Process chemicals, including cleaners, degreasers, coolants,sealants, metalworking fluids, brazing fluxes, rust inhibitors,and bearing slushing compounds, may be added directlyto air-conditioning or refrigeration systems or may be left asresidue after an attempt has been made to remove them froma system component.Someof these chemicals have been shownto cause degradation of refrigerants and/or compressor lubricants,and their compatibility with the refrigerant/lubricantsystems needs to be determined to ensure the long-term reliabilityof air-conditioning and refrigeration equipment. As theheating, ventilation, air-conditioning, and refrigeration(HVAC&R) industry transitions to lower global warmingpotential(GWP)refrigerants,manyresearchanddevelopmentprograms have been focused on hydrofluorolefins (HFOs),which have been evaluated as alternative refrigerants tohydrochlorofluorocarbons (HCFC) and hydrofluorocarbons(HFC). Previous research on the compatibility of processchemicals withHFCrefrigerants and polyolester (POE) lubricantsprovides a sound knowledge base for the evaluation ofHFO/POE systems. This research project was conducted todetermine the chemical reactivity of process chemicals inHFO/POE systems and their impact on the performance andreliability of HVAC&R systems, with the following objectives:1. Determine the effects of the selected process chemicalson the chemical stability of HFO/POE.2. Compare the chemical reactivity of process chemicals inHFO/POE to that of the same chemicals in R-134a/POE.increased total organic acid (TOA), presence of metals in solution,presence of reaction products (such as fluoride ions in the[HFO blend]/POE system). This study showed that the extentof reaction depends on the chemical and its concentration,while previous studies with R-134a/POE showed that it alsodepends on the aging temperature and the aging time.However, the decision of whether a chemical is compatible foruse in a refrigeration system is highly subjective and dependson the user, the application, and the equipment.
Citation: 2019 Winter Conference, Atlanta, Ga, Technical Papers