Ground source heat pumps (there are also air source heat pumps) are the most energy efficient means of heating, ventilating and air conditioning a domestic property.  They are increasing in popularity for new build and renovation projects because of the positive impact on the environment as well as their efficiency.  They can be used to provide most, if not all of a home’s heating and domestic hot water.

What are ground source heat pumps (GSHPs)?

Ground source heat pumps transfer heat from the ground into a building to provide heating and in some cases hot water.

How do ground source heat pumps work?

Ground source heat pumps work by circulating water through buried pipes, which absorb the heat from underground.  The principle is similar to a refrigerator, except that the temperature requirement is the reverse.

A ground source heat pump has three key characteristics:

1 Ground Loop

Closed circuit piping filled with water and treated with antifreeze is buried underground, and is pumped around the pipe, absorbing heat from the ground as it circulates.  The shape of the loop is dependent on the type of hole it has been placed in, i.e. a spiral or horizontal pipe would be used in trench dug holes, whereas a vertical pipe would be used in a borehole.

2 Heat Pump

A ground source heat pump operates with three main components working together.  These are the method of absorbing the heat using the water in the pipe (referred to as the evaporator) and the compressor, which is the means of moving the liquid around, compressing the gases present to the temperature required.

3 Condenser

The condenser passes the heat to a hot water tank which in turn feeds the distributing system (either under floor heating / radiators or hot water).

Why should I use ground source heat pumps?

When the amount of energy used to run a pump is calculated against the amount of heating supplied (and what this would have cost from another source) there are two savings to be made:
 
1 On heating bills; and
2 CO2 emissions.

As a general guide, the efficiency of the system should mean that it uses a quarter of what it produces to power the pump. It has been designed to heat a whole building, and does not require any external fuel, making it very energy efficient.

Benefits

• Based on current fuel prices ground source heat can be a cheaper form of space heating than mains gas,   oil, LPG and electric storage heaters. 
• Ground source heat generates less CO2 emissions than even the most efficient condensing gas or oil boiler with the same output. 
• Maintenance costs are likely to be lower than conventional gas fired systems.
• Heat pumps supply more energy than they consume by extracting heat from their surroundings.
• Heat pumps can also be used for cooling and can supply domestic hot water in some instances.  
• Heat pumps can achieve a co-efficient of performance (COP) of three or more.  This means that 3kW of heat energy is delivered for every 1kW of electricity used to power the pump.

What are the drawbacks for using ground source heat pumps?

• Although the running costs can be less than they would be for oil, coal or LPG, a ground source heat pump is not always cheap to run, especially if electricity is used to operate the compressor and pump.Ground source heat pumps are relatively expensive to install but cost effective where mains gas or oil is not available. 
• Ground source heat is most effective for dwellings with low heat demand – therefore measures to improve the energy efficiency of existing dwellings should be implemented in retrofit cases. 
• Ground source heat pumps use similar technology to that employed in domestic refrigerators or freezers.  System refrigerants in the ground loop can be toxic or flammable and have global warming potential. However new types and blends of refrigerant with minimal negative impacts are being developed and a correctly fitted system will greatly reduce leakage potential.

To arrange a non-obligatory ground source heat pump consultation and feasibility assessment please complete the online enquiry form

Although ongoing expansion plans are in place, the renewable energies team currently operates within a local area comprising Cheshire, Manchester, Liverpool, Shropshire and North Wales.  Whilst we welcome enquiries from other parts of the country, because we are happy to assist in the provision of information for renewable energy, we are unable to offer a service of delivery on a nationwide basis at this stage.