APOLOGIES FOR LOSS OF WATER PRESSURE Many people have asked about the recent drilling rig which was located outside ‘The Carrier’ in the centre of the village. Firstly, please accept our apologies for the noise, and especially for the short term loss of water pressure to some residents. The drilling rig was there to drill two boreholes down to some 125 metres depth. These are to supply heat recovered from the ground to supply a ground source heat pump which will be installed shortly in our home.
A technical explanation follows: Each borehole has a loop of plastic pipe inserted, through which a glycol/water mixture, similar to anti-freeze in cars, is circulated. This is called a ground loop, and one can be seen in the following picture, awaiting later connection to the pipes to the house. A
temperature increase within the ground loop fluid of just 3˚C or 4˚C
is all Ground Source Heat Pumps require. The returning warmed
liquid is fed into a Heat Exchanger / Evaporator. The Evaporator The purpose of the Evaporator within the heating pump is to take the collected ground source heat out of the ground loop liquid and return it cooled to the pipe for the next cycle. It does this by using a refrigerant that boils at approximately -10˚C. The act of boiling turns the refrigerant into a vapour which is then moved into the Compressor. The Compressor The Compressor does exactly what the name suggests: the vapour is compressed in volume and as its volume reduces, the temperature increases to levels of between 75˚C and 125˚C. The gas is then fed through a Heat Exchanger within the heating pump. The Heat Exchanger Feeding the hot gas through a condenser allows the refrigerant to turn back into a liquid. As it condenses, its heat is passed into the Heat Exchanger which supplies the domestic hot water and powers the central heating system using the ground source heat extracted originally. The Expansion Valve To complete the closed circuit of the Ground Source Heat Pump, the only thing which needs to be done is reduce the pressure of the condensed liquid. This is achieved via the Expansion Valve. Pros of ground source heat pumps
Cons of ground source heat pumps
How green is a ground source heat pump? A ground source heat pump system can help to lower your carbon footprint as it uses a renewable, natural source of heat – the ground. According to the EST, a heat pump with mid-range efficiency uses a third of the energy needed in an average gas or oil boiler to produce the same amount of heat. A heat pump also requires a supplementary source of power, usually electricity, to power the heat pump, so there will still be some resulting CO2 emissions. Malcolm Ingham |
News Archive >