University of North Carolina at Chapel Hill
Chapel Hill, North Carolina

Completion: 2005
Size: 14,100 GSF
Cost: $13,372,000

The South Chiller Plant expansion consists of a two-story building and an adjacent thermal storage tank for the production, storage and distribution of chilled water for UNC buildings. The steeply sloped site, determined by Ayers/Saint/Gross’ campus master plan, is inadequate for academic and student life use but suitable for an energy plant. The ground elevation, where the tank is placed, was selected to optimize fluid dynamics so that the water is able to reach the upper levels of taller buildings on campus.

The building was designed so the exterior of the first level, which consists of offices, operations and control room, and support areas for engineering facilities staff, is adjacent to the street. The facade is architecturally consistent with surrounding buildings. The basement level has a work room, and machinery is accessed from the rear of the building out of site of street activity. The roof’s screen walls enclose the cooling towers and containment basin.

The thermal storage tank contains 4 million gallons of water that is cooled at night when energy costs are lower. The water is then distributed as needed. The height and width of the tower are engineered so that the hot water and chilled water are separated by a thin layer of warm water, thereby maximizing energy efficiency.