Toward TiO2 Nanofluids—Part 2: Applications and Challenges

Abstract The research about nanofluids has been explosively increasing due to their fascinating properties in heat or mass transportation, fluidity, and dispersion stability for energy system applications (e.g., solar collectors, refrigeration, heat pipes, and energy storage). This second part of the review summarizes recent research on application of TiO2 nanofluids and identifies the challenges and opportunities for the further exploration of TiO2 nanofluids. It is expected that the two exhaustive reviews could be a helpful reference guide for researchers to update the knowledge on research status of TiO2 nanofluids, and the critical comments, challenges, and recommendations could be useful for future study directions.