Project Description. Projected build start date 01 May 2010 Projected date of occupation 01 Nov Belfast, County Antrim, Northern Ireland

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Luke Rodgers
5 years ago
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It is already relatively energy efficient having an RD SAP rating of 57 (band D) compared to the average in Northern Ireland of 50.

This house is part of a terrace of mixed social and private dwellings, so external wall insulation can not be used.

1 Project name Eco-Energy Retrofit, Grove Housing Association, Belfast Project summary The mid terrace solid wall house built in 1896, is located in North Belfast and owned by Grove HA. It is already relatively energy efficient having an RD SAP rating of 57 (band D) compared to the average in Northern Ireland of 50. There is currently no insulation under the floor slab so this will be replaced with one sitting on 200mm of phenolic insulation. This house is part of a terrace of mixed social and private dwellings, so external wall insulation can not be used. Internal wall insulation, Passivhaus windows and doors and good airtightness will secure the thermal envelope. To reduce PE demand, a condensing systems boiler, MVHR, LEDs and gas clothes drier will be installed, with a 1.72kWp PV array generating electricity on site. Project Description Projected build start date 01 May 2010 Projected date of occupation 01 Nov 2010 Project stage Under construction Project location Belfast, County Antrim, Northern Ireland Energy target Retrofit for the Future Build type Refurbishment Building sector Public Residential Page 1

2 Property type Mid Terrace Existing external wall construction Solid Brick Existing external wall additional information Unrendered Existing party wall construction Solid brick Floor area 89 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 Eco-Energy (NI) Ltd Eco-Energy (NI) Ltd Grove Housing Association, North Belfast Hugh Green RIBA Eco-Energy (NI) Ltd Eco-Energy (NI) Ltd Brian Murray Ltd W.B.Evans & Co Alba Thermals Ltd (Thermal bridging & condensation analysis) Design strategies Planned occupancy Family of four. Two adults and two children. Space heating strategy Natural gas system boiler coupled to a 145 litre DHW hot water cylinder. No secondary heating. The MVHR (mechanical ventilation heat recovery) system will recover the heat contained in the stale exhaust air via a heat exchanger, pre-heating the incoming fresh air. Water heating strategy Fuel strategy Renewable energy generation strategy Passive solar strategy Space heating boiler as above, coupled to a 145 litre hot water cylinder. Main gas. Mains electricity kwp of roof mounted PV array. The rear south facing windows are small and shaded by adjoining houses and yard walls. PHPP predicts available solar gains of 2.8kWh/m2/year. Solar gain will be maximised in the retrofit by using Passivhaus windows with narrow frame widths to provide maxiumum glazed area. Page 2

3 Space cooling strategy Daylighting strategy Ventilation strategy Airtightness strategy Opening windows to provide passive cross ventilation will cool in the day and purge the house at night. This will allow the option of switching off MVHR in the summer, reducing primary energy (PE) demand. Internal solar blinds and external roll out solar shading will control the solar gain in the summer season if required. Daylighting factors currently pre retrofit, front room 1.8, dining room 1.2, kitchen 1.6. The window openings within the walls of the house are fixed dimentionally. The windows to the south facing rear of the house are surrounded by the high walls of an enclosed yard and adjoining houses. The glazed area of each retrofitted Passivhaus window will be maximised by the use of narrow frames widths increasing the glazing area from what it is currently, improving daylighting with a higher daylight factor. A mechanical ventilation and heat recovery (MVHR) system will be operating throughout the heating season. The MVHR summer bypass option will draw fresh outside air from the cooler shaded north side of house and supply it into the house in the summer. Alternatively, the MVHR can be turned off in the summer to reduce PE demand and the house cooled with cross ventilation by opening windows. Masonary walls parged down to the floor slab and between floor joists. Floors taped to the walls to create an airtight seal. Internal insulation plywood substructure cut to encompass floor/ceiling joists between floors with taped joints to provide an air tight seal. Airtight membrane/vapour barrier mounted inside roof structure, bonded to parged masonary walls. Services (pipes,cables, ducting, etc) penetrations through airtight barrier sealed with gaskets, tape or airtight sealant and windows sealed to wall/airtight membrane. Socket outlet/switch boxes. ceiling roses, etc, sealed for airtightness. Page 3

4 Strategy for minimising thermal bridges Modelling strategy Insulation strategy Other relevant retrofit strategies Thermal bridging analysis conducted on each potential thermal bridge using THERM software. Replacement floor slab on top phenolic insulation will have edge insulation to minimise the thermal bridge to the adjoining walls. Flanking insulation will be installed on the internal party walls to minimise thermal bridging and prevent condensation at the junction of the party wall and external wall. Aerocell and closed cell foam insulation inserted around the face and sides of window/door frames to minimise the thermal bridge with the masonary. Whole house modelling using PHPP. The PV output was calculated manually using a PV yield for Northern Ireland of 850kWh/year per kwp. The 8 module 1.720kWp array has a predicted annual yield of 1.720kWp x 850 = 1.462kWh. Combination of aerogel and phenolic internal insulation installed on the external walls to achieve a U-value of 0.15W/m2K. Replacement of existing concrete floor (which has no insulation) with a concrete slab over phenolic insulation to achieve a U value of 0.10 W/m2K. Edge insulation to minimise thermal bridging between floor slab and walls. Removal and replacement of existing attic bedroom ceiling to allow for the installation for a combination of different types of insulation to achieve a U-value of 0.10 W/m2K. Passivhaus windows with a U value of 0.8 will be installed. Due to health and safety issues, the extent of and the length of time required to complete this initial retrofit, the tenants will be accommodated in an alternative unnoccupied spare house within the existing HA stock. For any future small scale retrofit roll out, it envisaged a spare house will be available to keep alternative (hotel) accommodation costs low. To minimise traffic disruption in narrow terraced streets and reduce the transport carbon footprint, it is proposed that all the retrofit components are containerised offsite. The loaded10 foot (the width of a terraced house) container, can then be placed in the road directly outside the house. Page 4

5 Other information (constraints or opportunities influencing project design or outcomes) 1) Standby killer electrical circuits installed in each room to enable appliances with a standby mode plugged into green socket outlets, to be switched off from one central switch. 2) A bath/shower drain water heat recovery/heat store system will pre-heat incoming mains water. This potential saving has not been entered into PHPP. The performance will be measured by installing heat meters on the inlet and outlet of the unit. 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) Primary energy requirement (kwh/m².yr) previous forecast measured Renewable energy (kwh/yr) Renewables technology forecast measured PV's Energy consumed by generation Airtightness ( 50 Pascals ) Date of test Test result Pre-development airtightness 19 Apr Final airtightness 01 Jan Space heat demand Annual space heat demand ( kwh/m².yr ) Pre-development forecast measured Whole house energy calculation method PHPP Page 5

6 Other energy calculation method Predicted heating load Other energy target(s) 11 W/m² (demand) The project target is to achieve 3 litre house status, a term recognised in Europe depicting a house that consumes less than 3 litres oil equivalent/m2/year (30kWh/m2/year) for space heating. An aspirational target is to achieve 25kWh/m 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 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) Page 6

7 Windows light transmittance Rooflights description Rooflights light transmittance Rooflights U-value Page 7

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Project Description. Projected build start date 12 Apr 2010 Projected date of occupation 28 Feb

Project Description. Projected build start date 12 Apr 2010 Projected date of occupation 28 Feb http://lowenergybuildings.org.uk Project name PassivHaus Retrofit - Octavia Housing Project summary PassivHaus retrofit of a three storey solid brick Victorian terraced house in a conservation area. Produce