A heat pump is a device, which moves heat energy from one place to another and from a lower to a higher temperature. A domestic refrigerator is a heat pump. Heat is removed from the contents (the source) and discharged elsewhere (the sink). In heating applications, heat is removed from ambient air, or water, soil or bedrock) and delivered to where it is needed. In cooling applications, the reverse happens and heat is removed, to be discharged to the ambient air, water, soil or rock.

Heat pumps use a little energy (usually in the form of electricity) to move available energy as heat from A to B. For every unit of energy purchased as electricity, several units of heat are delivered. So, relating the energy purchased to the energy delivered, heat pumps can be 300% or 400% efficient.

Businesses with some land may wish to consider this old idea in an innovative way to provide heat for their buildings.
 

Some useful links include:

UK Heat Pump Network - http://www.heatpumpnet.org.uk/

Energy Saving Trust - http://www.est.org.uk/myhome/generating/types/groundsource/

Heat Pump Association - http://www.feta.co.uk

IEA Heat Pump centre - http://www.heatpumpcentre.org/

Action Renewables - http://www.actionrenewables.org/techgshp.htm