Heat pumps use a refrigerant liquid, which is pumped between the warm and cool areas and evaporates and condenses to transfer the hear.
Heat pumps are actually quite simple and have 4 main components:
- Refrigerant Liquid
At one end of the system, the refrigerant liquid is evaporated and absorbs heat due to the low pressure. The compressor pump them moves the liquid through to the condenser, whilst increasing the pressure. The liquid is then condensed due to the high pressure, and releases its heat into the surroundings.
At low pressure in the evaporator, the liquid can absorb heat even in incredibly low temperatures, making it a great system even in winter.