%0 Journal Article %A Huang, Chien %A Lin, Wei-Keng %A Wang, Sung-Ren %D 2016 %I Begell House %K surface tension device, two-phase flow, evaporation performance %N 3 %P 175-195 %R 10.1615/JEnhHeatTransf.2017015985 %T ANALYSIS OF THE IMPACT OF U-SHAPED STRUCTURE FOR HEADS OF LOOP THERMOSYPHON SOLAR WATER HEATER ON THERMAL STORAGE EFFICIENCY %U https://www.dl.begellhouse.com/journals/4c8f5faa331b09ea,1540645840acbe95,259a8f9e7c445209.html %V 23 %X 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. %8 2017-08-23