Stiebel Etron GSHP

How does a ground source heat pump work?

Heat pumps work by moving heat from one place to another. In the case of ground source heat pumps, the sun’s heat is collected from the ground (or a body of water) via a circulating loop of glycol (antifreeze). When the loop reaches the heat pump a refrigerant circuit extracts the heat energy which is then used for heating and hot water.

The magic of heat pumps is that they can use ground with an average temperature of 10 degrees to heat hot water to up to 60 degrees all year round. This is because, although the ground loop may only gather a few units of energy per metre of loop, it makes this small gain across a very large area in which the heat is constantly replenished by the sun and precipitation. This adds up to a lot of units of energy which can then be concentrated into the relatively small area of your home.

Why are ground source heat pumps so green and efficient?

Traditional systems require about one unit of electricity or gas to generate one unit of heat. For every unit of electricity heat pumps can produce between 4 and 5 units of heat.

Because such a high proportion of the heat output from a heat pump comes from a sustainable environmental source, CO2 emissions are substantially lower than traditional fossil fuel systems. This helps to reduce your carbon emissions and save the planet.

Can a heat pump work on my existing home?

Ground Source heat Pump Brochure   Drawing Heating Energy from the Ground Brochure

The Benefits of using a Ground Source Heat Pump (GSHP)

  • Reduced fuel bills, especially if you are replacing oil, coal, LPG or direct electric
  • Not reliant on fuel deliveries
  • Protection from fossil fuel cost inflation
  • Can supply all your hot water and heating demands all year round
  • Life span up to 25 years
  • Reduced carbon emissions
  • Very low maintenance, no need to have a regular flue services etc
  • Earn significant income from the Renewable Heat Incentive (RHI)

Is a ground source heat pump suitable for me?

Is your garden suitable for a ground loop? Your garden needs to be around 3 times larger than the floor area of your property for a horizontal loop (for new build homes twice as large should be sufficient) .Vertical borehole loops can also be used in some situations where this area is not available. You will need access for a digger or drilling machine. If you have a large pond, stream or access to other water you might want to consider siting your loop in the water, as water transfers heat even more efficiently than soil.

What space do you need to fit the ground source heat pump? The size of the project dictates the size of heat pump(s) required. As a guide, a ground source heat pump is around 600mm x 600mm (same size as a fridge) but projects often also require a buffer tank, these range in size according to the project.

What is a buffer tank for? Buffer tanks must be considered carefully as part of the system design for a heat pump used for space heating.

Heat pumps, like cars, are less efficient if they start and stop frequently. Buffer tanks allow a pump to run for longer periods of time increasing efficiency. If a single room calls for heat it can use energy stored in the buffer tank first, delaying the need to start the pump again.

Buffer tanks also allow the potential to store energy from other sources such as solar panels.