Experimental Investigation on Tribological Characteristics of Biodegradable Refrigeration Oil using Pin on Disc Tribometer

The present study addresses the issue of the tribological behaviour of cylinder liner and piston ring material of a hermetically sealed reciprocating compressor of Vapour Compression Refrigeration system under the influence of pentaerythritol ester based biodegradable refrigeration oil and compare with synthetic refrigeration oil (Polyol ester-ISO 68grade) using the pin on disc tribometer. Synthesis of pentaerythritol ester based biodegradable refrigeration oil for household domestic refrigeration compressors was carried out via successive transesterification of rapeseed oil. The biodegradable refrigeration oil was blended equally with synthetic refrigeration oil to formulate the best biolubricant. Further Energy Dispersive X-ray (EDX) technique was adopted for the chemical characterisation of the pin material surfaces. The wear behaviour of the tested pin materials were evaluated using scanning electron microscope. The results show that under same investigational conditions 50% blend of pentaerythritol ester biodegradable refrigeration oil (PBRO 50) with synthetic refrigeration oil demonstrated superior friction reduction performance and inferior wear reduction performance as compared to synthetic refrigeration oil.