Ground Source Heat Pump

Ground source heat pumps collect energy stored in the earth  and use it to heat water in a cylinder for distribution to taps, appliances and radiators. They can also cool the house in summer. This is the most advanced technology available for home heating, hot water and cooling. because the earth itself ‘stores’ energy it is an extremely reliable and constant energy source, it creates no harmful emissions and uses a very small amount of electricity to drive the pumps themselves.

It is by far the most efficient of any home energy system.

Ground source heat pumps have a coefficient of performance of up to 400%, which means one unit of energy is used to create 4 units (eg 1 kWh of electricity can create 4kWh of heat energy) In comparison a good quality condensing combi boiler can be 90% efficient ( 1kWh of gas will create 0.9kWh heat energy).

The heat conversion process of heat pumps happens at a much lower temperature, compared with fossil fuel burning appliances. For this reason it is essential that the installation property is well insulated.

Underfloor heating is the ideal system to run from a heat pump as the whole floor becomes the heat transfer surface (because the surface area is so large the temperature can be a lot lower than a standard heating system), alternatively radiators can be oversized to try to maximise the heat transfer surface area.

The constant geothermal heat is absorbed from the earth by a buried heat collector pipe, for a large domestic system this pipe could be up to 220 metres long. As not all properties have large enough grounds for this length of collector pipe there are a number different systems for burying the collector

The underground heat collector:

• can be laid in narrow trenches around a metre below the surface (this method takes up the most ground surface area)
• can come coiled like a slinky  and buried in a trench (this takes substantially less ground area but requires a much wider trench)
• can be buried in a deep borehole or several shallower boreholes. Boreholes are drilled vertically into the ground then filled with the collector pipe (the most costly option but the only option if space is limited)