In May of 1994, Wellesley College became one of the first colleges in the U.S. to supply 100% of its electrical energy needs, while improving air quality and supplying surplus electrical capacity to the Town of Wellesley. Four natural gas burning, low-emission engines, designated by the Department of Environmental Protection as “Best Available Technology”, achieve 90% plant efficiency generating 5.6 Megawatts of Electricity, while recovering 8000 lb/hr of Steam, 400 tons of Chilled Water through a steam absorption chiller, as well as Domestic Hot Water. This comprehensive system results in a net savings to the College in excess of $1 million per year.

 

To house the engines and heat recovery systems, the college built a new 5,000 square foot Cogeneration Plant, consisting of the Engine Room, Heat Recovery Boilers, Transformer and Control Room, as well as internal offices and an enclosed walkway connecting Physical Plant offices to the rest of the Central Utilities Plant. Organization of these elements within a limited site, and maintaining continuous plant operations was a major challenge of the project. The location of heat recovery boilers and steam absorption chillers allowed these units to be operated by existing boiler and chiller plant personnel, minimizing operating costs.

 

Because of the noise level generated by the reciprocating engines, the acoustic design of the building envelope was important, given the plant’s location in the heart of the College Campus. Sound-attenuation measures included heavy laminated glass acoustic windows, masonry wall construction with concrete roof deck, ventilation stack silencers and specially designed copper intake hoods, that prevent rain and snow intake while providing superior sound attenuation to conventional louvers.