Air Source Heat Pumps

As fully qualified Mitsubishi installers and with the Government accreditation, customers are entitled to grants.

Applications:

• ASHP run from electricity. This means that you can be free from gas and oil.
• ASHP generated heat is at a lower temperature than conventional boilers, therefore this is suitable for under floor heating.
• ASHP are a good backup for a solar system. An ASHP can ‘top up’ heat in your cylinder if it has been a poor solar day.

How do Air source heat pumps work?

An ASHP is a sealed circuit within which is an evaporator, compressor, condenser and an expansion valve.

A fan blows atmospheric air over the evaporator which contains liquid refrigerant. The relative warmth of the air evaporates the refrigerant therefore transferring heat energy from the air, to the refrigerant (now a gas).

This gas is compressed (in the compressor) causing an increase in temperature, and then condensed back to a liquid.  When condensing, heat energy in the refrigerant is released. The liquid, now under high pressure is then allowed to expand in the expansion valve, turning it to a saturated vapour before passing back into the evaporator to repeat the process.

It is the release of heat energy during condensation which allows ASHP to produce more energy than is used to drive it.

Ecodan Air Source Heat Pump Brochure (3603 KB)

Why are ASHP ‘green’ when they run on electricity?

This is a highly efficient method of heating water. For 1 kWh of electrical energy put in, you get approximately 2.5 kWh of heat energy out.

Advantages of ASHP:

• They are relatively small and compact and do not require any storage of fuel
• They are a highly efficient method of heating, particularly when coupled with underfloor heating

Disadvantages of ASHP:

• As they produce less heat than conventional boilers your home needs to be well insulated.
• They do not work very well with radiator systems due to the lower temperature output.
• They are expensive to install