Solar Air Heaters Classifications and Enhancement: A Review

Solar air heaters (SAHs) are renewable energy systems that utilise solar radiation to heat air, offering sustainable solutions for space heating, agricultural drying, and industrial processes. These systems are simple in design, cost-effective, and environmentally friendly, making them essential to the renewable energy landscape. However, challenges such as low thermal efficiency, dependency on climatic conditions, and significant thermal losses limit their adoption. Recent advancements in design, materials, and operational strategies have significantly improved their performance. This review explores the principles of SAHs, innovations in design, thermal storage integration, and efficiency enhancement techniques. Applications in various sectors are discussed, highlighting ongoing research to maximise efficiency while maintaining economic viability and ecological benefits.