R. Iyankumar, Arun Prasad Murali, Abdellatif M. Sadeq, Mohamed Iqbal Shajahan, Karuppaiah Selvakumar, Karthik V. Shankar, Jayant Giri, Hassen Sabeur
ABSTRACT Solar thermal collector technology is crucial for capturing renewable energy to support sustainable thermal uses. Nonetheless, traditional designs frequently experience optical losses, ineffective thermal storage and variable performance under different levels of sunlight. This review conducts a systematic assessment of the development and categorization of solar thermal collectors, spanning from non‐concentrating to high‐concentration systems. It emphasizes their thermal efficiency, sustainability, and performance based on application, through an in‐depth comparative analysis of their thermal characteristics, optical efficiency, structural progress, and material advancements. This review is unique in its combination of hybrid nanofluids, PCMs, innovative receiver designs, and passive tracking options to emphasize synergistic enhancements. Recent advances in experimental techniques have shown that high‐efficiency solar concentrators, such as refractive secondary systems, can achieve optical efficiencies surpassing 90%. When these are paired with heat transfer fluids enhanced by nanofluids, thermal efficiency can be boosted by approximately 53%. Moreover, fully replacing fossil fuel heating with optimized solar thermal systems can lead to CO 2 emission reduction ranging from 69% to 77%. The results emphasize the crucial role of integrating design to enhance performance. This broader implication serves as a guide for creating compact, affordable and highly efficient solar thermal systems designed for both industrial and decentralized uses.