Experimental study and optimization of a dual model cycle for cascade refrigerator

A new cascade refrigeration cycle has been proposed, which can operate in two models with an internal heat exchanger employed in the low-temperature cycle to recycle the cooling. The corresponding refrigerator apparatus was been designed and built. The feasibility and performance of the cascade refrigeration cycle were investigated through experiments. Detailed suggestions were put forward to improve the system performance on the basis of experimental data, such as increasing the efficiency of regenerator, optimizing compression ratio, enhancing the heat-exchange of condenser, optimizing the cooling output by the evaporator, and adding a bypass between the condenser-evaporator's inlet and outlet. The COP of the improved cycle is enhanced, which showed the dual model cycle for cryogenic refrigerator is feasible and has a promising foreground.