Optimal criteria for different parameters of an irreversible regenerative intercooled Brayton cycle under maximum power and maximum ecological COP conditions

Abstract

SYNOPSIS An irreversible regenerative intercooled Brayton cycle under maximum power output and maximum ecological coefficient of performance (ECOP, defined as the power output divided by the loss rate of availability) conditions is presented in this paper. The power output, thermal efficiency and ecological COP are optimised with respect to the cycle temperatures, intercooling and cycle pressure ratios for a given set of operating conditions. The maximum power output, maximum efficiency, and maximum ECOP, and their corresponding temperatures at different state points, as well as the cycle pressure ratio, are calculated for given values of the intercooling pressure ratio and other cycle parameters. It is found that there exist optimal values of turbine outlet temperature, intercooling and cycle pressure ratios at which these performance parameters (i.e. the power output, thermal efficiency and ECOP) attain their maximum values and the optimal values of these parameters are different for different performance parameters for the same set of operating conditions. It is also found that there exist optimal values of thermal efficiency and ECOP at which the optimised power output attains its maximum value but the power output corresponding to the maximum ECOP and maximum thermal efficiency is lower than the maximum that can be attained. The present cycle model is general and the results obtained by earlier workers are special cases of this cycle model.