Project name Gentoo Retrofit Bid 1 Project summary Refurbishment of 2no. Semi Detached houses using Passivhaus principles

Transcription

1 Project name Gentoo Retrofit Bid 1 Project summary Refurbishment of 2no. Semi Detached houses using Passivhaus principles Project Description Projected build start date 05 Apr 2010 Projected date of occupation 18 May 2010 Project stage Under construction Project location Sunderland, Tyne & Wear, England Energy target Retrofit for the Future Build type Refurbishment Building sector Public Residential Property type Semi-Detached Existing external wall construction Masonry Cavity Existing external wall additional information Traditional cavity wall construction Existing party wall construction Blockwork cavity wall Floor area 78 m² Floor area calculation method PHPP Page 1

2 Project team Organisation Project lead Client Architect Mechanical & electrical consultant(s) Energy consultant(s) Structural engineer Quantity surveyor Other consultant Contractor Gentoo Sunderland Ltd Devereux Architects Gentoo Sunderland Devereux Architects Alan Clarke Ltd (Mech) & Gentoo Construction (Elec) Alan Clarke Ltd Gentoo Construction Gentoo Construction Gentoo Construction Design strategies Planned occupancy Space heating strategy Water heating strategy Fuel strategy Renewable energy generation strategy Passive solar strategy Space cooling strategy Daylighting strategy Ventilation strategy As at present: Gas condensing boiler to use existing radiator central heating system. Room compensated boiler flow temperature control. A-rated low energy circulation pump. Solar thermal using roof-integrated flat panels, twin coil cylinder with 100mm insulation located in warm loft. Gas boiler back up, no immersion heater. Existing supplies: mains gas and electricity None Retaining existing opening sizes. Full glazing to south facing kitchen door. Thanks to modest glazed areas PHPP shows that natural ventilation will be sufficient. Thermal mass retained inside the building will aid night cooling if required. Existing window openings used, with increased glass area and double glazing rather than triple. Winter ventilation using mechanical heat recovery ventilation. Automatic relative humidity control. MVHR unit located in kitchen for ease of access for maintenance. Opening windows for use in summer. Page 2

3 Airtightness strategy Strategy for minimising thermal bridges Modelling strategy Insulation strategy Other relevant retrofit strategies Other information (constraints or opportunities influencing project design or outcomes) Roof air barrier membrane sealed to parge coat of render on masonry wall. Windows taped to wall and gaps filled with flexible expanding foam. Solid ground floor. Rubber seals around pipe, flue and cable penetrations (eg pro clima grummet). Party wall enclosed by treatment of both semidetached houses together. Thermal bridge free approach: roof insulation over rafters to enable full thickness to go over eaves and gable and join external wall insulation. Windows fixed to external surface of wall so within the external insulation layer. Wall insulation extends below ground (without base rail) down to foundations to minimise floor heat loss. This has been modelled using Therm to check internal temperatures and heat loss. PHPP (whole house energy and overheating) Therm for thermal bridging External "overcoat": Over rafters to raise roof, using glass fibre, U=0.11 External wall insulation using graphite EPS, U=0.13 No floor insulation as tenants remain in situ. Insulation provided by carpet and underlay, and by below ground wall insulation. Windows use highly insulating PVC frame (U=0.8) and high performance double glazing (U=1.1) with stainless spacers. Tenants remain in the houses throughout. Two semi detached houses are retrofitted together to eliminate problems at party wall (cavity entirely enclosed in airtight thermal envelope) and enable removal of chimney. Treating two houses together has limited the budget and forced a focus on cost-effective measures. Energy use Fuel use by type (kwh/yr) Fuel previous forecast measured Electri c Gas Oil 0 LPG Wood Primary energy requirement & CO2 emissions Page 3

4 Annual CO2 emissions (kg CO2/m².yr) Primary energy requirement (kwh/m².yr) previous forecast measured Renewable energy (kwh/yr) Renewables technology forecast measured - - Energy consumed by generation Airtightness ( 50 Pascals ) Date of test Pre-development airtightness - Final airtightness - Test result Annual space heat demand ( kwh/m².yr ) Space heat demand Pre-development forecast measured Whole house energy calculation method Other energy calculation method Predicted heating load Other energy target(s) PHPP 16 W/m² (demand) Building services Occupancy Space heating Hot water Ventilation Controls Cooking Lighting Appliances Renewables Strategy for minimising thermal bridges Building construction Storeys Volume Page 4

5 Thermal fabric area Roof description Roof U-value Walls description Walls U-value Party walls description Party walls U-value Floor description Floor U-value Glazed doors description Glazed doors U-value Opaque doors description Opaque doors U-value Windows description Windows U-value Windows energy transmittance (G-value) Windows light transmittance Rooflights description Rooflights light transmittance Rooflights U-value Page 5

6 Project images Page 6