A ground source heat pump is a new and clean way of heating buildings in the UK. It uses pipes buried in the garden to extract heat from the ground. This makes use of renewable energy stored in the ground, providing a very energy efficient way of heating buildings. The system can be used throughout the year as temperature beneath the ground stays constant, even during winter.
Ground source heat pumps use solar energy that is naturally stored in soil, bedrock and groundwater as a heat source. It does require electricity to operate and for every unit of electricity that the system uses it efficiently produces up to five times as much heat energy.
It can be used to heat water for radiators or under floor heating systems. It can also be used to pre-heat water before it goes into a more conventional boiler.
How it works
The ground source heat pumps use collectors that run beneath the ground to transfer heat from the ground into your home. There are many types of collectors available to be installed:
- Borehole collector – this is a vertical collector which requires a bore hole to be drilled through the ground. The hole must be approximately 50m to 200m deep.
- Horizontal ground collector – these are pipes buried across the ground, in lengths, about 1m to 2m deep.
A mixture of water and antifreeze are circulated around a loop of these collectors. As the liquid travels around the loop it absorbs heat from the ground and this energy is transferred through a system of evaporation and condensation to be delivered to the heating system of the house. The heat can then be used for radiators, under floor heating and hot water use.
The electrical and plumbing required with this system is straightforward and easy to install. It requires only a 240V mains supply and simple flow and return connections to internal and external wall circuits.
Benefits
- Reduces carbon dioxide emissions dramatically. An average a ground source heat pump could save around 540kg of carbon dioxide every year when replacing an oil boiler.
- Ground heat is free so after initial costs water bills would be greatly reduced.
- Minimal maintenance and operating costs.
- Eliminates fuel bills as ground source heat pumps run on electricity, so there"s no need to pay for gas, oil or solid fuels to heat your house.
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Installations and where it is used
The ground source heat pumps can be installed almost anywhere, provided there is sufficient space to lay the ground loops or drill a bore hole. The length of the ground loop depends on the size of your home and the amount of heat you need. Longer loops can draw more heat from the ground.
There is a wide variety of building types suitable for installation and it is particularly appropriate for low environmental impact projects.