2.2.1 Open-cycle gas turbine cogeneration systems
Most of the currently available gas turbine systems, in any sector of applications, operate on
the open Brayton (also called Joule cycle when irreversibilities are ignored) cycle where a
compressor takes in air from the atmosphere and derives it at increased pressure to the
combustor. The air temperature is also increased due to compression. Older and smaller units
operate at a pressure ratio in the range of 15:1, while the newer and larger units operate at
pressure ratios approaching 30:1.