Renewable Technology

Ground Source Heat Pumps

Ground source heat pumps provide hot water and heating to buildings in what is one of the cleanest and most efficient ways to produce thermal energy. A ground source heat pump uses collector pipework to harness the constant latent geothermal heat in ground water to produce thermal energy ideal for heating and hot water. Ground source heat pumps use electricity and so for every 1kW of electricity used to operate the heat pumps, 4KW of heat energy is produced.

A ground source heat pump works by extracting energy stored in the ground using pipework filled with a water/antifreeze mix within trenches 1200mm below the surface. The heat pump then circulates this cold fluid around the array of pipes, extracting energy from the surrounding ground. It is critical that sufficient pipe is buried and spread over a large enough area so that this energy extraction is sustainable meaning ground temperatures will return to normal before the start of each heating season.

Where adequate ground isn’t available for horizontal collector’s we can install boreholes to install vertical pipes to extract latent heat from the rock below the surface. The warmed fluid coming back from the ground array transfers energy across a heat exchanger to a very cold refrigerant gas. The then warmed gas passes through an electrically driven compressor where it is compressed, generating the high grade heat needed to provide heating and hot water for your building.

Advantages:

• Fuelled by natural resources

• Cheaper running costs than natural gas, lpg or oil

• High reliability

• RHI payback scheme qualifier

• Safety with no fossil fuels required

• No fuel storage required

• Optimum living comfort with consistent year round heat

• Qualifies for 5% VAT rate

• 25-30 year life span

• Enhanced property value

Air Source Heat Pumps

As with the GSHP an air source heat pump is also based on a very simple principle similar to the domestic refrigerator, using a vapour compression cycle. Unlike the GSHP an ASHP is sited externally and uses a fan to draw in outdoor air to the evaporator within the unit.

When the outdoor air meets the evaporator it turns the refrigerant into gas. Thereafter the gas is compressed, leading to it reaching a high enough temperature to feed the heating and hot water system within the building. Air source heat pumps can produce enough heat down to -15° meaning they can adequately and efficiently heat homes and businesses in our climate 12 months of the year.

They are also inverter driven allowing the unit to use only the electricity needed based on how much heat is required. A well installed heat pump should run at a Seasonal Coefficient of Performance (SCOP) of 3:1 on average throughout the year. This means that for every 1kWh of electricity needed to run the compressor 3kWh of heat will be generated by the heat pump. At an electricity cost of 12p/kWh therefore a heat pump will cost around 4p/kWh to run.