Design and modeling of a honeycomb ceramic thermal energy storage for a solar thermal air-Brayton cycle system

Solar thermal air-Brayton cycle system stands out among distributed power systems with high reliability, compactness, low cost and little water consumption, but its operation is affected by the availability and stability of solar energy. Thermal energy storage (TES) is necessary for dispatchable power generation and stable operation of solar thermal air-Brayton systems, but there are insufficient studies on the integrated TES-solar air-Brayton cycle system. In this paper, a honeycomb ceramic TES was designed for a 10 kW-scale solar air-Brayton cycle system based on the steady state off-design cycle analysis. The TES presented high efficiencies in the charging and discharging experimental tests, which were 79.6% and 76.5%, respectively. The air leakage between the ceramic modules was founded to affect the outlet air temperature and module temperature. Besides, a one-dimensional transient TES model was developed and validated. A feasible stand-alone operation strategy for the system was finally simulated based on the transient system model, which showed that constant output electric power (similar to 12 kW) and extended power generation duration of 3 h could be realized by integrating the TES. This work contributes to the design and modeling of TES for solar air-Brayton cycle systems as well as the system operation strategy analysis. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study designed a high-efficiency thermal energy storage system for a solar thermal air-Brayton cycle system and validated its performance through experiments; found that gas leakage affects system temperature; and simulated a stand-alone operation strategy for the system based on a one-dimensional transient model.