Development of a compensation chamber for use in a multiple condenser loop heat pipe

Abstract

The performance of many electronic devices is presently limited by heat dissipation rates. One potential solution lies in high-performance air-cooled heat exchangers like PHUMP, the multiple condenser loop heat pipe presented here. This device features a number of design improvements that lead to significant increases in performance relative to state of the art heat exchangers. In this work, a compensation chamber is developed and implemented to ensure the operational stability of the device across a wide range of operating conditions. A computational model of the device was developed using COMSOL Multiphysics v3.5a to allow for design optimization and performance evaluation. The accuracy of this computational model was established by comparing simulation results to experimental data. Analytical models were used to identify operating points of interest, which were simulated to compare the performance of various designs. The final design featured reduced thermal resistance between the vapor in the evaporator and the compensation chamber, and increased thermal resistance between the compensation chamber and the ambient air relative to past designs. This design reduced the risk of condenser flooding and evaporator dry out, improving the operational stability of the device. This design was implemented into a ten-condenser prototype, where experiments validated its performance. The compensation chamber did not require any electrical heaters, reducing the power consumption of the device and increasing its COP. Finally, general recommendations and guidelines are presented for use during the design process of future compensation chambers.