Ground Source Heat Pumps (GSHP) are widely used to provide efficient heating, hot water and cooling to domestic and commercial properties.

An alternative to Biomass, of which we have been installing many projects, are Ground Source Heat Pumps.  If there is space available, a suitable electrical supply, and the ability to match the heat emitters in the building to the low flow temperatures produced by heat pumps, then this is a very attractive, efficient, and clean way of heating.

As with any installation project, we assess the particular merits of each job, certain properties just arent suitable for biomass and GSHP could be ideal, and vice versa, but we would not try to sway you one way or the other.


A ground source heat pump system consists of 3 main parts:

  • Ground heat collector system: generally this consists of loop of pipes buried underground to transfer energy to and from the system.
  • Heat pump unit: located inside the building plant room, with the buffer tanks and other associated equipment
  • Heating and cooling distribution system: underfloor heating is best suited to the low flow temperatures of heat pumps, but correctly sized radiators work well too.

The extraction of ground energy using heat pumps requires a collector system. Collector systems commonly used to extract heat from the ground are vertical borehole collectors, horizontal ground collectors and groundwater systems.

  1. The ground absorbs low-grade solar energy by means of direct sunlight and rain. This gives the ground a year round temperature of approximately 8 – 12 °C.
  2. A cold water antifreeze mix is pumped through the ground within a series of looped, energy absorbing pipes, or deep ground bore holes.
  3. As heat naturally flows from warmer to cooler places, the anti-freeze mix circulating around the array is constantly warmed by the grounds low-grade heat.
  4. The heated antifreeze mixture is fed into a heat exchanger called the ‘evaporator’. On the side of the evaporator there is a refrigerant, which acts as a heat transfer fluid.
  5. When the water antifreeze mixture enters the evaporator it begins to boil and turn into gas. This gas is then fed into a compressor, increasing the pressure, which makes the gas temperature rise.
  6. The hot refrigerant gas then flows into a similar, second heat exchanger called a ‘condenser’ with identical heat transfer plates. This condenser delivers water hot enough to serve space heating and hot water needs.
  7. Having transferred its heat, the refrigerant gas reverts to a liquid, which is passed through an expansion at the end of a cycle to reduce its pressure and temperature, ready to commence the cycle all over again.