A novel design of hybrid high-temperature solar receiver and thermochemical energy storage system

Highlights: • Corrugated tubes have higher heat transfer as well as more pumping power. • Sinusoidal model has the best thermal–hydraulic performance. • Cell density in the honeycomb structure has a significant effect on the reaction. • The total amount of stored heat is 137 MJ, of which 33% is in the form of latent heat. Small-scale concentrated solar powers (CSP) integrated with micro gas turbines can be mentioned as an effective way to power off-grid and rural areas. One of the most important challenges of using such no fuel-assisted systems is the intermittent nature of solar radiation and unavailability at nights. To overcome this issue, in this research new design for a high temperature solar receiver combined with a triple (sensible, latent, and chemical) storage was presented. In the first part, solutions to increase heat transfer to reach higher outlet temperature of the solar receiver to integrate with the thermochemical reactor are presented. For this purpose, three new pipe models including sinusoidal, triangular, and trapezoidal tubes are proposed instead of straight tubes. Based on the results, Corrugated tubes have significantly higher heat transfer as well as more pumping power compared to straight tubes and the sinusoidal model has the best thermal–hydraulic performance. In the second part, numerical modeling of a thermochemical reactor with honeycomb structure, which uses Co₃O₄/CoO as a redox pair, is performed and the results of the developed model are validated against the experimental results and two important parameters in the reactor design including cell density and channel wall thickness of the honeycomb structure is investigated. In the last section, the designed solar receiver is integrated with a thermochemical heat storage, and the performance evaluation of solar receiver integrated with triple storage are presented. The results delighted that the designed solar receiver hybrid with thermochemical energy storage, with the solar receiver efficiency of 68% and energy storage capacity of 137 MJ is capable to provide the required inlet temperature of turbine (1073 K) about 100 min in off-sun condition. In addition, the new design, by meeting the main constraints provided by the micro-gas turbine, has the ability to store up to three times more energy than the latent heat storage alone.