovery ventilation system if the ventilators are installed; that the standard of 0.5 time /h air exchange rate can be fully achieved. Therefore, the installed ventilator will at least pump out 1.4m3 exhausted air /m2 .h and transfer 70% heat of it to the same amount of fresh air taken in(the height of room is 2.8 m). The drawbacks of those assumptions are from the facts that in places where there are no ventilators installed, residents would rather close the window at cost of indoor air quality during winter time and air exchange rate is quite low especially at nights; that the current Dest-h version (residential buildings) doesn’t support the stimulation of heat recovery ventilation system. Thus, a simplified calculation is introduced as below based on the working theory of heat recovery ventilators.
Fresh air to house temperature = (indoor temperature-outdoor temperature)* heat recovery rate +outdoor temperature (9)
The energy saved= (fresh air to house temperature-outdoor temperature)*heat recovery rate* air volume* air density* air heat capacity (10)
The electricity input for a typical heat recovery ventilator is usually 60 w to maintain a 140 m3/h exchange rate or 0.5 time/ h air exchange rate for a 100 m2 apartment.
The final calculation results shows that 20.5 kW.h/m2 can be saved during the heating season; that 2.16 kW.h/m2 electricity input is needed for operation.
7.7 Heating fee system
As mentioned above, the heating fee in cities is charged only according to heating area and it can’t be solved solely by technology but is rather an issue also related to welfare system and heating market. So it is easy to understand in some demonstration projects, after installation of thermal meters, there are still no big changes in heating fee system. In Tianjin city, which is recognized as the pioneer of reformation, the heating fee is first collected according to area and then a proportion is paid back by heating providers at the end of heating season if the data show energy saved by the resident above a baseline. The proportion is decided by heating provider in order to avoid financial loss in case of too much energy is saved by residents.42
Before a more advanced method is proposed, we should notice that unlike water, gas, or electricity consumption, however, heat consumption is not totally individualized because the flats are also heated externally by the heat from the neighbouring flats and it is more obvious when the insulation is not so good. A test carried out in Beijing shows that the flat without heating can maintain its temperature at 10 degree with the heat provided from the neighbouring units during heating period. Also, the location, orientation and shape of the flat influence the energy need. 43 Thus, here we suggest that there can be two steps in practice. First step is a combination of fixed charges and consumption charges to reflect the real consumption but also compensate the effects of internal heat transfer and other factors. Then the method of charging only or mainly based on individual unit consumption is introduced when the knowledge is enough. At the same time, the residents are not allowed to set the room temperature too low.
Then heating price is another issue. In a policy oriented market, the heating price doesn’t reflect the real cost. In Hohhot, the heating price in 2005 was 2.25 yuan/month.m2 and it is same as the price set in 1998 while the cost of water, electricity and coal has been increasing dramatically (refer to figure 18). There are more than 200 heating companies in Hohhot but all of them would be in serious financial trouble without large aid from government.44 But it is clear that when the heating market is open, heating price will be more flexible. Here we use
31 Residential buildings energy performance of China
average increase rate of water, coal and electricity as the increase rate of resource cost for coal boiler and increase rate of electricity for heat pump. From the case of Hohhot mentioned above, we get 8% for coal boiler and 3% for heat pump.
Water price Coal price (100yuan/ton) (100yuan/ton) Heating fee (100yuan/ton) Electricity price (yuan/kW.h) Figure 18 Price comparison between 1998 and 2005 7.7 Discount& inflation rate
As discussed in LCC part, the rate of price inflation (electricity, fuel, wage, etc) and the rate of return on the next best available use of funds should be decided to proceed LCC calculation.
For heat pump, the energy cost mainly comes from electricity usage thus the electricity price inflation rate is seen as inflation rate of the resource cost. From the experiences of Huhohot, we select 2% as the inflation rate.
For boiler, the energy cost comes from water, electricity and coal usage. Due to lack of detailed information, the average inflation rate of water (12%), electricity (2%) and coal (10%) price is used as the general resource inflation rate, which is 8%.
For wages, according to data of 2005, 14% wage increase rate is selected. Also, we assume that allowances for repairs and maintenance increase at the same rate as consumer index, which is 2%.
As to rate of return on the next best available use of funds, based on the facts most residents will take housing fund loan to buy apartment, we assume the second better choice for the investment is to provide housing fund loan to other residents instead of buying extra energy saving devices. So we pick yearly housing fund loan interest as the discount rate, which is 4.14%.
The discount and inflation rates are concluded in the following table.
Items Inflation rate Discount rate 4.14% Boiler 8% Resource cost Heat pump 2% Operation cost Wage 14% Repairs and maintenance 2%
32 Residential buildings energy performance of China
8 Calculation 8.1 Basic settings
Based on the general information and also the real situation of Wuhai, the following types of envelopes will be evaluated:
(1) Current situation Single glazing, 370 mm wall without insulation, normal flat roof, no thermostatic valves
(2) Thermostatic valves Single glazing, 370 mm wall without insulation, normal flat roof, thermostatic valves
(3) Improved ones building envelopes Double glazing, wall R (representative wall), and roof 100mm, thermostatic valves
(4) Triple glazing window Triple glazing, R wall (representative wall) and roof 100mm, thermostatic valves
(5) 370mm wall with 100 mm EPS insulation Double glazing, 370mm wall with 100 mm EPS insulation and roof 100mm, thermostatic valves
(6) Roof with 150 mm EPS insulation Double glazing, wall R (representative wall), and roof 150mm EPS, thermostatic valves
(7) Triple glazing, 370mm wall with 100 mm EPS insulation and roof 150mm, thermostatic valves
(8) Mineral wool Triple glazing, 370mm wall with 100 mm and roof 150mm of mineral wool, thermostatic valves
The heat consumption is calculated by the software of DeST and adjusted by the standardized method. Here two heating sources are picked, hydronic boilers and heat pumps. Using the data given in chapter 5.3, initial investment and operation cost are calculated on heat consumption and the heating source. The calculation year is 2007.
Figure 19 user interface Figure 19 is the user interface of DeST for calculation. The calculation results are listed in table 17 and table 18.
33 Residential buildings energy performance of China
U Values Price Total cost Heat consumption No Envelope components (w/m2.k) yuan/m2 yuan/m2 KW.h/m2 Single glazing 4.7 32.09 370 mm wall without insulation 1.57 34.43 1 126.521 75.02 Normal flat roof 1.26 60 No thermostatic valves ------Single glazing 4.7 32.09 370 mm wall without insulation 1.57 34.43 2 128.521 53.4* Normal flat roof 1.26 60 thermostatic valves --- 1.54 Double glazing 3 38.68 3 Wall R 0.6 107.60 241.8 25.83 Roof with 100 mm EPS insulation 0.417 94 Thermostatic valves --- 1.54 Triple glazing 1.8 46.96 4 Wall R 0.6 107.60 250 23.45 Roof with 100 mm EPS insulation 0.417 94 Thermostatic valves --- 1.54 Double glazing 3 38.68 370mm wall with 100 mm EPS insulation 0.417 142.03 5 276.25 18 Roof with 100 mm EPS insulation 0.417 94 Thermostatic valves --- 1.54 Double glazing 3 38.68 Wall R 0.6 107.6 6 253.82 24.94 Roof with 150 mm EPS insulation 0.417 106 Thermostatic valves --- 1.54 Triple glazing 1.8 46.96 370mm wall with 100 mm EPS insulation 0.36 142.03 7 296.55 15.07 Roof with 150 mm EPS insulation 0.29 106 Thermostatic valves --- 1.54 Double glazing 3 38.68 370mm wall with 100 mm mineral wool 0.42 68.88 8 179.0 17 Roof with 150 mineral wool 0.35 70 Thermostatic valves --- 1.54 Table 17 Price and heat consumption figure (1) * adjusted according to experiences from Shengyang project, 30% reduction of energy consumption achieved after application of thermostatic valves. (2) m2: indicates the construction area
Operation cost (yuan/m2) Envelope type Boiler Heat pump 1 18.9 13.0 2 15.32 11.13 3 10.2 7.45 4 9.56 7.15 5 8.52 6.65 6 9.86 7.53 7 7.96 6.09 8 12.31 8.33 Table 18 Heat pump and boiler cost comparison (calculation year 2007)
34 Residential buildings energy performance of China
1 2
\HDU 3, 4, 6 5 NZKP 8 7
HQHUJ\FRQVXPSWLRQ FRVW\XDQP (36LQVXODWLRQ PLQHUDOZRRO
Figure 20 Envelope cost Vs energy consumption
From table 17 and figure 20, we can easily see that as the insulation cost increases, there is not much space left to reduce the heat consumption (from point 3 until point 7); that if the area ratio of window to wall is not big enough, the change from double glazing to tri-glazing only makes slight difference on energy consumption (from point 3 to point 6); that the better insulation of roof doesn’t give much impact on the overall energy performance of the building, but is important to the floor just below it (from point 3 to point 4); that mineral wool can achieve a better insulation quality with lower cost (point 8).
D
RSHUDWLRQFRVW\XDQP (QHUJ\FRQVXPSWLRQ.ZKPD KHDWSXPS %RLOHU Figure 21 operation cost of heat pump and boiler From table 18 and figure 21, we can observe that operation cost curve of heat pump is lower than that of coal boiler. A quite interesting phenomenon is the tendency that the lower the energy consumption, the smaller differences of operation cost between two alternatives. Thus, one dilemma comes out that the implementation of better insulation technology, which intends to reduce the energy consumption, will reduce the positive economic effects of using heat pump. On the other hand, using methods of less operation cost will prolong the payback time of using better insulation technologies and materials. In one word, the implementation of one better method will reduce the possibility of using the other.
What is more, if the resource cost, such as cost of water, coal, is low, then difference between operation costs of heat pump and boiler and gains from better insulation would be very small, which leads to a long pay back period for methods of higher initial investment.
The initial cost, operation cost and energy saving benefits of heat recovery ventilation system are listed as below:
Heating method Initial cost Operation cost Energy saving cost (yuan/m2) (yuan/m2.a) (yuan/m2.a) Boiler 20 0.8 16.5 Heat pump 20 0.8 7
35 Residential buildings energy performance of China
8.2 NPV calculation
NPV initial is the difference between initial investments of two alternatives. NPV5 means the NPV (net present value) of first 5 years’ operation cost of one alternative. NPV 5 means the differences between NPV5 of two alternatives. The definitions are also applied to NPV10 andNPV 10.
To judge if overall performance of one alternative is better than another alternative after 5 or 10 years, we addNPV initial toNPV 5 orNPV 10 .If the result is negative, then the alternative is better. The detailed concept is explained as below:
NPV for alternative 1= NPV1 initial investment+ NPV1 operation cost (11)
NPV for alternative 2= NPV2 initial investment + NPV2 operation cost (12)
NPV for alternative 1- NPV for alternative 2= NPV1 initial investment+ NPV1 operation cost -(NPV2 initial investment + NPV2 operation cost )=( NPV1 initial investment - NPV2 initial investment )+ (NPV1 operation cost- NPV2 operation cost )= NPV initial+NPV 5 orNPV 10 (13)
Three comparisons are carried out as below separately for envelope, heating method and heat ventilation system. Detailed calculation procedure can refer to excel document “NPV”.
Envelope comparison:
(1) comparison with heating method of Boiler
Table 19 Envelopes comparison with boiler Number 1 2 (1) 3(2) 4 5 6 7 8 Initial investment 126.51 128.521 241 250 276 253 296 179 NPV 5 102.80 83.54 55.01 52.55 46.91 54.09 43.881 45.88 NPV 10 230.72 188.35 125.61 120.20 107.79 123.59 101.13 105.52 NPV initial 2.011 9 35 12 55 -62 NPV 5 -19.26 -2.46 -8.1 -0.92 -11.13 -9.13 NPV 10 -42.37 -5.41 -17.82 -2.02 -24.48 -20.09 NPV initial+ -17.249 6.54 26.9 11.08 43.87 -71.13 NPV 5 NPV initial+ -40.359 0 3.59 17.18 9.98 30.52 -82.09 NPV 10 (1) The comparison is made between 1 and 2. The aim is to evaluate Thermostatic radiator valves. (2) From 4 until 8, the target for comparison is 3.
(2) comparison with heating method of Heat pump
Table 20 Envelopes comparison with heat pump Number 1 2(1) 3(2) 4 5 6 7 8 Initial investment 126.51 128.521 241 250 276 253 296 179 NPV 5 67.53 56.02 38.97 37.50 34.13 38.42 32.32 33.51 NPV 10 136.94 114.52 81.34 78.47 71.91 80.27 68.39 70.71 NPV initial 2.011 9 35 12 55 -62 NPV 5 -11.51 -1.47 -4.84 -0.55 -6.65 -5.46 NPV 10 -22.42 -2.87 -9.43 -1.07 -12.95 -10.63 NPV initial+ -9.499 7.53 30.16 11.45 48.35 -67.46 NPV 5 NPV initial+ -20.409 0 6.13 25.57 10.93 42.05 -72.63 NPV 10
36 Residential buildings energy performance of China
(1) The comparison is made between 1 and 2. The aim is to evaluate thermal valves. (2) From 4 until 8, the target for comparison is 3.
From table 7, table 8 and figure 4, we can see that further increasing thickness of EPS layer don’t generate a positive economic result while mineral wool can be a quite good choice taking EPS’ place due to its cheap price and good insulation quality; that tripe glazing window may not be a good enough choice compared with double glazing one at this moment; that thermal valves should be promoted because of its obvious energy saving effects and low cost.
Heat recovery ventilation system
The NPV calculation shows that the payback time for heat recovery ventilation system is 3.1 year with heat pump, 1.24 year with boiler.
The calculation results are concluded in figure 21, as below:
Heat recovery ventilator Triple glazing, Thermal valves 100 EPS wall insulation, Mineral wool insulation 150 EPS roof insulation,
5 year 10 year
Figure 22 Payback time categories of products
Heating method comparison:
Envelope 1 and 3 are used as base to evaluate those two heating methods.
Table 21 Heating methods comparison Items 1 (traditional envelope) 3 (current one) NPV initial 50 50 NPV 5 Boiler 102.80 55.01 Heat pump 67.53 38.97 NPV 5 -35.27 -16.04 NPV 10 Boiler 230.72 125.62 Heat pump 136.94 81.34 NPV 10 -93.78 -44.28 NPV initial+NPV 5 14.73 33.96 NPV initial+NPV 10 -43.78 5.72
Heat pump with Heat pump with envelope 3 envelope 1
5 year 10 year Figure 23 Payback time categories of products To heating methods, with traditional envelope, heat pump lies in the 5 to 10 years zone while with currently promoted envelope, the payback time would exceed 10 years. As said above, implementation of better insulation technology, which intends to reduce the energy consumption, will reduce the positive economic effects of hiring heat pump and prolong the payback time.
37 Residential buildings energy performance of China
8.3 Sensitivity analysis A sensitivity analysis is the process of varying model input parameters over a reasonable range (range of uncertainty in values of model parameters) and observing the relative change in model response. 3 is used as the case for sensitivity analysis. Parameters include resource cost, resource price inflation rate, initial investment and output is NPV 10.
Original Sensitivity NPV 10 +10% NPV10* figure factor Initial investment 100 125.61 110 127 11.07% Resource cost 13.5 125.61 14.85 131.5 46.89% Resource inflation rate 8% 125.61 0.088 127.75 17.04% discount rate 4.14% 125.61 0.04554 123 -20.78%
From the calculation, we can see that all the sensitivities factors concerning those parameters are less than 1, which means NPV is not sensitive to those parameters.
38 Residential buildings energy performance of China
9 Conclusions and suggestions: In this report, several main questions are solved, including the payback time of several envelopes and heating components, the market status of different products and heating fee system analysis. The main findings and calculations are concluded as below:
Payback time
From calculation, with the parameters set in this model, the results show that compared with current requirements, it is not economic to upgrade double glazing window to triple glazing window or increase the thickness of EPS layer beyond a level because of too long payback time.
Also the results show that mineral wool, as insulation material, is much better than EPS owing to its cheap price and good insulation function. However, the reason why it is not commonly used in Wuhai and other parts of China is because the material quality and installation method are not so good.
As to thermal valves and heat recovery ventilators, the payback time of those two components all lie within 5 years and should be further promoted.
To heating method, if the energy consumption is lower than a certain point, compared with traditional boilers, heat pump may not be a good choice considering economic gains.
To attic, it is more related with residents’ habits thus not discussed here.
Market status
This investigation shows all of the products mentioned in this report are commercially available in Chinese market from low quality products to advance ones. The foreign companies in this built environment sector are mainly from the USA, Japan, France, German and Denmark, etc. Several big Swedish companies, including Maxit Group, Ikea, also paly an active role in the market.
There are also small/middle size Swedish companies there struggling to promote their services and products, alone. They prefer to hire local representatives instead of building sort of cooperation with Chinese partners. This phenomenon may come from the first principle of Swedish Trade Council, which is “No Joint Venture with Chinese Companies”. This principle is highlighted in its presentation and its consultant services to Swedish companies with interest in Chinese market.
Heating fee System
The current heating fee system (charging fee according to heating area but not real heat consumption) is the biggest obstacle to promote products with better energy saving effects. No volunteer activities can be expected without renovation on this heating fee system.
Two possible models are proposed in this report. First model is that within current heating fee system, a platform can be built among government, developer and heating companies, and initial cost can be shared by three sides. The detailed percentage can be further discussed. So if the real energy consumption and operation cost are reduced, with the same fee level, it will be a profitable business to provide heat and the money can be repaid in a long term.
Second model is under future heating fee system, in which the heating fee is charged partly or fully according to real heat consumption, consumers can be easily motivated to pay the extra
39 Residential buildings energy performance of China cost. For most of Chinese people, they will take loans to buy apartments. Some sort of energy saving loan or interest benefits can be provided by government to further encourage the residents to using better energy saving technologies.
For Swedish companies, several suggestions are given below:
(1) If the payback time lies within 5 year zone, then further research can be done for localization.
(2) If the payback time lies out of 5 year zone, we can check the current status and put our focus on improvement of current products instead of updating. For example, according to survey, though there are double glazing windows in the market of China, the insulation quality and airtightness are not as good as those of Swedish products. Also the calculation shows maybe it is not a proper to use triple glazing at this moment. Thus idea can be improving double glazing instead of changing it.
(3) It can be a good choice to find a Chinese partner in various forms if the company is a small one and wants to enter Chinese market. Most of times, according to a Swedish lawyer firm, small/middle size companies will find their products have no big difference with the ones already presented in Chinese market and it is more about network and market exploration.
40 Residential buildings energy performance of China
Appendix 1:
Calculation steps of standardized method
Heat loss through the envelope: QKFttjnw() n Q : amount of heat transferred through the envelope of the room, (W) K : the heat transfer coefficient of the envelope. [W/ (m2K)] F : heat transfer area of the envelope. [m2] tn : indoor design temperature in winter.[C] tw : outdoor design temperature in winter. n : temperature difference correction factor.
QQ(1 )(1 )(1 ) hj chfLmlg j
Qh : heat loss transmitted through the envelope with consideration of other correction factors. : correction factors
Heat loss through air infiltration the door or window
Qc0.28pwnnwn Ltt ( ) Q : heat loss due to the cold air going inside through the door or window.(W) o C p : heat capacity of air, ckJkgCp 1/(.)
wn : ambient air density of outdoor design temperature. L : cold air infiltration rate tn : indoor design temperature in winter tw : outdoor design temperature in winter
b LLLm01
L0 : theoretic cold air infiltration rate through window or door gap.(m3/m.h) l1 : the length of the slot of the outer door and window.(m) m : overall window or door correction factor of different orientations and heights after consideration of building shape, airflow. b : window or door infiltration index, b=0.56ˉ0.78
La ()wn v2 b 012 o a1: outer door or window infiltration factor. (m3/(m.h.pa^b) vo: the speed of wind of the most frequent direction at benchmark height.(m/s)
1/b mCtt C() n C C h
Cr : heat pressure coefficient.
C f : wind pressure difference factor. n : orientation correction factor for cold air infiltration with wind pressure effects. C : ratio of valid heat pressure difference to valid wind pressure difference on the window or door.
41 Residential buildings energy performance of China
Ch : height correction factor.
0.4 Chh 0.3 hh tt' C 70z ntw 20.4 ' Cvto h273 t n hz: Elevation of window or wall. t`n: shaft design temperature
Appendix 2
Loan interest rate
+RXVLQJIXQGORDQ 5HSD\PHQW 0RQWKO\ 7RWDO 3HULRG LQWHUHVW WLPHV UHSD\PHQW UHSD\PHQW /RDQ 0RQWKO\ 42 Residential buildings energy performance of China Reference: 1 Luo Bing. Energy consumption of construction sector takes approximately 35% of national energy consumption, (March, 06). http://chanye.finance.sina.com.cn/js/2006-03-08/279993.shtml, Sep. 06 2 Ministry of Construction of China, Notes about the outline of the eleventh five-year plan of energy saving in construction sector, (050603). http://www.cin.gov.cn/tech/other/2005060306.htm, Sep, 06. 3 Wuhai municipality. Outlines of the eleventh five-year Housing development plan of Wuhai, (2006-11-10), http://www.nmg.xinhuanet.com/mscz/2006-11/10/content_8488498.htm, Sep.06 4 ASTM, (1999), E917-99 standard practice for measuring life-cycle costs of buildings and building systems, American Society for Testing and Materials, Philadelphia, Pa. 5 Arif Ileri, Shahrokh Moshiri, Common fuel and heating system options on the energy usage, pollutant emissions and economy. Energy and Buildings 38 (2006) 266–272 6 Afif Hasan.Optimizing insulation thickness for buildings using life cycle cost. Applied Energy 63 (1999) 115f124 7 G.A. Florides.etc. Measures used to lower building energy consumption and their cost effectiveness. Applied Energy 73 (2002) 299̢328 8 Drury B. Crawley, ect. Contrasting the capabilities of building energy performance simulation. Ninth International IBPSA Conference, Montréal, Canada,2005. http://gundog.lbl.gov/dirpubs/BS05/BS05_0231.pdf , Sep. 06 9 Dest introduction document http://www.dest.com.cn/chinese/theory/1introduce/DeST%20A%20Simulation%20Tool%20in%2 0HVAC%20Commissioning.pdf 10 Ministry of Construction of China. Design code for residential buildings. GB50096-1999 11 Chen sheng, Di hongfa. The analysis of thermal environment of several residential buildings in Beijing. Journal of Xi'an University of Architecture & Technology 33 (2001) 34-40 12 Ministry of Construction of China. Notes about collecting suggestions about new “Residential Building Energy Saving Design Standards”, (060802). http://www.cein.gov.cn/news/show.asp?rec_no=15026, Oct. 06 13 Hui, S. C. M., 2000. Building energy efficiency standards in Hong Kong and mainland China, In Proc.of the 2000 ACEEE Summer Study on Energy Efficiency in Buildings, 20-25 August 2000, Pacific Grove, California. 14 John Gilbert Architects. Swedish Housing Standards. http://www.johngilbert.co.uk/resources/swedish.html, Oct. 06 - 15 Hakan Falk. Thermal Building Codes for developing countries http://energysavingnow.com/buildingcodes/buildingcodedev.shtml, Oct. 06 16 Proposal for a Directive of the European Parliament and of the Council on the energy performance of buildings http://europa.eu.int/smartapi/cgi/sga_doc?smartapi!celexplus!prod!DocNumber&type_doc=COMi nal&an_doc=2001&nu_doc=226%20&lg=en, Nov. 06 43 Residential buildings energy performance of China 17 Ministry of Construction of China. 2005 statistical bulletin of city and towns housing situations, (0607). http://www.cin.gov.cn/statis/dt/2006070301.htm, Oct. 06 18 Xinjingbao. 15 billion housing area will be added in next 15 years. http://cn.realestate.yahoo.com/060419/394/27beg.html, Oct. 06 19 Notes on supply structure adjustment and price stabilization of residential housing. http://www.china.org.cn/chinese/PI-c/1223227.htm, Nov. 06 20 Hong Qing. Construction glass market development tendency analysis and prediction. Construction material database, 2006. http://info.research.hc360.com/2006/06/26103419950.shtml, Nov. 06 21 Ministry of Construction of China. Notice on print and distribution of “List of Energy saving, land saving construction technologies promoted by Ministry of Construction of China”, (060405). http://www.cin.gov.cn/INDUS/file/2006040508.htm, Nov. 06 22 Chinese Energy Conservation Research Institute. External insulation method investigation, 06083. http://www.chinajsb.cn/gb/content/2006-08/31/content_186543.htm, Nov. 06 24 Shanghai real estate market review: let common people take a share of development “cake”, (031227). http://business.sohu.com/2003/12/27/67/article217506715.shtml, Nov. 06 25 Wang Shouhua ect. Construction handbook, fourth version, 2003, China Construction press, pg 1390 26 Wang Shouhua ect Understanding and application of roof engineering technic codes, 2005, China construction industry press, pg 89 27 Minister of Construction of China. Survey on application of ground coupled heat pump in Beijing, 050401. http://www.cc.ln.gov.cn/lantu/lantu_hydt_view.asp?id=820, Nov. 06 28 Niaoling province Sci.& Tech. research center. All the new buildings in Shengyang will use ground coupled heat pumps in 2007, 061106. http://www.chinainfo.gov.cn/data/200611/1_20061106_146741.html, Nov. 06 29 Wuhai governmental information centre. Wuhai accomplished investment of 300 million on infrastructure construction. http://www.wuhaidj.com/snews/detail.asp?n_id=3630 30 Wuhai governmental information centre. Wuhai Heating supply construction plan of 2006 has been decided, 060308. http://www.wuhai163.com/show.asp?id=1069, Nov. 06 31 Heating, Ventilation & Cooling online information centre. Shengzheng culture centre heating & cooling stimulation and analysis, 060409. http://www.ehvacr.com/jszx/lw/jjjs/200604/3772.html, Nov. 06 32 Dest climate data base, stored in software package 33 Daihua. Application of cogeneration in Netherlands. SHANGHAI GAS 2000 No.2 P.28-34 http:/www.wanfangdata.com.cn/qikan/periodical.Articles/shmq/shmq2000/0002/000204.htm,Dec. 06 China renewable energy communication center. Summary of domestic and international municipal waste treatment situation. http://www.crein.org.cn/paperfiles/paper/tech- paper/citywaste.htm, Dec. 06 44 Residential buildings energy performance of China 35 Wuhai municipality. Suggestions on scientific exploration and use on water resources. http://www.wuhai.gov.cn/wuhaizhengxie/lanmu/readnews.php?tablename=jianyanxiance&id=12 36 China Science Energy. Basic theory of ground coupled heat pump. http://www.cseht.com/jsjl.htm, Dec. 06 37 Economic analysis of heat pump application http://engine.cqvip.com/content/tk/98197x/2005/000/001/gc13_tk1_12089666.pdf, Dec. 06 Comprehensive analysis report on underground water resources of Wulan village of Wuhai,2004 http://engine.cqvip.com/content/tv/90934a/2004/000/001/gc62_tv1_10289531.pdf, Dec. 06 Economic analysis of application of low temperature ground coupled heat pump http://www.cseht.com/%BC%BC%CA%F5%BD%BB%C1%F7/%B5%CD%CE%C2%B5%D8% C8%C8%C8%C8%B1%C3.htm, Dec. 06 Shengyang city will promote ground coupled heat pump for heating supply, 060919 http://news.soufun.com/2006-09-19/813919.htm, Dec. 06 Notes on aerated cement bricks, 061107 http://www.cin.gov.cn/tech/other/2006011077.htm, Dec. 06 Question on heating fee system of charging according to area, 060206 http://news.xinhuanet.com/fortune/2006-02/06/content_4140633.htm, Dec. 06 Feng Guoming. Discussion on heating fee on individual heating, Journal of Shanxi construction. volume 35, 2005, pg: 112-113. http://engine.cqvip.com/content/citation.dll?ID=11674473, Jan. 07 Huhohot, governmental heating fee compensation to low income residents can’t solve all the problems. http://news.xinhuanet.com/house/2005-11/14/content_3777488.htm, Jan. 07 45 Project context Evaluation of energy performance and cost of different energy saving solutions in residential Sustainable City project in Wuhai by IVL buildings of China New campain movements in China for energy saving in buildings sector Yang Xuan Supervisor better understanding of Chinese regulations, market Anna Jarnehammar (IVL) Lennart Nilson (KTH) better understanding of payback time of different suggested alternative products in local conditions better understanding of invisible barriers. The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Focus Methodology Literature review Information source: valid up-to-date internet resource, contacts in governmental and research organizations, products manufacture companies, construction companies and real estate development companies. Chinese regulations, residential buildings and current energy saving status in China On-site survey Current situation of Wuhai (Sustainable City project site) Two-week in Wuhai and Beijing Energy performance and cost of different envelopes and heating methods Energy consumption simulation Dest software: Auto-CAD aided program, takes consideration of thermal gains in the form of solar heat, heat given off by people, equipment, lighting, etc. District heating Barriers of introducing Swedish know-how Standardized method: following the steps proposed by Energy source Heating, ventilation and air conditioning design code, Heat pump used here for readjustment on caculation results Exterior wall Initial cost Envelope Window Calculation Roof Life Cycle Cost (LCC) Thermostatic radiator valves & meter Heat recovery ventilation system Operation cost Energy cost, wages, management fee, etc Heating fee Heating fee system The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 1 Map Several factors Energy Consumption and Cost Regulations the overall system, determine the minimum requirements in future. Building energy consumption efficiency (insulation quality, energy saving devices) Heating methods determines the original cost of heating consumption per unit. Heating fee system determines the cost born by end users. The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Regulations description-Overview Regulations description -overview Features of Chinese building regulations: Present target •Complicated system The present target is to achieve 50% energy savings by 2010 compared with the consumption of typical •Many different formats and types, from national energy laws, regional codes to department regulations. Chinese residential buildings (“base buildings”) designed in 1980–1981. (20% from thermal insulation and •Still developing 30% from building systems and management). As to building energy and related codes, it is the Ministry of Construction of China that is responsible for Component Material K-value Heat loss Sweden BBR issuing and publication of the main codes. Then local governments make their owns based on the main (w/k.m2) (%) (k value w/k.m2 ) codes. Exterior wall Solid brick(370mm) 1.57 25.6 0.18 Main codes: Exterior window Single glazed 6.4 23.7 1.3 Design Standard for Energy Efficiency of Residential Buildings in Hot Summer and Chilly Winter Zone Roof Flat hollow concrete 1.26 8.6 0.13 Stairwell wall Brick or concrete 1.83 10.8 (JGJ 134-2001) Design Standards for Energy efficiency of residential Buildings in Hot Summer and Warm Interior door Wood 2.91 2.8 Winter Zone (JGJ 75-2003) floor Reinforced concrete 0.3 2.3 0.15 Balcony door Plate steel 6.4 3.0 The residential energy code (JGJ 26-95 Infiltration* 23.2 Thermal design code for civil building GB 50176-93 Base building Design code for residential buildings. GB50096-1999 Most existied buildings are still similar to this type etc.. The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 2 Regulations description- Thermal insulation Regulations description -Heating, air-conditioning and ventilation Regulation comparision with Sweden In China, there is no single regulation covering all the fields of heating, air conditioning and Big gap between two countries can be easily found: ventilation. So several Chinese codes and basic information concerning those fields are listed below and can be referred to for further research. window Outer wall Outer roof floor slab outer door 2 Similar climate (W/m .K) 3.2 0.5 0.5 0.5 2.0 Heating China temperature control and heat allocation measures should be designed for each family. strictest(w/m2.k), China 1.7 0.33 0.33 0.28 1.5 No indication on what kinds of heating methods should be used. BBR* U values(w/m2.k), China 1.3 0.18 0.13 0.15 1.3 In 2000, EU was working on establishing the Danish Thermal Building code, identical to the Swedish Cooling prior 1978, to be a minimum directive for EU member countries. When applying the model building No Special requirements regulation in Denmark in each member state, energy consumptions of most of EU countries except Sweden decreased dramatically. Ventilation Required for kitchen and bathroom Air exchange rate 30 m3/h according to Indoor air quality standards No mention about heat recovery systems The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Residential buildings in China-General description Residential buildings in China-Insulation Growth rate: 1000 km2 Residential buildings area increase per year and would continue for Window another 10 years by estimation. Frame - Aluminium and Plastic steel Glass – from single glazing to double glazing 2 2 U values – from 4.1 W/ (m ·K) to 2.4 to 2.7 w/ (m ·K) Market ELOOLRQVTP \HDU Frame materials 10% UHVLGHQWLDOEXLGOLQJDUHD 35% 55% 20% Building Height: middle high rise residential building (seven to nine) and High rise 80% residential buildings (10 floors or more) are normal because of high population density Plastic others Aluminium Thermally broken Normal frame Apartment area: from June 1, 2006, 70% of units or more of the newly planned residential Market share of frames buildings should have usage area lower than 90 m2/unit, in order to control total housing price Aluminium frame market share Layout: slab layout and point layout 80% of glass is produced for single glazing The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 3 Residential buildings in China-Insulation Residential buildings in China-Insulation Exterior wall Roof Composite structure: Roof types: from flat roof to sloped ones ( reconstruction work) Layer: stones, concrete or bricks; Insulation material: polystyrene board and polystyrene foaming granule Market Thousands of companies exist for insulation materials, excluding small ones. Flat roof Slope roof The prices can vary a lot for quality difference. Insulation material Mineral wool In 2006 March, a list of around 20 companies is published by Ministry of Construction and PE board distributed to the governments, construction companies of different levels. The technology Board insulation layer EPS board and materials supplied by those companies would be considered first as the request of XPS board Ministry of Construction. Asphalt expanded perlite board Cast-in-place insulation layer Asphalt expanded perlite Cast in place XPS The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Energy related characteristics- heating method Energy related characteristics- Heating fee system District heating: the most common way Only according to heating area, not relates with energy consumption Reconstruction plan to replace pipes, install heating consumption meters, etc. Possible heating source (in Wuhai) Time scale Expectations Before 2006 Heating Season Part of Government office buildings should be reconstructed Before 2008 Heating Season All the government office buildings should be reconstructed Combined heat and power (CHP or congeneration) 2006-2010 ( 11th Five Year’s Plan) Reconstruction proportion of the existing buildings Big cities: 35%; Middle cities: 25%; use by-product heat of electricity power station as the heat source for district heating Small cities: 15%; 2006-2010 ( 11th Five Year’s Plan) All the newly built buildings Hydronic boilers burn coal, gas or bio fuels to generate hot water for heating Barriers unclear heating fee standards, bad envelope insulation quality, heavy reconstruction, work and technical problems of devices. Heat pumps Transfer heat from air, ground or water to apartment or in opposite direction. The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 4 Energy related characteristics-Cooling & Ventilation Wuhai Status (Sustainable City) Cooling Market description Traditional air conditioner or fan average income of citizens: 15000 SEK/year apartment price: 1700 SEK/ sq m2 in city centre Current Situation most buildings don’t meet current standards Ventilation Transitional period with suggested method from 2006: Opening windows and doors or air exchange fan 370 mm brick + 60 mm EPS Double glazing window No special pipe network for ventilation Heating source: Cogeneration heat and power with coal as fuel, hydronic boiler with coal Heat recovery ventilation: gradually accepted after SARS (Severe Acute Respiratory Heating fee: according to area, decided by Price Bureau but not market for welfare reasons Syndrome) in 2002. In the market, there are several dozens of companies which supply heat Development recovery ventilators. Technologies or products are mainly developed from Japanese or French ones. Huge reconstruction work in near future to meet energy saving standards Residents’ attitudes Energy performance of buildings is not taken into consideration when buying house Sensitive to price fluctuation of public goods ,especially old generation Domestically made products may be low quality but foreign ones are expensive The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Calculation Strategy Calculation Strategy Audience Group Payback time Calculation results might have little impact on final decisions if the audience group is not identified or if we imposed our so called good ideas without enough or right communication. The payback time of higher price products should not exceed 5 years at most, otherwise it would be quite difficult to convince consumers to buy, or government to agree Government is seen as audience group For example, a governmental officer usually will not stay at the same place for five years, so achievements after 5 years are not his anymore. Energy saving activities are policy oriented instead of market driven Benchmark The current 50% energy saving standard as the benchmark for the comparison Stakeholders Function& Power Aim Government Set up the rules for actors Fulfill the mission set by central government (departments, Supervision on actors Increase financial income and reduce debt. Proposed as the second best Redesign or quit design institute) Absolute authority Minimize costs to society Best alternative Ability to intervene the market Pursue political and economic achievements with governmental orders Heat company Government owned welfare 10 year Supply heating 5 year company Developer Develop houses under the rules Invest less money for higher profits Consumers Buy or not Spend less money for higher quality house The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 5 Simulation - Building description Simulation-Climate condition Building Model: 'DLO\7HPSHUDWXUH ć˅ 'U\EXOEWHPSHUDWXUH GDLO\DYHUDJHWHPSHUDWXUHV ć GDLO\KLJKHVWWHPSHUDWXUH ć GDLO\ORZHVWWHPSHUDWXUH ć Use local weather condition The heating season : from November 1 and April 1. (Model made by CAD) During most of the time in winter, the outside temperature is lower than -5 degree or even -10 degree. Thus, The building comprises 5 floors with 2 apartments, 1 unheated stairway, usuage air coupled pump may not be a good choice concerning the current technology level and possible cost. area 86 sq m2/unit. The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Simulation-Heating method Simulation-Hydronic boilers Cogeneration The initial investment of boilers with coal :100 yuan/m2. the best available technology in Wuhai Running expenses (coal, water, electricity fee) : 13.5 yuan/m2. heating season (1) abundant coal resource No. Items Price Amount (2) short distance between cogeneration plants an heating districts 2 (3) possibility of CDM project when transferring fuel types. 1 Coal, water, and electricity fee 13.5 yuan/m 2 Management fee (wages) 700 yuan/cap. month 2 For places where pipe network of Cogeneration can’t reach: allowances for repairs and 3 1.8%*initial investment maintenance Hydronic boilers Vs Heat pump 4 Company management fee 2.5%*(1+2+3+4) 5 Total cost 1+2+3+4 Hydronic boiler still in use in some places Here we assume that the running expenses correlates with heat consumption. Then we can get the following Heat pump formula: There are more than 700 water wells in Wuhai and the average density of well is 1.2 well/square kilometres. current running expenses Possibility to use water coupled heat pump in parts of the area running expenses heat consumption current heat consumption The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 6 Thermal conductivity Conductance U Total cost Wall type Thickness(mm) Simulation-Heat pump Simulation- Envelope type (w/m.k) (W/m2.k) (yuan/m2) Wall 1 390 1.57 40 Clay brick 370 0.814 The data from a heat pump project located in Tianjin city Plaster 20 0.814 is chosen as a reference Wall 1(base building) is Wall 2 470 0.518 145 commonly used during 80s, Clay brick 370 0.814 The system is designed for both heating and 90s and the main target for the Plaster 20 0.814 conversion work. Wall 2, 3, 4 Expanded polystyrene cooling 60 0.041 (EPS) 60% of initial investment as the initial investment for are promoted by the Plaster 20 0.814 heating system part government and normally used and wall 5 is also a good Wall 3 320 0.57 145 alternative. porous brick 240 Electricity fee= heat consumption/COP electricity price Plaster 20 0.814 COP: Coefficient of performance, usually 3 Expanded polystyrene 60 0.041 (EPS) No. Items Price Amount Average of 2,3 4, 5: Plaster 20 0.814 representative wall Wall 4 320 0.7 135 See formula 1 Electricity fee 0.37 yuan/ kWh porous brick 240 above Plaster 20 0.814 Expanded polystyrene 2 Management fee(wages) 700 yuan/cap.month 1 60 0.06 granule allowances for repairs and 3 1.8%*initial investment Plaster 20 0.814 maintenance Wall 5 340 0.609 75 4 Company management fee 2.5%*(1+2+3+4) Plaster 20 0.814 5 Total cost 1+2+3+4+5 Aerated concrete block[i] 300 0.209 Plaster 20 0.814 The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Simulation- Envelope type Simulation- Envelope type Representative wall Envelope Type U value Cost Conductance Window(1) Single glazing window 4.7 150-250 yuan/ m2 Total cost Wall type Thickness(mm) U (yuan/m2) 2 (W/m2.k) Double glazing window with Plastic steel 2.7-3.1 210-350 yuan/ m frame *the heat capacity of materials is not considered R wall 363 0.6 125 here. Double glazing with heat broke aluminium 2.7-3.1 400-800 yuan/m2 frame *Price list: (used for price calculation above ) Flat roof or slope roof N/V 250-350 yuan/ m2 Roof (2) 2 Component type Materilas type Cost Slope roof with attic N/V +1000 yuan/m Aerated concrete 45-48 yuan/m2 Clay brick(37cm) 35 yuan/m2 (1) The prices of windows, even of same type, can vary a lot. Here the selection of prices 2 is based on construction material price list of Baotou. The brands are Fenglv and Hailuo. Basic layer Hollow clay brick(37cm) 35 yuan/m Concret bricks (240) 35 yuan/ m2 (2) The cost of flat roof is not available now. However, based on experience from reconstruction project, we Expanded polystyrene (EPS) (60mm) 85-130 yuan/ m2 Exterior wall(1) assume that the sloop roof is 300 yuan/m2 or 1000 yuan/m2 higher than flat roof. Expanded polystyrene granule (60mm) 100 yuan/ m2 Insulation layer Extruded polystyrene (XPS) (40mm) 95-148 yuan/ m2 Mineral board (100m) 30-40 yuan/m2 The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 7 Simulation- Heat Recovery Ventilation System Simulation- Discount& inflation rate The market price is around 2000 yuan/unit, including installation fee. Coefficiency of Performance is from 3 to 4 Items Inflation rate source Assumptions for energy saving calculation Discount rate 4.14% Bank load rate •airtighness of envelopes is good average inflation rate of Boiler 8% water (12%), electricity (2%) and coal (10%) •standard of 0.5 time /h air exchange rate can be fully achieved Resource cost Electricity price Heat pump 2% Operation cost inflation rate Calculation formulas Wage 14% data of 2005 Repairs and maintenance 2% Consumer index Temperature of fresh air to house = (indoor temperature-outdoor temperature)* heat recovery rate +outdoor temperature The energy saved= (fresh air to house temperature-outdoor temperature)* heat recovery rate* air volume* air density* air heat capacity The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Calculation Calculation –envelope system Heat consumption: calculated by the software of DeST and adjusted by the standardized method. Current situation (base building) Single glazing, 370 mm wall without insulation, normal flat roof, no thermostatic valves Two heating sources: hydronic boilers and heat pumps. Thermostatic valves Single glazing, 370 mm wall without insulation, normal flat roof, thermostatic valves The calculation year is 2007. Improved building envelopes Interface of Dest Double glazing, wall R (representative wall), and roof 100mm, thermostatic valves Triple glazing window Triple glazing, R wall (representative wall) and roof 100mm, thermostatic valves 370mm wall with 100 mm EPS insulation Double glazing, 370mm wall with 100 mm EPS insulation and roof 100mm, thermostatic valves Roof with 150 mm EPS insulation Double glazing, wall R (representative wall), and roof 150mm EPS, thermostatic valves Triple glazing, 370mm wall with 100 mm EPS insulation and roof 150mm, thermostatic valves Mineral wool Triple glazing, 370mm wall with 100 mm and roof 150mm of mineral wool, thermostatic valves The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 8 Calculation U Values Price Total cost Heat consumption No Envelope components (w/m2.k) yuan/m2 yuan/m2 KW.h/m2 Calculation Energy consumption Single glazing 4.7 32.09 370 mm wall without insulation 1.57 34.43 Envelope cost Vs energy consumption with different envelopes 1 126.521 75.02 Normal flat roof 1.26 60 No thermostatic valves ------ Analysis results Single glazing 4.7 32.09 1 370 mm wall without insulation 1.57 34.43 as the insulation cost increases, there is not much space left 2 128.521 53.4* to reduce the heat consumption Normal flat roof 1.26 60 2 thermostatic valves --- 1.54 the change from double glazing to tri-glazing only makes \HDU slight difference on energy consumption Double glazing 3 38.68 3 5 4 better insulation of roof doesn’t give much impact on the Wall R 0.6 107.60 8 6 3 241.8 25.83 NZKP 7 overall energy performance of the building Roof with 100 mm EPS insulation 0.417 94 HQHUJ\FRQVXPSWLRQ FRVW\XDQP Thermostatic valves --- 1.54 mineral wool can achieve a better insulation quality with lower cost Triple glazing 1.8 46.96 Wall R 0.6 107.60 (36LQVXODWLRQ PLQHUDOZRRO 4 250 23.45 Roof with 100 mm EPS insulation 0.417 94 Thermostatic valves --- 1.54 Double glazing 3 38.68 370mm wall with 100 mm EPS 0.417 142.03 5 insulation 276.25 18 Roof with 100 mm EPS insulation 0.417 94 Thermostatic valves --- 1.54 ...... The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Calculation Payback time operation cost of heat pump and boiler Analysis result: NPV for alternative 1= NPV1 initial investment+ NPV1 operation cost operation cost curve of heat pump is lower D NPV for alternative 2= NPV2 initial investment + NPV2 operation cost than that of coal boiler the lower the energy consumption, the NPV for alternative 1- NPV for alternative 2= NPV1 initial investment+ smaller differences of operation cost between two alternatives NPV1 operation cost -(NPV2 initial investment + NPV2 operation cost )= ( NPV1 initial investment - NPV2 initial investment )+ (NPV1 operation cost- NPV2 operation cost )= NPV initial+NPV 5 or NPV 10 RSHUDWLRQFRVW\XDQP (QHUJ\FRQVXPSWLRQ.ZKPD Heat pump with Better envelope Triple glazing, KHDWSXPS %RLOHU Mineral wool insulation Heat pump with 100 EPS wall insulation, One conflict comes out: Thermal valves normal envelope implementation of better insulation technology reduce the positive economic effects of 150 EPS roof insulation, using heat pump using heating methods of less operation cost will prolong the payback time of using better 5 year 10 year insulation technologies and materials Payback time categories of products The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 9 Conclusions & suggestions Suggestions For the moment the market is a trial and error with a lot of different ways to fulfill the new Payback time regulations. In general, we can see energy saving market of China is now coming to a transitional Mineral wool and Thermal valves are good alternatives. Thicker EPS , triple glazing, Heat period. pump are open to question. To Swedish companies: Market status (1) be careful with payback time The voice of Swedish companies in built environment sector is very small. (2) be more aggressive in network and market exploration. Middle/Small Swedish companies, if want to enter Chinese market, will face fierce competition both from Chinese domestic and international competitors. (3) Find the right group if without Swedish government’s aid money as backup.( for example, governmental design institutes or big developers should be the ones to contact first ) Heat fee system The current heating fee system (charging fee according to heating area but not real heat consumption) is the biggest obstacle to promote products with better energy saving effects. No volunteer activities can be expected without renovation on this heating fee system. The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ Something beside thesis Real Estate Status in Beijing Development Cost Apartment market price Average monthly income per person Land: 1500 Construction: 1500 Bank load interest: 500 Thanks very much!! Design fee: 40 Advertisement: 200 In total: 3740 yuan/m2 Average: 10000 yuan/m2 2000yuan/moth.cap (In wuhai, 1000yuan/m2) (In wuhai, 1800yuan/m2) (In wuhai,1500/ moth.cap) 1 real estate is a high profit industry 2 it is difficult for normal people to buy an apartment 3 huge demand for built environmental products The results of this study regarding air pollution is administered by IVL. The results of this study regarding air pollution is administered by IVL. www.ivl.se More information, data and reports are to be found at www.ivl.se More information, data and reports are to be found at www.ivl.se/en/rapporter/ www.ivl.se/en/rapporter/ 10 TRITA-IM 2007:29 ISSN 1402-7615 Industrial Ecology, Royal Institute of Technology www.ima.kth.se