How does combined heat and power (CHP) cogeneration work?
There are two types of CHP installations, topping and bottoming operations. In topping operations, a fuel source such as natural gas, diesel, gasified coal or crude oil is used to power a prime mover such as a gas turbine or reciprocating engine. Attached to this prime mover is an electrical generator that produces electricity. Waste heat from the prime mover is captured and used to produce steam for use in a nearby industrial or commercial operation. The steam produced in the second phase of CHP topping operations can be used for processing, or local heating or cooling needs. For cooling loads, an absorption chiller is used. In bottoming operations, excess heat from an existing industrial operation is recovered and used to generate electricity. The resulting electricity can either be used within the industrial facility or sold to the local utility. When excess electricity is sold in this way, it is absorbed by the distribution grid. Bottoming cycle operations could use the heat from a
