We design the right borehole array to suit the heat requirement of the property. Typically a borehole is 100 metres deep, we then install the required probe which consists of a flow and return pipe 32mm or 40mm diameter, this is made from SDR11 plastic probe, at the bottom of the borehole loop or probe is a U bend to allow circulation up and down the borehole. A typical borehole would collect around 5Kwt of heat, dependant on the heat required arrays of these boreholes can be configured so as to abstract the required heat for a system. At the surface these loops or commoned together using manifolds which then feed to the heat pump. This whole circuit is referred to as a “Brine” or “Collector” Circuit, even though it is actually filled with an ethylene glycol mixture to prevent. On completion the boreholes are grouted using a sand cement and bentonite grout which seals the borehole and protects the probes. The design life of the collector circuit is 50 years. The discharge from the heat pump into the brine circuit is as low as -1 degrees Celcius, the circulating fluid is required to have heated up a minimum of 3 degrees, it is this small uplift in temperature that the heat pump “amplifies” up to a usable 35 degree temperature. The heat pump itself does not generate heat but merely converts low grade heat as explained above.
A heat pump uses refrigeration technology which is long established, a heat pump for British home heating requirements is, in essence, a fridge working backwards. The source of the energy would normally be the air, the earth, or water, even though some more adventurous installations recover heat from the weirdest heat sources. Heat pumps benefit over existing boilers by not requiring any flue, there are no dangerous emissions. A heat pump can provide a total energy solution as 75% of the heat derives from the air or ground the balance 25% being electricity from the national grid which powers the heat pump, thus it can totally heat your home.