Solar Process Heat Technology in Action: The Process Hot Water System at the California Correctional Institution at Tehachapi

Solar process heat technology relates to solar thermal energy systems for industry, commerce, and government. Applications include water preheating and heating, steam generation, process hot air, ventilation air heating, and refrigeration. Solar process heat systems are available for commercial use. At the present time, however, they are economically viable only in niche markets. This paperdescribes a functioning system in one such market. The California Department of Corrections (CDOC), which operates correctional facilities for the state of California, uses a solar system for providing hot water and space heating at the California Correctional lnstitute at Tehachapi (CCI/Tehachapi). CCI/Tehachapi is a 5100-inmate facility. The CDOC does not own the solar system. Rather, it buysenergy from private investors who own the solar system located on CCI/Tehachapi property; this arrangement is part of a long-term energy purchase agreement. United Solar Technologies (UST) of Olympia, Washington is the system operator. The solar system, which began operating in the fall of 1990, utilizes 2677 m2 (28,800 ft2) of parabolic trough solar concentrators. Thermal energy collected bythe system is used to generate hot water for showers, kitchen operations, and laundry functions. Thermal energy collected by the system is also used for space heating. At peak operating conditions, the system is designed to meet approximately 80 percent of the summer thermal load.