Investigations of thermo-hydrodynamics, structural stability, and thermal energy storage for direct steam generation in parabolic trough solar collector: A comprehensive review

Abstract

The first generation of the parabolic trough collector (PTC) solar power plants uses synthetic oil as a heat transfer fluid (HTF) in the solar field. Direct steam generation (DSG) in the solar field is the next generation advancement by replacing oil with water-steam. The DSG improves the power generation's cost-effectiveness in terms of higher thermal efficiency, lower overall cost, and excellent scale-up potential. This technology experienced significant development in the last two decades. In this article, an extensive review of DSG technology development and challenges in commercialization is presented. The experimental and numerical investigations performed to size and design both the solar field and its control system to maintain the desired operating characteristics are discussed. The design of solar field components for high-temperature applications and effective process control systems for two-phase flow operations are the current challenges that need to be addressed. The benefits and limitations of various methods of steam generation and different DSG processes are discussed. The thermal instability in the DSG solar field due to the presence of two-phase flow in the solar collectors must be resolved to commercialize this technology. The demonstration of the thermal energy storage (TES) system has indicated that the unavailability of a cost-effective TES system with adequate storage capacity is likely to disappear in the future, which will improve the grid integration and dispatchability of DSG solar power plants.