RT Journal Article ID 259a8f9e7c445209 A1 Huang, Chien A1 Lin, Wei-Keng A1 Wang, Sung-Ren T1 ANALYSIS OF THE IMPACT OF U-SHAPED STRUCTURE FOR HEADS OF LOOP THERMOSYPHON SOLAR WATER HEATER ON THERMAL STORAGE EFFICIENCY JF Journal of Enhanced Heat Transfer JO JEH(T) YR 2016 FD 2017-08-23 VO 23 IS 3 SP 175 OP 195 K1 surface tension device K1 two-phase flow K1 evaporation performance AB Loop thermosyphons are high-efficiency two-phase heat transfer devices capable of transporting thermal energy over long distances. In this paper, we present experiment results for three loop thermosyphon designs for use in solar water heaters: non-U-symmetric loop (asymmetric type), top-U-symmetric loop (symmetric vapor heads type), and both-U-symmetric loop (symmetric vapor and liquid heads type). Experiments were conducted to investigate thermal storage efficiency and temperature distribution under various heat loads and fill ratios. Our results demonstrate the importance of fill ratio and shape of the structure on thermal storage efficiency. The highest thermal storage efficiency values obtained in this study were as follows: non-U-symmetric loop (64.7%), top-U-symmetric loop, (79.8%), and both-U-symmetric loop thermosyphon (73.8%). Our simulation of daily operations revealed that a top-U-symmetric loop provides the best overall performance. PB Begell House LK https://www.dl.begellhouse.com/journals/4c8f5faa331b09ea,1540645840acbe95,259a8f9e7c445209.html