SEGUIN, TX — “When we hear nothing from the students or staff about the comfort system, we know we’re doing a great job,” said Thomas Dodgen, director of the physical plant at Texas Lutheran University.

He was referring to the recent chiller plant improvement, a project that involved the design and installation of a combination chiller plant, with both electric centrifugal chillers and a gas-fired absorption unit. With this hybrid system, the university has placed itself in a favorable negotiating position with energy suppliers, and has increased system reliability.

Dodgen said that by the mid-1990s, chiller improvements were necessary. “We had only 950 tons of useable chiller capacity, and on hot days we were sending out water at up to 58 degrees F. We could barely meet sensible load.” The chiller plant consisted of two older centrifugal chillers.

The university worked with BMW Engineering of Corpus Christi and with Trane San Antonio to evaluate options for plant improvement.

When the decision was made to install the hybrid system, BMW chose two Trane CenTraVac™ Model CVHF electric centrifugal chillers rated at 500 tons each, and one Trane Horizon™ direct-fired absorption chiller rated at 500 tons, for a total capacity of 1,500 tons. The new chiller plant was started up in 1997 and since then, the school has added three buildings totaling 78,000 square feet. Despite that, the chiller plant continues to carry the full cooling load.

“School districts, universities, and hospitals from all over the U.S. have called or visited us, asking about our experience,” added Dodgen. “We tell them we really like the hybrid approach. We feel we made the right decision.”

Publication date: 09/30/2002