Ordinary Portland concrete nowadays represents a viable and cheap option as a thermal energy storage (TES) medium in concentrated solar power (CSP) technologies. Current TES CSP applications are typically based on molten salt tanks which are very expensive and suffer from high corrosion problems. Contrarily, concrete presents series of pro such as: simplicity, quite good sensible TES, high availability, easy fabrication, good mechanical properties (even after the exposure to high temperature), and finally, a thermal expansion coefficient near to that of steel, minimizing problems related to the interface between the cementitious material and the heat exchangers (commonly made of steel). In this context, a correct design of the TES medium, composed of the cementitious material (Cementitious materials are nanoscale materials) and the heat exchangers (pipes), plays a key role in both the performance impact as well as on the overall costs of the CSP device. Therefore, it is necessary to optimize TES systems by varying all variables providing the best performance: i.e., number of tubes, their arrangement in the block, as well as the correct selection of the employed cement-based material. To achieve an optimized configuration and design, a finite-element-based approach is implemented for simulation purposes. In these simulations, the number of pipes and their arrangement were varied and, in addition, different alternative mortars to ordinary Portland cement were manufactured and used as input parameters. The alternatives prove to be more efficient than TES as. They reduce the volume of the molten salt tank by 17% and the surface area of the heat exchanger by 29% (high-cost savings) compared to the PC (Portland cement) reference system.

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