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Effect of CuO Nanolubricant on R134a Pool Boiling Heat Transfer



Mark A. Kedzierski, M Gong


This paper quantifies the influence of CuO nanoparticles on the boiling performance of R134a/polyolester mixtures on a roughened, horizontal, flat surface. Nanofluids are liquids that contain dispersed nano-size particles. A lubricant based nanofluid (nanolubricant) was made with a synthetic ester and 30 nm diameter CuO particles stably suspended in the mixture to a 4 % volume fraction. For the 0.5 % nanolubricant mass fraction, the nanoparticles caused a heat transfer enhancement relative to the heat transfer of pure R134a/polyolester (99.5/0.5) of between 50 % and 275 %. A smaller enhancement was observed for the R134a/nanolubricant (99/1) mixture, which had a heat flux that was on average 19 % larger than that of the R134a/polyolester (99/1) mixture. Further increase in the nanolubricant mass fraction to 2 % resulted in a still smaller boiling heat transfer improvement of approximately 12 % on average. Consequently, significant refrigerant/lubricant boiling heat transfer enhancements are possible with nanoparticles. Thermal conductivity measurements and a refrigerant\lubricant mixture pool-boiling model were used to suggest that increased thermal conductivity is responsible for only a small portion of the heat transfer enhancement due to nanoparticles. Further research with nanolubricants and refrigerants are required to establish a fundamental understanding of the mechanisms that control nanofluid heat transfer.
International Journal of Refrigeration-Revue Internationale Du Froid


additives, boiling, copper (II) oxide, enhanced heat transfer, nanotechnology, refrigerants, refrigerant/lubricant mixtures


Kedzierski, M. and Gong, M. (2009), Effect of CuO Nanolubricant on R134a Pool Boiling Heat Transfer, International Journal of Refrigeration-Revue Internationale Du Froid, [online], (Accessed April 23, 2024)
Created January 6, 2009, Updated February 19, 2017