How Do Ground Source Heat Pumps Work?

A type of renewable energy that is used all over the world to supply commercial premises and homes with heat, ground source heat pumps are used increasingly in Australia. Making use of the thermal properties of the earth, this technology is used to heat radiators, underfloor central heating systems and hot water tanks in all sorts of properties. Installing a heat pump means that homes need to rely on much less energy from traditional sources, such as electricity or gas. How do they work?

• In The Loop

A typical ground source heat pump uses a loop system to heat a mixture of normal water and anti-freeze. Circulating this fluid from a building to deep into the earth beneath, heat energy from within the ground is absorbed by the fluid passing through. Usually referred to as a ground loop, this circulatory system uses specialist pipework. To retain heat within the loop a pre insulated pipe is commonly used to increase the efficiency of the system. This can be the sort of piping that is used for a chilled water pipe, for example. So long as the pipes used are thermally retentive, then the heated fluid should be transferred to the home without losses. After the hot liquid in the system has passed through to a heat exchanger – and given up its energy – it is then returned back down into the ground to be warmed up all over again. Because even a few metres down under the earth has a relatively constant temperature, the closed ground loop system can be used throughout an entire year, no matter what the weather is like above ground.

• Transferring Heat

When hot water reaches the ground level, it is not used directly, but transfers its energy via a heat exchanger. This is commonly achieved via a series of plates which have a large surface area for greater efficiency. A heat exchanger then passes on the energy it has captured to a hot water tank or central heating system, as preferred. It is worth noting that heat exchangers are commonly used in Australia for things other than ground source heat pumps. Similar technology can be found in swimming pools, power plants and diesel engines, among other things.

• Benefits

The advantages of using ground source heat pump include:

• A low maintenance regime

• No fuel deliveries

• Lower carbon emissions

• Decreased energy costs

• Ability to heat buildings and water