Effect of several irreversibilities on the thermo-economic performance of a realistic Brayton heat engine cycle

The thermo-economic study of a more realistic regenerative Brayton cycle heat engine with finite heat capacity of external reservoirs is presented in this paper. The external irreversibility is due to finite temperature differences between the external reservoirs and the heat engine while the internal irreversibilities are due to the non-isentropic processes in the compressor and turbine and the regenerative heat loss. The thermo-economic function is defined as the power output divided by the total cost plus the running and maintenance costs of the system. The objective function is optimized with respect to the cycle temperatures and the optimum performance parameters are calculated for a typical set of operating conditions. It is found that the effect of the turbine efficiency is more than that of the compressor efficiency on all the performance parameters. It is also found that the effects of the sink-side heat capacitance rate are more than those of the heat capacitance rates on the source-side and working fluid on all the performance parameters of the cycle for the same set of operating condition.