Engineering giant Mitsubishi Electric has this week unveiled a new air conditioning system that it claims can not only heat and cool a building but also capture waste heat and use it to heat water to temperatures of up to 70 degrees centigrade.

The company said that its new PWFY City Multi water heater uses heat pump technology to capture hot air that would otherwise be expelled from the building and redirect it to heat up water.

Product marketing manager, Philip Ord, said that the UK's temperate climate and the need to heat most buildings meant there was huge potential for firms to make better use of the waste heat their offices generate. "We have tried to look at where there are other needs for a heating load within a building and see where the excess energy from heat recovery can be used," he added. "Hot water is therefore an obvious target and we have designed a product that can even work with off-the-shelf water cylinders."

A spokesman for Mitsubishi Electric explained that while heat pumps are now commonly used in modern air conditioning systems to transfer heat from hot areas such as datacentres or south facing rooms to cooler parts of the building excess heat still goes to waste. He added that the new technology used a refrigerant cycle to maximise the energy in this hot air and use it to heat water.

Mitsubishi claims that as the system relies on waste heat it is over three times more energy efficient than gas boilers. "In terms of efficiency the system can operate at up to 300 per cent," explained the spokesman. "That is to say that you can feed in 1KW of electricity and by harvesting the ambient air and exploiting the refrigerant cycle you can get 3-4KW of heat energy."