Mind The Gap: an 8' Wide Eco-House
We have shown a few narrow houses lately; they are wonderful demonstrations of how people can live with a smaller footprint. Luke Tozer is building a new 8' wide home for his family-"Only an architect would buy that house and think '8ft wide - how exciting'," says the 36-year-old.
Such a narrow home sandwiched between two others would not have too much heat loss in the first place, but Luke worked with Arup to ensure that it was as environmentally friendly as possible, with passive solar design, a ground source heat pump, photovoltaics and rainwater harvesting to flush the toilets. He estimates it will use one third of the energy of a conventionally built house.
Ground source heat pumps are not very common yet in the UK- according to the Independent "There are still only about 3,000 in Britain, which has historically relied on oil and gas, prices for which have been kept artificially low."
The Independent goes on to explain them in detail:
Below the first metre of soil, the ground (in the UK at least) is pretty much - summer and winter - a constant 12C. In winter, a water and meths mix will be pumped through three 50m-long pipes that run into the ground. This mix comes out of the ground at 12C, runs through the heat pump which extracts and condenses the heat into the underfloor heating circuit, thereby cooling the mix to zero or minus 2C. It then goes back into the ground and comes out again at 12C and repeats in a cycle.
"It's a very similar process to what a fridge has, where you've got a cool inside circuit and a hot outside circuit," says Luke, co- director of Pitman Tozer Architects. "The amount of electricity that you use to drive the process is between a third and a quarter of the energy of a condensing gas boiler, so it's a very efficient. In terms of energy consumption, it should be much less than having a conventional boiler."
In summer, the process can be reversed. The heat in the underfloor heating within the building is extracted by the heat pump and pumped into the ground loop, where it cools. Hot water (for baths and showers) is provided by the heat pump in the same way as winter but only for an hour or two per day (at night using cheap electricity). ::Independent and ::Pitman Tozer Architect and ::Archinect