A Quick Guide to Ground Source Heat Pumps
Ground source heat pumps (GSHPs) use buried pipes to extract heat from the ground. This heat is then used to heat radiators, warm air or underfloor heating systems as well as hot water in your home.
A ground source heat pump circulates a fluid mixture of antifreeze and water through a loop of pipe called a ground loop. This loop is buried in your yard, where it absorbs thermal energy from the ambient heat present in the soil. Even in the coldest winter months, the ground still retains residual heat, so the heat pump can be used year-round.
The length of the ground loop depends on the amount of heat you need and the size of your home. Longer loops can draw more heat from the ground, but need more space to be buried. If there is not enough space in your yard for a horizontal ground loop, a very deep vertical borehole can be drilled instead.
Benefits of ground source heat pumps
Ground source heat pumps provide a number of benefits:
• Higher efficiency, resulting in lower heating bills
• Lower carbons emissions, depending on the fuel type you are replacing
• No fuel deliveries are needed
• Very little maintenance is needed
Unlike gas furnaces, heat pumps produce heat at lower temperatures over much longer periods. This means that during the winter, they may need to be on all the time in order to produce enough warmth to heat your home. You will also notice that radiators do not get as hot as they do when heated with gas.
Ground source heat pumps are more difficult to install than air source pumps, because ground source pumps require drilling and trenches for installation. However, ground source pumps make up for their more difficult installation by being much more efficient. Water source heat pumps can be a viable and highly efficient alternative for homes that are near to bodies of water such as streams and lakes.
How do ground source heat pumps work?
First, the loops of pipe buried underground absorb small amounts of heat from the soil. The fluid carries the heat with it as it is pumped into a compressor that releases the heat contained in the fluid by compressing it. This heat is then used to provide hot water for the rest of the house. The ground-loop fluid, now at a lower temperature, returns to ground where it absorbs further thermal energy from the ground continuously as long as heat is required.
Normally the loop is installed in trenches about six feet deep, but you do not have enough space in your yard, you can install a vertical loop down into the ground to a depth of up to 300 feet for a typical house.
Heat pumps do require some electricity to run, but they can greatly reduce your carbon footprint since they the heat they extract from the ground, the air, or water is continually renewed by natural thermal processes.
Will a ground source heat pump work for my home?
In order to decide if a ground source heat pump is right for your home, there are several key questions you should ask:
• Is your yard suitable for a ground loop? It doesn’t necessarily have to be particularly large, but it will need to be accessible to digging machinery.
• Is your home well insulated? Since heat pumps work best when producing heat at lower temperatures, they work much better in homes that are sufficiently insulated and have lower heat requirements.
• What type of heating system will you use? Because they work better with lower water temperature than radiators, underfloor heating systems are ideal to be paired with ground source heat pumps.
• Is the system part of a new development? Combining the installation with other work in your home can reduce the cost of installing the heat pump system.