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HEAT PUMPS - HOW IT WORKS

Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, air, or water is constantly being renewed naturally

GROUND SOURCE HEAT PUMPS

Ground source heat pumps (ground to water) use pipes buried up to 1.2m deep to extract heat from the ground or from vertical bore holes drilled as deep as 150 metres. It circulates a mixture of water and antifreeze around the buried ground loop. Heat from the ground 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 (average 10°C), so the heat pump can be used throughout the year - even in the middle of winter.

REVERSIBLE HEAT PUMPS

A reversible heat pump provides all year round heat, plus cooling in summer. Reversible heat pumps can be air, water or ground source.

For heating a reversible heat pump uses conventional refrigeration technology to extract the energy stored in the environment and raise it to a temperature suitable for space heating and hot water. In cooling mode reversible heat pumps can be passive or dynamic. The high energy costs of air conditioning and the negative effects on employee performance of an overheated building make the cooling effect of a reversible heat pump particularly attractive.

AIR SOURCE HEAT PUMPS

Air source heat pumps (air to water) extract heat from the outside air in the same way that a fridge extracts heat from its inside. It can get heat from the air even when the temperature is as low as -25° C . The heat from the air is absorbed at low temperature into a fluid. This fluid then passes through a compressor where its temperature is increased, and transfers its higher temperature heat to the heating and hot water circuits of the building.

Air source heat pumps require less space than ground source and are ideal for domestic, commercial and industrial installations. The relatively mild UK climate in many regions, allows air source heat pumps to approach the performance range of ground and water source heat pumps, with a reduced installation cost. But Air Source Heat Pumps can be more efficient over the heating season depending on the location, type of unit used and application. For example a high efficient Air Source Heat Pump installed in Penzance on under floor heating would be more efficient than a Ground source heat pump installed using horizontal ground collectors. This is because the mean air temperature is greater than the mean ground temperature for a system designed to IGSPA standards.

Water source heat pumps extract heat from water. The heat is absorbed at low temperature into a fluid. This fluid is passed through a compressor where its temperature is increased, and transfers its higher temperature to the heating and hot water circuits of the building. The year round availability of water at temperatures between 7°C and 12°C make aquifers, lakes and ponds attractive sources of energy for heat pump technology, particularly if the water quality is high enough for it to be circulated directly through the system. Environment agency consent may be required for extracting water.

Heat Pumps are particularly suited to low temperature systems such as underfloor heating and fan assisted radiators.

HOW CAN WE HELP?

HEAT PUMPS - FAQs

What are the advantages of Heat Pumps?

Heat pump systems offer a more steady heating system than the peaks and troughs associated with a conventional boiler. They are more suitable for under-floor heating systems or larger radiators, which give out heat at lower temperatures over longer periods of time.

Is the building suitable?

Space is required to house the heat pump. You will require a place outside or inside your building where a unit can be fitted to a wall or placed on the ground. Air source heat pumps will need plenty of space around them to get a good flow of air. We can install on roof tops. Ground source heat pumps require space to lay the loops underground, or a vertical bore hole.

Is the building insulated?

One of the key questions we ask clients is whether their properties are well insulated. As with any heating system there is little point in generating heat if it is easily lost through the building. This is particularly the case with heat pumps as they work best when steadily producing heat at a lower temperature than traditional boilers.

What are the benefits of heat pumps?

Reduced energy bills, especially if you are replacing conventional electric, coal, oil or LPG gas heating

Generate an income through the government’s Renewable Heat Incentive (RHI) which offers financial incentives to those who use renewable heat technologies in their houses, community buildings or businesses

Reduced carbon emissions, although they do have some impact on the environment as they need electricity to run.

Will it provide enough heat in winter?

The heat pump system would be designed and sized to provide the correct amount of energy to heat your building to an outside design temperature of -4°C or below (depending on your location), maintaining an internal temperature of 21°C. -4 Deg C is the design temperature set by CIBSE and MCS, however, for colder climates we would design lower. It is also worth noting that there is thermal lag, so even though the outside temperature may fall to below the design temperature, it will take some time for the building to react.

What maintenance is required?

It is recommended that the heat pump unit itself is a sealed unit and has no real serviceable parts, however it is recommended that a check is carried out on the ground loop circuit antifreeze levels every 3 - 5 years. It is also recommended that cylinders and pumps should be serviced annually.

 

 

Useful Links

Read the full Ofgem full information pack.