Diesel combustion of oil and refrigerant mixture during pump-down of air conditioners.

In this study, we aimed to reproduce the diesel combustion that may occur during the pump-down of air conditioners and measured the pressure inside the compressor when this combustion occurred. As refrigerants, we examined R1234yf, R32, R410A, R134a, R22, and R125, and investigated different combinations of refrigerants and lubricating oil by changing the refrigerant concentration. We determined that the combustion accidents that may occur during pump-down are caused by the diesel combustion of the air, refrigerant, and oil mixture even though the refrigerant is categorized as being non-flammable.

本研究旨在复现空调泵抽排空过程中可能发生的类柴油燃烧现象，并同步测定该燃烧发生时压缩机内部的压力。本次实验选取R1234yf、R32、R410A、R134a、R22及R125作为受试制冷剂，通过调节制冷剂浓度，探究了制冷剂与润滑油的多种组合工况。研究结果表明，尽管上述制冷剂均被归类为不可燃制冷剂，空调泵抽排空过程中可能出现的燃烧事故，实则由空气、制冷剂与润滑油混合物的类柴油燃烧所致。