Comparative study on heat transfer characteristics of nanofluidic thermosyphon and grooved heat pipe

The present study used TiO 2 -nanofluid with different volume ratios as the working fluids of a therrmosyphon and grooved heat pipe and investigated various parameters such as volume concentration of nanoparticles, orientation, heat flux, and cooling media. Further, the present study used nanofluids and dispersed TiO 2 -nanoparticles into pure water with each cross-blended concentration of 0.05%, 0.1%, 0.5%, and 1%. The authors observed the best heat transfer performance in the 0.05% concentration with thermosyphon. The present study presents the enhancement of heat transfer performance with TiO 2 -nanofluids, and fabricated a heat pipe from a straight stainless steel tube with an outer diameter and length of 10 and 500 mm, respectively. At the optimum condition for the pure refrigerant, the thermosyphon with 0.05% TiO 2 -nanoparticle concentration gave 1.40 times higher efficiency than that of pure water.