Thermodynamic efficiency evaluation of a low pressure turbo expander cryogenic cycle based on exergy analysis

Abstract

Thermodynamic analysis, using the exergy or entropy methods, is usually carried out for better insight into the physical meaning of the losses encountered in a cryogenic plant. From the results of such analysis, it is possible to evaluate the individual efficiencies of the various processes and to identify those calling for an improvement. It is also possible to determine thermodynamic efficiency of the cycle as a whole. The technique involves determination of entropy changes or exergetic losses in each of the processes making up the cycle. Based on the exergy analysis, it has been possible to evaluate specific work requirement, overall thermodynamic efficiency, Specific cooling capacity, work requirement per kg of liquid nitrogen product and coefficient of performance of the turbo expander cryogenic cycle using hydrogen and helium as the refrigerant.