This is the geothermal system for the central heating and hot water, to heat 16 radiators
and supply three bathrooms. Heat is obtained from 90metres down, where the temperature
is always about 14degrees, and a heat exchanger heats the water to about 65degrees.
We get back almost 4Kwh of heat for every kWh used to power the system. Virtually
a free lunch (but serious capital cost)