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FWT are specialists in the supply and installation of closed loop ground source heat pumps, with many years experience and an extensive portfolio, we install systems throughout South Wales and Southwest England. We offer turnkey solutions for GSHP installations; that is we undertake all the work needed to get the system up and running from the initial design to installation and commissioning ensuring you get the right system for your home or property.
FWT are accredited installers and distributors for Kensa Heat Pumps. Combining engineering ingenuity and years of ground source expertise, every heat pump in the Kensa range has been designed and tested to exacting standards for optimum efficiency and ease of use.
Ground Source Heat Pumps are an established technology that have been around for over 50 years. Radiation from the sun heats the earth; the earth then stores the heat and maintains, just two metres down, a temperature of around 10°C even throughout the winter. A ground source heat pump uses a ground heat exchange loop to tap into this constantly replenished heat store to heat buildings and provide hot water This is broadly the same principle as the heat pump bolted to the back of a conventional refrigerator. Instead of extracting heat from your fridge and depositing the warmer air into your kitchen, a GSHP extracts the heat from the ground and transfers it into your home for heating and/or domestic hot water.
The heat pump circulates a mixture of water and antifreeze around a loop of pipe, called a ground loop, which is buried in your garden or lake. Heat from the ground or lake is absorbed into the fluid and then passes through a heat exchanger into the heat pump. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year, even in the middle of winter.
The length of the ground loop depends on the size of your home and the heat load you require. Longer loops can draw more heat from the ground, but need more space to be buried in. If space is limited, a vertical borehole can be drilled instead.
In order to provide initial guidance on the suitability of your property for a ground source heat pump installation we typically need to know the following:
(as listed by The Energy Savings Trust)
FWT are accredited installers and distributors for Kensa Heat pumps.
The trenches for the ground loop are usually at least 1.2 metres deep, 1.5 metres wide and around 50 metres in length. Normally 2-3 50 metre trenches are required for a domestic installation.
Slinkies are the name given to the coiled loops of piping that are installed in the trenches and collect the heat from the surrounding earth.
The flow rates for the different ground loop trenches need to be balanced using special flow valves and a manifold system. This can either be installed in the plant room or at the head of the ground loop in an underground chamber.
The trench from the heat pump to the ground loop needs to be of adequate depth and the flow and return pipes are sized to minimise friction loss. All underground joints are usually electro fused.
The heat pump and connections are usually installed in the plant room. This picture shows the under floor distribution manifold.
This installation shows the heat pump, buffer vessel and hot water cylinder.
Brief overview of how a heat pump works
This graph clearly shows that the temperature of the ground just below the surface remains more of a constant throughout the seasons. This is why a ground loop that is only 1.2 – 1.5 metres deep can be a reliable form of heat, it also shows that a borehole of 100m will have even less or no temperature fluctuation throughout the seasons.