Over-Designed Campuses Lead to Waste

A recent entry on the Greening the Campus blog opens with a provocative question: “Would you wash your hands with a fire hose?”

Richard Johnson, director of sustainability at Rice University, discusses the problem of “over-designing” various systems in buildings, which leads to waste. His blog entry focuses on a heating-and-cooling system in a recently designed building on the Rice campus:

[The] engineering consultant originally recommended 2,000 tons of cooling. An internal team from Rice whittled this down to 300 tons of cooling — an 85-percent reduction. To date, the building’s actual consumption has not peaked above 40 tons, although it eventually will. The difference between the original recommendation and the actual peak from operations to date is a factor of 50. That’s over-design! As a comparison, when we wash our hands under a sink, the stream of water is typically flowing at a rate of 2.5 gallons per minute. If this were over-designed by a factor of 50, the flow rate would be 125 gallons per minute, which is typical for a fire hose. So again I ask the question, would you wash your hands with a fire hose? Certainly not, and no consultant would recommend that we do so. But when it comes to energy, we’ll get the equivalent of a fire hose to wash our hands if we’re not careful.

Mr. Johnson makes various recommendations for the design process to avoid this kind of waste — those recommendations mainly focus on good communication among people with expertise and a close look at data.

I also recall a session at the 2007 annual conference for the Society for College and University Planning that focused on over-design of laboratories — in particular the over-design of lighting. Another issue raised in that session was segregating lab functions to limit how much costly high-capacity ventilation was needed.