How it Works...
Our environment is full of energy – even at sub-zero temperatures there is plenty of energy available. Heat pumps use conventional refrigeration technology to extract the sun’s energy stored in the environment and raise it to a temperature suitable for heating purposes.
There is nothing new about heat pumps, hundreds of thousands are installed globally each year, with the main markets being Scandinavia, Germany, France and Japan. Not forgetting we all have a heat pump in our homes already – the fridge in our kitchen works on exactly the same principle!
Air source heat pumps are able to produce more energy than they consume. The heat pump absorbs heat from the outside air and raises it to a level suitable for heating. The heat pump is made up of 4 main components that carry out this refrigeration cycle to produce the energy to heat your home and hot water.
1. Energy from the outside air is transferred to the liquid refrigerant that is circulated through the evaporator. As the refrigerant is much cooler than the air, heat is transferred from the air to the refrigerant causing the refrigerant to change state from liquid to gas.
2. The heated refrigerant gas is then compressed by the electrically driven compressor, which reduces its volume but increases its temperature significantly.
3. The compressed hot gas is now drawn into the heat exchanger (condenser) where it is surrounded by the water from the property’s heating system. As the gas is much hotter than the water, the gas gives up its heat to the water and condenses back into liquid form, but still at a high pressure.
4. The cooler liquid refrigerant then passes through an expansion valve which reduces the pressure. The liquid refrigerant is now able to absorb heat from the external air, allowing the cycle to begin again.
Get more out than you put in
- Heat pump efficiency is measured by the Coefficient of Performance (CoP), which is the ratio between the amount of heat delivered and the electrical power consumed by the compressor.
With conventional boilers, 1 unit of input energy provides less than 1 unit of output heat. But with a Dimplex air source heat pump, the conversion of renewable heat into useable energy means that for every unit of electrical input energy, 3 – 4 units of heat output are produced by the heat pump.
The amount of heat output produced for every unit of input energy (ie the CoP) varies continually dependent on a number of factors – including the outside air temperature and the type of heating system – however, under optimum conditions this can be as high as 4.5 or more at certain times of the year. A well designed system should achieve an average CoP over the year of more than 3 when used to produce heating and hot water.
- Heat pump efficiency is measured by the Coefficient of Performance (CoP), which is the ratio between the amount of heat delivered and the electrical power consumed by the compressor.