Experimental investigation on the heat transfer performance of a loop thermosyphon with dual vapor lines

This study experimentally investigates the thermal performance of a loop thermosyphon (LTS) featuring dual vapor lines and one liquid line. Three filling ratios (FR), such as 20 %, 30 %, and 40 % of the total LTS volume, are tested with deionized (DI) water as the working fluid under vertical orientation. Results reveal that the optimal thermal performance occurs at a 30 % FR, with the lowest thermal resistance of 0.089 °C/W recorded at 360W. At the maximum power input, the evaporator wall temperature reaches 85.5 °C for the optimal filling ratio (OFR). Incorporating dual vapor lines enhances the vapor movement from the evaporator to the condenser, thereby reducing heat accumulation at the compensation chamber. Consequently, the LTS achieves a maximum thermal efficiency of 85.44 % at 30 % FR. Dual vapor lines facilitate faster vapor flow to the condenser section, resulting in quicker condensation and an increased liquid descending rate to the evaporator. Henceforth, the experimental findings and discussions of the proposed LTS are expected to be a valuable guide for the upcoming engineering designs in developing LTS that are intended for cooling data centers.