The application of heat pumps can be found from pool water heating, domestic and commercial hot water heating applications. The heat pump in question is used for domestic hot water heating and consists of a hot water cylinder and a heat pump.
See Diagram:
1. Heat pump compressor
2. Thermostat to regulate the temperature
3. Evaporator to collect the heat from the ambient air
4. Expansion valve
5. 300L hot water cylinder
6. Sterilisation element to kill unwanted bacteria
7. Solar heat exchanger to connect solar panel (Not required – Customers option)
8. Copper jacket to transfer the heat into the water.   

Note: The heat pump completely replaces the hot water geyser.