WHAT IS A GROUND SOURCE HEAT PUMP?

WHY INVEST IN A GROUND SOURCE HEAT PUMP

There are quite a few amazing benefits to switching your power source to the highly efficient and low carbon ground source heat pump. The major incentive is, of course, that the building that you install a heat pump in will immediately benefit from lower carbon emissions. As business owners and homeowners, we are all looking for ways to reduce our carbon footprint and this is a sure-fire way to do so.

Alongside this, you’ll experience a much-improved quality of air. Ground source heat pumps are affordable to install, they are efficient, and also compatible with other renewable technologies that you might already have installed or are planning to install. When you consider these benefits and the expert advice and professional guidance from a prestigious company such as Clade, it is hard to see any other choice than to make the switch today.

CLOSED-LOOP SYSTEMS

These tried and true ground source heat pumps have been around for over 50 years. This established technology effectively uses natural heat. These closed-loop systems harness the power of solar radiation. Sun radiation beams down and heats the earth, then stores this heat. These efficient pumps extract this heat via a ground heat exchange loop to tap into these naturally replenishable heat stores. The extracted heat is powerful enough to heat buildings, provide hot water and more.

A mixture of water and antifreeze is circulated around a loop pipe called a ground loop. This will be buried in a garden or lake. The powerful solar heat stored in the ground or lake is absorbed into the fluid and then passes through an intelligent heat exchanger into the heat pump. Because the heat stored in the ground or lake remains at a consistent temperature under the surface, the heat pump can be effectively used throughout the year, including during Winter.

The ground loop length can be tailored to accommodate the size of your home and the heat load you require. Typically, longer loops can draw more heat from the ground. However, these need more space to be buried in. In circumstances where there’s not enough space, a vertical borehole can be drilled as an alternative.

OPEN-LOOP SYSTEMS

Just like closed-loop systems, these water source heat pumps operate by efficiently extracting thermal from a water source close to the property which requires heating. The thermal energy is collected and converted into heat and hot water. An adequate body of water close by is required for water source heat pumps to function. This makes them ideal for homeowners who have a lake, river, stream or borehole close by.

Water flows through the pump and the heat is extracted by the open-loop system installed and then discharged back to its source. This makes them super efficient — more efficient than closed-loop pumps. However, there are additional regulations to consider from either the Environment Agency for England and Wales or the Scottish Environment Protection Agency (SEPA). You’ll need to gain consent from either of these bodies to install and use one of these systems. This is because these systems actively pull water into the system for operation, and the water needs to be clean, safe and sufficient for the system to draw and filter the water to and fro the main water source.

BORE HOLES

Ground source heat pump boreholes extract heat energy from rock. They’re vertical ground arrays or collectors used to extract heat energy from rock to a ground source heat pump. They effectively save space, minimising any disruption in heat pump installation projects. Typically only 150mm width of garden space is required per borehole. The depths of boreholes generally range from 60m-200m.

They work by collecting solar energy stored in the surface soil that dissipates through rock layers. This provides a stable and sustainable heat source. During installation, a U-shaped straight pipe is inserted into the borehole and connected through a trench to the ground source heat pump. The surrounding space is backfilled with a thermal grout to ensure thermal conductivity from the ground to the borehole pipe.

Ground source heat pump boreholes are generally used for large commercial projects, district heating schemes and even smaller sites where space saving is a priority. They also prove a great solution for when there’s insufficient space for horizontal arrays such as slinky pipes in trenches. One borehole is typically required per property. The ground source heat pump circulates heat transfer fluid through the U-pipe.

Boreholes are more expensive than slinky pipes. This is due to additional preparation and drilling costs. However, boreholes are becoming economically viable through Shared Group Loop Array schemes for multiple residential properties, large commercial projects and any site with heat loads above 100 kW. Reduced mobilisation costs for the drilling rig, on-site scalable efficiency and the degree of diversification applied to save money in the long run.

SLINKIES (SLINKY PIPES)

Slinky pipes, or slinkies, collect heat from surface soil. They do this roughly 1.2m below the ground. The soil continuously gains and replenishes most of its heat from solar energy. From this, they’re able to effectively maintain a consistent temperature of between 8-12°C year-round. Soil was the first heat source used to work with ground source heat pumps, and continues to be a reliable source for heat pumps. This makes Slinkies continuously viable and naturally efficient heating.

Slinkies work by extracting heat through pipeworks from surface soil buried in trenches. This pipework is between fine layers of sand to ensure optimal contact with the ground for maximum heat extraction. In another trench header pipe work connects the slinky to the ground source heat pump by a manifold. Global and water are pumped around the pipework which absorbs energy stored in the ground and effectively transfers thesis energy back to the heat pump. The pipe is able to extract heat from the earth year-round and can last for a lifetime — up to 100 years.

Slinkies are very effective and easy to install. The ground array required is sized appropriately to meet the building’s required heat load. For every 60m of pipe, about 1 kW of energy is typically absorbed from the ground. They’re the most common method of all ground array collectors used for individual property projects.