UNIVERSITY BUILDS "ICE HOUSE" TO COOL CAMPUS By Mike Field When Charles Carroll Jr. moved into Homewood in 1802, the new house came equipped with all the modern conveniences. There were Argand lamps in the parlor that provided enough bright, even light to read comfortably by at night; an ingenious "flushing" chamber pot in the master bedroom that precluded midnight runs to the outhouse; and somewhere on the grounds-- perhaps near the kitchen--the Carrolls had their very own ice house, a subterranean vault that servants would fill with blocks of ice in the winter so that, come summer, the estate's fashionable occupants could enjoy the uncommon luxury of cooled drinks and other chilled foods as a way to beat the heat. Times have changed, and the need to provide cooling capabilities in the heat of summer is no longer considered a luxury. But the idea of using ice storage as a means of providing that cooling had long since gone the way of oil lamps and chamber pots, until recently, that is. In December, the university broke ground on its own high-tech, late 20th-century version of the venerable ice house. Located in four enormous subterranean concrete vaults, the new north chiller plant, as it is called, will make and melt iceberg-sized blocks of ice on a daily basis during the cooling season to provide much of the air conditioning and other cooling needs of the Homewood campus. "Most of the cooling needs on the Homewood campus are provided by water that is chilled to 42 degrees Fahrenheit and then piped throughout the campus in underground tunnels," said acting director for engineering services Wendy Pinnix, who is overseeing the construction of the north chiller plant, now being built adjacent to the Bloomberg Center, behind the Athletic Center. "In the university's current system, the water is chilled through the use of huge compressors and refrigerants, not unlike a home refrigeration system," Pinnix said. "The cold water is then pumped to the campus buildings, where tertiary pumps circulate the water through coils within the buildings' air handling units. In some cases, such as the lasers in the astrophysics lab, the chilled water is used indirectly to cool research and scientific equipment." The new chiller plant will not replace the existing system, but augment it, by providing ice--made at night when electricity rates are lowest--to finish putting the chill in the campus's chilled water system. "This is entirely a utility company-driven technology," said Gil Morin, president and founder of the G.F. Morin Co., which provided the university with the cooling equipment for the new system. "On a hot summer day, a utility company like BGE will operate at 100 percent of capacity in order to provide for all the cooling needs, while at night it will run at something like 50 percent capacity," Morin said. "In recent years, the utility companies have been practicing load management, where they have been encouraging the use of electricity at night and discouraging its use during the day." By offering substantially lower electricity rates during the night--and sweetening the deal with generous cash rebates toward the construction of energy-efficient and load-managing systems--BGE hopes to be able to accommodate projected higher energy demands without having to go through the expense and turmoil involved in building new power plants. In Hopkins' case, the university will save an estimated $400,000 annually in electricity, and BGE has committed to a substantial rebate of approximately $660,000 toward the construction of the first phase of the $3.4 million project. If all goes according to schedule, the system will be running by the end of the year. "We built this system bigger than we currently need with an eye to expanding it in the future," Pinnix said. "When we bring the system on line, we'll only be using two of the four concrete chambers to make and store ice. When the university expands its cooling needs, we'll be able to expand with two more ice chambers." Each concrete chamber is essentially a large, watertight tank, approximately 23 feet wide by 51 feet long and filled with water to a 15-foot depth. Each chamber contains four ice coils made from thousands of feet of coiled steel piping. At night, giant compressors chill an ethylene glycol mixture to about 24 degrees and circulate the cold fluid through the pipes. Gradually, huge tubes of ice form around the coils until, the next morning, the tank is full of ice tubes, allowing just enough room for the remaining unfrozen water to circulate around and through them. "The ice water is pumped to a heat ex-changer that in turn cools the water that circulates through campus," Morin said. "It doesn't provide all the cooling necessary, but it greatly reduces the amount of work the regular chiller compressors must do, and so saves substantial amounts of the expensive daytime electricity." The new Hopkins chiller plant is just one of a half dozen or so similar plants now coming on line in the Baltimore area. BGE estimates that in the past 10 years, about 40 such systems have been put in operation, including sites at the Baltimore Museum of Art, Union Memorial Hospital and the Applied Physics Laboratory. "There is nothing unique or unusual in the technology needed to make ice," Morin said. "What's new and somewhat novel is the production and collection of ice at off-peak hours for use during the hottest part of the day." The Homewood campus north chiller ice storage facility may be new, but its basic premise is hardly novel. Ice in summer heat is a wonderful way to keep cool, as any of the fashionable men and women sipping their chilled drinks on the Homewood veranda 200 years ago would have readily agreed.
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