Project Description. Projected build start date 02 Aug 2010 Projected date of occupation 03 Dec Existing external wall construction

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1 Project name Tower Hamlets - naturally ventilated Passivhaus Retrofit Project summary 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. Project Description Projected build start date 02 Aug 2010 Projected date of occupation 03 Dec 2010 Project stage Under construction Project location London, London, England Energy target Retrofit for the Future Build type Refurbishment Building sector Public Residential Property type Mid Terrace Existing external wall construction Solid Brick Page 1

2 Existing external wall additional information Existing party wall construction 215mm thick brick exposed on ground floor, rendered above Solid Brick Floor area m² Floor area calculation method PHPP Project team Organisation Project lead Client Architect Mechanical & electrical consultant(s) Energy consultant(s) Structural engineer Quantity surveyor Other consultant Contractor Bere Associates Limited (in association with Ove Arup & Partners) Bere Associates Limited (in association with Ove Arup & Partners) Southern Housing bere:architects Ove Arup & Partners Ove Arup & Partners Rodrigues Associates e-griffin Consulting N/A Not yet appointed Design strategies Planned occupancy Space heating strategy Water heating strategy Fuel strategy Renewable energy generation strategy Passive solar strategy 3 people 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. Solar hot water (with gas condensing boiler backup) Mains gas and mains electricity. Solar for hot water & heating. N/A 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. Page 2

3 Space cooling strategy Daylighting strategy Ventilation strategy Airtightness strategy Strategy for minimising thermal bridges Modelling strategy Insulation 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. Existing east and west facing window siizes and positions retained. Low iron content replacement glass to maximise daylight transmission. 100% passive approach using natural ventilation & passive stack ventilation (PSV). 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. 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. 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. 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. Page 3

4 Other relevant retrofit strategies Other information (constraints or opportunities influencing project design or outcomes) 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. 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. Energy use Fuel use by type (kwh/yr) Fuel previous forecast measured Electri c Gas Oil LPG Wood Primary energy requirement & CO2 emissions Annual CO2 emissions (kg CO2/m².yr) previous forecast measured Page 4

5 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 - 6 Test result Final airtightness 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 18 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 Thermal fabric area Page 5

6 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 6

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