Experimental Study on Heat Transfer Characteristics of Thermosyphon with Methanol-Based Binary Working Fluid

Abstract

Compared with the single working fluid, the binary mixture working fluid can further extend the operating temperature range and enhance the heat transfer performance of a thermosyphon. In this paper, an experimental test system was designed and implemented to study the heat transfer characteristics of the thermosyphon. Methanol employed as the base fluid, 10 kinds of binary mixtures were prepared by adding different volume fractions of deionized water and ethanol separately. The effects of filling ratio, heat flux, and working fluid type on the heat transfer characteristics of the thermosyphon were analyzed and discussed. Moreover, the start-up characteristics were also explored. The experimental result shows that the filling ratio has a significant impact on the performance of the thermosyphon, and the optimal filling ratio is about 30% in this study. The start-up times of the thermosyphon with different binary mixture working fluids remain consistently, which are in the range of 200–300 s. It is worth mentioning that the start-up time of methanol-based binary mixture working fluid with 5% DW is 200 s, which is nearly 33% earlier than that with 50% ethanol. The thermosyphon with methanol-based binary mixture working fluid containing 5% DW presents a reduction of 7.3 °C in the maximum temperature difference and a remarkable 57.0% decrease in thermal resistance when contrasted with the thermosyphon using methanol working fluid. The results of this paper have important significance for the practical application of methanol-based binary mixture working fluid.