Ground Source Heat Pumps

Installation of borehole
Installation of borehole

Ground Source Heat Pumps use pipes to extract heat from the earth. The heat is used to supply radiators or underfloor heating systems and sometimes hot water. They can also be used to cool buildings. Ground temperatures remain relatively constant throughout the year and this can be used as a heat source in winter and a heat sink in summer.

A loop of pipe can be installed into the ground either vertically or horizontally, depending on land availability. For large areas of land horizontal pipes are preferable as it is cheaper to install at shallow depths. On smaller sites, vertical pipework is installed which takes up a very small amount of space but the boreholes, which can be up to 100m in depth, are much more expensive to install. Vertical pipework can be relatively unobtrusive and installed quickly. Some geology is not suitable. A survey is required to assess suitability.

Open loop systems extract water from an underground well and require extraction permission from the environment agency. Closed loop systems use a pipe filled with a mixture of water and antifreeze. The longer the loop the more heat that can be gained but this means a greater land area is required or deeper boreholes.

Heat is obtained through a heat exchanger. Electricity is used to run the pump which can be supplied from a PV or wind turbine. Between 3 – 4 times more energy is generated than is used to drive them.

Ground source heat pumps work well with underfloor heating systems which require lower temperatures than traditional wet systems. Max CO2 savings for heating can be up to 20%.

Link to short examples

What should I do?

Investigate the geology and identify land availability to identify whether appropriate.

WLGA - CLILC Llywodraeth Cynulliad Cymru / Welsh Assembly Government