Cooling with Sunlight

This article was originally published in Blue 02: Systems and Structure in 2010. You can see the article in its original format, and other articles, online.

With green issues all the rage, I am reminded of our project for the British Pavilion at Expo ’92 in Seville. We won the competition 20 years ago and subjected ourselves to a period of enormous excitement and celebration.

The competition concept was entirely based on a response to the climate in Seville which, as Spain’s hottest city, was known as “the frying pan of Europe”. We thought that we should recognise that people had being living there quite happily for centuries without the huge expense of cooling systems and air-conditioning. We resolved to find out how they had managed.

We quickly saw that the massive masonry walls of the older buildings played an important part in modifying the huge variation in temperature from nighttime to daytime. We also saw that air movement was carefully contrived by having large doorways leading into small courtyards so that cool air from the narrow, shaded streets was drawn up through the courtyard and out of the open top. A third factor was the use of water – not just the apparent cooling effect of a small fountain in each courtyard surrounded by plants and ferns, but also the psychological effect of having running water.

The aim for our design was to try to make life bearable for the visitors to the Expo which needed to be held at the hottest time of the year.

The first priority seemed to be to block the very strong afternoon sun, as our site was on the Western perimeter. We did this by using a stack of standard storage tanks filled with water to provide the necessary inertia. Next we determined to ‘shield’ the building so that no direct sunlight fell on it. We did this with fabric louvres on the roof and the end walls. Finally, we added what was to become the key design feature of the building. This was a 70’ x 200’ 'water wall'. Solar panels between the fabric roof screens provided power for pumps to push water to a channel at the top of the building. Water was allowed to run from this channel down the face of the glazed façade. This created a wonderful patterned waterfall effect which greatly intrigued queuing visitors.

As this wall faced east (meaning that it was rapidly in the shade), it had the effect of cooling down the whole building. The building became famous for being a cool oasis for visitors. They also benefited from the longest bar on the Expo site which supplied them with (surprisingly cool) British beer.

We won the prize for the least energy used by any of the 106 National Pavilions on the Expo site and I believe that this project kindled the great interest in energy and sustainability that the Grimshaw office has pursued ever since.