How it works of heat pump is similar to a refrigerator. Only in the refrigerator heat is transferred from the inner chamber to the rear wall, and the heat pump from the environment in the heating system. The heat pump works by the Carnot cycle.
- A brine* circulates in a collector loop and absorbs heat energy from the bedrock, ground, air or water.
- In a heat exchanger (evaporator) the tepid brine in the collector loop meets refrigerant** circulating in the refrigerant loop. The refrigerant heats up and converts into gas.
- The pressure of the refrigerant is raised in the compressor, which also raises the temperature to a useable level.
- Via a condenser, the refrigerant releases the heat to the heating system for the house, and in connection with this the refrigerant is cooled.
- The refrigerant circulates further. The pressure is lowered in an expansion valve. It reduces the temperature, the refrigerant returns to liquid form. The process restarts when the refrigerant once again meets the brine.
* Brine is a mixture that cannot freeze, for example water together with alcohol or glycol.
** These days environmentally friendly refrigerants such as carbon dioxide and hydro carbons are used. Freon was previously used.