Status: Renewable as it is indirect solar power
What is it?
Ground source energy can be extracted from the low-temperature heat found at shallow depths in the Earth’s crust. This temperature stays relatively constant. The heat can be taken directly from the Earth or a shallow coil system is used just below the surface of the ground. At this depth it actually uses indirect solar power. It is a great way to heat or cool a house.
How is it used?
There is a circuit of underground pipes outside the house, and a heat pump inside the house.
Anti-freeze circulates in the pipes, absorbing the heat from the soil around it.
This heat is transferred into a liquid where it is boiled, compressed and vaporised and passed through the system to make heat.
The system can be run in reverse so it takes heat from the house and transfers it to the ground.
Advantages and disadvantages of using ground source energy
- It does not produce any pollution
- Running costs are very low
- It reduces heating bills and consumption of other, non-renewable, energy resources
- All pipe-work is below ground so there is minimal effect on the environment
- The effectiveness of the system will vary with the seasons. However, installing the correct amount of pipe should compensate for this variation
Where can you find it?
Anywhere you are able to lay a pipe just below the surface of the ground. Some systems also use boreholes and heat pumps to raise the temperature to 40–50°C for under-floor heating and radiators.
How many systems in the UK?
Around 250 systems are installed every year in the UK.
The use of ground source energy for individual homes is likely to increase as installation prices drop.
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