Heat transfer fluids are applied in solar thermal power plants to transfer the heat which is generated in the solar field to a power cycle or heat storage.
Key technical requirements to these heat transfer fluids are:
Further, social and economic requirements such as low costs and sustainable availability need to be met. Besides the risks which are inherent to operation at the required high temperatures, the fluids should not bring along further danger to people and environment.
Heat transfer fluid cycle in solar thermal power plant. Source: DLR
In the field of solar chemistry, the properties of new heat transfer fluids are studied – especially at high temperatures. Promising candidates are silicon oils, which are used mainly in line focus systems. Nevertheless, the properties of well-established heat transfer fluids are still an important field of research. Especially the evolution of their properties over time and the consequences for the power plant components is currently investigated. The goal is to optimize the heat transfer fluid regeneration in order to increase the life time of important components like the solar receiver and thus reduce the electricity generation costs of solar thermal power plants.