A heat pump uses an air source vapour compression cycle to transfer heat from the outside air into the water stored inside a geyser.

It can therefore, transfer heat by collecting it from the air and then compressing or concentrating it to ultimately heat the water to a temperature higher than the outside air temperature.

1. Evaporator to collect heat from the ambient air
2. Compressor to drive the cycle and pump the energy from the evaporator to the condenser
3. Condenser to transfer heat into the water
4. Expansion Valve to reset the cycle for collection of heat on the evaporator side