Experimental analysis of heat transfer of heat-pipes using water-ethanol solutions as the working fluid

In this paper heat pipes have been constructed and tested using solutions of ethanol and water at different concentrations as the working fluid. Tests were carried out to investigate the effects of ethanol concentration as well as the pipe evacuation and the use of a wick inside the pipe to ensure a continuous performance of the system. The tests indicate that ethanol in the solution enhances the heat pipe performance at low heat fluxes, and that concentrations of 75% and 50% show the best performance characteristics in transferring heat. It was concluded that using a wick do not add much effect to the enhancement of a heat pipe performance. It was also determined that heat pipes at higher operating temperatures have higher heat transfer coefficients. A comparison of the experimental results with those obtained from a previously developed model reveals a good agreement between the experiments and the model predictioNS