General performance of an irreversible three heat source refrigerator

This work deals with the study of an irreversible refrigeration cycle controlled by three heat sources. Following the basic idea to treat the entire system as a combined cycle of an internally irreversible two heat source engine driving an internally irreversible two heat source refrigerator, we select a classical configuration to derive a fundamental optimum formula. Each one of these irreversible engine are characterized by the irreversibility factors Iw and Ir, respectively. Therefore, the predicted optimal plant performance coefficient and the relationship of that with the cooling effect reveal a unified description of various refrigerators of three heat sources previously reported in finite time thermodynamics. The numerical results show clearly the physical influence of these irreversibility factors together with the thermal resistances on the global performance of the refrigeration plant.