Effect of CuO Nanoparticle Concentration on R134a/Lubricant Pool Boiling Heat Transfer With Extensive Analysis

Published

September 20, 2007

Author(s)

Mark A. Kedzierski

Abstract

This paper quantifies the influence of CuO nanoparticle concentration on the boiling performance of R134a/polyolester mixtures on a roughened, horizontal flat surface. Nanofluids are liquids that contain dispersed nano-size particles. Two lubricant based nanofluids (nanolubricants) were made with a synthetic ester and 30 nm diameter CuO particles stably suspended in the two mixtures to a 4 % and a 2 % volume fraction, respectively. As reported in a previous study for the 4 % volume fraction nanolubricant, a 0.5 % nanolubricant mass fraction with R134a resulted in a heat transfer enhancement relative to the heat transfer of pure R134a/polyolester (99.5/0.5) of between 50 % and 275 %. The same previous study had shown that increasing the mass fraction of the 4 % volume fraction nanolubricant resulted in the smaller, but significant, boiling heat transfer enhancements. The present study shows that use of a nanolubricant with half the concentration of CuO nanoparticles (2 % by volume) resulted in either no improvement or boiling heat transfer degradations with respect to the R134a/polyolester mixtures without nanoparticles. Consequently, significant refrigerant/lubricant boiling heat transfer enhancements are possible with nanoparticles; however, the nanoparticle concentration is an important determining factor. Further research with nanolubricants and refrigerants are required to establish a fundamental understanding of the mechanisms that control nanofluid heat transfer.

Citation

NIST Interagency/Internal Report (NISTIR) - 7450

Report Number

7450

NIST Pub Series

NIST Interagency/Internal Report (NISTIR)

Pub Type

NIST Pubs

Download Paper

https://doi.org/10.6028/NIST.IR.7450

Keywords

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

Citation

Kedzierski, M. (2007), Effect of CuO Nanoparticle Concentration on R134a/Lubricant Pool Boiling Heat Transfer With Extensive Analysis, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.IR.7450 (Accessed October 11, 2025)