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Key Info

More efficient than closed loop systems
Space heating, DHW and drinking water
Utilise the water for other uses
Borehole water supplying your heating requirements as well as your water

Heat Pumps - Open loop

FWT are specialists in the supply and installation of open loop ground source heat pumps, we have an extensive portfolio and many years experience. We install systems throughout England, the Southwest and South Wales . 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 install Kensa heat pumps. Kensa are the UK’s most popular ground source heat pumps brand (Source: BSRIA 2019) with an award-winning heritage since 1999. Kensa Heat Pumps manufactures the UK’s widest range of ground source heat pumps and accessories.

FWT are approved Kensa heat pump installers. We choose the heat pump best suited to your application, we are able to work closely with your heating contractors/builders to ensure the final specification is well designed and integrated.

Heat pumps typically require very little maintenance and are a growing part of the renewable energy sector. They are environmentally friendly as they don’t burn fossil fuels, have low running costs are very energy efficient (they can be up to 460% efficient) and produce no on-site emissions. They also attract the highest level of Government Incentive for heating systems through the Renewable Heat Incentive (RHI).

Open loop heat pump overview

Open source heat pumps utilise abstracted water from a borehole or water course, they then extract the heat from the water to use for space and domestic hot water (DHW) heating before either returning the water to another borehole or water course or using it as a private water supply. As water is a more efficient transmitter of heat than soil, open loop systems are often more efficient than closed loop systems. Although they are often more efficient consideration needs to be given to whether an abstraction licence is required. Typically you need approximately 3litres/min for each kW of heat required. If you have a 15kW heat pump you would need to abstract 45 litres/min which, over a 10-hour heating day would equate to 27m³ which is above the limit of 20m³ which you can abstract without a licence.

Typically open loop systems are used with a borehole-based system, but springs, streams and rivers can also be used. In the case of the borehole system, the borehole pump provides a constant supply of ground water to the heat pump. In any case the water then passes through a heat exchanger in the heat pump and the heat from the water is transferred to the distribution system. The temperature of the groundwater stays fairly constant all year, so the heat pump can be used throughout the year, even in the middle of winter.

The depth of the borehole and the quantity of water required from it depends on the size of your home and the heat load you require. Large properties will need a larger quantity of water to support the bigger heat pump. Before any ground source heat pump system is designed or installed a copy of detailed heat loss calculations or SAP (Standard Assessment Procedure) report will be required to establish the heat load on the property.

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:

  • The size of the property including plans if available (square meterage of areas to be heated)
  • A copy of your SAP report or EPC if available
  • A map detailing the boundary of your property

The benefits of open loop ground source heat pumps

  • Can provide a water supply as well as space and domestic hot water heating
  • Could lower your fuel bills, especially if you replace oil or conventional electric heating
  • Generally more efficient than closed loop systems
  • Could provide you with an income through the government’s Renewable Heat Incentive(RHI)
  • Could lower your home’s carbon emissions, depending on which fuel you are replacing
  • Don’t need fuel deliveries
  • Environmentally friendly
Further information is available

Background information on open loop GSHP

Heat pump sizing open loop

Is an open loop ground source heat pump suitable for me

Main component parts of an open loop heat pump system

Open loop heat pump costs savings and earnings

Open loop heat pump efficiencies maintenance and impact

Practical things to consider before installing an open source heat pump

Step by step guide to installing an open source heat pump system

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