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|Volume 11 |Issue 26| June 29, 2012 ||
In Cold Comfort
There is nothing like the pleasingly cool, indoor temperatures ensured by air conditioners during summertime but it comes at a great environmental cost
Akram Hosen Mamun
Air conditioners are probably the most physically seductive mass produced commodity since the 20th century. In a scorching, breezeless summer day during a heatwave, walking into the air conditioned office from the broiling humid air of the street gives a pleasure that is unparalleled by any other means. If you are driving an air conditioned car, you will, nevertheless, be hit by the oppressive temperature, when you walk from the parking lot to the lobby. But how often do we take the time to consider the effects our little islands (i.e. offices, cars, shopping malls, homes, class rooms etc) of controlled temperature have on the environment? Not that often, because the comfort we get from these machines is unlike any other.
According to a study by The Carbon Trust, an organisation that operates globally to work towards low carbon economy, air conditioners almost double a building's energy consumption and emissions. Car air conditioners can also cause an additional 15 percent fuel consumption by the engine. Those who pay attention to the causes and consequences of global warming may realise by these two factors that indiscriminate usage of air conditioners is catastrophic for our environment.
Only two decades ago, air conditioners were not as ubiquitous as they are now in the city. People worked in offices, went for shopping, and attended class rooms with other more eco-friendly ventilation systems. But in recent decades, a noticeable change in architectural trend has taken place. Buildings with huge windows and high ceilings have been replaced by skyscrapers with walls made of glass and with smaller windows. The height of the ceilings has also been reduced to a significant extent.
Dr Ishrat Islam, associate professor of urban and regional planning, Bangladesh University of Engineering and Technology (Buet) says that the fact that the walls of huge shopping complexes and offices are being made of glass reflects that our architects and urban planners do not consider the regional natural environment when they construct buildings. "In fact, we do just the opposite. We fail to see that these designs are good for countries in the colder parts of the world where people need their work places and homes to be warm," she says. Heat always gets trapped in glass. As a result, the buildings that are covered on all sides by glass walls need a lot of artificial ventilation. "I admit that the glass walls are good to look at. But they are not suitable for our environment," she adds.
In contrast, the remaining old buildings in Old Dhaka are quite different. Dr Ishrat points out that those buildings have thicker walls and larger windows to let natural air and light in. They have a built-in system for cross ventilation which keeps the insides cool in summer. Having a little open space around the buildings is also crucial to have natural ventilation.
Contemporary buildings have just the opposite features. They are designed for artificial light and ventilation, with no spaces around them. The sliding glass doors, known as thais, that are widely used as windows open only half way. "My daughter can't read without having the AC on. She barely gets the touch of natural air and light," says Syeda Rizwana Hasan, Chief Executive, Bangladesh Environmental Lawyers' Association. To draw the reasons why the buildings have taken their present form, she says that designers and engineers have reduced the standard height of the ceilings and thickness of the walls to save money. The size of the windows has also become smaller than before.
"It has something to do with the kind of place we live in. The old concept of neighbourhood is not present anymore," she says. In the large housing projects, people from all over the country live in one building. "People do not even know their neighbours. The families turn their apartments into forts with closed windows. The air inside these apartments becomes so unhygienic that an air conditioner becomes the only solution for them," Rizwana concludes.
This extensive use of air conditioners can be harmful in more ways than one. They suck away the hot air inside the building or car and release the heat outside. During the process, they produce a lot heat of their own and consume a lot of electricity. Much of the electricity we have is produced by burning fossil fuel that leaves an enormous amount of carbon dioxide and other greenhouse gases in the environment. The earth's temperature has increased by 1 degree Fahrenheit in the last century. Experts believe that it is the increased burning of fossil fuel that has caused the increase in temperature. So, during the scorching days of the prolonged summertime, when we save ourselves in the cold comfort of air conditioners, we actually crank up a device that exacerbates global warming.
Bringing changes in the ways our offices, universities and houses are being built can be an effective step towards a more eco-friendly ventilation system in the future, informs Dr Ishrat. Covering the walls with foliage and growing plants on the roof can also have a soothing effect in both winter and summer. The class rooms and the faculty offices in Buet do not have air conditioning. She says that the students and the academics suffer from heat in the summer. "But not even during the last heat wave, did we find the heat unbearable," she adds. The class rooms have large windows in at least two sides of the rooms to allow cross ventilation. There are also electric fans and other natural ventilation systems that work efficiently in the university.
Besides the environmental costs, too much exposure to air conditioning also has adverse effects on health, asserts Rizwana Hasan. Researchers at New York University Langone Medical Center have found that people who spend most of the summer in air conditioned homes and offices, are at increased risk for colds and other upper respiratory infections in summer months. A study published in the US International Journal of Obesity had found links between obesity and air conditioners – appetite seems to soar in air conditioned spaces.
Rizwana Hasan says that by protecting the open spaces of the city, and bringing changes in architectural designs, we will be able to reduce our overdependence on air conditioners. Turning down the air conditioning now will ensure our future generations a cooler world to live in.
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