The Domestic Heat Pump Association represents manufacturers of heat pumps for the purposes of domestic space heating and hot water service provision.  The Association works with Government, energy suppliers and the related heating industry sectors to promote the benefits of domestic heat pumps and stimulate growth in the market sector across the UK.

What are Heat Pumps?

Heat pumps are based on conventional refrigeration technology converting a high volume of low grade heat from the environment to a lower volume of higher grade heat. The heating and hot water system operate exactly the same as they do with a boiler so consider that the heat pump is providing a form of heat service, in much the same way as a boiler but through a thermodynamic process rather than combustion.

Heat pumps use a carbon and cost free input energy (from the air or ground) which is converted into useful heat. This means that where a heat pump has a co-efficient of performance of say 4, 75% of the energy is from the environment with 25% from the electrical energy.

1. Large quantity of low grade heat absorbed from the environment. Changes refrigerant from a liquid to a gas (in the Evaporator)
2. Refrigerant is compressed (using an electrically driven compressor), raising its temperature
3. Heat exchanger (Condenser) then extracts the heat from the refrigerant and transfers it into water
4. Refrigerant passes through an expansion valve, reducing its temperature and turning back into a liquid
    

Source: Dimplex

The conversion process uses electricity to drive the compressor within the heat pump cycle but so long as the efficiency of the heat pump is greater than 100%, it is energy and carbon efficient. For example, a typical 4kW ground source heat pump is 400% efficient in that it gives 4kW of useful heat for every 1kW of electricity used. This is expressed normally as a spot measurement called Coefficient of Performance (in this case a CoP of 4). Efficiencies of 250-500% are generally available in the UK. Conditions of operation determine the spot measured Co P i.e. Air/ground temperature and Water flow temperature. Those conditions tend to be from laboratory conditions and not real in use testing. 

If a householder uses a renewable energy tariff then the input energy is also carbon free, creating a truly renewable and zero carbon system.

What types of Heat Pump are available?

Heat Pumps are normally classified by their heat source and means of delivering useful heat. The most commonly available heat pumps in the UK are:

Ground source to Water: As above but providing useful heating through underfloor heating systems and medium temperature radiators. For more information click here

Air to Water: These are commonly used to provide domestic hot water and space heating for dwellings. For more information click here

Air to Air: air is used as the low grade heat source and air is also how the heat is delivered to the space. These are commonly used as reverse cycle heat pumps (providing heating and cooling).  For more information click here

 

To learn more about the benefits of heat pumps click here.

To learn more about the savings potential of heat pumps click here.

For frequently asked questions about heat pumps click here.