During operation, the DHW heat pump absorbs the heat from the recirculation air or the extract air and conveys it to the evaporator. It contains a refrigerant that heats up at low temperature before turning to vapour. Since the temperature of the vaporised refrigerant is not yet high enough to heat the water, this is followed by a compression process. In this process, the steam is conveyed to a current-driven compressor, which compresses it until the required temperature is reached.
In the final step, the heated refrigerant vapour transfers its thermal energy to the built-in DHW cylinder, cools down and condenses. The refrigerant liquid is then expanded at high pressure by an expansion valve while it continues to cool down considerably. Once the refrigerant is back in its initial state, the compression process can begin again.