A Guide to Ground Source Heat Pumps

It may not be one of the most talked about of energy sources, but a surprising amount of hospitals, schools and offices are looking into the ground for their heating energy sources. Ground source heat pumps can provide a great source of heat energy for larger buildings as well as your own home; and with the ground being so readily accessible, its popularity is growing.

The ground provides a constant source of heat energy, even in the winter when the snow has fallen. If you dig just a few metres underground the temperature of the earth can be found to be approximately 10 to 12 degrees centigrade. Therefore, a ground source heat pump can make good use of this heat to help generate heating for homes and businesses.

A ground source heat pump has two parts to it; the first element is its pipe that is deep within the ground collecting the excess heat from the earth; and the second is the heat pump, which increases the temperature of the heat obtained from the earth. The heat pump consists of a large box that will increase the temperature of the harvested heat up to 65 degrees centigrade; converting it into a form that can then be used to heat buildings.

How does the technology of a heat pump work?

Think of the heat pump as your fridge, but with it doing the total opposite by heating rather than cooling. A fridge takes the heat from inside of it so that the air space inside is colder, and a heat pump takes the heat from outside to inside to heat your home. It works by circulating anti-freeze and water in its pipes, which then attracts the heat from the ground, absorbing it so it can be used in your home.

The piped contraption will be installed in the adjacent ground underneath the building it is being used in, being installed just 2 to 3 metres underground. The pipe may be installed in a loop or straight line, and they sometimes run through boreholes that are bored vertically into the ground and run much further into the earth (approximately 100 metres).

Is a Ground Source Heat Pump recommended?

This type of heating is recommended as being greener than your standard heating as it is considered incredibly efficient, despite the fact that it does still use electricity, so it isn’t completely ‘renewable’. Figures show that around 3-4 kilowatts of heat is generated from just 1 kilowatt of electricity that is put into the system.

One of the major downfalls of the technology is the disruption it would cause to your garden should you choose to have it installed. It would involve a lot of digging through your garden, but this will only be a cosmetic issue for a temporary period of time as the pump is installed underground and will not need maintaining on a regular basis.

Would a Ground Source Heat Pump be right for me?

There are several factors that you will need to take into consideration before you go ahead with having a ground source heat pump installed in your home. For instance, the heat that is created by these pumps will not match what is currently produced by your boiler, which is fine for tasks such as warm-air or underfloor heating but it will not be sufficient enough for warming your water.

It can pre-heat the temperature of the water so it requires less heating when you do come to require it and you can just top this up with your immersion heater.

This lower output of temperature that is created by the pump also means that it is highly recommended that homes already have maximum insulation and draught proofing before getting it installed, otherwise it will be highly ineffective. If your home doesn’t have the right amount of insulation you could find that the ground source heat pump just doesn’t provide you with the heat energy that your home requires.

Yow will also need to take into consideration if and how the pump is going to fit into the back garden; not too much space is required but if you are having a loop trench installed that is horizontal to the ground, this may require 80 metres or more. The size of the pump system will depend entirely on how much output you require from it and what pipe system you are having installed. Speak with the installer to see which will be the best type for you and your garden.

Also think about how any equipment, such as boring and digging tools are going to be brought into the back garden to carry out the work, as some large access point may be required.