Ground Source Heat Pumps
What are they?
Ground source pumps work on the same principle as a refrigerator system, but in reverse. In the same way that your fridge uses refrigerant to extract heat from the inside, keeping your food cool, a ground source heat pump extracts heat from the ground and uses it to heat the inside of your home.
The sun heats the ground so the ground source heat pump is actually using solar energy to operate. They take low grade energy from the ground and turn it into usable energy in the home for heating water and central heating systems.
There are two different types:
Open Loop systems:
These systems take ground water and pump it up to the surface, extract the heat energy and then return it to the ground.
Closed Loop systems:
These systems pump water around a sealed polyethylene pipe which is buried underground. The water is heated by the ground as it goes around the pipe. It then takes the hot water into the heat pump and pumps it around the house and then returns cold water back out to be pumped around the system and warmed up again.
What’s the benefit?
Ground source heat pumps are designed to heat a whole building. They require energy to run the pump but are generally more efficient than boilers running central heating systems. If the electricity that is required to operate the pump is made on site by a renewable source then the running of the whole process can be carbon neutral.
If you don’t have renewable systems in place then the pump can run off mains electricity. The efficiency of a ground source heat pump system is measured by the coefficient of performance (CoP). This is the ratio of units of heat output for each unit of electricity used to drive the compressor and pump for the ground loop. Average CoP is around 3-4 although some systems may produce a greater rate of efficiency. This means that for every unit of electricity used to pump the heat, 3-4 units of heat are produced, making it an efficient way of heating a building. If grid electricity is used for the compressor and pump, then you should consult a range of energy suppliers to benefit from the lowest running costs.
On average you can save £400 - £800 on your heating bills and 2-8 tonnes of carbon dioxide per year.
How can Footprint Building help?
We sell ground source heat pumps from our showroom. We can recommend, supply and install them as required. If you are considering one for your home then give us a call and we will be happy to come and do a free site viewing to discuss your individual requirements. We can also discuss grant options available to you.
Answers to frequently asked questions:
1. Are they suitable for my home?
Ground source pumps require a large amount of space outside to install. Typically, a closed loop systems will either need a 10 metre trench (for every 1 kw of heat), 1.5 m deep, or they can be buried vertically in a borehole, which is normally between 50 – 90 m deep.
Ground source heat pumps also work most efficiently with an under floor heating system as they require a lower temperature to run effectively.
Other considerations:
- Have you installed insulation measures? Wall, floor and loft insulation will retain the heat and therefore lower your heat demand and make the system more effective. (see our insulation section for more information)
- What is the annual heat demand for the building, including hot water if required?
- What is the average ground temperature at the location?
- What are the local ground conditions – can a trench or borehole be easily dug into the ground outside?
2. Do I need planning permission?
Since 6th April 2008 changes to permitted development rights for renewable technologies have lifted the requirements for planning permission for most domestic micro generation technologies in England.
Ground Source Heat Pumps are permitted under the new legislation. For more information look at: planning permission for renewable energy technologies.
For Wales, Scotland and Northern Ireland you will have to check with your local planning office.
3. Are there any grants available?
There are grants available from the Low Carbon Buildings Programme for Ground Heat Pumps but we do advise to check for updated information regarding these grants.
In England and Wales there are grants of up to £1200 available for the installation of Ground heat pumps, regardless of size but limited to a 30% limit of total installation cost. (To be reviewed in April 2009)
There are also other grants available and we can advise you on which grant may be best for you. You can book a free eco consultation with us to discuss your own personal requirements.
Check here to see what grants are available for renewable systems in your area.
Further information
For more information on ground source heat pumps please pop into our showroom on:
42 Pembroke Rd, Clifton, Bristol, BS8 3BQ, or give us a call to discuss your individual requirements: 0117 3179571.
