Ground loops, continuous or slinky, geothermal probes, closed loop, boreholes with open loop...

How the Ground Source Heat pump Works

A Ground Source Heat Pump is a unit that uses the heat from the ground or from groundwater to provide space and/or water heating.

All Ground-Source Heat Pumps have two parts: a circuit of underground piping outside the building, and a heat pump unit. The piping circuit can be what is called Open or Close Loop. There are two variations of the Closed Loop: vertical and horizontal (which refers only to the way the ground loops are arranged. Regardless of the type of Ground Source Heat Pump, it can be seen that a major reason for their superior efficiency is because they extract heat from a source that is free, the ground. In addition, they take heat via solar gain from the atmosphere i.e. the ground temperature increases and is regenerated on a daily basis via solar energy.(A body of water acts as a similar source of natural heat).

Collection methods

Ground loops, continuous or slinky
These systems can be referred to as slinky type collectors and are positioned to a depth of 1.0 metres below ground level horizontally within the grounds of the property. These horizontal collectors collect heat from the surrounding ground but also take heat via solar gain from the atmosphere.
Geothermal probes, closed loop
These systems circulate a water/antifreeze mixture around a circuit flowing continuously from the Heat Pump and down the pipes set within the borehole. This fluid extracts Heat from the ground via the geothermal probes set within the borehole and brings the heat back to the Heat Pump.
Boreholes with open loop

Here ground water from an underground source is pumped up from the source to the Heat Pump. The heat is extracted and the water is then piped back down onto the ground.

Boreholes with a closed loop Geothermal Probe system will extract heat from the ground at depths of up to 300 metres. However boreholes at any depth from 10 metres to 100 metres allow varying amounts of heat to be extracted reliably using heat energy from the earth.

The Heat Pump unit itself will continue to operate as long as it is able to gather the correct amount of heat from the ground. This is why the specification and installation of the ground collectors must be carried out to a high quality level. A well designed but badly installed system will provide the same poor results as a badly designed but well installed system. Therefore a total project management approach is required to ensure that sufficient care is taken to ensure that all components are compatible and of high quality and importantly the design is secure in terms of future performance.