Performance Analysis of Foam Ice Production System with Direct Contact Refrigerant Spraying in PCM Material Based on Dynamic Two-stage Refrigeration Cycle Driven by DPES

Abstract

A 2kW dynamic two-stage refrigerant direct injection refrigeration system directly driven by distributed PV energy was investigated by combining experiment and simulation. The simulation results were in good agreement with the experimental data with -1.03% relative error of instantaneous generation power and 5.16% relative error of COP. And then, the refrigeration performance of R22, R134a and R318 were tested and the average COPs were 6.16, 5.80 and 8.70, respectively. More importantly, relatively environmentally friendly refrigerants R407C and R410a had better refrigeration performance and the COPs were 6.13 and 8.52. Finally, the dynamic performance parameters of refrigerant injection and the influence of component parameters on refrigeration COP were analyzed. The wall thickness of the plate heat exchanger had a negative effect on the heat transfer coefficient of the exchanger and the COP of the second refrigeration system. The average increase rates were - 0.234 kW/(m²°C) and -0.017. The exchange area of exchanger had a positive effect on the COP and refrigerant mass flow of the second refrigeration system. The average increase rates were 12.92 m^-2 and 0.0209 kg/(s·m²). Moreover, the effect of refrigerant injection speed on refrigeration performance, COP and outlet refrigerant temperature, was greater than that of injection pressure. Changing capillary inner diameter had a greater effect on the refrigeration performance than changing the length of capillary. Therefore, it was faster to optimize the refrigerant the refrigerant direct injection refrigerant performance by adjusting the capillary inner diameter.