The concept of a “heat pump” has been around for over a hundred years and they are found in many everyday objects like fridges and air conditioning systems. Heat pumps transfer energy from one place to another in the form of heat. This is done by taking advantage of the physical properties of liquids and gases as they change from one state to another in what’s known as the refrigeration cycle.
A special liquid called a refrigerant is warmed up and turns into a gas. The gas is then re-compressed. During this compression process the “latent heat” absorbed during the first stage of the cycle is released. The liquid is then goes back to the start to be warmed up again and so the cycle continues. In this way heat can be extracted from one place and moved to another. In the case of a domestic refrigerator it’s from the inside of the fridge to the outside. The noise we hear when our fridges are running is the compressor in action.
The heat pumps we install for heating and cooling buildings operate in exactly the same way. If we want to heat a building then energy is extracted from the environment and transferred into the building. In the case of cooling the process is reversed.
Types of Heat Pump
Ground source heat pumps get their energy from the ground. The ground temperature in the UK is around 10°C for most of the year. We use heat pump technology to extract the useful energy from the ground and elevate its temperature to a level suitable for building heating. The energy is captured from the ground in a variety of ways. In the case of air source heat pumps the energy comes from the air. Energy can be taken from the air even at very low outside temperatures which many people find surprising. More...
Efficiency
The energy we are taking from the environment is effectively inexhaustible, renewable and free. We do however need to use some energy (electrical usually) to drive the heat pump refrigerant cycle. The key to heat pump performance is the efficiency of the overall process. In a well designed system it’s possible to get efficiency levels of greater than 400%. That means that a single unit of energy used to drive the system produces 4 units of usable heat in our building. This efficiency factor is called the Coefficient of Performance or COP. At this level of efficiency a heat pump provides one of the lowest energy, lowest carbon heating systems possible. By getting a good proportion of our energy from the environment we can also operate a heat pump system more cheaply than most alternatives.
Heat Distribution
One of the major factors in achieving high efficiency in a heat pump system is the type of heat distribution being used. Under floor heating is often the best solution but there are other alternatives.
There are many myths about heat pump technology that sometimes preclude its use on a project. We have prepared this guide which will hopefully answer some of the common ones. If you need more information please contact us.
