Giving Vent

This article focuses on new ideas that offer to breathe some fresh air into the conventions of indoor climate control. Since most of the air drawn out of a room gets returned, contamination becomes hard to get rid of. Even without recycling, variations in the amount of air delivered to different parts of the building create pressure differences that force air through interior spaces. Chemical fumes, mold spores, and viruses get circulated from room to room and floor to floor. This is bad enough during cold and flu season, but it is a design feature that could become a complication should the American offices again become the target of biological terror like the anthrax attacks in the fall of 200l. Variable air volume (VAV) systems have other flaws, including one that Bernard Bloom addresses with a passion: difficulty controlling moisture in cool, damp conditions. VAV systems often use air conditioning as the main control for humidity. VAV systems dominate the commercial ventilation and cooling market. About 95 percent of major office buildings use them in one form or another. They cost less to build than competing systems and have the reputation for being cheaper to run.