Experimental study of a large-area ultra-thin flat heat pipe for solar collectors under different cooling conditions

作者：Zhong, Guisheng; Tang, Yong; Ding, Xinrui^*; Rao, Longshi; Chen, Gong; Tang, Kairui; Yuan, Wei; Li, Zongtao

来源：RENEWABLE ENERGY, 2020, 149: 1032-1039.

DOI：10.1016/j.renene.2019.10.093

• Large-area ultra-thin flat heat pipe
• Filling ratio
• Cooling conditions
• Thermal resistance
• Heat transfer

Due to the demands of thermal performance enhancement of heat pipe solar collector, the fabrication of large-area flat heat pipes with the advantages of low cost and outstanding thermal performance has become more urgent. In this paper, a large-area ultra-thin flat heat pipe (LUFHP) with multiple parallel microchannels was fabricated by the aluminum extrusion process. Its total thickness is only 1.5 mm while the effective width is 170 mm. The effect of different filling ratios on the thermal performance was investigated under natural air convection and forced water cooling, respectively, including heat transport capability and thermal resistance. The experimental results indicate that the maximum heat transport capabilities for natural air convection and forced water cooling are 40 W with an optimal filling ratio of 25% and 25 W with an optimal filling ratio of 30%, respectively. The minimum total thermal resistances of the LUFHP are about 0.22 degrees C/W (natural air convection) and 0.73 degrees C/W (forced water cooling), which decrease by 74% and 57% compared with these of aluminum plate, respectively. That is, the proposed LUFHP shows better thermal performance under NAC for the replacement of aluminum plate in a wider range of heat load.