空气源热泵除霜性能测试系统设计

Defrosting performance test system design of air source heat pump

为实现空气源热泵产品除霜性能测试工况的低温高湿环境,设计一种长期低温运行设备及其温度耦合控制系统,通过2套制冷系统的除霜模式与制冷模式的交替循环,解决因蒸发器结霜而导致制冷量下降问题。基于实际测试系统和研究,提出切入除霜、除霜结束的判定依据:电加热输出为零且环境测试间内干球温度高于设定值0.1℃作为切入除霜判定依据;在除霜过程中,蒸发器制冷剂出口温度高于环境测试间干球温度10℃,且蒸发器空气侧阻力小于150Pa作为除霜结束判定依据。该方案能够解决环境测试间内因空气处理机组蒸发器除霜需求而造成的干球温度和相对湿度的剧烈波动问题,保证环境测试间内低温高湿环境工况的长期稳定,提高除霜工况的测试准确性。

In order to realize the low temperature and high humidity environment for the defrosting performance test condition of air source heat pump products,a long-term low temperature operation equipment and its temperature coupling control system are designed.Through the alternating cycle of defrosting and refrigeration modes of two sets of refrigeration systems,the decline of cooling capacity caused by frosting of the evaporator is resolved.Based on the actual test system and research,the judgment basis of cut in defrosting and the end of defrosting is put forward:the judgment basis of cut in defrosting is that the electric heating output is zero and the dry bulb temperature in the enviromental testing room is higher than the set value by 0.1℃;in the defrosting process,the evaporator outlet temperature of refrigerant is 10℃higher than the dry bulb temperature in the enviromental testing room,and the air side resistance of the evaporator is less than 150 Pa as the basis for judging the end of defrosting.This scheme can solve the issue of severe fluctuation of dry bulb temperature and relative humidity caused by the defrosting demand of AHU evaporator in the enviromental testing room,ensure the long-term stable operation of low temperature and high humidity environmental conditions in the enviromental testing room,and improve the test accuracy of defrosting conditions.