Airport to use cogenerated steam, electricity to run chillers

Miami International Airport will install a 3.5 MW cogeneration system to power three 2500 chillers that will meet cooling needs through the end of the century while reducing electricity costs by about $1 million a year. The $4 million topping-cycle system will include a heat-recovery boiler and a steam turbine that will directly turn one of the centrifugal chillers. A microprocessor-based control system will bring the other two chillers on line as needed. If this phase proves successful, a second system with three more chillers will continue the expansion program. A feasibility study indicated that cogeneration could reduce the airport's $8 million energy costs by 2%. A major factor in the project's payback will be whether the power will be wheeled back from the utility grid or sold outright to the utility on an as available basis.