Tower Hamlets - naturally ventilated Passivhaus Retrofit
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as PDF The property is a 3 bedroom mid terrace single family residence built in the 1960 s. Our proposals seeks to upgrade the property to Passivhaus energy standards, but taking advantage of the UKs milder climate (versus Passivhaus colder German origins), design out much key mechanical equipment complexity, turn reduced energy demand into smaller simpler plant configurations and develop simpler installation techniques.
Retrofit for the future ZA521E
Tower Hamlets - naturally ventilated Passivhaus Retrofit : Project images
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Energy and fuel use
Measured data from renewable generation is not yet available.
Fuel use
| Pre-development | Forecast | Measured | |
| Electricity use | 3029 kWh/yr | 1539 kWh/yr | 4496 kWh/yr |
|---|---|---|---|
| Natural gas use | 43306 kWh/yr | 3495 kWh/yr | 7559 kWh/yr |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | 551 kWh/m².yr | 75 kWh/m².yr | 191 kWh/m².yr |
|---|---|---|---|
| Annual CO₂ emissions | 103 kg CO₂/m².yr | 16 kg CO₂/m².yr | 40 kg CO₂/m².yr |
| Annual space heat demand | - | 23 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 | 75 kWh/m².yr | 191 kWh/m².yr |
| Annual CO₂ emissions offset by renewable generation | 16 kg CO₂/m².yr | 40 kg CO₂/m².yr |
Calculation and targets
| Whole house energy calculation method | PHPP |
|---|---|
| Other whole house calculation method | - |
| Energy target | Retrofit for the Future |
| Other energy targets | - |
| Forecast heating load | 18 W/m² demand |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | 6m³/m².hr @ 50 Pascals |
|---|---|---|
| Final air permeability test | - | 1.78m³/m².hr @ 50 Pascals |
Project description
| Stage | Under construction |
|---|---|
| Start date | 02 August 2010 |
| Occupation date | 03 December 2010 |
| Location | London London England |
| Build type | Refurbishment |
| Building sector | Public Residential |
| Property type | Mid Terrace |
| Construction type | Solid Brick |
| Other construction type | 215mm thick brick exposed on ground floor, rendered above |
| Party wall construction | Solid Brick |
| Floor area | 104.2 m² |
| Floor area calculation method | Treated Floor Area (PHPP) |
| Building certification |
Project Team
| Organisation | Bere Associates Limited (in association with Ove Arup & Partners) |
|---|---|
| Project lead person | Bere Associates Limited (in association with Ove Arup & Partners) |
| Landlord or Client | Southern Housing |
| Architect | bere:architects |
| Mechanical & electrical consultant | Ove Arup & Partners |
| Energy consultant | Ove Arup & Partners |
| Structural engineer | Rodrigues Associates |
| Quantity surveyor | e-Griffin Consulting |
| Consultant | N/A |
| Contractor | Not yet appointed |
Design strategies
| Planned occupancy | 3 people |
|---|---|
| Space heating strategy | Conventional radiator system with oversized radiators served by solar collector and backed up with condensing gas boiler. Future-proofed for connection to district heating. Specialist heat recovery windows to preheat fresh air. Heat recovery using room surface thermal mass to absorb room heat gains, retain overnight and re-emit into room. |
| Water heating strategy | Solar hot water (with gas condensing boiler backup) |
| Fuel strategy | Mains gas and mains electricity. Solar for hot water & heating. |
| Renewable energy strategy | N/A |
| Passive Solar strategy | Existing house has east & west windows. Morning and evening passive solar gain. House largely heated by internal heat gains. Room surface thermal mass for absorbing and subsequently emitting solar heat. |
| Space cooling strategy | 100% passive approach using natural ventilation & passive stack ventilation (PSV). Passive cooling using room exposed thermal mass coupled with summer night-time window ventilation. Existing facades are east & west. |
| Daylighting strategy | Existing east and west facing window siizes and positions retained. Low iron content replacement glass to maximise daylight transmission. |
| Ventilation strategy | 100% passive approach using natural ventilation & passive stack ventilation (PSV). |
| Airtightness strategy | Detailing at jointing between surfaces to maintain airtightness continuity between roof and overcladding insulation. Passivhaus detailing around windows and other openings. Particular care and supervison of M&E penetrations. Careful detailing and site supervision of joist voids in walls. Preliminary testing to help site identify air leakage routes. |
| Strategy for minimising thermal bridges | In principle overcladding thermal insulation is provided to all walls with continuity into roof. Insulation continued below ground down to wall footings. Ground floor insulation layer added. External horizontal insulation added where necessary. Detailed design to include computer thermal analysis of all principle thermal bridges to ensure minimium cost to achieve Passivhaus standard. |
| Modelling strategy | PHPP used to establish extent and standard of insulation needed. Prototype demonstation measured data used to quantify heat recovery window potential. Past project experience used to assess room thermal mass heat recovery potential. Amended parameters reflecting the above were then fed into PHPP. In phase 2 detailed design stage, finite element analysis will be used to value engineer windows and thermal mass extent. |
| Insulation strategy | In principle overcladding thermal insulation is provided to all walls with continuity into roof. Insulation continued below ground down to wall footings. Ground floor insulation layer added. External horizontal insulation added where necessary. |
| Other relevant retrofit strategies | A completely prefabricated mechanical services module is to be inserted, containing condensing boiler, thermal store solar hot water and controls. No mechanical ventilation system is used. The aim is to simplify the site works, ensure no site adaptions and achieve consistent reliable minimum maintenance operation of the mechanical plant. This unit is to be developed with a UK supplier to achieve a unit that is better matched to a UK house (dimensions for passing through doors), and with smaller capacity components to better match the reduced demand of a very low energy demand home, than is available from European suppliers. |
| Contextual information | The house is not listed and is not located within a conservation area. The design of the house is typical of 1960s social housing stock in the borough which is now looking dated. A new external insulated render system will therefore provide a cosmetic improvement. We have discussed our proposal with Tower Hamlets planning department and received the following responses: David Williams, Development Manager at Tower Hamlets has stated that the council is fully supportive of best practice approaches and energy efficiency measures in particular and that the proposals for upgrading this property are fully convergent with the council Core Strategy for Sustainability. |
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 |