Significant improvement in transient thermal storage and management performance through a novel packed-bed three-phase heat pipe

To minimize thermal resistance and to maintain the dynamic compatibility between the heat pipe (HP) and the phase change material (PCM), this study proposes an innovative packed-bed three-phase thermal storage heat pipe (PB-3P-TSHP). In this design, the PCM is encapsulated within thin-walled stainless-steel spheres and packed inside the HP cavity. This integrated configuration combines the exceptionally heat transfer capability of HPs with the high latent heat storage (LHS) potential of PCMs, thereby enhancing transient thermal storage and management performance. Experimental results demonstrate that the PB-3P-TSHP achieves improved thermal performance compared with the conventional PCM module and the HP with the same external dimensions. The PB-3P-TSHP extends the chip allowable operating duration by 5.3 times relative to the conventional PCM module at a heating power of 70 W and by 1.65–1.77 times compared with the conventional HP. Notably, despite utilizing only 75.6 g of PCM—about 40% of the amount used in the conventional PCM module (186.7 g)—the PB-3P-TSHP demonstrates significantly enhanced transient thermal management performance, highlighting its efficient PCM utilization. Additionally, the system maintains excellent temperature uniformity, comparable to that of the conventional HP. A transient energy balance model is also developed for quantitatively theoretical calculations, decoupling sensible heat, latent heat, and environmental heat dissipation in the PB-3P-TSHP. Moreover, the PB-3P-TSHP exhibits excellent cycling stability, effectively mitigating stability issues commonly encountered due to the direct interaction between the PCM and the heat transfer fluid in the HP. Finally, high-power LED chip heat dissipation experiments confirm that the PB-3P-TSHP shows significant potential in addressing the cooling challenges faced by electronics under intermittent high heat-flux conditions.