This review provides a brief overview of the most commonly used HTFs in CSP applications—molten salts, synthetic oils, nanofluids, and gaseous fluids—highlighting their distinct thermophysical properties, applications, and performance characteristics. CSP plants typically use two types of fluids: (1) heat-transfer fluid to transfer the thermal energy from the solar collectors through the pipes to the steam generator or storage. Organic Rankine Cycle (ORC) is named for its use of an organic, high molecular mass fluid that boils at a lower temperature than the water. Among many well-proven technologies, the ORC is one of the most favorable and promising ways for low-temperature applications. In comparison to water, organic.