Experimental investigation on a novel method for set point temperature controlling of the active two-phase cooling loop

How to cool the accumulator and realize a stable set point temperature at the lowest cost is the key for the practical spacecraft application of two-phase thermal control system. The paper points out a novel method to combine thermoelectric coolers (TECs) with thermal bus of an active two-phase cooling loop. The novel method is realized by using the cold plate of a TEC to control the accumulator temperature while the hot plate is cooled down by subcooled liquid in the main thermal bus. Experiments have proved the feasibility and stability of the new design, which not only improves the accuracy from ±0.4 °C to ±0.1 °C but also increases the cooling speed to 0.31 °C/min when the input power of the TEC is 10 W. Some important performance characteristics demonstrated in this paper included: (1) operation of an active two-phase thermal system driven by mechanical pump; (2) a special evaporator with 15 m length and 2.6 mm diameter; (3) robustness and reliability of the system under various test conditions; (4) effectiveness of TECs and a rapid dropping speed in controlling the MPCL operating temperature; and (5) a higher controlling accuracy of the evaporator.