Second-Law Efficiency Analysis of Gas-Turbine Engine for Cogeneration

To make the best use of our available energy resources, exergy analysis was conducted to determine the second-law efficiency for a modified GM 501K gas-turbine engine operating on a Cheng cycle. Based on the measured data for power generation, high temperature gas was bled from the exit of the gas-generator turbine to a heat exchanger for heating additional water as cogenerated processing steam. Considering the energy content and the exergy of the processed steam together with the power generation as the desired products, the Cheng cycle can be operated in a wide range of power and processing steam cogeneration. The first-law efficiency was found to be between 30% to 39% and the second-law efficiency between 49% and 63% when the power delivery varies between 26% and 100%