A review study on the modeling of high-temperature solar thermal collector systems

Concentrated solar power technologies are gaining more attention in the last two decades in order to replace the conventional power technologies and reduce their environmental impact. Among the developed concentrating technologies, parabolic trough solar collector and solar tower are the most mature and dominant technologies. As part of the continuous development of these technologies, significant efforts have been deployed to predict and improve their performance, and therefore reduce their cost and make them more competitive. In this context, numerous analytical and numerical studies have been developed and presented in the literature. This review aims to summarize the state-of-the-art modeling approaches used to simulate, predict and evaluate the optical, thermal and dynamic performance of high-temperature solar thermal collectors. The review includes the different analytical and ray tracing models used to determine the non-uniform flux on the receiver aperture. Energy balance models are also presented as simple and easy computational models suitable to predict the thermal performance at a reasonable time and computational cost, whereas Computational Fluid Dynamic models are more convenient to study the details of the coupled fluid flow and heat transfer in the internal and external flow. The review also includes dynamic models such as the lumped capacitance models which are used to simulate the dynamic characteristics of the heat transfer fluid and interaction with the solar receiver under transient conditions. The dynamic behavior of the whole solar plant using different codes is examined. Furthermore, different features and capabilities of those approaches are also analyzed and compared. Finally, the use of numerical modeling in the development of new designs and assessment of the use of nanofluids is discussed. In summary, this work presents a comprehensive review of the existing numerical models and could serve as a guideline to develop new models for future trends in concentrating solar technologies.