Climate Resilience Feasibility Study of Facilities at Fraser Canyon Hospital
Michal Bartko and Iain Macdonald
A1-010678.2
29 September 2017 Climate Resilience Feasibility Study of Buildings at Fraser Canyon Hospital
Author Michal Bartko, Ph.D. Research Officer
Approved Trevor Nightingale, P.D. Program Leader, High Performance Buildings, NRC Construction
Report No: A1-010678.2 Report Date: 29 September 2017 Contract No: A1-010678 Agreement date: 16 December 2016 Program: High Performance Buildings
26 pages
Copy no. 1 of 4
This report may not be reproduced in whole or in part without the written consent of the National Research Council Canada and the Client.
CLIMATE RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
Table of Contents
List of Figures ...... v List of Tables ...... v Executive Summary ...... vii 2. Introduction ...... 1 2.1 Methodology ...... 2 2.2 Fraser Canyon Hospital, Hope ...... 2 3. Site Visit and Analysis ...... 3 4. Weather Data Analysis ...... 5 4.1 Future Weather Predictions ...... 8 4.2 Analysis of on-site sensor recorded data ...... 12 5. Variables with the Highest Impact on Energy Efficiency ...... 15 6. Building Models ...... 15 6.1 Analysed Cases ...... 17 6.2 Results of Simulations ...... 17 6.2.1 Acute and Lodge Buildings ...... 17 6.2.1.1 Cooling Energy Consumption ...... 17 6.2.1.1 Cooling Coil Capacity ...... 19 6.2.2 Lodge Addition Building ...... 20 6.2.2.1 Cooling Energy Consumption ...... 20 7. Scenario Evaluation ...... 22 8. Energy Performance Evaluation Tool ...... 23 9. Summary and Discussion ...... 23 Appendix A: Buildings of Fraser Canyon Hospital Appendix B: Summary of the Model Inputs Appendix C: Building Envelope Retrofit Scenarios
Final Report A1-010678.2 iii CLIMATE RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
Final Report A1-010678.2 iv CLIMATE RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
List of Figures
Figure 1. Examples of Infrared (IR) photos used for building envelope analysis ...... 4 Figure 2. Example of data logger placement for longitudinal measurement of temperature and relative humidity ...... 5 Figure 3. Summer outdoor air temperatures (2009 to 2011)…………………………………….…..6 Figure 4. Summer outdoor air temperatures (2012 to 2014)…………….…………………….…….7 Figure 5. Summer outdoor air temperatures (2015 and 2016)……………………………….……...8 Figure 6. Summer outdoor air temperatures for 2016, and predictions for 2020 ...... 10 Figure 7. Summer outdoor air temperatures predictions for 2050 ...... 11 Figure 8. Comparison of average Monthly (June to September inclusive) outdoor temperatures for 2016, and predicted values for 2020 and 2050 ...... 11 Figure 9. Outdoor and indoor temperature runs, example June 2017…………………………… 12 Figure 10. Outdoor and indoor relative humidity runs, example June 2017……….. …………… 12 Figure 11. Thermal Comfort Conditions by ASHRAE……………………………………………… 13 Figure 12. Geometrical model of Acute and Lodge buildings ...... 16 Figure 13. Geometrical model of Lodge Addition building ...... 16 Figure 14. Cooling energy consumption for the Acute and Lodge buildings for two occupancy conditions: (i) Standard , and; (ii) Worst case scenario for (June to September inclusive) of 2016 and that predicted for 2020 and 2050 ...... Error! Bookmark not defined.18 Figure 15.Total Cooling Energy Consumption for Acute and Lodge Buildings…………………. 19 Figure 16. Cooling coil capacity: Acute and Lodge Buildings ...... 19 Figure 17. Future predictions of indoor temperature above set point temperatures ...... 20 Figure 18. Cooling energy consumption for the Lodge Addition building for two occupancy conditions: (i) Standard , and; (ii) Worst case for (June to September inclusive) of 2016 and that predicted for 2020 and 2050...... Error! Bookmark not defined.21 Figure 19. Cooling coil capacities for various retrofit scenarios…………………………...……… 22 Figure 20. Future predictions for HVAC system demand…………………………………………..25
List of Tables
Table 1. Matrix of simulation instances ...... 17 Table 2. Cost estimates of retrofit options…………………………………………………………... 23
Final Report A1-010678.2 v CLIMATE RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
Final Report A1-010678.2 vi CLIMATE RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
Executive Summary
In January 2017, Lower Mainland Facilities Management (LMFM) and the National Research Council (NRC) launched an energy and climate resilience feasibility study. This study focused on the Fraser Canyon Hospital (FCH) in Hope, BC. The FCH study was intended to help inform how the FCH facility may be retrofitted and how new facilities may be designed, to reduce risks and increase resilience in the context of B.C.'s climate change reality. Specifically, the project will contribute to FH’s work in assessing and developing resiliency plans for 50% of their core sites by 2020 and 100% by 2025.
This final report provides a summary of work and reports on findings from five activities:
Site visit to the Fraser Canyon Hospital (FCH) to interview operations staff, administrators, and conduct a review of building energy systems to help inform whole building performance models; FCH performance assessment (ability to maintain acceptable indoor environmental conditions) for current and future weather conditions using whole building performance models; Retrofit scenario evaluation; Analysis of indoor temperature and relative humidity (RH) data recorded by sensors installed during the site visit; Development of a simple software tool to enable evaluation of alternative energy efficiency measures and to explore which measures have the greatest potential for energy reduction/savings and GHG reduction.
Key findings from the study include:
FCH operations and administration staff report elevated temperatures in the building during events of extreme heat. Operations staff reported that the HVAC system was operating at full capacity most daytime hours during the summer. Maximum recorded indoor temperature did not exceed 24°C between January 26th and June 26th 2017. Thermal bridging as well as air leakage apparently was occurring in susceptible places such as wall-floor and wall-roof connections and at window locations within the walls. Several retrofit options were numerically evaluated for the FCH facilities. The most desirable solution when considering energy efficiency, environmental impact, potential emergency situations as well as retrofit costs included building envelope upgrades to achieve greater thermal resistance and horizontal shading elements above windows; additionally, these upgrades permitted attaining grater levels of climate resiliency.
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Climate analysis: Weather projections for years 2020 and 2050 were made using a commercial tool. The annual maximum temperature was predicted to increase from 36°C in 2016 to 40°C in 2020 and 44°C in 2050. The number of days in a year when the ambient temperature exceeds 30°C is predicted to increase from 9 days in 2016, to 23 days in 2020, and to 36 days in 2050. Therefore the risk of extreme heat impacting FCH delivery of medical services will increase unless mitigation measures are implemented.
Whole building performance analysis: Base-building loads due to heat loss/gain through the envelope are the dominant load for the HVAC system. In the future the HVAC system will have insufficient capacity to respond to the predicted increased severity of extreme heat events. Simulations for the future years (2050) showed there would be a 50% increase in cooling load and that cooling coil capacity would have to increase by 30% to offset this increased load. As a result, without effective mitigation it is reasonable to expect the number of events when the thermal comfort is not maintained will increase with time. Modeling results and thermal imaging highlighted the need to consider envelope upgrades as a mitigation measure. Increases in capacity and efficiency of the HVAC system are also required.
Indoor temperature and Relative Humidity (RH) data analysis: Indoor temperatures and RH in 15 locations in all three FHC facilities were monitored between February and June 2017. During this period several days with higher than normal external temperatures were recorded by the Hope Airport weather station. Corresponding indoor temperatures increased to max 24°C and RH to max 60%. Both variables were within or at the limit of standard thermal comfort requirements.
Retrofit scenarios evaluation: Six options were evaluated. Out of the six options, retrofitting the building envelope to increase the thermal resistance to R35 for walls and R50 for roofs, in combination with horizontal shading of windows to control solar gain represents the most feasible option considering economical, and energy performance criteria.
Simplified energy efficiency evaluation tool: A simple stand-alone web-based tool was developed to evaluate energy performance of the model considering future weather predictions for the years 2020 and 2050.
Final Report A1-010678.2 viii CLIMATE RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
Climate Resilience Feasibility Study of Buildings at Fraser Canyon Hospital
by Michal Bartko, PhD and Iain Macdonald, PhD
1. Introduction
In spring 2016, lower mainland facilities management (LMFM) conducted high-level climate resilience assessments on five Fraser Health (FH) and Vancouver Coastal Health (VCH) acute care facilities. Based on discussions with on-site staff, operational strains due to extreme weather events were identified. Extreme heat was identified as particularly problematic in 2009 and 2015.
With projected increases in frequency and severity of extreme heat events, LMFM explored with Health Canada (Climate Change and Innovation Bureau) and the National Research Council (NRC) options for in-depth technical analyses to gauge how current buildings and assets may respond to future extreme heat events and how to minimise operational impacts caused by elevated temperatures in these facilities.
In January 2017, LMFM and NRC launched an energy and climate resilience feasibility study. This study focused on the Fraser Canyon Hospital (FCH) in Hope BC. The FCH study is intended to help inform how the FCH facility may be retrofitted, and how new facilities may be designed, to reduce risks and increase resilience in the context of B.C.'s climate change reality.
This final report provides a summary of work and reports on findings from five activities:
Site visit to the Fraser Canyon Hospital (FCH) to interview operations and maintenance staff, administrators, and conduct a review of building energy systems to help inform whole building performance models; FCH performance assessment (ability to maintain acceptable indoor environmental conditions) for current and future weather conditions using whole building performance models; Analysis of indoor temperature and relative humidity (RH) data recorded by sensors installed during the site visit; Retrofit scenario evaluation; Development of a simple software tool to evaluate alternative energy efficiencies of the model by changes to the parameters with highest impact on energy consumption.
With care, the results presented here could be generalised and used to provide a very early indication of risk for the Province’s portfolio of hospitals as well as to motivate further work to fully assess the risk and develop a robust mitigation strategy through whole building energy models informed by weather data projections as far out as 2050.
Final Report A1-010678.2 1 CLIMATE RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
1.1 Methodology
Information on extreme heat and humidity events occurring during the 2009-2016 period, including reports by facility and emergency management personnel on operational impacts, was reviewed to develop a representative extreme event for model calibration. For this project an extreme event is defined as one presenting an operational challenge that the site could not respond to with resources readily available, within a reasonable timeframe. There are a number of steps in this phase which are described below:
Problem definition — Key background information was reviewed to establish additional information required for collection at the site. Develop whole building model(s) — Scalable models were created to simulate the building and its energy systems to obtain estimates of the environmental conditions in the building just before, during, and just after the climatic event(s). The model(s) were calibrated using weather data, energy data and BAS data. Root cause determination — Calibrated model(s) were used to identify the root cause of the impact (i.e., which energy systems were unable to effectively respond to the extreme heat and humidity). Models were calibrated to the peak events between 2009 and 2016. Scenario evaluation — The models were used to assess the effectiveness of various mitigation options for high indoor temperature and high RH mitigation. Models consider components of the complete HVAC system, envelope, etc. For each option a rough order of magnitude cost is given. Each option was tested against the environmental extremes in the period 2009 to 2016, and temperature and humidity extremes projected for 2050 with different intensities and durations. The 2050 weather projections are based on an A2 scenario of Special Report on Emissions Scenarios (SRES) by Intergovernmental Panel on Climate Change (IPCC).
1.2 Fraser Canyon Hospital, Hope
The municipality of Hope, British Columbia with population of approximately 6000 is located at the eastern end of Fraser Valley and southern end of Fraser Canyon. Local climate is humid all year around averaging at 65%, with recorded extreme temperatures of +40.6°C in summer and -25°C in winter.
The building complex at Fraser Canyon Hospital located in southern part of Hope consists of three buildings:
1. Acute Care – Built in 1958 with parts added in 1990 this building is two storeys with spaces for patient recovery, Operation Room, Labs and mechanical systems 2. Lodge – Built in 1990 this is primarily a long-term care facility for the elderly; and 3. Lodge Addition – Built in 2007 this provides expanded capacity for long-term care of the elderly.
Photos of each of these buildings are provided in Appendix A.
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2. Site Visit and Analysis
On January 26th 2017 a site visit was conducted. NRC met with the operations and administration staff to learn how staff and patients were impacted by severe heat. NRC also conducted an inspection and review of the building energy systems.
Interviews with the Administrator revealed that during extreme heat events there is the perception that the temperature in the hospital does rise and may accelerate fatigue by medical staff.
FCH operations staff provided the NRC team with a complete tour of all HVAC facilities in the buildings and provided details of HVAC operation during extreme heat events. It was reported that the “HVAC systems cannot keep-up” with the thermal loads during events which is consistent with the reports from the Administrator of increased temperature in FCH. The tour provided an opportunity to confirm equipment identified in previous energy audits, identify large process loads (lab and kitchen equipment, etc.) and thus inform whole-building energy models made by NRC.
In addition to the HVAC system review a thermal performance survey was conducted using an Infrared (IR) camera; examples of IR photos used for the building envelope analysis are given in Figure 1.
The analysis of the IR images, examples of which are given in Figure 1, showed that the Acute building with concrete walls had a higher potential for thermal losses in and showed evidence of thermal bridging. Thermal bridging at stud locations was also apparent for the exterior walls of both Lodge buildings. Thermal bridges and air leakage occurs in susceptible places such as wall-floor connections and at window through-wall penetrations. It is typically caused by inadequate sealing at the perimeter of the components which leads to air leakage in cold months.
In addition to the IR survey, 15 data loggers were deployed in various locations throughout all three buildings. An example of a data logger location is shown in Figure 2. Data are presented later in this report.
Final Report A1-010678.2 3 CLIMATE RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
Figure 1. Examples of Infrared (IR) photos used for building envelope analysis.
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Figure 2. Example of data logger placement for measurement of temperature and relative humidity.
3. Weather Data Analysis
An initial analysis of the Airport Hope weather station data for the period 2009 to 2016 was conducted to identify periods when extreme heat events occurred. These periods were defined as times when the ambient dry bulb temperature exceeded 30°C. The following periods were identified:
2009: June 1st to 4th, July 27th to August 2nd 14 days 2010: July 7th to July 10th, August 12th to 17th 8 days 2011: August 21st, September 10th, 11th 3 days 2012: August 4th to 8th, August 15th to 18th 8 days 2013: June 29th to July 1st, July 15th and 16th, September 10th to 14th 6 days 2014: July 10th to 16th, July 28th to August 4th 8 days 2015: June 25th to July 9th, July 17th to 19th, July 29th to August 3rd 25 days 2016: August 18th to 26th 10 days
In general, for the period 2009 to 2016 a trend in the maximum ambient (outdoor) dry bulb temperature increase was not observed. However, the number of days with critical temperatures (duration of heat waves) increased from 1 to 4 days in 2009 and up to 3 to 6 days in 2016 with an extreme example of 15 consecutive days of excess heat occurring in 2015. After investigating daily peak temperature, the variation of temperature with time of day was analysed. This analysis revealed that the average duration of outdoor ambient temperatures above 30°C is 6 to 8 hours (rising between 11am and 1pm and decreasing between 5pm and 7pm). In a few extreme cases the duration was 10 hours. Examples of summer outdoor air temperatures for years 2009 to 2011 are given in Figure 3, 2012 to 2014 in Figure 4 and for 2015 and 2016 in Figure 5.
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40 2009
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20 deg C deg
10 14 days above 30°C
0
40 2010
30
20 deg C deg
10 8 days above 30°C
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40 2011
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20 deg C deg
10 3 days above 30°C
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Figure 3. Summer outdoor air temperatures (2009 to 2011).
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40 2012
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40 2013
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40 Figure 4. Summer outdoor air2015 temperatures (2012 to 2014).
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CLIMATE0 RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
40 2015
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Figure 5. Summer outdoor air temperatures (2015 and 2016).
Additionally, using data from weather station at the local airport obtained from Environment Canada, weather analysis for summer 2017 was added. The maximum outdoor temperatures exceeded 30°C in sixteen days:
2017: June 24th, August 1st to 4th , August 26th to 30th, September 2nd to 6th 16 days
3.1 Future Weather Predictions
Environment and Climate Change Canada is currently updating weather predictions for future years as part of a comprehensive program on climate change. In the absence of these updated weather predictions, data for this study were generated using a University of Southampton study1 in which a weather morphing procedure was applied to the current weather data to provide weather predictions for the years 2020 and 2050.
1 Mark F. Jentsch: Climate Change Weather File Generators, Technical reference manual for the CCWeatherGen and CCWorldWeatherGen tools, Version 1.2, Univ. of Southampton.
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The approach was based on Scenario A2 of the Special Report on Emissions Scenarios2 (SRES) utilized before year 2014, when it was superseded by the Representative Concentration Pathways3 (RCP). In terms of the current evaluation methodology the SRES A2 scenario falls slightly above the RCP6.0 scenario for the year 2100 for which CO2 emissions were predicted as 800ppm (A2) and 730ppm (RCP6.0) respectively.
Figure 6 and Figure 7 show that the projected maximum temperature in the summer period will increase from 36°C in 2016 to 40°C in 2020 and 44°C in 2050. Also the number of days above 30°C is projected to increase from 9 in the present model (2016) to 23 days in 2020 and 36 days in 2050. Summers are projected to have greater highs and there will be more days with temperatures above 30°C.
A comparison of the average monthly outdoor temperatures for the months of June to September, inclusive, in 2016 and predicted values for 2020 and 2050 for the same months is provided in Figure 8. As can be seen, all projected values for monthly average temperature are to rise in 2020 and again in 2050 in comparison to those of 2016.
2 Special Report on Emissions Scenarios, IPCC 2000, Cambridge University Press, ISBN 0 521 80081 1 3 https://en.wikipedia.org/wiki/Representative_Concentration_Pathways
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2016 9 days above 30°C
2020 23 days above 30°C
Figure 6. Summer outdoor air temperatures for 2016, and predictions for 2020. 2050
Final Report A1-010678.2 10 2016
2020
CLIMATE RESILIENCE FEASIBILITY STUDY OF FACILITIES AT FRASER CANYON HOSPITAL
2050 36 days above 30°C
Figure 7. Summer outdoor air temperatures predictions for 2050.
30.0 june july Average Outdoor Temp, °C august september 25.0
23.3 23.9 20.0 21.1 21.1 20.0 19.4 18.9 17.8 17.2 15.0 16.1 16.1 15.0 10.0
5.0
- 2016 2020 2050
Figure 8. Comparison of average Monthly (June to September inclusive) outdoor temperatures for 2016, and predicted values for 2020 and 2050.
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3.2 Analysis of on-site sensor recorded data
Between January 26th 2017 and June 27th 2017 temperature and relative humidity data were continually recorded every 15 minutes at 12 locations throughout the three buildings where care staff work. On August 29th 2017 during the second site visit, the devices were retrieved for later analysis of the data. (3 sensors were not found on deployed locations). During the period of data logging, there was only one day (24th of June) when the outdoor temperature was above 30°C at the local weather station at the Hope airport. Figure 9 shows an example of the corresponding indoor air temperature for the fourth week of June 2017 for the sensor placed in a patient room with south east orientation, at the Level 1 of the Acute Care building. 35
30
25
C ° 20
15
Temperature, 10 T out 5 T in 0 21-Jun 22-Jun 23-Jun 24-Jun 25-Jun 26-Jun 27-Jun 28-Jun
Figure 9. Outdoor and indoor temperature runs, example June 2017.
100 90 80 70 60 50 40
30 Relative Relative Humidity, % 20 RH out 10 RH in 0 21-Jun 22-Jun 23-Jun 24-Jun 25-Jun 26-Jun 27-Jun 28-Jun
Figure 10. Outdoor and indoor relative humidity runs, example June 2017.
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The indoor temperature oscillations between 20.5 and 23.5°C were recorded, while outdoor temperature varied between 8.3 and 31.5°C. The RH runs for the corresponding periods are shown in Figure 10.
The above sensor data example represents the highest variations of all sensors. Analysis of data recorded by remaining sensors in rooms with occupancy showed temperature variations within 2°C ranging between 22 and 24°C. Relative humidity values varied between 30 to 60%. Both Temperature and RH variations for all monitored locations are within the range of thermal comfort requirements by ASHRAE 55 standard (discussed below).
3.3 Predicted Thermal Comfort
In this study thermal comfort was predicted using the methodology defined in ASHRAE Standard 554 with estimates of temperature and relative humidity obtained from energy model5 predictions specific to the FCH. Thermal comfort is a highly individual factor affected by numerous factors: metabolic rate, clothing insulation, air temperature & radiant temperature (combined for operative temperature), air speed and relative humidity. Depending on relative humidity levels, the operative temperature can vary between 21.5 and 28°C with natural air exchange (0.1m/s air speed). The RH levels should be in the range 20 to 60%. The thermal comfort conditions as defined by ASHRAE are presented in Figure 11.
4 ANSI/ASHRAE Standard 55: Thermal Environmental Conditions for Human Occupancy (2013). 5 ASHRAE 90.1: Energy Standard for Buildings (Hospitals Template).
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Figure 11. Thermal Comfort Conditions by ASHRAE.
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4. Variables with the Highest Impact on Energy Efficiency
The total thermal load of a building is the sum of base-building loads (required to offset heat transfer though the building envelope and are typically defined by HVAC loads) and process loads (associated with equipment associated with the business or activities within the building).
Often for non-industrial buildings, base-building loads associated with heath flow through the building envelope are more important than process loads. This is the case for the FCH (as shown in Figure 14 where increasing occupancy by 100% (impacting mostly process loads) results in a change of about 15% in total building load).
Walls and roofs are often designed to prescriptive thermal resistance values in code. For the climate zone in which the FCH is located would require: R20 for walls and R30 for roofs, according to the NECB 2015. The air leakage impact can also be significant. Air leakage however is highly dependent on air barrier design details and the quality of workmanship during construction stage. As such, it is very difficult to model. The value of air flow change rate per hour for occupied spaces was considered 2.0; relatively large value, typical of the vintage of the FCH buildings. HVAC efficiency, shading and building occupancy play also important role in evaluating overall energy efficiency of buildings.
5. Building Models
The FCH buildings were modelled using OpenStudio6: a collection of software tools to support building energy modelling. The OpenStudio uses the US-Department of Energy (DOE) developed EnergyPlus7 simulation program. EnergyPlus is widely recognised in North America as the most effective and flexible platform for modelling whole building performance. EnergyPlus enables coupled heat and mass transfer modelling for hourly or sub-hourly time steps; allowing for integrated, simultaneous solution of conditions in thermal zones and HVAC systems response. The software is capable of modelling radiant and convective heat effects that affect surface temperatures, thermal comfort as well as condensation calculations.
Figure 12 shows a representation for the energy model for the Acute and Lodge buildings and in Figure 13 for the Lodge Addition building. The models were refined after an initial presentation and the geometry and space allocation was updated in agreement with information provided by the client.
6 https://www.openstudio.net/ 7 https://energyplus.net/
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Figure 12. Geometrical model of Acute and Lodge buildings.
Figure 13. Geometrical model of Lodge Addition building.
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5.1 Analysed Cases
Multiple simulations were undertaken to examine the effect of climate change and as well, changes to occupancy patterns as may be required when considering extreme events. For example, during extreme heat events there is typically an increase in hospital admissions (process loads will increase). In this project, the worst case scenario was defined as a doubling of hospital occupancy.
As shown in Table 1 many different simulations were required to investigate the possible weather and occupancy scenarios.
Table 1. Matrix of simulation instances Model Weather file (epw) Occupation
Standard Standard, present Worst case Acute and 2020 Morphed Standard Lodge (Southampton) Buildings Worst case 2050 Morphed Standard (Southampton) Worst case Standard Standard, present Worst case Lodge 2020 Morphed Standard Addition (Southampton) Building Worst case 2050 Morphed Standard (Southampton) Worst case
5.2 Results of Simulations
For each simulation case, the monthly building energy consumption “Cooling energy consumption” and the HVAC size “Cooling coil capacity” required to maintain thermal comfort was extracted from the simulation results. The results for the Acute and Lodge Buildings are first provided followed by those for the Lodge Addition Building.
5.2.1 Acute and Lodge Buildings
5.2.1.1 Cooling Energy Consumption
The results derived from the simulation for cooling energy consumption for the standard and increased occupancy conditions are given in Figure 14 and Figure 15.
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Standard Occupancy 90.0 june july Cooling loads, MWh 80.0 august september 70.0 70.3 69.8 60.0 63.0 63.3 50.0 57.1 58.0 57.4 51.6 51.6 48.1 47.2 40.0 44.3 30.0 20.0 10.0 - 2016 2020 2050
Worst Case Occupancy 90.0 june july Cooling loads, MWh 80.0 august september 80.9 80.0 70.0 72.4 72.7 60.0 65.6 66.8 65.9 58.9 58.9 50.0 55.1 53.9 50.4 40.0 30.0 20.0 10.0 - 2016 2020 2050
Figure 14. Cooling energy consumption for the Acute and Lodge buildings for two occupancy conditions: (i) Standard , and; (ii) Worst case scenario for (June to September inclusive) of 2016 and that predicted for 2020 and 2050.
The simulation models show that with 100% increased occupancy as a worst case during extreme events there would be a 15% increase in cooling energy consumption over the four summer months (comparing the upper figure to the lower). Considering future climate conditions (for both normal and increased occupancy) the worst case occupancy scenario would increase in energy consumption by ~40%.
Results suggest that cooling loads of the building are not dominated by process loads which would scale with occupancy, but that the dominant loads associated to the base-building loads are the thermal loads through the envelope. This would suggest the need to consider envelope upgrades as a potential mitigation measure.
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350 Total cooling loads, MWh 300 285.7 257.9 249.1 238.0 250 225.1 207.5 200
150 Std Occ +100% Occ 100
50
0 2016 2020 2050
Figure 15.Total Cooling Energy Consumption for Acute and Lodge Buildings
5.2.1.1 Cooling Coil Capacity
The design cooling coil size is the capacity of the HVAC cooling coil required to maintain the building at a constant design temperature. By comparing the cooling coil capacity needed to respond to various scenarios against the current design it is possible to assess the risk of the building to have elevated temperatures beyond design for thermal comfort.
As can be seen in Figure 16, the current capacity of the cooling coil is represented by the left hand blue column (standard occupancy). The increased higher occupancy demand and future demand (2050) with increased number of extreme days would require an increase in cooling capacity (approx. 32%) to maintain current conditions.
700 Cooling Coil Capacity, kW 600 577 500 501 500 434 400
300 2016 2050 200
100
0 Standard Worst Case Occupancy
Figure 16. Cooling coil capacity: Acute and Lodge Buildings.
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Similar conclusion can be drawn from data in Figure 17 where the current cooling unit would not be capable of providing required cooling capacity to adequately condition the interior spaces when the building is subjected to increased climatic loads expected in the future.
The increase in the number of hours with indoor air temperatures above the thermostat set point (taken to be 21°C in the models) does not seem affected to a great extent by increased occupancy, but mainly by the increased number of warmer days and the extended duration of heat waves between now and 2050. Again this points to base-building loads as being dominant.
Hours with Temperatures above Setpoint 70 57.5 60 54.7
50
40 2016 30 2020 20 16.8 2050 9.8 10 0 0.2 0 Standard Worst Case Occupancy
Figure 17. Future predictions of indoor air temperature above set point temperatures.
5.2.2 Lodge Addition Building
5.2.2.1 Cooling Energy Consumption
The results derived from the simulation for the Lodge Addition building in respect to cooling loads for the standard condition for 100% increased (worst case scenario) occupancy are given in Figure 18.
For the Lodge Addition, simulation models showed with the worst case occupancy during extreme events, there is a 20% increase in cooling energy consumption over the four summer months (comparing the upper figure to the lower one). Considering future climate conditions (for both normal and increased occupancy in year 2050) the increase in energy consumption is ~50%.
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Standard Occupancy 25.0 june Cooling loads, MWh july 20.0 august september 15.0 16.4 16.1 14.7 14.7 13.2 13.2 13.2 10.0 11.7 11.7 10.8 10.6 9.7
5.0
- 2016 2020 2050
Worst Case Occupancy 25.0 june july Cooling loads, MWh august september 20.0 20.2 20.2 18.2 18.2 15.0 16.4 16.7 16.4 14.4 14.7 13.5 12.9 10.0 12.0
5.0
- 2016 2020 2050
Figure 18. Cooling energy consumption for the Lodge Addition building for two occupancy conditions: (i) Standard , and; (ii) Worst case for (June to September inclusive) of 2016 and that predicted for 2020 and 2050.
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6. Scenario Evaluation
Six retrofit options were evaluated:
1. Original building envelope remains and a new chiller with a capacity to cover for 2050 predictions is installed. 2. Option 1 plus adding horizontal shading above all windows facing east, south and west 3. Retrofit building envelope components (roofs & walls) to levels reasonably achievable with today’s technology (R-35 wall; R-50 roof). 4. Option 3 plus adding horizontal shading above all windows facing east, south and west 5. High performance insulation (R-50 wall; R-70 roof) applied to the envelope components of newly built building. 6. Option 5 plus adding horizontal shading above all windows facing east, south and west.
Retrofit options for the building envelope are summarized in Appendix C.
As presented in Figure 19 for 2050 weather conditions, increasing the envelope R- value and additional shading should help decrease the cooling loads. There are a number of intermediate cases. Also shown in the figure is the 2016 baseline cooling load. Table 2 presents class E estimates of costs for each retrofit option for Acute and Lodge buildings and separately for the Lodge Addition building. Considering energy performance as well as the cost estimation, Option 4 - the combination of building envelope improvement with horizontal overhang shading of windows facing east, south and west should be given serious consideration. It is worth noting the insignificant difference between Options 4 (wall and roof upgrades) and 6 (new wall roof constructions) including shadings suggesting there are many pathways to achieve a target performance level.
550 Cooling coil Capacity, kW 500 500 479 2016 1) Orig Env
450 434 437 431 2) Orig + Shade 413 408 3) Retrofit 400 4) Retrofit + Shade 5) High Perf Insul
350 6) HP Insul + Shade
300
Figure 19. Cooling coil capacities for various retrofit scenarios.
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Table 2: Cost estimates of retrofit options
Retrofit option Acute & Lodge Lodge Addition
1) Orig Env, New chiller $240k $150k
2) Orig + Shade $410k $240k
3) Retrofit $2.525M $615k
4) Retrofit + Shade $2.695M $705k 5) New HP Insul. (Including $20.500M $4.350M original building demolition) 6) HPI + Shade. (Including $20.670M $4.440M original building demolition) Note: Ductwork not included in the estimate
7. Energy Performance Evaluation Tool
A simplified tool to evaluate alterations in model energy performance of Acute and Lodge building was created and is provided as a stand-alone web based tool.
The most significant parameters affecting building energy performance and summer thermal comfort were incorporated in the tool. Namely, the value of thermal resistance of the building envelope: R values of walls (R20, R35 and R50) and roofs (R30, R50 and R70), U value (U0.35, U0.25 and U0.15) of windows, solar heat gain coefficient (SHGC 0.6 and SHGC 0.3) of windows; degree of horizontal shading of windows (0 shading and 0.5 shading, representing the horizontal projection of 0.5 times the window height) and efficiency- coefficient of performance (COP 3 and COP 5) of cooling units of mechanical systems. The option whereby the tool would account for an increase in facility occupancy during heat events was also included (20% occupancy increase), as well as the choice of future weather predictions for the years 2020 and 2050.
The output provided from use of the tool includes: consumption of cooling energy for summer months (June to September) and the number of hours when the indoor temperature increased above a set-point 21°C. The hours are stated for a thermal zone with the highest number of hours above the set point (an office on a west wing of Level 2 of the Acute care building).
8. Summary and Discussion
Key findings and observations include:
8.1 Site visit: FCH operations staff and Administration report elevated temperatures in the building during events of extreme heat. Operations staff report that HVAC system is operating at full capacity for most of the summer.
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Analysis of the IR images showed that the Acute care building having concrete walls had higher potential for thermal losses in the wall as well as occurrence of thermal bridges. Thermal bridging at stud wall locations is also apparent for both Lodge buildings. Thermal bridging as well as air leakage is apparently occurring in susceptible places such as the wall-floor and wall-roof connections and as well at windows locations within the wall.
8.2 Climate analysis: The local climate analysis was carried out in two steps. In the first step the Environment Canada hourly climate data were analyzed to determine the occurrence and durations of extreme weather events between 2009 and 2016. Maximum temperatures did not increase over the period, however the duration of heat waves increased from 1 to 4 days in 2009 and up to 3 to 6 days in 2016; an extreme example is that of a 15 day heat wave in 2015. In the second step, projections for years 2020 and 2050 were made using a future morphed climatic data generator: the maximum temperature increased from 36°C in 2016 o to 40°C in 2020 and o to 44°C in 2050. The number of days in a year when the ambient temperature exceeds 30ºC is predicted to increase from 9 days in 2016, to 23 days in 2020, and to 36 days in 2050. The risk of extreme heat impacting FCH delivery of medical services will increase unless mitigation measures are implemented.
8.3 Whole building performance analysis: Base-building loads due to thermal energy through the envelope are the dominant load for the HVAC system. In comparison the cooling required to offset process loads is small (medical instrumentation, kitchen activities, etc.); this requirement should scale with occupancy devices. In the future the HVAC system will have insufficient capacity to respond to the predicted increase in severity of extreme heat events; this is illustrated in Figure 20 in which is shown the future predictions for HVAC system cooling capacity and demand over time. Simulations for future years (2050) showed a 50% increase in cooling loads and cooling coil capacity would have to increase by 30%. The number of hours when the thermal comfort is not maintained is predicted to increase to 57 hours in 2050 during summer months. Modeling results and thermal imaging highlight the need to consider envelope upgrades as the primary mitigation measure. HVAC system capacity and efficiency upgrades are secondary mitigation measures. Building envelope upgrades in combination with horizontal overhang shading of windows facing east, south and west are believed to represent the most appropriate retrofit option before updating the HVAC system.
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700 40
600 35
30 500 25 400 20 kW 300 15 200
10 Numberof heat events 100 5
0 0 2016 2020 2050 Cooling Capacity (kW) Cooling Demand (kW) Capacity Shortfall (kW) Thermal Discomfort (Events)
Figure 20. Future predictions for HVAC system demand. Note: Number of heat events represents the number of days with external temperature increase above 30°C (based on Figures 6 and 7)
This report has shown that severity of extreme heat events experienced by FCH facility will increase as time passes. It is expected that the maximum exterior temperature will increase, as will the frequency and duration of these events. While this study focussed on FCH there is cause to believe that these trends will also be experienced at other locations in BC and in other provinces in Canada. As noted in the report Environment and Climate Change Canada (ECCC) is updating weather data for the whole of Canada.
Given the statements above, it is tempting to generalise the results and findings of this project. Extreme care should be given in the extrapolation of the findings and of applying the accompanying prediction model to circumstances that are different than those found at FCH. The model which was based on input data specific to the FCH building showed that base building loads – those from space conditioning to offset external thermal and solar loads – were dominant compared to process loads – those due to delivery of hospital services. This may not be the case in all hospitals with the relative importance being determined a number of factors many of which can be varied in the interface to the models supplied with this report. What cannot be varied is the geometry of the building, namely its footprint, height, and orientation, as well as the window to wall ratio. These are key parameters in determining exterior thermal loads so the model cannot be applied to other buildings with different geometries.
A more complete assessment of the risk due to extreme heat events and to provide guidance on mitigation and policy measures that could be implemented as mitigation across BC, would require a larger, more comprehensive study that would include archetype medical buildings representative of the complete medical building stock in BC.
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In advance of a such study, it is likely safe to say that if a building is struggling to maintain adequate environmental conditions in the building, the situation will get worse with time; a long term plan extending to 2050 or beyond needs to be developed for the rehabilitation of buildings to respond to the thermal loads which are expected to become more severe. This should not be interpreted as overdesign of the HVAC system so there is capacity for the future as this will lead to inefficiencies in the near and mid-term. But rather it means the plan must have stages where performance upgrades are linked to planned maintenance and equipment replacement periods so as to reduce the total cost of ownership. As noted above, a comprehensive approach is required when rehabilitating a building portfolio.
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Appendix A: Buildings of Fraser Canyon Hospital
Acute Building
Lodge Building
Lodge Addition Building
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Appendix B: Summary of the Model Inputs
Outdoor environmental conditions
- Hourly Hope Airport weather station data
Modelled indoor air set points
- Air temperature 21°C - RH 30%
HVAC System
- Air Loop with Electrical DX Cooling Coil and Gas Fired Heating Coil with Outdoor Air exchange System. - Parallel Gas Reheat Unit for each thermal zone - HRV (Heat recovery system) non employed
Building Envelope Assemblies
- Acute and Lodge Model
Wall assembly (Acute building), R 7
• Concrete wall 150mm • XPS 50mm • Gypsum board 12.7mm
Roof assembly (Acute building) R 12
• Modified asphalt membrane • Thermal insulation, wood-base board 100mm • Steel metal deck • Ceiling board 12.7mm
Wall assembly (Lodge building) R 17
• Stucco • Sheathing membrane • OSB 11mm • Stud wall with glass fiber insulation 150mm • PE vapour barrier 6mil • Gypsum board 12.7mm
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Roof assembly (Lodge building) R 27
• Asphalt shingles • OSB 11mm • Attic air space • Thermal insulation, cellulose fibre 250mm • OSB 11mm • Ceiling air space 300mm • Ceiling board 12.7mm
- Lodge Addition Model
Wall assembly, R 17
• Vinyl siding • Sheathing membrane • OSB 11mm • Stud wall with glass fiber insulation 150mm • PE vapour barrier 6mil • Gypsum board 12.7mm
Roof assembly, R 27
• Asphalt shingles • OSB 11mm • Attic air space • Thermal insulation, cellulose fibre 250mm • OSB 11mm • Ceiling air space 300mm • Ceiling board 12.7mm
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Appendix C: Building Envelope Retrofit Scenarios
Retrofit Building Envelope Assemblies
- Acute building, Wall assembly, R 35
• EIFS (Stucco + thermal insulation 120mm) • Concrete wall 150mm • XPS 50mm • Gypsum board 12.7mm
- Lodge and Lodge Addition Building, R 35
• Vinyl siding • Furring strips (air gap 40mm) • Thermal Insulation 75mm • Sheathing membrane • OSB 11mm • Stud wall with glass fiber insulation 150mm • PE vapour barrier 0.15mm • Gypsum board 12.7mm
- Very High Performance Insulation Wall assemblies: • EIFS on solid masonry and/or double-stud walls
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