Thermal Performance of Two-phase Loop Thermosiyphon under Different Filling Ratios and Heat Transfer Distances

To address the thermal challenges of electronic chips in an energy-efficient manner, this study proposes an optimized two-phase loop thermosiyphon (TPLT) system featuring a mini-channel evaporator, finned condenser, and flexible tubing. This design ensures reliable performance over extended distances while accommodating high heat fluxes and complex cooling scenarios. The effects of filling ratio and heat transfer distance on thermal performance were systematically investigated. Experiments were conducted under controlled ambient conditions of 20℃ and 40% relative humidity. To minimize radial heat losses and ensure measurement accuracy, a layered insulation system was implemented, consisting of alternating wraps of thermal insulation wool and plastic packaging. Results demonstrate that the thermosiyphon's performance is highly dependent on the filling ratio, with thermal resistance initially decreasing before rising as the filling ratio increases. Under high heating power conditions, the system achieved a remarkably low thermal resistance of 0.004 K/W. The maximum heat transfer capacity reached 800 W, underscoring the system's robust performance. Notably, when the heat transfer distance was extended from 3.7 m to 5.7 m, thermal resistance increased only marginally, while the heat transfer limit decreased by a mere 50 W, confirming the system’s exceptional suitability for long-distance heat dissipation. These findings offer significant insights for thermal management in advanced electronic devices, demonstrating the potential of the proposed TPLT design as an efficient and scalable cooling solutions for high-power applications.