Solar Dryers With Thermal Energy Storage: System Integration, Mathematical Modeling, and Review of Sensible and Latent Heat Technologies

Abstract

To overcome the challenge of solar intermittency (a major constraint in drying operations that limits activities to daylight hours and compromises efficiency and product quality), this paper presents a critical review of solar dryers combined with thermal energy storage systems, focusing on sensible heat storage (SHS) and latent heat storage (LHS) technologies. Experimental and numerical literature published from 2016 to 2026 is synthesized and classified into SHS, LHS, and hybrid systems, comparing primary performance indicators, including drying time, efficiency, specific moisture extraction rate, and economic feasibility. Key findings indicate that SHS systems using materials such as pebbles, sand, or granite enhance drying efficiency by 2%–28%, reduce drying time by up to 30% compared with open‐sun drying, and offer payback periods (PBPs) as short as 2–2.12 months. LHS systems using phase change materials (e.g., paraffin wax and lauric acid) extend drying by 3–5 h after sunset, achieve exergy efficiency up to 98.1%, and save 36–70.5 h of drying time, though with higher initial costs. Hybrid SHS–LHS systems show synergistic advantages, including 10%–14.2% improvements in drying efficiency, PBPs of 0.39–1.82 years, and improved product quality and nutrient retention. The review concludes that SHS is more beneficial for low‐cost, low‐temperature applications, whereas LHS provides superior temperature stability and extended heat storage, making it suitable for high‐value or continuous drying processes. A comprehensive mathematical modeling framework and meta‐analysis of cost‐effectiveness are also presented to guide system selection. Future work should focus on material properties, system design optimization, and cost‐efficiency to enhance adoption in sustainable agricultural and industrial drying sectors.