Summary

With the phaseout of CFC12, the use of HFC134a and polyolester oil became the preferred refrigerant/oil combination for the refrigerator appliance industry. The critical problem of this refrigerant/oil combination is the propensity for the capillary tubes to clog with a variety of organic contaminants. Some organic contaminants remain in the refrigerating system during manufacture or assembly and others are generated in the compressor shell through oil and refrigerant chemical deterioration. In spite of the strong technological impact of this problem, very few works on this matter can be found in the literature. The available works are mostly research reports of durability testes where a system operates during a certain time with a known concentration of contaminant and the flow rate of nitrogen gas is measured. The evaluation is based on the flow rate drop ratio per operating hours. [...]

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