An appraisal method of exergy cost minimisation for co-generation systems

This study introduces an exergy cost-minimisation appraisal method for a simple gas turbine co-generation system. Optimisation of a gas turbine co-generation system of the electric output class of 17 MW is examined for a variety of turbine inlet temperatures of 950–1,300°C. An optimum value of the turbine inlet temperature exists for exergy cost minimisation and is estimated to be 1,200°C since the manufacturing price of the gas turbine increases greatly above 1,300°C. This fact shows that the rising manufacturing cost of the gas turbine constitutes an important effect for future development of higher temperature systems.

Keywords: gas turbine cogeneration systems, exergetic cost minimisation, exergy, thermal efficiencies, optimisation, turbine inlet temperatures, high temperature systems, cost appraisal