2017 Volume 34 Issue 3 Pages 181-191
Risk assessment of lower GWP refrigerants assuming explosion accidents of compressor during pump-down of air conditioner was experimentally investigated. Penetration of air into refrigerant tube was experimentally simulated by adiabatic compression of refrigerant, air and lubricating oil for the compressor. Lower GWP refrigerants; R 1234yf and R32, and conventional refrigerants; R 410A and R 22 were tested for comparison. PAG oil and POE oil were used. The effect of the oils for the combustion was studied by comparing the results with different oils and amount of oil. It was revealed that the upper flammability limit of refrigerant became higher and the maximum pressure at combustion was higher with lager amount of oil. The flammable range with POE oil was significantly smaller than that with PAG oil. Thus, the accidents during pump-down are greatly affected by burning characteristic of the lubricating oils as well as that of refrigerants.
