Thermal Performance of a Heat Pipe with Different Working Fluids

Abstract

The use of Heat pipes, for a variety of applications, has increased worldwide due to them achieving high thermal efficiencies. Heat pipes in evacuated tube solar collector systems, in modern domestic water heating, comprise of a sealed envelope of a copper pipe, which contain a small quantity of working fluid. The Heat pipe transfers energy by the latent heat of the evaporation of the working fluid in a heating section. This vapor travels to the cold portion of the heat pipe and condenses. The circulation is completed with the condensate flowing back through the container’s inner wall to the heating section by gravity. Tests were conducted using a test apparatus specifically made for the purpose of comparing the relevant attribute of thermal performance of Heat pipes containing different working fluids. A commercially available heat pipe, with its proprietary working fluid, was used as a reference in comparing its thermal performance efficiency (57.1%) with those of identical heat pipes containing distilled water, methanol, acetone and ethanol as working fluids. The results from the experiments achieved thermal efficiencies of 63.1%, 60.5%, 57.6%, and 42.1% respectively.