St Loyes Extra Care Facility PHPP Pre-Assessment Report Gale ...
St Loyes Extra Care Facility PHPP Pre-Assessment Report
Gale & Snowden Architects & Engineers July 2011
Gale & Snowden Architects
St Loyes Extra Care Facility – PHPP Pre-Assessment Report
Page 2 of 10
St Loyes Care Home PHPP Pre-Assessment Report Prepared by:
Tomas Gärtner
Checked by:
Maria Gale/David Gale
Project:
St Loyes Care Home
Version:
Final
Date:
July 2011
Job No:
B1103
Reference:
Projects\Current\B1103 St Loyes Care Home \Reports & Specs
Rev No
Comments
Date
This document has been produced by Gale & Snowden for the St Loyes CCA project and is solely for the purpose of outlining the results from the initial PHPP modelling of this project. It may not be used by any person for any other purpose other than that specified without the express written permission of Gale & Snowden. Any liability arising out of use by a third party of this document for purposes not wholly connected with the above shall be the responsibility of that party who shall indemnify Gale & Snowden against all claims costs damages and losses arising out of such use
Gale & Snowden Architects Ltd 18 Market Place Bideford Devon EX39 2DR T: 01237 474952 F: 01237 425449 www.ecodesign.co.uk Company No. 5632356 VAT Registration No. 655 9343 06
Gale & Snowden Architects
St Loyes Extra Care Facility – PHPP Pre-Assessment Report
Page 3 of 10
Executive Summary This report illustrates the key findings of the PHPP pre assessment for the St Loyes Extra Care Facility project modelled under current weather conditions and also future weather data provided by Exeter University’s Prometheus project.
Main Findings All three construction methods will result in Passivhaus compliant designs for space heating demand, primary energy demand and overheating, when modelled with the current weather file, and without a requirement for additional shading. The heavy weight construction without additional shading performs better with regards to overheating and will result in a lower daily temperature swing from solar gains than the light weight or medium weight approach. The effect from devices that control solar gains in summer and also adequate ventilation appear to have a greater impact on reducing overheating in summer than thermal mass. If a successful strategy to control solar gains in summer can be implemented (e.g. overhangs and/or shutters) then a natural ventilation strategy via opening windows is sufficient to limit overheating in summer to acceptable levels for all four weather scenarios and independent from the method of construction.
Gale & Snowden Architects
St Loyes Extra Care Facility – PHPP Pre-Assessment Report
Page 4 of 10
Contents Executive Summary ....................................................................................................................................................... 3 Contents......................................................................................................................................................................... 4 1.0 Introduction .............................................................................................................................................................. 5 1.1 This Report ........................................................................................................................................................... 5 1.2 Thermal Assessment & Calculation ..................................................................................................................... 5 1.3 Heat Loss Methodology ....................................................................................................................................... 5 1.4 Building Fabric and Mechanical Design ............................................................................................................... 5 2.0 PHPP ....................................................................................................................................................................... 6 2.1 Passivhaus Standard ........................................................................................................................................... 6 2.2 Weather Files ....................................................................................................................................................... 6 2.3 Shading ................................................................................................................................................................ 6 2.4 Thermal Mass ...................................................................................................................................................... 6 2.5 Ventilation............................................................................................................................................................. 7 3.0 Conclusions ............................................................................................................................................................. 7 3.1 PHPP Pre Assessment ........................................................................................................................................ 7 3.2 Overheating .......................................................................................................................................................... 8 3.3 Space Heating Demand ....................................................................................................................................... 9 References..................................................................................................................................................................... 9 Appendix A – Results Matrix........................................................................................................................................ 10
Gale & Snowden Architects Ltd
St Loyes Care Home – PHPP Pre-Assessment Report
1.0 Introduction 1.1 This Report
Page 5 of 10
1.3 Heat Loss Methodology The heat loss methodology used for the simulation is as follows: •
The purpose of this report is to illustrate the key findings of the PHPP pre assessment for the St Loyes Care Home project with regards to overheating, space heating demand and specific primary energy demand.
The method is based on calculations of monthly energy balances
•
It treats the whole building as one zone
•
It takes into account internal casual gains and solar gains.
It assesses the initial designs for compliance with the Passivhaus standard.
•
It takes into account building orientation and properties of the materials used
•
It utilises local weather data
Furthermore various shading and construction methods with regards to the inclusion of thermal mass have been modelled under current and future weather data for the years 2030, 2050 and 2080 to assist the design team in developing a climate change adaptation strategy.
1.2 Thermal Assessment & Calculation The building design has been modelled using the Passivhaus Planning Package (PHPP). The PHPP is a design tool allowing specialist planners to assess and calculate the energy demand for low energy buildings. It was developed using dynamic simulations [AkkP 13] that were then validated by monitoring results of completed Passive Houses over the last 20 years. The result is a simplified model which pairs reliable results with justifiable effort for data acquisition [Feist 1994] . The Passive House Planning Package (PHPP) provides tools for:
Using the above methodology the PHPP allows for predictions of annual space heating demand, heating load and frequency of overheating in summer.
1.4 Building Design
Fabric
and
Mechanical
It is understood that the project is still at outline planning stage and that no detailed design has been worked up to define the construction of the building fabric. Therefore all simulations have been prepared on the basis of the following recommendations and assumptions which are all based on good practice guidance from the Passivhaus Institute. All modelling results will need to be verified at a later design stage when more accurate information is available to confirm the performance of the actual building fabric design. Building Fabric Design
•
calculating energy balances (including U-value calculation)
•
specifying and designing windows
A passive design strategy is to be followed including super insulation, high levels of air tightness and high performance triple glazed windows and doors:
•
designing the comfort ventilation system
U-values
•
determining the heating load
•
estimating the summer comfort
•
design the heating and hot water supply
Walls Floor Roof Windows Doors
Whilst the PHPP has been utilised as a design tool for this project, this information is also valid as an initial assessment to show compliance with the Passivhaus Standard.
0.15 0.15 0.1 0.85 0.85
W/sqmK W/sqmK W/sqmK W/sqmK W/sqmK
Thermal bridge free design Glazing
g-value = 0.5 U value = 0.58
Air tightness
0.6
ac/h
(installed) (installed)
Gale & Snowden Architects Ltd
St Loyes Care Home – PHPP Pre-Assessment Report
Ventilation Efficiency >85 % Electric Efficiency
Gale & Snowden Architects & Engineers July 2011
Gale & Snowden Architects
St Loyes Extra Care Facility – PHPP Pre-Assessment Report
Page 2 of 10
St Loyes Care Home PHPP Pre-Assessment Report Prepared by:
Tomas Gärtner
Checked by:
Maria Gale/David Gale
Project:
St Loyes Care Home
Version:
Final
Date:
July 2011
Job No:
B1103
Reference:
Projects\Current\B1103 St Loyes Care Home \Reports & Specs
Rev No
Comments
Date
This document has been produced by Gale & Snowden for the St Loyes CCA project and is solely for the purpose of outlining the results from the initial PHPP modelling of this project. It may not be used by any person for any other purpose other than that specified without the express written permission of Gale & Snowden. Any liability arising out of use by a third party of this document for purposes not wholly connected with the above shall be the responsibility of that party who shall indemnify Gale & Snowden against all claims costs damages and losses arising out of such use
Gale & Snowden Architects Ltd 18 Market Place Bideford Devon EX39 2DR T: 01237 474952 F: 01237 425449 www.ecodesign.co.uk Company No. 5632356 VAT Registration No. 655 9343 06
Gale & Snowden Architects
St Loyes Extra Care Facility – PHPP Pre-Assessment Report
Page 3 of 10
Executive Summary This report illustrates the key findings of the PHPP pre assessment for the St Loyes Extra Care Facility project modelled under current weather conditions and also future weather data provided by Exeter University’s Prometheus project.
Main Findings All three construction methods will result in Passivhaus compliant designs for space heating demand, primary energy demand and overheating, when modelled with the current weather file, and without a requirement for additional shading. The heavy weight construction without additional shading performs better with regards to overheating and will result in a lower daily temperature swing from solar gains than the light weight or medium weight approach. The effect from devices that control solar gains in summer and also adequate ventilation appear to have a greater impact on reducing overheating in summer than thermal mass. If a successful strategy to control solar gains in summer can be implemented (e.g. overhangs and/or shutters) then a natural ventilation strategy via opening windows is sufficient to limit overheating in summer to acceptable levels for all four weather scenarios and independent from the method of construction.
Gale & Snowden Architects
St Loyes Extra Care Facility – PHPP Pre-Assessment Report
Page 4 of 10
Contents Executive Summary ....................................................................................................................................................... 3 Contents......................................................................................................................................................................... 4 1.0 Introduction .............................................................................................................................................................. 5 1.1 This Report ........................................................................................................................................................... 5 1.2 Thermal Assessment & Calculation ..................................................................................................................... 5 1.3 Heat Loss Methodology ....................................................................................................................................... 5 1.4 Building Fabric and Mechanical Design ............................................................................................................... 5 2.0 PHPP ....................................................................................................................................................................... 6 2.1 Passivhaus Standard ........................................................................................................................................... 6 2.2 Weather Files ....................................................................................................................................................... 6 2.3 Shading ................................................................................................................................................................ 6 2.4 Thermal Mass ...................................................................................................................................................... 6 2.5 Ventilation............................................................................................................................................................. 7 3.0 Conclusions ............................................................................................................................................................. 7 3.1 PHPP Pre Assessment ........................................................................................................................................ 7 3.2 Overheating .......................................................................................................................................................... 8 3.3 Space Heating Demand ....................................................................................................................................... 9 References..................................................................................................................................................................... 9 Appendix A – Results Matrix........................................................................................................................................ 10
Gale & Snowden Architects Ltd
St Loyes Care Home – PHPP Pre-Assessment Report
1.0 Introduction 1.1 This Report
Page 5 of 10
1.3 Heat Loss Methodology The heat loss methodology used for the simulation is as follows: •
The purpose of this report is to illustrate the key findings of the PHPP pre assessment for the St Loyes Care Home project with regards to overheating, space heating demand and specific primary energy demand.
The method is based on calculations of monthly energy balances
•
It treats the whole building as one zone
•
It takes into account internal casual gains and solar gains.
It assesses the initial designs for compliance with the Passivhaus standard.
•
It takes into account building orientation and properties of the materials used
•
It utilises local weather data
Furthermore various shading and construction methods with regards to the inclusion of thermal mass have been modelled under current and future weather data for the years 2030, 2050 and 2080 to assist the design team in developing a climate change adaptation strategy.
1.2 Thermal Assessment & Calculation The building design has been modelled using the Passivhaus Planning Package (PHPP). The PHPP is a design tool allowing specialist planners to assess and calculate the energy demand for low energy buildings. It was developed using dynamic simulations [AkkP 13] that were then validated by monitoring results of completed Passive Houses over the last 20 years. The result is a simplified model which pairs reliable results with justifiable effort for data acquisition [Feist 1994] . The Passive House Planning Package (PHPP) provides tools for:
Using the above methodology the PHPP allows for predictions of annual space heating demand, heating load and frequency of overheating in summer.
1.4 Building Design
Fabric
and
Mechanical
It is understood that the project is still at outline planning stage and that no detailed design has been worked up to define the construction of the building fabric. Therefore all simulations have been prepared on the basis of the following recommendations and assumptions which are all based on good practice guidance from the Passivhaus Institute. All modelling results will need to be verified at a later design stage when more accurate information is available to confirm the performance of the actual building fabric design. Building Fabric Design
•
calculating energy balances (including U-value calculation)
•
specifying and designing windows
A passive design strategy is to be followed including super insulation, high levels of air tightness and high performance triple glazed windows and doors:
•
designing the comfort ventilation system
U-values
•
determining the heating load
•
estimating the summer comfort
•
design the heating and hot water supply
Walls Floor Roof Windows Doors
Whilst the PHPP has been utilised as a design tool for this project, this information is also valid as an initial assessment to show compliance with the Passivhaus Standard.
0.15 0.15 0.1 0.85 0.85
W/sqmK W/sqmK W/sqmK W/sqmK W/sqmK
Thermal bridge free design Glazing
g-value = 0.5 U value = 0.58
Air tightness
0.6
ac/h
(installed) (installed)
Gale & Snowden Architects Ltd
St Loyes Care Home – PHPP Pre-Assessment Report
Ventilation Efficiency >85 % Electric Efficiency
