First law and Second law analysis of Al2O3/TiO2 nano composite lubricant in domestic refrigerator at different evaporator temperature

Abstract

This paper presents the preparation and analysis of Al2O3, TiO2 nano lubricant and Al2O3–TiO2 nano composite lubricant for domestic refrigerator using R134a refrigerant as working fluid. The nano particles and nano composite particles were added to the Polyol ester (POE) oil lubricant with volume concentration of 0.02 g/200 ml in the ratio of 0.1 gL−1. The experiments are conducted for six different samples. The sample S1 contains only POE oil which is presently used in all domestic refrigerators and considered as a base line sample for comparison. There are two nano lubricant samples S2 and S3 with Al2O3/POE oil and TiO2/POE oil respectively. There are three nano composite lubricants samples S4, S5 and S6 mixed with different composition of Al2O3 and TiO2 in the ratio of 75% Al2O3/25% TiO2/POE oil, 50% Al2O3/50% TiO2/POE oil and 25% Al2O3/75% TiO2/POE oil respectively. The test conducted at different evaporator temperature such as −10 °C, −12 °C, −14 °C, −16 °C and −18 °C in evaporator with reference to 27 °C environment state. Based on the analysis, R134a with nano lubricant and nano composite lubricants were found to improve the performance of the system compared to R134a with POE oil lubricant. The results revealed that best performance is given for R134a with 50% Al2O3/50% TiO2 nano composite particle mixture in POE oil.