The optimal operating temperature of the collector of an irreversible solar-driven refrigerator

A universal irreversible solar-driven refrigerator model is presented, in w hich not only the irreversibility of heat conduction but also the irreversi bilities resulting from the friction, eddies and other irreversible effects inside the working fluid are considered. On the basis of this model and th e linear heat-loss model of a solar collector, one of the important paramet ers, called the optimal operating temperature of the collector of a solar-d riven refrigerator, is derived by using the finite-time thermodynamic theor y. From the result, the maximum overall coefficient of performance of the r efrigerator is determined and some significant problems are discussed. The results obtained here are quite realistic and universal, insofar as all the corresponding results derived by using the reversible and endoreversible m odels and the model considering only the internal irreversibility cycle can be deduced from them. Thus, they may provide some new theoretical bases fo r further exploitation of solar-driven refrigerators. Furthermore, some sho rtcoming in the related literature are pointed out.