Thermodynamic Analysis of a Mixed-Refrigerant Auto-Cascade J-T Cryocooler with Distributed Heat Loads

Abstract

In this paper, an effort is made to go further into the thermodynamic process of the Auto-Cascade refrigeration cycle using multicomponent zeotropic mixtures as working fluids. The exergy method is employed to analyze the thermodynamic characteristics of components and the whole refrigeration cycle. Specially, the condition that there are extra-distributed heat loads along the heat exchangers is considered. Extensive comparison is made between the single stage J-T cycle and a typical Auto-Cascade cycle at the same condition. At the calculation conditions presented in this paper, the total exergy gained in the MARC is 6.6% better than the single stage cycle, and 9.5% better in the situation with distributing heat loads. The results show that using appropriate Auto-Cascade cycle can improve the performance of the refrigerator.