Naturally Cool

Dr David Leppinen, of the Department of Applied Mathematics and Theoretical Physics, and colleagues are looking at ways to reduce energy consumption by designing buildings that ventilate naturally.

The key to their model is the use of an atrium - a large room that runs the full height of the building and connects the outside environment with the internal spaces.

"It acts like a chimney ventilating the work areas," explained Dr Leppinen of DAMTP.

"However we know very little about how the air mixes in these interconnected spaces - or how heat from humans and equipment drives air circulation."

To tackle this problem the team have devised a method of visualising air movements based on the phenomenon that causes the shimmer seen above a tarmac road on a hot summer day. The same phenomenon occurs, usually on a smaller scale, wherever there is a source of heat.

A camera is focused on a screen showing a collection of random dots - any air movement due to heat will be detected as an apparent shift in position of the dots. Feeding the results into a computer enables a comprehensive picture of air movement within the structure to be built up.

"This is not just about energy saving and environment," says Dr Joanne Holford, another member of the team. "There is evidence that people are more productive in a naturally ventilated building."

Visitors to the Royal Society's Summer Science Exhibition will be able to see the heat plume from their own hand by using a synthetic schlieren system (exhibit 13).

The exhibition takes place from 2-4 July 2002 at t/he Royal Society, 6-9 Carlton House Terrace, London SW1Y 5AG. Free to enter, it is open from 10am to 4.30pm each day, except Tuesday when it opens slightly later at 12.30pm. Anyone interested in attending can find out more by calling 020 7451 2574.