Information About Ground Source Heat Pumps
Also known as a geothermal heat pump, a ground source heat pump (GSHP) can save energy by using the heat from the Earth to increase the efficiency of home heating and cooling systems. In order to do this, GSHP employs a heat exchanger also called a loop of pipes.On this page we are going to look at the different types of heat exchangers you can choose from:
Closed Loop Systems
In this type of system, the Earth’s heat is used as a source of energy. The heat exchanger circulates the liquid (water and antifreeze) in a closed loop system of pipes buried underground. The heat exchanger will transfer the heat between the refrigerant in the heat pump and the antifreeze solution circulated through the pipe. Furthermore, the heat exchanger can have different configurations:
Horizontal Heat Exchanger
A horizontal heat exchanger is the most common method of heat extraction in the UK and less costly to install. Horizontal loop systems are mostly used in residential installations. Excavation for horizontal loop fields is around half the cost of a vertical drilling. This systems is composed of pipes that run horizontally in the ground. The advantage of the horizontal heat exchanger is that pipes can be laid under driveways or gardens without disturbing them.
The depth at which the loops are installed is crucial to the energy efficiency. Usually, there are two pipes, buried at 1 to 3 m underground. Loops installed closer to the surface benefit from the heat absorbed from the sun, while on the other hand, they will cool down faster in winter season.
A slinky system of loops will allow more pipes(6-8) in a shorter trench, making possible the installation of the loop in areas restricted in size.
Vertical Heat Exchanger
A specialist contractor will bury a pipe to a depth of around 60-120 m. The size and number of boreholes also varies according to the land where they need to be installed, the heat dispersion and the size of the heat pump. Plastic U-pipes are put in the borehole and after the pressure test, the hole is filled with materials that can be pumped up. The cost of digging a borehole is usually high but once the ground source heat pump starts functioning no major interventions on the site are required.
Radial or Directional Drilling
This kind of system is the choice, when buildings or other constructions are already present. Small holes are being drilled into the ground in order to insert the pipes. Using this system, gardens, yards, houses, etc. do not need to be opened up. The cost of these systems is usually in between the costs of vertical and horizontal drilling.
Pond or Lake
If a body of water is available on the site, it can be used to collect heat. A system of pipes is ran underground from the building and into the pond. Although this is the most cost- savings method, the following factors must be considered:
- Quality criteria
Open Loop Systems
The second and oldest type of heat exchangers used is an open loop.This system works best when you have a powerful resource to explore. Generally open loop systems require a site with aquifers or groundwater.
Two wells are drilled in order to reach the water source and install the pipes. Also known as direct exchange, the open loop system will pump the water directly to the heat pump, where the heat is extracted. Then the water is released back into the ground through a second well, called the rejection well.
The rejection well must have enough capacity for disposal of all the water passing through the heat pump. Additionally, the water can be disposed into a river, lake or pond. The heat pump only extracts the heat from the water, no chemicals involved. However, you must check with your local authorities about regulations in your area.
Installation of the Heat Pump
Accurate knowledge of the property is required when choosing the right heat exchanger. You should also consider :
- Temperature of the Earth
- Soil formation
- House heating and cooling peaks
Since technical knowledge is required, a ground source heat pump installation must be done by professional and trained individuals. Our specialist suppliers can provide you with an accurate assessment and a free quote. Simply fill in the information form on the right.
Get Quotes on Ground Source Heat Pumps!
If you have decided to purchase a ground source heat pump, but you are not sure which type you would like, we are ready to help you. Fill out the form on this page with your personal preferences and information, and we will provide you with up to four different suppliers of heat pumps. You are free to choose the offer that best suits your needs. The service is free, without obligation, and takes only a few minutes.