Ground Source Heat Pumps
What is a ground source heat pump?
Ground source heat pumps use naturally occurring heat in the ground or bedrock to heat domestic and commercial properties and provide hot water. Ground source heat pumps are an environmentally friendly alternative to conventional electric, oil and gas central heating systems and can reduce your fuel bills. They generate a lower amount of carbon dioxide than fossil fuel burning boilers. Although ground source heat pumps do need electricity to operate, they generate more heat than they need to run and the heat source is both renewable and natural. Heat pump systems are relatively new to the UK but are a tried and tested technology, having been developed primarily in Sweden.
Ground source heat pumps run most efficiently at lower temperatures over longer periods of time. A larger surface area is needed to emit similar temperatures to those provided by conventional heating systems. These systems work best with underfloor heating but also work effectively with larger radiators. To maintain a comfortable temperature during the winter, it is likely the ground source heat pump will be in operation constantly. Another benefit of ground source heat pumps, besides being low-carbon, is that they do not require expensive or regular maintenance. They are also safer because there is no risk of carbon monoxide poisoning or scalding from hot water. Heat pump systems produce water hot enough for domestic purposes but they don’t overheat water like conventional boilers can.
How do ground source heat pumps work?
Similar to how refrigerators take warm air and make it cool, Ground Source Heat Pumps take cool air from the ground and make it warm. Ground source heat pumps absorb heat from the ground or bedrock through brine filled tubes that are run either horizontally in trenches or vertically in boreholes. The ground stays at a relatively stable temperature all year round, which means that heat can be extracted from the ground even in the depths of winter. When the lukewarm brine meets the freezing refrigerant in the heat exchanger the refrigerant evaporates. This gas is then condensed, which generates heat that is transferred to the central heating circuit via a condenser. The cycle is endless because an expansion valve reduces the pressure of the refrigerant, cooling it and allowing the process to begin again.