University cuts electricity costs The University of Central Florida (UCF), the nation's second-largest university based on enrollment, spends more than $1 million a month on electricity. In an effort to reduce these costs, UCF built its own cogeneration power plant to supply one-third of this electricity.

The plant relies on a four-stroke spark-ignition engine fueled by natural gas that has 18 cylinders and provides an electrical output of 5.5 megawatts (MW) at 60 Hz. The engine achieves a maximum power generation efficiency of 47.3 percent, with a total efficiency of 87.5 percent, and starts up within five minutes or less. NOx emissions produced by the engine are 320 parts per million.

UCF projects the plant will generate about $2.5 million in savings per year, substantially cutting electricity costs and reducing its environmental impact by 30 percent. The plant is also designed to capture rejected heat from the engine and use it to fuel an absorption chiller, producing 1,000 tons of chilled water to supplement the campus' underground cooling system.

Using steam for heating and cooling
The University of Connecticut (UConn) built a cogeneration facility at its Storrs campus that uses natural gas with oil as a back-up fuel source to fire three gas turbine generators to produce electricity. Waste heat from the turbines is used to produce steam, which is then used in a steam turbine generator to produce additional electricity. Low-pressure steam is distributed for campus use. The facility provides electricity of approximately 24 megawatts (MW), a steam capacity of 200,000 lbs. per hour and a chilled water capacity of 6,300 tons. The cogeneration plant meets nearly all of UConn's projected electricity needs.

The cogeneration plant at the State University of New York-Stony Brook (SUNY) provides energy to the school and its 900-bed capacity hospital. The system generates up to 280,000 pounds of steam per hour to the university for its heating and cooling needs, as well as 40 MW of electricity; satisfying all of the university's power needs. Excess capacity is sold to the Long Island Power Authority (LIPA). The plants main source of electrical power is derived from a dual-fuel turbine engine that runs on both natural gas and No. 2 oil. The efficiency of the plant is in the range of 80 percent. Clark University's cogeneration system uses a 1807 kW electric generator, driven by a 2500 HP natural gas-fired diesel engine.

New York University's (NYU) cogeneration plant is one of the largest private cogeneration plants in New York City, and provides electricity to 22 NYU buildings, up from seven buildings with the old plant. The plant approaches 90 percent energy efficiency while producing 13.4 MW of electricity - twice the output of the previous oil-fired system. Greenhouse gas emissions and air pollutants are reduced by 23 percent and 68 percent, respectively, compared to the previous system.

The plant also produces space heat, along with hot and chilled water, to 37 buildings on the Washington Square Campus, and is expected to save the university $5 to $8 million in energy-related costs per year. Because the plant relies on two 5.5-MW gas turbines and a 2.4-MW steam turbine, it avoids the consumption of 500,000 gallons of fuel oil annually. Steam is used to power the gas turbines, as well as a turbine-driven chiller that produces cold water. Hot water is also produced by extracting the steam's heat using two high-temperature exchangers.

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