Thermal Store retrofit pilot
Download
as PDF The project aims to retrofit a typical 1940s cavity constructed home without the need to decant tenants. It reduces lifestyle energy costs through the application of occupant awareness, best in class smart appliances, together with building fabric measures to achieve predicted reductions in CO2 emissions of 81%. The project pilots the use of a novel application of solar thermally recharged ground bores Thermal Store Retrofit Pilot for a heat pump based heating and hot water system. This has only been used in the UK on a novel commercial application. Building fabric measures additionally include external insulation with a brick slip finish and improvements in constructional airtightness by attention to quality of workmanship on site.
Retrofit for the future ZA428E
Thermal Store retrofit pilot : Project images
Click on image to preview full size
Energy and fuel use
Measured data from renewable generation is not yet available.
Fuel use
| Pre-development | Forecast | Measured | |
| Electricity use | - | - | 8007 kWh/yr |
|---|---|---|---|
| Natural gas use | - | - | - |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| heat from heat pump | - | 3480 kWh/yr | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | - | 96 kWh/m².yr | 221 kWh/m².yr |
|---|---|---|---|
| Annual CO₂ emissions | - | 23 kg CO₂/m².yr | 52 kg CO₂/m².yr |
| Annual space heat demand | - | 2134 kWh/m².yr | - |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| Renewables Technology | - | - |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | 96 kWh/m².yr | 221 kWh/m².yr |
| Annual CO₂ emissions offset by renewable generation | 23 kg CO₂/m².yr | 52 kg CO₂/m².yr |
Calculation and targets
| Whole house energy calculation method | SAP |
|---|---|
| Other whole house calculation method | - |
| Energy target | Retrofit for the Future |
| Other energy targets | - |
| Forecast heating load | - |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | 4.86m³/m².hr @ 50 Pascals |
|---|---|---|
| Final air permeability test | - | 3.65m³/m².hr @ 50 Pascals |
Project description
| Stage | Under construction |
|---|---|
| Start date | 04 May 2010 |
| Occupation date | 12 July 2010 |
| Location | Redhill Surrey England |
| Build type | Refurbishment |
| Building sector | Public Residential |
| Property type | End Terrace |
| Construction type | Masonry Cavity |
| Other construction type | Offset party walls |
| Party wall construction | Brick cavity |
| Floor area | 90.5 m² |
| Floor area calculation method | Treated Floor Area (PHPP) |
| Building certification |
Project Team
| Organisation | Raven Housing Trust |
|---|---|
| Project lead person | Raven Housing Trust |
| Landlord or Client | Raven Housing Trust |
| Architect | Wates Living Space |
| Mechanical & electrical consultant | Wates Living Space |
| Energy consultant | Inbuilt Ltd |
| Structural engineer | Wates Living Space |
| Quantity surveyor | Wates Living Space |
| Consultant | Wates Living Space |
| Contractor | Wates Living Space |
Design strategies
| Planned occupancy | Extended family - 7 persons |
|---|---|
| Space heating strategy | Heating from ground bore heat pump system with ground recharge by solar thermal |
| Water heating strategy | Domestic Hot Water from ground bore heat pump system with recharge by solar thermal |
| Fuel strategy | Mains electricity |
| Renewable energy strategy | NA |
| Passive Solar strategy | Solar gains via triple glazed windows (U=0.8W/m2K) with a high G factor utilising existing window reveals . |
| Space cooling strategy | Use of exposed thermal mass of plastered masonary construction to smooth out effects of internal and external gains. Removal of peak heat emissions from kitchen using balanced flow cooker extractor hood. Location of heat emitting appliances white goods outside the heated envelope. Multi speed ventilation through MVHR with summertime bypass with nightime cooling. |
| Daylighting strategy | Kitchens and living rooms daylit via original window reveals , daylighting maximised via low frame factor and high G factor glazing. |
| Ventilation strategy | MVHR throughout the house with openable windows and summertime bypass of MVHR |
| Airtightness strategy | Existing plastered finishes to be retained to maintain existing level of airtightness. Improvement upon measured airtightness level identified at feasibility stage by remedying service penetrations to 3m3/m2h. Cavity wall to be filled to reduce the risk of ventilation losses. |
| Strategy for minimising thermal bridges | Detailed 3-d cold bridge analysis to be undertaken and iterated with architect and constructor of key junctions. Continuous insulation on ceiling and walls maintained into eaves and compensated by extending the eaves. |
| Modelling strategy | Whole house modelling was undertaken utilising relatively simple SAP and extended SAP models but with boundary conditions based upon archetypal cold bridge analysis (TRISCO) and measured evidence so as to facilitate scenario modelling 1) Assessed airtighness levels and 2) Confidence levels in suitability of ground conditions for a ground bore heat pump |
| Insulation strategy | Application of external wall and cavity insulation with brick slip cladding to achieve U value 0.15W/m2K. Improvement of ceiling insulation within the loft area to achieve U value 0.145W/m2K. Improvement of windows to achieve a U value of 0.8 W/m2K |
| Other relevant retrofit strategies | We are planning to undertake the package of measures with tenants in situ so as to avoid the need to decant. |
| Contextual information | The constraint on the project was to provide a significant reduction in CO2 emissions without affecting the external appearance significantly and without the need for decanting the householders. Early liaison with tenants and planning officer have identified key areas to address in the detailed design stage to meet non-energy requirements. The provision of advanced AA++ rated appliances to an external utility room and redesigned kitchen provides greater spatial flexibility to the extended family. |
Building services
| Occupancy | NULL |
|---|---|
| Space heating | NULL |
| Hot water | NULL |
| Ventilation | NULL |
| Controls | NULL |
| Cooking | NULL |
| Lighting | NULL |
| Appliances | NULL |
| Renewable energy generation system | NULL |
| Strategy for minimising thermal bridges | NULL |
Building construction
| Storeys | |
|---|---|
| Volume | - |
| Thermal fabric area | - |
| Roof description | NULL |
| Roof U-value | 0.00 W/m² K |
| Walls description | NULL |
| Walls U-value | 0.00 W/m² K |
| Party walls description | NULL |
| Party walls U-value | 0.00 W/m² K |
| Floor description | NULL |
| Floor U-value | 0.00 W/m² K |
| Glazed doors description | NULL |
| Glazed doors U-value | 0.00 W/m² K - |
| Opaque doors description | NULL |
| Opaque doors U-value | 0.00 W/m² K - |
| Windows description | NULL |
| Windows U-value | 0.00 W/m² K - |
| Windows energy transmittance (G-value) | - |
| Windows light transmittance | - |
| Rooflights description | NULL |
| Rooflights light transmittance | - |
| Rooflights U-value | 0.00 W/m² K |