Development and investigation of a two-phase loop thermosiphon with a flat evaporator at different slope angles

We present the results of the development and experimental studies of a two-phase loop thermosiphon with a flat evaporator and ethanol as the working fluid. We investigated the thermal characteristics of the device within the temperature range of $20$–$80^{\circ}$C under the heat loads of $10$–$120$ W, a filling ratio of $40\%$, and slope angles within the range of $0^{\circ}$–$90^{\circ}$. The device is functional at all of the studied slope angles. The maximum heat load of 120 W was reached at the slope angle of $90^{\circ}$. Here, the average temperature of the evaporator surface was within $70^{\circ}$C and the maximum thermal resistance was equal to $0.41^{\circ}$C/W.