Heat Pumps

How Does a Heat Pump Work?

Very basically a heat pump REPLACES your element in your geyser.

A geyser element uses 3 or 4 kW of electricity per hour and a heat pump uses 1 kW per hour. So the heat pump will save you at least two thirds of your water heating costs.


How does it do this?

A heat pump uses a reverse refrigeration cycle to draw energy out of the ambient air, saving you a lot of money.

The 5 main components of a heat pump are :

– A fan
– An evaporator filled with refrigerant gas
– A compressor
– A heat exchanger
– An expansion valve.

1. The fan draws warm ambient air into the heat pump across the evaporator transferring energy to the ice cold refrigerant up to room temperature.

2. The compressor then “pumps” the gas heating it up to about 160 degrees – (think of how a bicycle pump gets hot when you compress the air in it)

3. The hot gas is passed through a tube in one direction and cold water from your geyser flows in the opposite direction so that transfer of hot energy to cold water occurs – this warms up the water.

4. The cooler gas is finally passed through an expansion valve so that it cools below freezing. (think of the cooling effect when you blow through a straw)

5. The whole cycle then repeats itself.

In this manner a 5 kW heat pump can produce 100 Liter of hot water per hour (when ambient temperature is above 20 degrees C)

A heat pump does work in cold weather. (As low as -4 °C)

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