Experimental thermal performance assessment of aluminum and copper heat pipes for refrigerated container applications

Research in the literature about using aluminum and copper heat pipes (HP) with different working fluids in refrigerated containers is limited. Therefore, an experimental investigation of a new potential of using two types of heat pipes for refrigerated container applications is conducted. The developed copper and aluminum HPs are experimentally investigated under various operating conditions with three working fluids. The copper heat pipe is investigated with ethanol, methanol, and acetone as the working fluids. The thermal performance aluminum HP is only investigated with acetone as a working fluid given the compatibility between the working fluid and the wall material. The developed HPs are investigated under a wide range of operating conditions in terms of input powers (5, 15, 30, 45, and 60 W), tilt angles (30°, 45°, 60°, and 90°), and filling ratios (15 % and 30 %). The condenser section of the HP is immersed in the bath containing dry-ice. Results show that the best thermal performance in terms of thermal resistance of 2.2 K/W is obtained, with copper HP with acetone as a working fluid at a filling ratio of 30 %, input power of 60 W, and vertical orientation. In addition, aluminum HP shows a competitive thermal performance with a minimum thermal performance of 2.6 K/W.