For many people, the concept of solar is the feel of radiant heat. This is only one form of solar energy.
Solar energy can also be extracted from:
- The light using solar PV panels to produce electricity.
- The heat in the air which heat pumps use to multiply the power efficiency of the electricity it consumes by three to seven times depending on the application.
Heat pump water heaters, have been sold by Siddons in Australia for more than 30 years successfully exploiting the heat in the air for efficient water heating. Even air temperatures as low as -5°C still provide a sufficient temperature differential to produce steaming-hot energy-efficient hot water.
This means that heat pump water heaters can operate even if there is no sun or during the coldest Australian winter, night and day.
Of course, the higher the air temperature, the greater the energy efficiency of the heat pump. For Siddons heat pumps, every 10°C rise in air temperature results in an efficiency increase (or electricity usage decrease) of around 20%.
We note that your household refrigerator works much the same way. Except that, whereas a fridge retains cold air whilst warm air is expelled, the heat pump uses a reverse application of this technology such that hot water is retained and cool air expelled.
For the technically minded, a diagram illustrating how a heat pump water heater works is as follows:
The key steps are:
- The heat in the air is absorbed into the refrigerant
- The refrigerant evaporates to become a gas
- The gas is compressed which superheats it up to 95°C
- The heat from the gas is transferred to the tank water via a heat exchanger
It is noted that, like electric element water heaters, a heat pump water heater also requires electricity to operate – in this case, to pump the refrigerant around the heat pump circuit.
However, a Siddons heat pump uses up to 75% less electricity than an electric element water heater.
The heat pump water heater heating process can be summarized as follows:
Siddons heat pump water heaters use a Dynamic Cycle Flow Heat Exchanger that heats all the water in the tank quickly and efficiently.
Depending on the air temperature and hot water demand, a Siddons heat pump water heater only needs to run for around two to three hours per day for a typical family, using around 3 kW/h of power per day.