GROUND SOURCE HEAT PUMP FAQS

Ground source systems use the ground as a means of absorbing and releasing heat. The heat pump system is extremely efficient and saves energy because the ground is at a constant temperature rather than the ambient which varies. The system is used for heating in cold weather and cooling in warm weather.

Ground source cooling uses the ground as a means of rejecting heat given off by the process. This Is then re-used for the heating cycle and thereby improving seasonal efficiency.

Ground source heating uses the ground as a means of rejecting the cooling process which is given off from the system. The heat is later recycled in cooler weather in order to improve the season efficiency.

They are the integral component of the ground source system. Ground source heat pumps (GSHPs) are used to generate the cooling or heating medium. They are extremely efficient. GSHPs can give COP’s of between 4.5 and 6. Therefore for every one Kilowatt of energy used to generate heating or cooling they give in return 4.5-6kw of heating or cooling as a useable load. On the other hand a gas boiler only returns 0.9 kilowatts of useable load for every one kilowatt of energy used.

These are the means of rejecting heat or cooling from the heat pumps. They are drilled to depths of between 70m and 300m in order to obtain the load required for the specific building. The bore holes are drilled using large rotary rigs to ensure that the stability of the bore hole is maintained until the ground loop is installed.

These are used to abstract up to 20 cubic meters of water per day and do not necessitate obtaining a licence or permission for the work involved. Potable water is used as an alternative to or alongside rain water harvesting systems in order to improve water quantity and quality. The water can be used when filtered to flush toilets and also to provide water for showers. The quality of the water can be as good as drinking water in some locations depending on the geology of the area being drilled.

Also known as ground source systems. However, geothermal systems are drilled to a much greater depth in order to capture high temperature water. Ground source systems tend to limit the drilling to 300m due to the operational pressure drop on the system.

Is the process by which rotary drilling rigs are used to drill the bore holes down to the required depth for the designed system? Specialist rigs using mud puppies are used to ensure that a quick and clean drilling operation is achieved.

Once the bore hole has been drilled HDPE pipe work is installed as a means of transferring the rejected heat or cooling into the ground. The diameter varies to suit each application 32mm, 40mm or 50mm. The HDPE ground loops are very robust and have a 25 year life expectancy. They are configured in a flow and return system leading up to a chamber where they are isolated on one side and a flow measurement fitted to the other.