The Independant
24 August 2006
Our love of air con is making the world even hotter
During this summer's record-breaking heatwave judges removed their wigs in court, Buckingham Palace guards headed for the shade and the lions at Colchester Zoo were given blood-flavoured ice blocks to lick. It's no wonder we've been snapping up portable air-conditioning systems in a big way to cool down. Currys says it was selling two air-conditioning units every minute during the hottest periods. Other retailers say they have been selling 10 times as many units as usual.
And it's not just about comfort. In the heatwave of 2003, 30,000 people died across Europe, the continent's biggest ever natural disaster. Since then, governments have put measures in place to prevent heat-related deaths, including the installation of portable air-conditioning systems in care homes, older hospitals and schools.
We can hardly be blamed for cocooning ourselves in air-conditioned offices, cars, shops and increasingly our homes - especially with temperatures last month averaging 7C higher than usual across southern England and Scotland. Global warming forecasts predict that, within 40 years, every summer will be as sweltering as the 2003 heatwave. But the irony is, as we run away from the effects of global warming, we only add to the problem.
Air-conditioning to control heat and humidity was first developed in the US, and has been around for more than 100 years, but did not become popular until after the Second World War. It works by ducting air across the colder, heat-absorbing side of a thermostatically controlled refrigeration system and directing it back into the living environment. In water-cooled air-conditioning units the waste heat is carried away by the flow of water. In portable units, the heat is generally fed away via a flexible hose that has to be put out of a window. While this might stop us sweating on stifling summer days, it also adds around 50 per cent to the energy costs of a building and in cars increases fuel consumption by 10 to 14 per cent - a major concern when it comes to the environment.
Up until now, this hasn't been a big issue in Britain - unlike in the US, where roughly one-sixth of all electricity generated is used to cool buildings. But with record sales of air-conditioning systems, and 75 per cent of new cars in the UK coming with air-con (reducing fuel efficiency by up to four miles per gallon), it's a different story. For the first time the power-grid operator, National Grid, is reporting noticeable surges in power consumption on hot summer days - a situation previously confined to cold winter days when heating systems are turned to full.
But the fact is, as the world heats up, so does our reliance on cooling systems that consume large amounts of energy and result in further pollution of the planet. "Air-conditioning puts enormous demands on the electrical system," says Marsha Ackermann, author of Cool Comfort: America's Romance with Air-Conditioning. "In the US most electricity is produced by burning coal. So, like winter heating, cars and other forms of transit, air-conditioning contributes to dirty air, acid rain and global warming."
Based on government data, Stan Cox, a scientist at the Land Institute, Kansas, calculated that more than 1,500kg of carbon dioxide is emitted each year air-conditioning the average US home. The effects of this are particularly bad at night, he says. Over the past five summers, very high minimum daily temperatures (scoring in the top 10 per cent historically) have been far more widespread in the US than during any other five-year period. In the past, outdoor air used to cool at night, giving people a chance to recover. Now it doesn't, which, says Cox, is one reason why more people are dying.
While air-conditioning clearly isn't the sole culprit responsible for global warming, its use looks set to increase, not decrease. Experts agree that the best long-term plan is to make sure that new housing takes climate change into account. The Government's chief scientific adviser, Professor Sir David King, is considering setting up a Government-backed project that will map out better ways of designing buildings for the future. "There are ways of doing passive air-conditioning that don't use energy, and you can build that into the design," he says.
Such systems are known as geothermal pumps, which use the ground as a kind of battery. In winter the pump uses heat from the ground to heat the building, and in summer discharges heat from the building to the ground.
In the UK there are more than 1,000 geothermal systems installed - most are domestic or in small buildings. The UK's largest geothermal system was built into the Gloucestershire Constabulary's new headquarters. It provides 646 kilowatts of heating and 756 kilowatts of cooling for the 400 staff working in the building.
The new Environment Centre for Wales building will be heated and cooled using geothermal technology. "There are many benefits [to geothermal energy]," says Professor John Farrar, director of the Institute of Environmental Sciences at Bangor University. "As well as cutting our use of non-renewable energy sources it also reduces carbon dioxide emissions to the atmosphere." The system has a 50-year life span, is virtually maintenance free and does not need cooling towers.
Specialists say that geothermal systems are well within the reach of middle-class householders. Patrick Sherriff, of geothermal Heating Installations, says it can cost as little as £5,000 to drill a bore hole hundreds of feet into the water-bearing chalk escarpment of the Chiltern hills that runs under London.
Greener attitudes to the way we cool down in summer are even changing in the US. "Just the other day, I was on the radio in Wisconsin during a heatwave - it was almost 32C at 6am," says Marsha Ackermann. "Yet virtually all of the callers were proud to say they found a way to minimise their use of air-conditioning by seeking shade, drinking cold liquid and taking hot baths."
Chilling the eco-friendly way:
Geothermal systems can be used to provide eco-friendly air-conditioning, heat and hot water in domestic or commercial environments.
In 2002, the Queen had contractors drill 400 feet into the chalk aquifer below the grounds to run a geothermal air-con system for the art gallery, built at Buckingham Palace to mark her Golden Jubilee.
She is planning on using the system to replace conventional heating sources for part of the palace.
The move inspired a trend among the super-rich to follow suit - Sir Elton John, Sir Richard Branson, and Paul Allen, the co-founder of Microsoft, have all got in on the geothermal act.
In 2004, Cornwall's Penwith Housing Association became the first in Britain to install geothermal systems for its tenants to heat and cool their homes.
President George W. Bush took the green heating and air-conditioning option when he installed a geothermal heat pump at his Texas ranch during the 2000 election campaign.
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