WINDOWS filled with water could save companies a fortune by cutting their use
of heating and air-conditioning systems, says a British engineer.
Keeping offices at a comfortable temperature all year round is an expensive
business. 鈥淭he bulk of the cost is from air conditioning to cool offices in the
summer,鈥� says Frederick McKee, the Essex-based engineer who invented the new
windows.
McKee says his windows could slash the cost of keeping offices warm in winter
and cool in summer. The system is based on double-glazed windows, but instead of
having an air cavity between the panes, McKee pumps water through the gap (see
Diagram). A chemical dissolved in the water absorbs infrared energy from
sunlight but is transparent at visible wavelengths. So while heat is absorbed by
the solution inside the windows, visible light passes straight through.
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Water from the windows circulates through a heat exchanger, allowing the heat
it contains to be stored for later use. Alternatively, the water can be pumped
to cooler, shaded parts of a building. In winter, when it is warmer inside the
building than outside, the solution absorbs heat from the office and radiates it
back in. 鈥淭he system basically enables us to put up a building that doesn鈥檛 need
cooling in the summer or heating in the winter,鈥� says McKee.
According to McKee鈥檚 calculations, the normal annual bill for heating and
cooling a 30-metre-square 10-storey building would be around 拢150,000.
With his new glazing system, the bill would be less than 拢3000 a year.
鈥淎s an idea, it鈥檚 brilliant. But persuading people it isn鈥檛 silly takes
time,鈥� says Peter Worburton, a director of London-based engineering firm Arup.
Tim MacFarlane of structural designers Dewhurst MacFarlane in London agrees:
鈥淧eople have a problem picturing water being pumped through their windows. They
worry about things like leaking and the system breaking down.鈥�
