A heat pump system circulates heat from an external energy source to a compressor inside a heat pump unit. It can collect low-grade heat from renewable sources such as water, ground or air to compress and deliver heating and hot water to a property.
What is a ground source heat pump?
A ground source heat pump is a renewable heating system. The ground source heat pump extracts low-temperature solar energy stored in the ground or water using buried pipework and compresses this energy into a higher temperature. A ground source heat pump provides a building with 100% of its heating and hot water all year round.
Committed to ground source technology
Since 1999, Kensa Heat Pumps has solely manufactured ground source heat pumps. Ground source holds the most potential for the UK’s whole scale decarbonisation of heating.
The distinction between an air source and a ground source heat pump is important. The ground holds a stable temperature of 8 to 12°C all year round, making the source constant and reliable. Air temperatures, however, can be unstable and inefficient, particularly in the winter and after dark, when you typically need your heating the most.
How does a ground source heat pump work?
Heat naturally flows from warmer to cooler places. A ground source heat pump exploits these physics by circulating a cold fluid through ground array pipework in the ground or water. It absorbs low-grade surrounding energy from external heat sources, such as rock, soil, lakes and streams.
The ground source heat pump then compresses and condenses this free energy to a higher temperature, and transfers it to the property’s heating and hot water system.
Having surrendered the absorbed energy from the ground to the heat pump, the fluid continues its circuit back to the submerged pipework to commence the cycle all over again.
See a ground source heat pump in action
Our simple video shows you exactly how a ground source heat pump works.
Click here for a detailed technical commentary from Kensa’s Technical Director and co-founder, Guy Cashmore.
Did you know?
We already have heat pumps in our homes. Standard refrigerators act like heat pumps in reverse, moving heat out of the fridge.
The process of how a heat pump works
1. A cold water anti-freeze mix is pumped through the ground within a series of energy-absorbing pipes, known as ground arrays. As heat naturally flows from warmer to cooler places, the anti-freeze mix circulating the array is constantly warmed by the ground’s low-grade heat.
2. Having increased in temperature, the anti-freeze mixture is fed into a heat exchanger called the evaporator.
3. Within the secondary sealed side of the evaporator heat exchanger is a refrigerant that acts as a heat transfer fluid. When the water anti-freeze mixture enters the evaporator, the energy absorbed from the ground is transferred into the refrigerant which begins to boil and turn into a gas.
The refrigerant never physically mixes with the water anti-freeze mixture. They are separated like sandwich layers by the plates of the heat exchanger which permit the heat transfer.
4. This gas is then fed into a compressor. The pressure of the refrigerant gas is increased in the compressor, which makes the gas temperature rise.
5. The hot refrigerant gas then flows into a second heat exchanger, called the condenser, which features an identical set of heat transfer plates.
6. The condenser delivers water hot enough to serve the space heating system and the property’s hot water needs. Having transferred its heat, the refrigerant gas reverts to a liquid.
7. This liquid is then passed through an expansion valve at the end of the cycle to reduce its pressure and temperature, ready to commence the cycle all over again.
What are the benefits of ground source heat pumps?
• The Renewable Heat Incentive income
Heat pumps play a huge part in achieving the 2050 net-zero target. To incentivise the adoption of renewable heating, Microgeneration Certification Scheme (MCS) approved ground source installations are rewarded with a seven or 20-year income through the Domestic or Non-Domestic RHI. Kensa’s MCS-approved heat pumps make this possible.
• Low carbon emissions & improved air quality
Boasting high efficiencies, ground source heat pumps emit no emissions and offer a low-carbon replacement for combustion fossil fuel systems.
According to statistics, 17,000 premature deaths could be prevented each year by reducing mortality and diseases linked to poor air quality. Ground source heat pumps do not create particulates, Nitrogen Oxide (NOx), or Sulphur Oxide (SOx) – all of which contribute to air pollution.
And it doesn’t stop there. The more that renewable sources of power such as solar and wind contribute to the electrical grid, the lower the carbon content of electricity. This means that the small portion of electricity consumed by a ground source heat pump will become less and less carbon-intensive in years to come.
• Efficient & affordable heating
Compared to oil or LPG, you can expect to save around 30-50% on heating bills.
A ground source heat pump is powered through electricity, creating 3 to 4kW of renewable energy for every 1kW of electrical power it consumes. This efficiency makes ground source heat pumps the most energy-efficient heating technology available, resulting in cheaper energy bills and low carbon.
• Free heat from the ground
From rivers to rock, ground source heat pumps absorb solar energy from a variety of natural resources. Unlike fossil fuels, ground source heat pumps offer a modern, cleaner and sustainable means to utilise naturally occurring energy from the ground. You can even tap into this energy from your own back garden.
• Installed inside your property
A ground source heat pump uses heat from outside your property. However, the heat pump itself is installed safely inside the property – in the same way as a traditional boiler. No louder than a kitchen appliance such as a dishwasher, the heat pump is easy to install in an airing cupboard or kitchen cabinet.
• A practical & safe alternative to fossil fuels
Ground source heat pumps have no annual servicing requirements, need minimal maintenance, and remove the hassle of fuel deliveries.
Compared to traditional gas boilers, oil or LPG systems, ground source systems aren’t vulnerable to fuel price increases or energy security threats. They also use a non-combustion fuel source, so there is no fire risk.
• Smart heating
When combined with smart controls, ground source heat pumps can save you even more money on heating. Smart heating uses property physics and preferences to create your desired heating schedule. It can take into account the cheapest time for electricity use – for example, operating a heat pump when the grid demand, price and carbon is lowest.
• Suited to all sorts of properties & projects
Heat pumps can be installed into any building from new to old and urban to rural, challenging the misconception that they are only for new builds.
New and existing properties reap the low-carbon and affordable advantages of ground source heat pumps. Boats, businesses, schools, tower blocks, holiday cottages, barn conversions, listed homes – you name it, a Kensa heat pump can almost definitely heat it.
• Cooling in the summer
A ground source heat pump can often deliver active or passive cooling to any property. Whether passively transferring the ground’s original temperature to the building or actively circulating chilled water, cooling is a useful function for commercial applications or homes in the summer.
• Compatible with other renewable technologies
Ground source heat pumps can be used with other forms of renewable technology or waste heat sources to further improve efficiencies, reduce costs and be part of a bigger solution. What about using waste heat from a data centre and providing cooling at the same time, or using your own excess electricity from your onsite generation?
To make your heating 100% renewable, heat pumps can be powered by onsite solar and wind energy for self-sufficiency. They can even absorb energy from sources such as wastewater – providing it is deep enough.
I think ground source heat pumps are the future of energy generation and everyone should embrace this technology.
Alistair Mackintosh, Selfbuilder
Can a ground source heat pump provide hot water?
Yes, Kensa ground source heat pumps are capable of providing hot water up to 60°C.
The maximum output temperature of a heat pump depends upon many factors, including the flow rate through the domestic hot water cylinder coil and the ground temperature.See more on hot water & heating
Are heat pumps noisy?
Ground source heat pumps – particularly smaller heat pumps – are not noisy. They often get confused with air source heat pumps, which due to their fans, tend to operate very loudly outside.
Noise will vary across different sized heat pumps. However, thanks to innovative insulation and advanced design in Kensa’s heat pumps, noise isn’t a common issue. In fact, the Shoebox and Evo heat pump series boast some of the quietest ground source heat pumps on the market.See noise ratings on our product pages
Does a heat pump work in cold weather?
Yes. Cold weather should not affect the performance of a ground source heat pump. Regardless of outside temperatures, the ground remains a stable temperature all year round; just 1.2m below ground it remains a fairly constant 8-12°C. This means your ground source heat pump will provide you with efficient heating and hot water whatever the weather.
Air source heat pumps lose efficiencies during the winter and overnight when the outside air temperature drops.Read our top maintenance tips
What maintenance does a ground source heat pump need?
As a non-combustion heating system, there is no annual servicing requirement for a ground source heat pump. It requires very little maintenance, and the unit is installed safely inside the home, away from damaging external elements.
Top tips for minimal maintenance
Over a heat pump’s 20-year lifetime, it’s sensible to check on its performance as you would with any other heating system. To prepare for the heating season, simple system checks can be performed by any installer, which include:
- Checking the heat collectors to make sure they’re absorbing the optimum amount of energy
- Looking over the distribution system’s room stats and programmers to make sure they’re operating and functioning correctly
- Making sure any battery-charged components have charge
- Ensuring the pressure of the system is above 2 bar
- Testing the gas charge pressure on the heating system’s expansion vessel
By maintaining your heat pump, you’re making sure it’s performing at its best. That way, it remains energy efficient, continues to save you money on your heating bills, and ensures and optimises continued payments from the Renewable Heat Incentive.
The game-changing Genesis System Manager
A world-first ground source heat pump controller, the Genesis System manager further minimises maintenance. As a current innovation in the Evo ground source heat pump, the Genesis can pre-empt and identify potential issues before they happen.See the Genesis
Is it difficult to install a heat pump?
No. For competent heating engineers or plumbers, installing a ground source heat pump can actually be easier than fitting a gas boiler!
The groundwork, such as boreholes or trenches for heat collectors, can be completed by subcontractors. This is external work dealt with by experienced groundwork specialists, and is separate to the heat pump installation itself.
A heat pump installation causes minimal disruption for occupiers or businesses. The majority of work is completed outside, and the heat pump installation within the property is no different to installing a boiler. Kensa’s heat pumps are designed to be easy to install, as they’re made especially for British properties.Discover our support services
Do heat pumps need planning permission?
Unlike air source heat pumps, most ground source heat pump installations are classed as permitted development – meaning they don’t need planning permission. However, there are some circumstances where planning permission is required. For instance, a property where more than one heat pump is installed, or projects where the ground array is installed any distance greater than 0.5 hectares.
Ground source heat pumps are designed to operate quietly. They can be installed inside, with no visual impact on the property. Air source heat pumps, on the other hand, are fitted on the outside of the property. They can be noisy, unattractive and affect the property’s appearance, which is why they usually require planning permission.
Why choose a ground source heat pump from Kensa?
Made for UK homes
Manufactured in our very own factory in Cornwall, Kensa’s ground source heat pumps are made especially for UK properties. This makes them simple to install and perfectly compatible with British buildings, schools, tower blocks and more.
Engineering ingenuity since 1999
With experience in all kinds of properties and renewable sources – from boats and businesses to lakes and soil – our ground source heat pumps have evolved from years of understanding and responding to the desires of installers and end users.
The comfort of technical support
No matter how new or old your Kensa heat pump is, every unit comes with the added comfort of technical support for years to come. Our pre and post-installation support team are on hand to give you support or advice should you ever need it.Browse our ground source heat pump range