Reducing carbon emissions
Air condition to save the planet
A ground-source heat-pump system at Mitsubishi Electric’s headquarters at Hatfield is linked to closed-loop coils laid in trenches to extract energy from the ground and help the system perform over 300% more efficiently than a traditional chiller/boiler combination.
The efficiency of modern air conditioning and its ability to exploit renewable energy make it part of the solution to reducing carbon emissions — not part of the problem. Philip Ord explains.Wherever you look these days, someone is talking about global warming and carbon emissions — whether on television, in the newspaper, on the radio, in workplaces or even in the local pub. The recent Stern report into the effects of global warming highlights the huge economic costs to us all of climate change. With half of the UK’s emissions of carbon dioxide directly attributable to construction and the built environment, we have to find ways of tackling the problem if the UK is to get anywhere near the Government’s stated aim of achieving a 60% reduction by 2050. However, we cannot simply just turn back the clock and revert to an age where we did not use so much power. Could you now live and work without your PC and the Internet for example? And how would any modern office cope without some form of mechanical heating and cooling? Commerce and industry is faced with a tricky balance of reducing the carbon footprint of buildings without diminishing the high levels of creature comfort that modern occupants expect. There is also the issue of the renewable-energy targets that many local planning departments are imposing. Natural-ventilation systems have been held up as the energy-free way forward. They certainly have merit, but are not without their problems as they simply cannot cope on their own with the varied extremes of hot and cold that even one British day can offer. Also, they cannot be used in every situation. Misconceptions Although there remain a lot of misconceptions about air conditioning, this is where it could actually come to the rescue! Stop someone in the street and ask them about air conditioning and energy consumption and you are unlikely to find many who understand or know about the huge revolution that VRF air conditioning has undergone in the past decade. What is still so surprising, though, is that this revolution has also passed some in the building services industry by. Inverter-driven systems, which consume only the power needed at a particular time for a particular need (rather than being either ‘off’, or ‘on at full power’) are increasingly being used. Certain VRF systems use the refrigerant circuit to transfer energy around a building to help balance simultaneous cooling or heating requirements. The growth of advanced control systems enables efficiency to be maximised. More recently, VRF systems are increasingly being linked with renewable energy technologies such as ground-source heat pumps and natural ventilation. Indeed heat pumps can extract free energy from earth, air or water to minimise running costs.