Performance analysis of a separator assisted dual-evaporators two-phase thermosyphon loop under heating power maldistribution condition based on an experimentally validated model

Abstract

Multiple evaporators two-phase thermosyphon loop is typical pattern which is utilized in the data centers. Under heating power maldistribution condition, the system could suffer in the temperature oscillation and performance degradation which limit its application. To solve this problem, a separator assisted dual-evaporators thermosyphon loop (SDTPTL) is evaluated and compared with traditional dual-evaporators thermosyphon loop (DTPTL) by using experimentally validated model. The simulation results show that the SDTPTL can always achieve better performances than the DTPTL at any operating conditions. Evaporator outer wall temperatures of two evaporators in the SDTPTL are lower than that in the DTPTL about 2.2––5.9 °C and 3.8–8.2 °C when heat load of evaporator2 (high heating power) ranges from 0.8 kW to 1.4 kW, and lower about 1.6–4 °C and 1.7–4 °C when heat load of evaporator1 (low heating power) ranges from 0.1 kW to 0.5 kW, respectively. Besides, compared with the DTPTL, the SDTPTL has a better benefit in evaporator outer wall temperatures at higher heat load and working fluid charge. In addition, to further improve the performances of the SDTPTL, the sensitivity analyses about structure configurations of the system are conducted as well. Results show that the system can achieve better performances at lower separator height. The evaporator outer wall temperatures of two evaporators can be decreased about 57.4 °C and 3.6 °C when separator height reduces from 0.8 m to 0.2 m. It is expected that this new cycle will be beneficial to develop dual evaporators thermosyphon loop under heating power maldistribution condition.