 |
Monday, 1 November 2010
Floor slab removal
To install the required depth of insulation to provide a U-value of 0.10 W/m2K, the concrete floor slab was removed which involved breaking the slab up with a pneumatic road drill being careful not to disturb any foundations or structural elements of the existing building. The photograph below shows the initial slab break up and is looking from the kitchen extension into the dining room/front lounge.
During excavation it was discovered that there was a step in the wall foundations approx 400 mm below the finished floor surface. This could be an original feature or as the result of underpinning at some time after the house had been built in 1896. This unforeseen step created problems as the thickness of insulation on top of the step could only be half of the designed thickness of 180mm.
Saturday, 18 September 2010
Ground floor slab core
The start of work was delayed owing to the property being vacated later than planned. A core sample of the solid ground floor slab was taken as seen in the above photograph. The drawings indicated 150mm of consolidated hardcore and 150mm of concrete/screed. The core showed approx 100mm of hardcore and 75 - 100mm of concrete/screed, with no insulation.
Tuesday, 8 June 2010
PHPP Verification work sheets pre and post retrofit
The post retrofit PHPP verification work sheet indicates a specific space heat load of 37 kWh/(m2yr), 7 kWh more than the project target of 30 kWh/(m2yr). The reduction in heat loss as a result of a reduction in the effect of thermal bridges post retrofit was an estimate which erred on the side of caution.
Monday, 24 May 2010
Airtightness test
BSRIA carried out the airtightness test in mid April, calculating the air permeability at 12.58 m3/(hr/m2). It appears that a disproportionate amount of air is leaking out from the 30 year old loft convertion. At the time of the test it was commented that without the attic, the 114 year old original construction would have an airtightness of around 8 m3/(hr/m2), which is lower than the current building regulations requirement of 10 for a new build.
Wednesday, 12 May 2010
UK manufactured products
WINDOWS
The quality of the windows are critical in not only hitting our aspirational space heating target of 30 kWh/m2/yr, but also from a thermal comfort perspective. There are a number of Passivhaus window manufactures in mainland Europe, but they all appear to only manufacture inward opening windows which are not suitable for the project house.
We contacted Munster Windows who have factories in Ireland (good from the Northern Ireland angle) and England. They are just bringing to market their outward opening 'PassiV' window and so we are in the process of obtaining the technical data required for input into PHPP. Its been a bit of a struggle as they are being asked for data which isnt normally printed in glossy brochures. But, we are getting there.......
The next question is the type of frame, PVC-U or timber? HA's favour low maintenance PVC-U. Window manufacturers wont commit to a performance guarantee on wood frames only commenting that they 'may last up to 20 years'. This means the possibility of 3 sets of windows between now and 2050, plus the associated stripping out and replacement of the internal insulation in the window reveals (how sustainable is this option?). Hence considering PVC-U with closed cell foam filled frames and quadruple glazing units to compensate for the higher U-value of the frame when compared to a thermally broken wood frame. Thermoplastics including PVC-U can be recycled up to around 10 times (according to the British Plastics Federation) but checking to see if the addition of a foam infill impacts on this.
Finding a closed cell foam to create a thermal break between the frame and the masonary proved time consuming. Eventually we came across Kewell Converters Ltd who produce a suitable foam in strip form.
BOILER
An additional requirement is that as the project house is a mile form the Belfast Lough, the MVHR heat exchanger needs to be made of plastic (as in a Paul unit) so it doesnt suffer corrosion from the salt laden air. The vast majority of heat exchangers in MVHRs appear to be alumiminum which renders them unsuitable.
Currently, although enquiries are continually being made with 'UK manufactures' of MVHR's, a Paul unit is the front runner.Retrofit measures In order to establish the appropriate retrofit technologies, a sensitivity analysis using PHPP (Passivhaus Planning Package) was carried out. The metrics for each selected technology were entered into PHPP individually and their affect on the dwellings overall energy balance analysed using the PHPP model of the existing house as the base line.
The quality of the windows are critical in not only hitting our aspirational space heating target of 30 kWh/m2/yr, but also from a thermal comfort perspective. There are a number of Passivhaus window manufactures in mainland Europe, but they all appear to only manufacture inward opening windows which are not suitable for the project house.
We contacted Munster Windows who have factories in Ireland (good from the Northern Ireland angle) and England. They are just bringing to market their outward opening 'PassiV' window and so we are in the process of obtaining the technical data required for input into PHPP. Its been a bit of a struggle as they are being asked for data which isnt normally printed in glossy brochures. But, we are getting there.......
The next question is the type of frame, PVC-U or timber? HA's favour low maintenance PVC-U. Window manufacturers wont commit to a performance guarantee on wood frames only commenting that they 'may last up to 20 years'. This means the possibility of 3 sets of windows between now and 2050, plus the associated stripping out and replacement of the internal insulation in the window reveals (how sustainable is this option?). Hence considering PVC-U with closed cell foam filled frames and quadruple glazing units to compensate for the higher U-value of the frame when compared to a thermally broken wood frame. Thermoplastics including PVC-U can be recycled up to around 10 times (according to the British Plastics Federation) but checking to see if the addition of a foam infill impacts on this.
Finding a closed cell foam to create a thermal break between the frame and the masonary proved time consuming. Eventually we came across Kewell Converters Ltd who produce a suitable foam in strip form.
BOILER
Due to the low space heat demand, we have tried to source a boiler of around 4kW to prevent boiler cycling. Although there are a couple of manufacturers of such a boiler in Germany, even though CE marked, apparently these do not have type approval for use in the UK.
Having attempted to convince a few manufacturers that there will be a demand for small boilers in the not too distant future, none would commit to the project and conjure up a small boiler. Choosing a boiler was also frustrated by manufacturers reluctance to provide technical information.
A Worcester Bosch 12kW systems boiler has been chosen not only as it appears to be the smallest genuinely UK manufactured unit available, but also the company provided all the technical information requested.
Having attempted to convince a few manufacturers that there will be a demand for small boilers in the not too distant future, none would commit to the project and conjure up a small boiler. Choosing a boiler was also frustrated by manufacturers reluctance to provide technical information.
A Worcester Bosch 12kW systems boiler has been chosen not only as it appears to be the smallest genuinely UK manufactured unit available, but also the company provided all the technical information requested.
A comment on the feed back from the TSB judges was that we should endeavor to use a locally made MVHR. We have been scouring the UK for a suitable unit, however, although often promoted as a UK product, it appears that many of the parts are made in distant countries such as China with the unit assembled in mainland Europe. These MVHR's therefore have no distinct advantage over the preferred choice of a Paul MVHR from Germany which has Passivhaus approval. Also, the specific fan power used by many other MVHR's is appreciably higher (+30%) and the heat recovery less efficient than the Paul. Worcester Bosch (our choice for the boiler) have an MVHR being lunched in the UK this summer, however, this is manufactured in Germany and doesnt have the same efficiency as the Paul.
An additional requirement is that as the project house is a mile form the Belfast Lough, the MVHR heat exchanger needs to be made of plastic (as in a Paul unit) so it doesnt suffer corrosion from the salt laden air. The vast majority of heat exchangers in MVHRs appear to be alumiminum which renders them unsuitable.
Currently, although enquiries are continually being made with 'UK manufactures' of MVHR's, a Paul unit is the front runner.Retrofit measures In order to establish the appropriate retrofit technologies, a sensitivity analysis using PHPP (Passivhaus Planning Package) was carried out. The metrics for each selected technology were entered into PHPP individually and their affect on the dwellings overall energy balance analysed using the PHPP model of the existing house as the base line.
Retrofit measures
The sequence in which these measures were considered follow the ‘Trias Energetica’ concept. Trias Energetica The ‘Trias Energetica’ (http://www.triasenergetica.com/) sustainable energy supply strategy was developed by the Dutch University of Delft in 1996. It consists of three sequential steps where each step should only be taken once the previous step has been exhausted.
Step 1: Reduce the demand for energy by avoiding waste and implementing energy-saving measures. The amount of heat lost in a dwelling is dependent on external surface area, insulation levels and air tightness.
Step 2: Use sustainable sources of energy instead of finite fossil fuels. Utilising sustainable energy source technologies such as photovoltaic’s, reduces reliance on primary energy and fossil fuels. High performance windows enable solar gain to contribute towards space heating requirements.
Step 3: Use fossil energy as efficiently as possible. Installation of a high efficiency heating system, thermal store and high efficiency appliances. A bath/shower drain water heat recovery/heat store system to pre-heat incoming mains water. (The water can then be recycled for toilet flushing).
Retrofit measures include:
Aerogel and phenolic internal wall insulation to reduce heat loss
Triple glazing
Reduction in thermal bridges
Air tight building envelope to prevent draughts and heat leaking out of the dwelling
Mechanical Ventilation with Heat Recovery (MVHR) unit to ensure excellent internal air quality and recover heat from the stale exhaust air
Photovoltaic module array to maximise the reduction of primary energy from the available roof area
High efficiency Band A gas systems boiler coupled to DHW tank
Intelligent controls to manage space heating and DHW requirements
Low flow aerated taps and shower head, low volume insulated bath, high levels of pipe insulation
'Home Energy Controller' domestic Building Energy Management System (BEMS), also displays data in real time and historical data to the resident
Smart meters for electricity/gas/water
The aspirational energy target is to achieve '3 litre house' status, a term recognised in Europe describing a house consuming less than 3 litres oil equivalent/m² of floor area/year (30kWh/m²/yr) for space heating. In Northern Ireland terms this equates to an annual gas heating fuel cost for the project house of approximately £130. The installation of a community heating system is being investigated. Connecting the project house to a system fuelled by a carbon neutral fuel such as biomass, would reduce the CO2 well beyond 80%, resulting in a near zero carbon retrofitted house. The Eco-Energy Retrofit is also one of the 14 UK projects chosen by the Building Research Establishment (BRE) to take part in the BREEAM domestic refurbishment pilot scheme aimed at developing a new BRE refurbishment Quality Assurance standard for existing properties.
Step 1: Reduce the demand for energy by avoiding waste and implementing energy-saving measures. The amount of heat lost in a dwelling is dependent on external surface area, insulation levels and air tightness.
Step 2: Use sustainable sources of energy instead of finite fossil fuels. Utilising sustainable energy source technologies such as photovoltaic’s, reduces reliance on primary energy and fossil fuels. High performance windows enable solar gain to contribute towards space heating requirements.
Step 3: Use fossil energy as efficiently as possible. Installation of a high efficiency heating system, thermal store and high efficiency appliances. A bath/shower drain water heat recovery/heat store system to pre-heat incoming mains water. (The water can then be recycled for toilet flushing).
Retrofit measures include:
Aerogel and phenolic internal wall insulation to reduce heat loss
Triple glazing
Reduction in thermal bridges
Air tight building envelope to prevent draughts and heat leaking out of the dwelling
Mechanical Ventilation with Heat Recovery (MVHR) unit to ensure excellent internal air quality and recover heat from the stale exhaust air
Photovoltaic module array to maximise the reduction of primary energy from the available roof area
High efficiency Band A gas systems boiler coupled to DHW tank
Intelligent controls to manage space heating and DHW requirements
Low flow aerated taps and shower head, low volume insulated bath, high levels of pipe insulation
'Home Energy Controller' domestic Building Energy Management System (BEMS), also displays data in real time and historical data to the resident
Smart meters for electricity/gas/water
The aspirational energy target is to achieve '3 litre house' status, a term recognised in Europe describing a house consuming less than 3 litres oil equivalent/m² of floor area/year (30kWh/m²/yr) for space heating. In Northern Ireland terms this equates to an annual gas heating fuel cost for the project house of approximately £130. The installation of a community heating system is being investigated. Connecting the project house to a system fuelled by a carbon neutral fuel such as biomass, would reduce the CO2 well beyond 80%, resulting in a near zero carbon retrofitted house. The Eco-Energy Retrofit is also one of the 14 UK projects chosen by the Building Research Establishment (BRE) to take part in the BREEAM domestic refurbishment pilot scheme aimed at developing a new BRE refurbishment Quality Assurance standard for existing properties.
Subscribe to:
Comments (Atom)
