HEAT PUMP - Ground Source

Image of an Ground Source Heat Pump System

Heat flows naturally from a higher to a lower temperature. Heat pumps reverse this natural flow, extracting heat energy from a cool source, such as the air, and delivering it to a building's heating distribution system commonly in the form of underfloor heating or low surface temperature radiators. An air to air heat pump system will distribute heat energy internally via a unit which resembles a standard air conditioning unit system. They provide space heating only.

In the same way a fridge uses refrigerant to extract heat from the inside in order to keep your food cool, a heat pump extracts heat from a range of sources, and uses it to heat your home and hot water (an Air to Air System will only provide space heating). It is important to note that your property has been adequately insulated before installing a heat pump system.

Ground source heat pumps do not tap into geothermal heat (heat retained within the Earth's core). Instead, they use solar heat that has been stored in the Earth's surface, the Earth acting as a huge solar collector. At 1-2 metres below the Earth's surface, the ground is at a very constant temperature throughout the year, around 8-10 degrees Celsius. This heat can be extracted by a Ground Heat Exchanger or Collector, which consists of a carefully calculated amount of loops (plastic piping) buried below the surface of the ground and plumbed in a closed loop. The heat pump then transfers this extracted heat to the building's heating distribution system.

The temperature of the ground-extracted heat is too low for direct use to heat our homes so it is necessary to upgrade the temperature of the heat using electricity in the heat pump to boost the ground-extracted, low grade heat to space heating levels.

The key to an effective ground source heat pump is that the energy required to make the heat useful (i.e. concentrated) is less than the energy required to provide the heat directly.

The coefficient of performance (CoP) is the key figure used with heat pump systems. It indicates the ratio of useful heat energy output to electrical energy input. A ground source heat pump system typically achieves a CoP of 3-4. This means that for every 1kWh of electricity input, you will get 3-4kWh of heat output.

Is my site suitable?

A ground source heat pump system requires external space, so your property will need a garden or other outdoor ground space that is adjacent to your property for the ground loops to be buried within. A moist, packed soil is more desirable to bury ground loops within than dry, loose soil as dry, loose soil traps air and therefore operates a lower thermal conductivity (more ground loops will be required in this instance).

Ground source heat pumps undoubtedly work best where properties have a lower heat demand or perhaps have an existing heating system which has a lower operating temperature than a conventional heating system, i.e. they work best in a property with underfloor heating or low surface temperature radiators.

To discuss your ground source heat pump requirements further please call now on 01934 622891, contact us or visit our showroom in Weston-super-Mare.

To conclude, key benefits of a ground source heat pump system include:

  • POTENTIALLY, earn a tax-free, index-linked income for the next 20 years (see Renewable Heat Incentives page)
  • Reduce your energy bills
  • So long as the CoP is greater than 2, CO2 emissions will be lower than a conventional heating system thus reducing your carbon footprint and the effects of global warming
  • Improve your property's energy efficiency rating
  • Increase the value of your property
  • Increases your awareness of energy use and encourages more energy efficient behaviour
  • Low maintenance
  • Very long lifetime (30-40 years)
  • Combined with an electricity-producing renewable technology, a solar PV system or wind turbine for example, this can become a complete renewable energy heating system