Oil Retention of Lower GWP Refrigerants and Lubricant Mixtures and Its Effect on Heat Transfer and Pressure Drop in Microchannel Type Air Conditioning Evaporators

This talk focuses on the lubricant retention characteristics of lower global warming potential (LGWP) refrigerants R32, R1234yf, and R454B. The speaker highlights similarities and differences of the oil retention characteristics between refrigerant R410A and the LGWP refrigerants in two types of microchannel evaporators used in air conditioning systems for residential applications. The oil in circulation with the refrigerants penalized the evaporators’ heat transfer capacity and increased the refrigerant-side pressure drop. For the LGWP refrigerants, the penalization of the heat transfer capacity was lesser than that observed for the refrigerant R410A at similar operating conditions.