Heat Pumps: A Beginners Guide
Ground source heat pumps are providing heat to more and more homes. The current high demand and prices for fossil fuels and their environmental impact is causing many people to consider more sustainable and cheaper heating options, and ground source heat pumps meet these demands. However, many home owners are not aware of them or have little understanding of how they work or what their benefits are. There are various types of pumps, but the following describes the most common.
What is a Ground Source Heat Pump?
Put simply, a ground source heat pump takes heat from one location and transfers it to another. It is effectively the same process as refrigeration except that the process is reversed. Solar heat is retained in the ground and remains at a constant temperature all year round. Ground source heat pumps tap into this heat in the ground and then distribute it through the home or building. Heat can also be drawn from water sources such as a well or river.
How do They Work?
Ground source heat pumps have few moving parts and are essentially simple devices. A ground heat exchanger made from plastic piping forms a closed loop and is positioned in the ground to a depth one metre for horizontal installations and up to five metres for vertical. The pipe is filled with a fluid or refrigerant which is pumped around the loop.
The fluid absorbs the ground heat and is pumped to a compressor which heats it further, then pumps it through the loop that is within the building. In the case of domestic properties this can be in the form of underfloor heating. The process can be reversed during warmer weather for cooling purposes. The pump itself will be outside the building in a place with good ventilation.
The first factor that decides which type of heat pump is suitable is land availability and condition. If plenty of land is available a horizontal ground loop is the most cost effective. If space is tight bore holes will have to be drilled to contain the piping. Although heat pumps can be used in conjunction with existing radiators, buildings with underfloor heating are ideally suited to accommodate heat pump technology.
Always use an experienced, professional contractor to install a heat pump. Aside from carrying out the installation, they will assess the building, determine the right kind of pump, and check that the electrical system can cope with the inclusion of a new heat pump.
- The benefits of ground source heat pumps are many:
- Reduced purchased energy used for heating (gas or electricity)
- Lower carbon emissions
- Few moving parts = highly reliable
- Low maintenance
- Long life expectancy (20-25 years, twice that for the ground coil)
- No combustible or noxious gases
With fossil fuels becoming scarcer, prices will continue to rise. As a result, sustainable, renewable energy systems will gain in popularity. Heat pumps fit this bill perfectly as they do not rely on fossil fuels, use around 75% less energy than systems which use oil or gas, and produce 3-4 units of heat for every one unit of electricity that they use. This makes them the perfect choice for heating the 21st Century home.