重力供液与直接膨胀制冷系统运行特性的实验研究

对给定的工况，进行重力供液与直接膨胀制冷系统的对比实验，了解重力供液与直接膨胀制冷系统工作特性的差异；在焓差室中，可以准确地测定系统的制冷量、风量和耗功等技术数据。实验表明，以增大制冷剂流速来强化换热，可以提高蒸发器的传热系数；并且在低温工况下，重力供液的蒸发器比直接膨胀供液的蒸发器有更佳的传热特性与传热效率，并不增加附加能耗。同时，建立了满足重力供液系统形成液体再循环的阻力平衡关系，分析循环倍率在不同工况下的变化规律。

Comparison Experiment of Refrigeration Systems with Supply Liquid Refrigerant by Gravity and Direct Expansion

The comparison experiments under the given operating conditions were conducted to determine the performance difference of refrigeration systems with supply liquid refrigerant for the evaporator by gravity and direct expansion. Some system technical data were measured in the Psychometric Rooms, including refrigerating capacity, airflow volume and energy consumption. The results indicate that increasing the refrigerant flow rate can enhance the coefficient of heat transfer of the evaporator. The gravityflooded evaporator has much better heat transfer characteristics and efficiency without additional energy consumption under the low temperature condition. In addition, the resistance equilibrium to meet the liquid refrigerant recirculation was established, and the variation of the circulating rate under different conditions was analyzed.