This study looks at the effects of pH on heat transfer, among other things, of nanofluids. Over 20% enhancement of thermal conductivity was noted with nanofluids containing 3wt% zirconium dioxide and titanium dioxide. Also noted, was the influence of pH on the stability of the nanofluids. The Derjaguin-Landau-Verwey-Overbeek theory states that nanoparticles become unstable, form clusters and precipitate, when their pH is near the isoelectric point. This leads to large clusters ...