Influence of nanoparticle shape factor on convective heat transfer and energetic performance of water-based SiO2 and ZnO nanofluids

► We study convective heat transfer of four different water-based nanofluids. ► ZnO and SiO2 nanoparticles each with two shape factors were used. ► Thermal conductivities and viscosities have been measured. ► Classical correlations are valid if measured thermal properties are used. ► An energy performance evaluation criterion does not show significant improvement.