Application of ZnO/TiO2 Nanocomposite for the Improvement of Heat Transfer Coefficient in Tube Heat Exchangers

The potential of nanofluids for the improvement of heat transfer coefficient in various heat exchange equipment has been considered and studied as a major application during recent decades. In this research, heat transfer coefficient of ZnO, TiO2 and ZnO/TiO2 nanofluids in a shell and tube heat exchanger has been studied experimentally. ZnO nanoparticle was synthesized through precipitation technique. Sol-gel and mechanical techniques were employed to synthesize the ZnO/TiO2 nano-composite. Particle size analysis (PSA), XRD, FTIR and FE-SEM techniques were used to characterize ZnO/TiO2 nano-composite. Based on the results, the nanofluid heat transfer coefficient was enhanced by increasing the nanofluid concentration and temperature. The heat transfer coefficient of TiO2 was higher than that of ZnO nanofluid and the heat transfer coefficients of nano-composites were higher than that of ZnO and TiO2 nanofluids and the base fluid. Also, the heat transfer coefficient and the overall heat transfer coefficient were increased 3.79 to 9.09 times and 4.27 to 9.14, respectively by increasing the nano-composite content.