Ground Source

Ground Source

Ground Source Heat Pumps utilise solar energy naturally stored in the soil, bedrock and groundwater as a heat source.  Ground Source Heat Pumps do use electricity to operate, but efficiently convert this into five times as much heat-energy for every unit of electricity used.

Ground Source Heat Pumps can be installed almost anywhere, depending on the area of land around the property.  There are three ways to install the 40mm geothermal pipe into the ground.  They are as follows:

Surface Collector
During the summer, the sun warms the ground and heat is stored in the soil. This heat is collected by burying plastic pipes just one metre under the surface with each length at least one metre apart. An environmentally friendly non freezing solution is circulated in the piping, collects this heat and transports it to the heat pump.

Typically the length of collector pipe required is between 200 and 600 metres depending on the heat demand and size of heat pump installed. The surface ground collector method is cost effective where sufficient useable land is available. The higher the water content of the soil the better.

Borehole Collector
Heat is collected in a similar way to the surface ground collector except the u-shaped collector piping is sunk into a borehole. The total borehole depth is again dependant on the size of heat pump and can be achieved across a number of separate boreholes which should be 15 metres apart. Typically the depth required can be between 70 and 190 metres.

Drilling a borehole needs to be carried out by a specialist contractor and may require permission depending on local conditions e.g. mine workings, tunnels etc. It tends to be more expensive than the surface ground collector.  A borehole requires little ground area and is suited to smaller plots and where a heat pump is replacing an existing fossil fuel boiler.

Lake Collector
Where a sufficiently large body of water is within easy reach of the house, collector piping can be secured to the bottom of the pond. Stored solar energy is again collected. The piping is buried one metre underground between the pond and the house. The water should be deep enough that it never freezes at the bottom where the piping is laid.