What is a Ground Source Heat Pump?
A Heat Pump is a highly efficient way to generate your own heat and hot water using stored energy in either the ground (a Ground Source Heat Pump) or the air (an Air Source Heat Pump).
A Ground Source Heat Pump can be sized to be suitable for individual properties, a number of properties in a district scheme, or for commercial buildings including community centres, schools, and leisure centres.
How does a Ground Source Heat Pump work?
It uses electricity to circulate a mixture of water and refrigerant around a loop of pipe – called a ground loop – which is buried in the garden or land. The heat pump uses a refrigerant fluid that boils at very low temperatures, picking up heat as it travels, and depositing that heat to where it’s needed within the property. The ground loop can be arranged in coils in your garden/land or, where space is limited, in deep boreholes.
The key benefit of a heat pump is that it typically produces between 3 and 4 kWs of useful heat from every kW of electricity used to operate the heat pump.
Things to consider when thinking about Ground Source Heat Pumps as a heating solution
- Space is a key consideration. You’ll need space for either the horizontal ground loop or the drilled bore holes. For a typical house 250m2 will be required for a horizontal loop and a smaller space for borehole. Space is also required for the internal unit which in a domestic installation is the size of a fridge. For district/community heating schemes there will the requirement for an internal plant room.
- Is the property off the gas-grid, meaning your main heating system is not a gas central heating system? A Ground Source Heat pump will typically offer lower CO2 emissions and offer a reduction in energy bills in comparison to any existing electric, LPG, or coal heating system .
- Is the property well insulated? A heat pump circulates the water round the radiator system or underfloor heating system at a flow temperature of between 35-55˚C, which offers a more gradual type of heat than a gas boiler that circulates water round the system at 82˚C. As a result it is very important that heat loss in the property is kept to a minimum, and it is recommended that the property has good levels of loft or wall insulation.
- As a heat pump is thermostatically controlled it will heat each room to the programmed temperature. With the lower flow temperatures you may need to increase the size of some of the radiators, to ensure the heat pump works most efficiently. That would be determined by a technical survey.
- For a district heating solution, you’ll also need to how piping will be run from the plant room to each individual property.
What funding is available for Heat Pumps?
For individual heating systems for one property the Renewable Heat Premium Payment is available. A £1,250voucher of can be claimed through the Energy Savings Trust, provided that you meet certain criteria. For more information click here.
If however, you plan to install a district scheme or a heating system for a non-domestic property, then the installation will likely be eligible for the Renewable Heat Incentive.
As part of British Gas Green Streets we installed a 16kW Ground Source Heat Pump in a community building in Tackley. The Renewable Heat Incentive will offer income over the lifetime of the scheme of over £15,000 to the community building.
In an installation we’re planning in a historic building, with a very large heat demand of over 1.1MWh the Renewable Heat Incentive would return a net annual gain of £2,000 against what was previously spent on the heating bills and lifetime earnings of nearly £750,000.
It is planned that a Renewable Heat Incentive will be available for individual heating systems from October 2012, the details of this are yet to be announced. For more information click here.
Where have Ground Source Heat Pumps been successful?
Tackley Village Hall, British Gas Green Streets Project
A 16kW Ground Source Heat pump with horizontal ground loop was installed as part of our community project Green Streets, for more info click here. The village hall will benefit from nearly £3,000 savings on their heating bills compared to direct and storage electric heating system they were on previously.