How does a heat pump work?

Heat pump is a technologically advanced system adjusted to make use of renewable energy sources. Its advantage is the ability to recover heat from the air, groundwater, or soil in your immediate environment. There are three types of heat pumps, diff ering in the energy source they employ: air/water, water/water, and brine/water heat pumps.

A heat pump consists of an evaporator that recovers heat from the environment (water, air, soil). In the evaporator, a refrigerant passes from liquid to gaseous state and then travels to the compressor. There, the vapours are compressed to increase pressure and temperature. Hot vapours are liquefied in the condenser unit, emitting the condensation heat to the heating medium. Then the refrigerant passes through an expansion valve where its pressure is again lowered, and continues back to the evaporator where the process is repeated. All heat acquired from the environment is free. Raising its temperature requires some energy. Hence, electric power is required for heat pump operation to power the compressor.

There are three basic versions of heat pumps according to the medium (environment) being cooled and the medium being heated: water/water, brine/water and air/water. When designating the type of heat pump, the sources from which the heat is taken away is indicated first, followed by the medium being heated.

Coefficient of performance - COP

The ratio between input power (electrical energy) and output heat (thermal energy) is normally between 1/3 and 1/5. The ratio between input energy and output heat is called Coeffi cient of Performance (COP). The value of COP depends on the type of heat pump and source of thermal energy in the environment. On average, annual COP for heat pumps is between 3 and 5 or more.