论文部分内容阅读
对重力供液制冷系统形成再循环的条件和再循环时蒸发器的传热性能进行理论分析,建立相应的数学模型。将重力供液制冷系统与直接膨胀供液制冷系统进行比较,得到两种不同制冷系统工作特性上的差异。通过在焓差实验室中测定制冷系统在不同工况下的压力、风量、制冷量以及耗功等技术参数,得到重力供液制冷系统和直接膨胀供液制冷系统在室外干球温度一定的情况下传热系数、制冷量以及系统COP的变化规律。实验表明:再循环的形成可以增大制冷剂流速同时充分润湿传热表面,强化换热效果显著,在测试的工况下蒸发器的传热系数可增大近40%,COP最大提高7.6%,低温工况的增幅更大。
The conditions of recirculation of the gravity supply refrigeration system and the heat transfer performance of the evaporator during recirculation are theoretically analyzed and corresponding mathematical models are established. The difference between the operating characteristics of two different refrigeration systems is obtained by comparing the gravity-fed refrigeration system with the direct-expansion liquid-feed refrigeration system. By measuring the pressure, air volume, cooling capacity and power consumption of the refrigeration system under different working conditions in the enthalpy difference laboratory, the gravity dry liquid supply system and the direct expansion liquid supply refrigeration system are obtained when the dry bulb temperature in the outdoor room is certain The heat transfer coefficient, the cooling capacity and the variation of the system COP. The experimental results show that the formation of recirculation can increase the flow rate of the refrigerant and fully wet the heat transfer surface. The heat transfer enhancement effect is remarkable. Under the test conditions, the heat transfer coefficient of the evaporator can increase by nearly 40% and the maximum COP by 7.6 %, Increase in low temperature conditions more.