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Fresh Air for Office Dwellers
Researchers study naturally ventilated buildings
By Lisa Scanlon

As the cocooned cubicle dweller knows all too well, sealed-off modern office buildings do not offer ideal work environments. "There's poor indoor air quality, and people seem much happier if they have access to outside air," says Leon Glicksman '59, PhD '64, professor of architecture and mechanical engineering. What's more, air-conditioning an office building takes an enormous amount of energy. So Glicksman, along with colleagues at MIT and the University of Cambridge, set out to find better ways to design buildings cooled by natural ventilation--where to locate windows, atriums, and fans so as to better draw fresh air through a building's interior.

Although the concept of natural ventilation seems simple, architects and engineers actually know little about it. "A lot of architects and designers have shied away from [natural ventilation] because they don't understand how it works," says Glicksman. "It's more complicated, because when the wind changes direction, you're going to get different conditions, and you have to be able to design [a building] to accommodate those conditions." To better understand what happens in a naturally ventilated building, the researchers began in May 2003 to monitor a new, successful building of that type in Luton, England. They measured temperature and energy usage throughout the building and took detailed measurements of airflow by, for example, videotaping helium-filled balloons as they floated through the building and its individual offices.

Back in Cambridge, MA, the MIT researchers built a one-twelfth-scale, 1.2-meter-tall model of the building. They used the temperature and airflow data they gathered in England to guide the placement of fans and heaters to replicate those ventilation conditions. The researchers hope that, once they analyze the data, they will be able to show that their scale model can be used to predict what would happen in the English building if, say, certain windows or vents were closed, or if the wind changed direction. If the simulation works, then architects and engineers can use similar models to evaluate designs for naturally ventilated buildings before construction, says Christine Walker, an architecture grad student who is working on the project.

The researchers are also creating simple, easy-to-use digital-simulation tools to encourage architects to try designing natural-ventilation buildings. Their software allows architects to check the energy efficiency of and airflow through their buildings before construction starts. The program will use certain information--the percentage of the exterior comprising windows, and the location of the building and the direction it faces--to determine approximate temperature and airflow throughout the building and to predict how much energy will be needed to heat, cool, and light it. "In many cases, [architects] don't have the budget to bring in mechanical engineers with high-powered computer-aided-design simulations," Glicksman explains. "This is something that allows people to very simply try out different designs."

The Cambridge-MIT Institute--an alliance between MIT and the University of Cambridge sponsored by the British government--is funding the project, which will continue for another year. After that, says Glicksman, perhaps his team will "even convince MIT to do a naturally ventilated building."