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Cornell University

Thermal Storage Tank

Built in 1991, the Thermal Storage Tank provided an additional peak capacity of 4,000 tons and was also a demand side management tool for decreasing the University's expenditure for electricity. The TST, acting like a large thermal flywheel, shifts cooling load on the chillers to off-peak times by charging the water in the tank.  The tank volume is cooled at night with spare chiller capacity and warmed by the campus cooling load during the day.  It allows the use of less-expensive overnight electricity rates, and reduces the need for additional chilling capacity.  This project not only was capable of shifting up to 4 megawatts of demand to off-peak hours; the total system efficiency increased by over 10%. This project won several awards including an ASHRAE society level Technology Award, the New York State Governor's Award for Energy Excellence and was also the feature story in the 1992 second quarter District Heating & Cooling Journal.

The Cornell Thermal Energy Storage Tank
Inside the Thermal Energy Storage Tank