Experimental Study of Closed-Loop Thermosyphon System Using Different Working Fluids

Abstract

Thermosyphon is a heat transferring device which transfers heat over long distance and where the liquid is returned to the evaporator by gravitational force. The closed-loop thermosyphon (CLT) transfers heat with phase change phenomenon. A large amount of heat is transferred from evaporator section to condenser section with a relatively small temperature difference. The thermal performance of closed-loop thermosyphon (CLT) is influenced by the governing parameters like filling ratio, heat input, adiabatic length, working fluids, etc. This paper investigates the effects of these parameters on thermal performance of closed-loop thermosyphon system for different working fluids. In this work the filling ratio (FR) is varied in the range of 30–80% in the step of 10% at various heat inputs of 0.5–2 kW with a step of 0.5 kW for each evaporator and adiabatic length (vapor line length) is taken as 200 mm. The working fluid used as methanol, ethanol, acetone, and distilled water. The performance plots of the performance parameters like thermal resistance, evaporative heat transfer coefficient (HTC), and condenser heat transfer coefficient for these different working fluids, heat inputs, and filling ratios are plotted and results are analyzed. From the result, it is found that acetone has comparatively lowest thermal resistance. Water has comparatively highest evaporative heat transfer coefficient as well as condenser heat transfer coefficient.