Heat pumps are becoming cheaper and more efficient thanks to developing technologies, steadily making them a viable alternative to oil and gas heating, experts say. Heat pumps, however, are still relatively unknown to most people.
This article will go over one type of heat pump: the ground source heat pump, which produces energy from natural heat in the ground. It will discuss how these machines work as well as ground source heat pump cost.
What is a ground source heat pump?
A ground source heat pump, or ground-to-water heat pump, is a type of heat pump which can be used to heat UK homes.
Heat pumps work on the principle of capturing and intensifying naturally-occuring outside heat (in the air or in the ground) to create a heating system for a building.
For a ground source heat pump, the heat is extracted from the ground a couple metres below the surface, where average temperatures are around 11-12℃.
Although such temperatures may not seem high enough to provide heating, heat pump technology intensely concentrates such heat to generate usable heat for homes.
Heat pumps can bring heat directly into the house, with radiators or underfloor heating for example, but can also serve as a way to generate and store hot water for taps, radiators, bathtubs and showers.
How does a ground source heat pump work?
A heat pump needs a cooling system, a loop of pipes that will carry cold liquid, to work.
The cold liquid that flows through the pipes is known as thermal transfer fluid (TFF) and is composed of water and antifreeze -- a vital component that drastically lowers the freezing point of water.
The use of antifreeze will enable very low temperatures without the pipes getting blocked up by frozen water.
The water-antifreeze mix is pumped through the ground in the system of pipes. As heat is naturally drawn to colder temperatures, the heat from the ground elevates the temperature of the liquid.
The slightly warmer liquid is pumped through a heat exchanger, or evaporator. A refrigerant pumps through the heat exchanger, which absorbs the energy gained from the ground. This absorption makes the refrigerant boil and then evaporate.
The new gas is led through a compressor, which pressurises the gas. The increase in pressure makes the gas’ temperature rise significantly, giving way to important quantities of heat.
The now-hot gas goes through a condenser, which generates hot water. It is this hot water that is used to heat your home.
Watch here for a step-by-step educational video on ground source heat pumps.
Using a ground source heat pump at home
Although ground source heat pumps seem like an ideal heating system for your home, you need to make sure that your property is suited to such an installation.
The most important factor is the energy efficiency of your home. In other words, make sure your property is insulated properly, since a heat pump will only work efficiently if little energy is lost.
If you have any questions about the energy efficiency of your home, the government provides EPC ratings here.
Heat pumps also require some space to be effective, so make sure that your property can house an entire heat pump system. The pump itself is similar in size to a large refrigerator, but the piping system takes up much more space.
What to consider when upgrading to a ground source heat pump
Pros of a ground source heat pump
- More sustainable: heat pumps are not considered renewable as such, since they require some electricity to function. They are, however, much more sustainable than gas or oil alternatives.
- Reduced bills: once your heat pump is installed, your energy bills will go down, as you are producing your own energy. Some estimates place savings at up to £1,400 per year.
- Multifunctional: during the summer period, heat pumps also work as a cooling system, bringing cold air into your home.
- Durability: they have a long life-span (of at least 50 years) and are extremely reliable.
Cons of a ground source heat pump
- High up-front cost: buying and installing a heat pump remains expensive.
- Difficult installation: installing a heat pump requires important work done to your property, which can have long-lasting repercussions on your building and the surrounding ground.
- Noise pollution: heat pumps are very loud, and can cause a disturbance to both you and your neighbours.
How much does a ground source heat pump cost?
Price
The initial price of a ground source heat pump will vary depending on the type and size of the system -- prices vary between £15,000 and £20,000.
Installation
Installation costs vary based on the type of system you opt for. The system depends on how much space you can allot to this system.
For a horizontal system (dug 1-2 metres deep), that takes up more land for the pipe system, you can look to pay between £2,500 and £4,500.
A vertical system (dug 50-100 metres deep) takes up less land space, but is also more expensive, at an estimated price of £8,000 to £10,000.
Running costs
In good news, a ground source heat pump has lower running costs than a traditional boiler, as it is considerably more efficient.
Whilst boilers cost an average 6p/kWh to run, ground source heat pumps come in at around 3.4p/kWh. This makes a heat pump much less expensive all year round, especially during winter months when more heating is required.
Maintenance
Heat pumps are also prized for their low maintenance requirements. They will need some attention throughout the year, but will cost around £100 to £200 to maintain -- much less than your average boiler!
Which ground source heat pump should I buy?
Luckily, many brands produce ground source heat pumps in the UK. The ideal heat pump will depend on the requirement of your home.
Some popular options available in the UK are:
Ground source heat pumps are a growing technology that enable households to control how their heat is produced. Cheaper and creating less pollution, ground source heat pumps are asserting themselves as a good solution for UK households to face rising bill costs and climate change fears.
