An introduction to ground source heat pumps

If you are a looking for a renewable and cost-effective way of heating your property, then your prayers could be answered with a ground source heat pump. “What on earth is one of those?” we hear you ask, well the team at Teckna Group is on hand to give you the lowdown.

This simple piece of technology comes hand-in-hand with a range of benefits and is perfect domestic and commercial projects. However, unless you work in the geothermal industry, it is probably something you’ve never come across before, and even if you have come across them, very few people have had someone actually take the time to explain how they work.

With this in mind, we thought we would provide a quick introduction to ground source heat pumps and answer some of the most frequently asked questions regarding the geothermal drilling process. From what a heat pump actually is to what the heat pump installation process might look like, read on to find out more.

What is a ground source heat pump?

A ground source heat pump is a heating and cooling system that is installed underground. Radiation from the sun heats the earth’s crust on a year-round basis and, essentially, the heat pump takes advantage of this fact. It transfers the natural heat into a ground loop (i.e. a network of buried pipes), passes it through an evaporator, compressor and condenser then release it for use.

Because the difference between the temperature of the ground beneath us isn’t massive, a complex system is required to essentially ‘amplify’ that temperature difference and render it useful for heating purposes. 

There are two main types of geothermal heat pump available, so it is important to consider which will be most suitable for your property. If there is sufficient space, the ground loop can be laid horizontally, approximately a metre below ground. However, in most cases – where available space is limited – vertical geothermal boreholes (around 15-100m deep) will be needed instead.

How does a geothermal heat pump work?

Geothermal heating may sound complicated, especially if you have no prior knowledge of how it works. However, it is actually a very simple process that can be broken down into 5 easy steps.

• Heat is extracted from the soil by the ground loop and absorbed into a refrigerant fluid
• This fluid is moved to an evaporator, where it is changed from a liquid to a gas
• This gas is subsequently compressed, allowing its temperature to rise
• It is then passed through a condenser, or heat exchanger, into a central heating system
• Finally, the cooled refrigerant fluid is released back into the ground and the cycle starts again

The ground source heat pump diagram highlights this process visually below.

Ultimately, if it sounds a bit like magic, that’s because it kind of is. But heat pumps are magic items that consistently put out heat if installed correctly, which is all you really need. 

How is a geothermal borehole installed?

Before a geothermal borehole can be installed, the first step is to organise geothermal surveys. This will indicate the thermal characteristics of your site, including whether the ground is suitable for a deep-seated borehole and whether it can be feasibly accessed by large borehole drilling equipment. Surveys will need to be conducted to assess the ground type as well, to check which drilling method to use.

Specialist geothermal well drilling rigs will then be used to dig a borehole and vertical pipes are inserted. The space between the pipes and the borehole wall is filled with a specialist type of grout, and, once all has been completed, a series of tests will be conducted to check that the system works correctly.

In certain installations, it can be more appropriate to lay horizontal pipes; if this is an appropriate approach, the geothermal technicians will let you know when they do that initial survey.

Ground source heat pump boreholes are typically drilled 5-6m apart and should be at least 6-7m from the nearest building. Their depth is determined by the size, insulation and heating capacity of the property and their cost varies depending upon your exact needs and requirements. All of these will need to be clearly outlined during your initial planning phase, to determine whether a heat pump is appropriate and if so, what that heat pump design should look like.

Who should use a ground source heat pump?

Ground source heat pumps aren’t just for those who want to create some kind of carbon-neutral, off-the-grid home. They’re an excellent solution in a wide range of different contexts, from urban homeowners to larger, rural commercial properties. 

So long as you have the land to drill the boreholes in and the properties in question are at least reasonably well insulated, you’ll likely find that you could be an ideal candidate for some sort of ground source heat pump as a source of thermal energy. 

What are the main benefits?

It’s a fair question – why exactly should you go through all the effort of getting a borehole drilled and a heat pump installed anyway? 

Cut costs

One of the main benefits of ground source heat pumps is the cost-cutting effect it has on your heating bills. If the property you need to heat is appropriately insulated, you could be able to save up to 75% on heating and hot water costs. 

Of course, the exact figure can depend on a whole host of variables, and will likely fluctuate from year to year, depending on electricity costs and the external temperature. 

However, it should pretty much always be cheaper than a conventional gas boiler, and with the way gas prices are heading, that cost-cutting is only becoming more prominent. 

Insulation from geopolitics

One of the most prominent emergent issues over the past half-decade has been how susceptible energy prices are to geopolitics. Wars in both Eastern Europe and the Middle East have had a huge impact on the price of oil across the globe, and it’s becoming increasingly important to try to find ways of insulating against these price changes. 

Ground source heat pumps can substantially reduce your vulnerability to these price changes. As the electricity grid switches over to locally located renewable energy sources, this insulation will eventually become complete.

Access government incentives

If you’re due for a heating system upgrade anyway, then you might as well make the most of the government incentives when it comes to heat pumps. 

There are substantial grants available, depending on your specific context, that can make the overall investment cost of these kinds of systems a whole lot more attractive. 

There are some handy online calculators that can help you work out how much you’re eligible for. It only takes a few minutes, so it’s definitely worth a look. 

Reduce carbon footprint

As a result of their efficiency, and the fact that they’re not dependent on some form of combustion to release heat, ground source heat pumps can be carbon neutral if powered by electricity from renewable sources. 

If you’re considering how to reduce either your own personal or your organisation’s carbon footprint, it’s a very tangible and effective way of cutting the emissions you pump out into the atmosphere.

Contact Teckna Group for geothermal borehole drilling

Teckna Group is a multi-disciplined drilling and civil engineering company, with a significant level of knowledge, experience, and expertise in this area. Working alongside accredited MCS ground source heat pump partners, we offer a comprehensive turnkey geothermal borehole drilling service – including geothermal surveys, geothermal well drilling and geothermal pipework – for both domestic and commercial projects.

We’ve dealt with all kinds of projects in this field, and bring our extensive experience to every project we work on. From planning to maintenance, we’re here to build and maintain the best systems possible for our clients, no matter what their operational requirements are. 

If you would like to find out more about geothermal heat pumps and how they could be of benefit to you and your property, why not get in touch? Our team of experts are always happy to help and will answer any questions that you may have. Either call us today on 01257 421700 or send an email to enquiries@tecknagroup.co.uk and we will respond as soon as possible.