Social housing supplement Technology and skills
sector skills gap
The lack of technological skills that plagued building services in the 1990s still haunts the sector today.
Richard Baines explains
B
lack Country Housing Group has been pioneering low carbon homes since 1993. In the beginning, we focused on new build, simply because in principle, it seemed
far easier. At Bryce Road, a development of 27 units in Dudley that was completed in 2004, we explored different types of construction and experimented with how to super-insulate them, using advanced computer simulation and determining their potential passive performance. We quickly saw a trade-off between mass and speed
of construction; mass helped us to keep the internal temperature fairly constant, delivering cool internal temperatures in summer and warmth in the winter. However, we subsequently learned that if you keep the sun out and are able to open the house up securely, a lower level of mass is required to keep the homes cool in summer. Reducing mass reduces the overall demand for energy, because less energy is needed to heat up a lighter building. But while we now have buildings with heat loss
rates in the order of 15-20kWh/sq m per year – well below the threshold for the efficient running of a conventional central heating system with a boiler and radiators – modulating condensing boilers at that time were just becoming available and the smallest unit we could get was 15kW. We decided, therefore, to share heat sources on
a district heating model. We installed a 5kWe/12k wheat-fuelled, micro-combined heat and power (CHP) system, in parallel with a 10kW ground source heat pump, a 3,000 litre heat store and two modulating condensing boilers as a back-up. We found that the >
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June 2010 CIBSE Journal
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