空调换热器长期运行性能衰减的加速实验研究
Accelerated Experimental Investigation on Long-term Performance Degradation of Heat Exchangers in Air Conditioners

为研究长期积尘对空调室外机性能衰减的影响，需要对空调室外换热器进行加速实验。本文提出了换热器加速测试方法，采用在高粉尘浓度环境下短时间积尘来模拟实际空调在低粉尘浓度下长期运行时的积尘效果，从而加快换热器的积尘进程以达到加速测试的目的。基于上述方法搭建了换热器加速测试实验台，对具有不同翅片结构与管排数的3种换热器样件进行2~10 h的加速积尘测试，预测其在室外运行1~5年后的性能衰减效果。测试结果表明：空调换热器使用5年后，1排管波纹翅片换热器、2排管波纹翅片换热器和2排管平直翅片换热器的压降增幅分别为21.8%、29.5%和25.0%，换热量衰减率分别为11.2%、19.3%和18.0%。
To investigate the effect of deposited dust particles on the long-term performance degradation of outdoor air-conditioner units, acceleration experiments on dust deposition were carried out in the present study. An acceleration-experiment method for short-term dust deposition with high dust concentration was proposed to simulate the actual long-term dust deposition with low dust concentration, and an experimental rig was established to perform the accelerating-dust test. Acceleration experiments for 2–10 h were carried out on three types of heat-exchanger samples with different fin structures and tube row numbers, and the test results were used to predict the long-term performance degradation of outdoor heat exchangers operated for one to five years. The results show that after five years of operation, the air-side pressure drops of a one-tube wavy fin-and-tube heat exchanger, a two-tube wavy fin-and-tube heat exchanger, and a two-tube plate fin-and-tube heat exchanger were increased by 21.8%, 29.5%, and 25.0%, respectively. Meanwhile, the air-side heat-transfer capacity was reduced by 11.2%, 19.3%, and 18.0%, respectively