Applications of phase-change materials in solar drying technology: A review

Solar drying offers a sustainable alternative to conventional drying methods by utilizing renewable energy in a controlled and efficient manner. Integrating phase-change materials (PCMs) into solar dryers enables efficient thermal energy storage, extending drying operations beyond sunlight hours, while improving product quality. This review discusses techno-economic aspects, recent advances related to PCM-based solar dryers in terms of configuration, PCMs being used and strategies adopted to enhance the performance of the same. The review also highlights user satisfaction/acceptance, operational convenience, worldwide adaptation as well as barriers and challenges with respect to the PCM-based solar dryers. A comparative analysis of PCM-based drying applications involving various crops and food products in particular, has also been conducted. Furthermore, some of the commercial solar dryers in the market together with their relevant product information have been presented. The paper concludes with insights into future research directions, including techno-economic feasibility and design optimization.