Hybrid Passive–Active Cooling Using a Single Closed Two-Phase Cooling System Integrated with Forced Aeration for Thermal Stabilization and Humidity Control in Paddy Storage

A major problem in tropical regions is maintaining stable thermal and moisture conditions during paddy storage. High ambient temperatures can accelerate grain deterioration and compromise storage quality. This study proposes a hybrid passive–active cooling strategy that integrates a single closed two-phase cooling (SCTPC) system with controlled forced aeration to improve the thermal stability of stored paddy. Unlike conventional storage systems, the proposed configuration combines passive two-phase heat transfer with forced convection to enhance heat removal and reduce moisture stratification. The effect of the load-matched SCTPC configurations on cooling performance and intergranular air humidity distribution was studied experimentally under four storage conditions and three grain loads. The integrated configuration consistently provided lower temperatures and reduced relative humidity stratification than the individual cooling methods, with a maximum 24 h mean intergranular air temperature (MIAT) reduction of approximately 4.4 °C relative to the corresponding ambient condition. A comparison with the representative literature showed that the proposed system performed within established engineering performance ranges. The results demonstrate the feasibility of the combined configuration for short-term laboratory-scale thermal and relative humidity control; however, the airflow field showed measurable spatial variability, and energy efficiency, long-term storage performance, and commercial-scale applicability were not directly evaluated.