Project Info:
We were approached by Colin the owner of Kimpton Road after being recommended by Stiebel Eltron for the Ground Source Heat Pump (GSHP). He was demolishing an existing property and building a highly insulated and efficient 270m2 zero energy sustainable house
Be Green were appointed as the renewables installer after working closely with the client and his architect to complete this prestigious development. We designed, installed and commissioned the heating and cooling system. This complete eco (renewables) package significantly contributed to the house being shortlisted in the Most Sustainable Construction projects of Hertfordshire County Council’s Building Futures Award
5 kw Ground source heat pump
Under-floor heating throughout, designed to work at low temperatures
Domestic hot water
Mechanical Ventilation and Heat Recovery (designed for cooling)
Comfort Cooling.
The extracted air from the MVHR has been designed to leave the house directly behind the ASHP, this relatively warm air will increase the heat pumps efficiencies in winter.
The house has three floors and because of the efficiencies of the building had heat losses of 17w/m or less than 5kW. Because of the low energy requirements it enabled Be Green, with the help of Rehau's technical team, to design the ground collector using 15 of the 18 x 12 meter deep piles (see pictures). So the ground collector pipes required for the GSHP are installed within the piles holding the building up, perfect, saving Colin the cost of drilling boreholes for the GSHP.
Be Green installed a Stiebel Eltron 5kW GSHP as well as their Hot water and Buffer tanks, these have been located in the garage some ten meters away from the house and connected underground via zero heat loss ground pipes.
The house also has Underfloor heating (UFH) on the first and second floors with radiators on the top floor.
Mechanical Ventilation and Heat Recovery (MVHR) has been installed so the house can breathe, allowing it to be built to be as air tight as possible. This helps the property achieve the high efficiencies but it also helps enhance the properties ambiance with controlled slow and gentle air movement throughout the home. The MVHR is designed to run at around 50 to 60% of its capacity during the winter, this reduces possible noise, lowers energy consumption and increase the heat exchange.
Running the MVHR at half its capacity enables us to increase the air movement in summer for greater cooling effectiveness. We can then enhance the cooling of the incoming air by connecting it to the ground pipes located in the properties piles and connected to the GSHP. With the GSHP off, by simply circulating this chilled fluid from the ground pipes (temperature of approximately of 6 to 9 deg C) and running it up through a cooling coil connected to the air inlet vent of the MVHR. We can now significantly cool the incoming air with virtually no running costs, indeed with the addition of Solar PV it will cost nothing to run; this gives the home background whole house Comfort Cooling.
As we have alluded to, to top the property off one whole side of the south facing roof has 35 PV Panels that will generate over 9,000kWh (Kilo Watt Hours) of electricity each year. This should be enough power to run the house including all its heating, hot water and cooling demands.
So Colin has built himself a carbon free home with no or very low running costs. Not forgetting he is also eligible for the Feed in Tariff subsidy for the Solar PV and the Renewable Heat Incentive grant of having the GSHP installed, these will more than return the cost of his investment and probably generate a small but significant tax free income for the next 7 to 20 years.
Technology Used in Project:
