Ground source heat pumps are an excellent and efficient alternative method of heating your home. Fuel savings and reduced carbon emissions are two advantages of implementing a ground source heat pump, and they can also be implemented to cool your home.

Ground source heat pumps process solar energy from the ground and compress it to provide hot water and/or heat to a property.

Fundamental to installing a ground source heat pump is the effective use of a ‘ground array’ – effectively a loop of pipes within the ground to extract the heat in the first instance.

Iso energy recommends the most economical and cost-effective way to extract heat from the ground via a ground array is to cover as large an area as possible. Therefore, the optimum times when a ground source heat pump should be used are when a large horizontal space is available.

Installation of an optimum ground array for a ground source heat pump

A typical ground array would be a number of geothermal plastic  collector pipes in trenches around 1 metre deep, up to 4 metres apart and between 100-150 metres long.  Each pipe is looped along both sides of the trench to form a loop, then each loop is connected into a manifold. Overall, the system effectively uses two main pipes – a flow and a return – which in turn run to the house to be connected to a heat pump.

After flushing the pipes with clean water and pressure testing, a biocidal  treatment is run through the pipes to prevent degradation. A mixture of water and glycol is introduced into the system to serve as an anti-freeze and heat transfer fluid for the thermal energy.

Factors affecting the efficiency of the system include :-

  • the thermal load of the building
  • the soil type and conditions of the ground
  • the capacity of the heat pump

Clearly, the larger the area of ground available for installation of the ground array and the better the soil conditions, the more heat could be provided by the pump.

Likewise, the greater the heat demand from the building, the greater the heat supply from the ground array is needed. However, it is possible to heat homes in winter and a swimming pool in the summer using a ground source heat pump.

Ground arrays can be subject to ground cooling or over extraction, which may result in freezing or reduced efficiency of the heat pump system. This is why it’s vital to use good quality manifolds, individual flow meters and balancing valves to ensure operational efficiency of the ground array.

Conclusion: ground source heat pumps are an excellent alternative method of heating homes

Whilst ground source heat pumps are a terrific way to heat homes, it is essential to ensure that the ground conditions are optimum for an effective ground array to be installed. Ideally, look for a large external space to install good quality collector pipes, but also the optimum ground conditions to ensure the best soil.