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.
| Sustainable technology in the 3400 m2 logistics centre of Olympus KeyMed at Southend include 50 boreholes 98 m deep linked to a Mitsubishi heat-pump system to enable the building to use the ground as an energy store for heating and cooling. |
There are even technologies available that can allow you to quickly and easily upgrade existing VRF air conditioning — with the benefits of increasing the efficiency of the equipment and safely removing older, more harmful refrigerants. All manufacturers of VRF air conditioning are quick to highlight the individual benefits of their own ‘unique’ systems — but, perhaps, this is where the problem starts? Because we as an industry have focused on winning market share over one another, we have not properly addressed the real area of potential growth (and therefore benefit to the end user and the country as well of course). That is the chance to replace traditional forms of heating and cooling with much more efficient VRF heat-pump air conditioning. Trials of a ground-source heat-pump system at our Hatfield offices, for example, have proved beyond doubt that, on average, it is over 300% more efficient than a traditional boiler/chiller combination. While that average figure is impressive, there are many occasions throughout the year where the heat pump system is over 500% more efficient than a traditional boiler at providing heating. These incredible efficiency levels are the reason that ground-source heat pumps make it onto the Government’s renewable-energy list, and the other advances mentioned earlier are the reasons why many air-conditioning systems now qualify for Enhanced Capital Allowances, commonly referred to as ECAs. Balancing the costs
Again though, I think there is a danger that this ECA message has also passed many people in the industry by. Under the Government’s ECA scheme, a company can offset the entire capital costs of new energy-efficient equipment against its end-of-year tax bill, effectively recouping the set up costs — so the fact that VRF has slightly higher initial costs than traditional boilers and chillers should no longer be an issue. You would expect me to say that about our own products, but if you look at the increasing evidence, it is clear that any modern, inverter-driven, air conditioning with advanced controls has the potential to help us reduce carbon emissions for the country, whilst ensuring that the high standards expected in modern life continue to be met. It really is time to install air conditioning to help save the planet! Philip Ord is City Multi product marketing engineer with Mitsubishi Electric. The company is hosting a series of free, CPD-accredited seminars on renewable energy targets and has produced a number of free CPD-accredited guides on the issues affecting the industry. Visit the web site below or call 01707 282880 for more information.