The need for hot water in our developments is as strong today as it always has been. However, these days when we consider water heating issues, we need to take into account the effect on the environment, as well as how economical a particular system may be. The development of modern heat pump technology proves that both can make ideal partners. Heat pumps cleverly exploit latent energy in air and convert this energy into heat.

There are two important renewable energy sources to heat water. They are both harnessed from the sun. Solar power uses the direct heat from the sun, while heat pumps use the heated air by the sun.

Not many people know about the advantages of extracting heat from air to heat water. The principle of a heat pump is very similar in operation to the operation of a refrigerator, but only in reverse.

It utilises the energy latent in the ambient air and can extract up to 80% of this free energy from the air, to provide enough hot water for a house. With a 300 litre cylinder, it delivers in excess of 500 litres of domestic hot water of up to 40°C.

The beauty of this technology is that the amount of electrical energy required to operate the heat transfer process is far less than the energy used by a conventional electric element. The fan and compressor consume 700 Watts of electricity to generate 4 kW of heat to the water cylinder, at an ambient temperature of 25°C (COP 4).

The heat pump system contains a fan that forces air through an evaporator. The evaporator contains very cold liquid refrigerant. The heat in the air passes through this evaporator and is absorbed by the refrigerant. The now warm gaseous refrigerant is then circulated in the system via a compressor. As it goes through the compressor, its pressure rises and the temperature increases further. From here it travels to the condenser where the heat from what is now a super hot refrigerant is transferred to the water supply tanks. The cooled down refrigerant then goes through an expansion valve, which reduces its pressure, cooling it further and the cycle starts again.

The energy use is approximately 25% of conventional electric hot water cylinders, saving you 80% if your electric bill.

Stiebel Eltron is Germany’s market leader in heat pump technology and has operated in South Africa for the past thirty years. Over 30 000 heat pumps are produced at the Stiebel Eltron factory each year.

With the predicted increase in energy costs and the cutting of greenhouse gas emissions, the WWK 300 A domestic heat pump makes real sense for the environment.

For further information, refer to the latest Stiebel Eltron download to SPECXpert 2007/8, as well as to section 75 in the Specifile Building Library and the Archi-Text Design Library.
Click to find out more about Stiebel Eltron heat pumps