Effective thermal management is crucial for Hyperloop vehicles to ensure the reliable operation of onboard systems and to prevent overheating under high-speed and vacuum-like conditions. Due to the near-vacuum environment in which a Hyperloop operates, passive cooling is largely ineffective, making an active thermal management system necessary. This study investigates the application of a direct contact latent heat storage system, which leverages the high energy density of phase change materials. Ice is used as the phase change material and water as the heat transfer fluid, forming a system that avoids emulsion formation and simplifies design by eliminating complex heat exchangers. An experimental setup was used to evaluate the impact of three ice shapes and three flow directions on cooling performance. The results indicate that neither crushed ice nor ice block alone provide the optimal thermal performance for Hyperloop cooling requirements in terms of both effective capacity and dynamic response. Crushed ice offers fives times faster thermal response but has a 42% less packing density, while ice block provides greater thermal mass but responds more slowly to dynamic cooling demands. Therefore, a balance between the two configurations must be identified to combine adequate heat transfer performance with sufficient cooling capacity.

Hyperloop transport operates in a low-pressure environment in which convective heat transfer is strongly limited, making conventional air-based cooling ineffective. One promising thermal management approach is therefore to absorb the waste heat generated during travel in a thermal energy storage (TES) system and dissipate it during stops. In this context, latent heat storage based on water–ice systems is particularly attractive because of its high energy density and nearly constant-temperature heat absorption. However, experimental validation of such systems beyond laboratory scale is still lacking. This study therefore investigated a large-scale direct contact latent heat storage (DCLHS) system for Hyperloop thermal management, using water as heat transfer fluid and ice as phase change material. The system was evaluated for two ice morphologies, crushed ice and ice block, under both constant and time-variant cooling power profiles representative of Hyperloop operation. The objective was to assess thermal performance, exergy efficiency, and hydraulic stability at application-relevant scale, and to identify morphology-dependent trade-offs relevant for system integration. The results show that the large-scale system can operate reliably under dynamic loads and that upscaling leads to smoother thermal behavior and reduced boundary effects. Crushed ice demonstrated superior thermal responsiveness, maintaining outlet temperatures close to the phase change temperature and achieving exergy efficiencies up to 0.72 at cooling powers up to 3.8 kW while enabling stable operation at 15 °C. In contrast, the ice block configuration provided higher volumetric energy density but exhibited delayed thermal response and required substantially higher mass flow rates, which limited operation to approximately 25 °C and reduced exergy efficiency to 0.03–0.35. Overall, the results show that large-scale DCLHS is a feasible option for Hyperloop thermal management, while also revealing that system behavior at larger scale is strongly influenced by storage morphology.