Following a series of technical studies, we decided that the best option is to use Ground Source and Air Source Heat Pumps to provide thermal energy into homes in Swaffham Prior.

Energy source

The Heat Network will use a ‘closed loop’ Ground Source Heat Pump to heat water which is delivered to homes and community buildings in the village.

How it works:

  1. The ground absorbs energy from the sun. This heat is stored by the earth’s mass
  2. We drill bore holes into the ground
  3. Pipes containing a mixture of water and anti-freeze flow through each bore hole
  4. Heat energy transfers from the earth to this fluid
  5. On the surface, an electronic heat pump raises the temperature of the fluid through a process of evaporation and condensation. This is the same process fridges use.
  6. The fluid is then distributed via a network of pipes around the village into homes and other community buildings
  7. Energy transfers from the liquid via heat exchangers to provide hot water and heat into homes
Diagram of how the energy source works, repeating steps 1 to 7 which are provided in text on the page

Energy Centre

We will locate the Energy Centre on land adjacent to Goodwin Farm off Heath Road, Swaffham Prior. We own this land which provides the space required for the bore holes. The Energy Centre will contain:

  • Heat pumps that move the liquid
  • Heat exchangers that transfer heat between liquids
  • Back-up boilers to support the renewable energy during peak hours

The Energy Centre building will be approximately the size of the Village Hall's main hall – around 8m x 12m.

At home

The Heat Network will supply hot water into homes through an insulated pipe to a Heat Interface Unit (HIU). The HIU measures approximately 60cm x 48cm x 30cm and may replace an existing boiler and water heater, or you may retain these in addition to the HIU.

From this point, you use the hot water produced for space heating or hot water supply.

The system is compatible with ‘Wet Systems’ that have warm water flowing through radiators or underfloor heating. You can retrofit homes without this type of heating, making use of various grants currently available.

How it works:

  1. The heated fluid from the network enters the Heat Interface Unit (HIU)
  2. The HIU is installed inside your home
  3. The HIU transfers heat from the heated fluid to water supplied to it.
  4. Hot water is then supplied to appliances as required
  5. Hot water is also circulated through radiators and underfloor heating
  6. The now cooled fluid exits the house through a return pipe back into the Heat Network
Diagram showing how the Heat Network works in the home. Information on image included in the 'How it works' text on page above diagram.

In the village

Reduced noise pollution from household boilers and fuel deliveries.

Individual oil boilers all produce air pollution emissions in the home. Similarly, large diesel vehicles often used to deliver oil lead to significant emissions.

Oil prices can fluctuate dramatically and unpredictably depending on the international wholesale market. A range of local and international changes affect prices, including:

  • Supply caps
  • Import / export tariffs
  • Geopolitics with oil producing nations
  • Exchange rates

Heat Supply

The system is guaranteed to deliver a minimum temperature to every house of 72°C when the outside temperature is 0°C or lower. This drops linearly to 62°C when the outside temperature is 20°C or higher.

This temperature is important to those with older houses which cannot be as well insulated. It is a potential selling point for this system over per-property air source heat pumps which typically only produce 55-60°C (though there do now appear to be higher temperature versions becoming available - see the Pure Thermal website).

If the required temperatures are not met, this counts as an interruption of the supply under the Heat Supply Agreement. This is even if heat at a lower temperature is being supplied.

The Heat Supply Agreement sets out the arrangements for compensation for all customers where supply of heat is interrupted. In addition, vulnerable customers will be supplied with an alternative heat supply if an interruption (including lower than expected heat) lasts longer than 12 hours.

There will be some variation in the Heat Interface Units (HIU) supplied to each home. Whilst most HIUs are a similar unit size, they vary in kWh output. Smaller and larger or older homes will have a different capacity HIU installed.

There are combi-HIU models available for installation in homes that replace combi boilers to provide both hot water and space heating.

How to join the Swaffham Prior Heat Network

Visit our page about how to join the Swaffham Prior Heat Network to check if your home is eligible and for more information on what is involved and how to sign up.