Internal Irreversibility Analysis and Optimization of a Refrigeration Plant

The present study develops a theoretical investigation on the optimal design of a refrigeration plant with considerations on both the external and internal irreversibilities. With the total heat transfer area constraint or the total thermal conductance constraint, the analytical solutions of optimal area-ratio and the corresponding maximum COP are obtained under a fixed cooling rate. The results show that the internal irreversibility can penalize the plant's COP, and the internal irreversibility has more significant effects on a freezing system than on an air-conditioning system. When there is no internal irreversibility, a special case of the analytical solution is exactly the same as that obtained from the previous study.