Mason Inman, New Scientist 7 Dec 09;
"In an environment like Singapore, it's pretty clear that these systems would pay for themselves in energy savings"
WE'RE used to taking command of our personal climate in planes and cars by using simple controls. Why not in buildings too?
A study of the effect of installing individual air-conditioning vents at office desks, and putting controls at each worker's fingertips, suggests it can cut a building's energy use in half.
The approach costs more to install than a conventional system, and has never taken off commercially. But engineer Stefano Schiavon at the University of California, Berkeley, and colleagues say their research shows the idea is worth revisiting, as companies and countries seek to cut emissions.
They simulated an office building in a hot, humid climate like that of Singapore, where air conditioning is relied on throughout the year. Results showed the building's energy use was cut by 50 per cent.
Personalised ventilation means less air needs to be cooled and pumped through a building because air needs only to be blown at desks, and not throughout entire rooms. Individual vents can also switch off automatically when a desk is vacant.
The result is that a room's temperature can increase while keeping people comfortable at work.
Raising a building's temperature even a little can save large amounts of energy. The Japanese government is campaigning to convince offices to discourage suits and ties, to allow office thermostats to be turned up slightly and save power.
"In an environment like Singapore, it's pretty clear that these systems would pay for themselves in energy savings," Schiavon says.
Air conditioning is a major driver of south-east Asia's electricity use, and accounts for the bulk of electricity used by buildings in Singapore.
Past research has shown personal ventilation can also make people more comfortable, and hinted it can limit the spread of airborne diseases.
The personalised approach isn't always suitable, though. Only workplaces where people tend to stay in one place would benefit, points out environmental engineer Peter Nielsen of Aalborg University in Denmark. Savings are also smaller in cooler climates, where on cold days the number of people directing warm air onto themselves causes the room to overheat.
