Experimental study on heat storage and release characteristics of thermal oil-based solid heat storage devices

Heat storage technology plays a pivotal role in promoting the global energy transition and optimizing energy utilization efficiency. The objective of this study is to design a solid-state thermal storage device that uses thermal oil as the heat transfer medium for operation in the low-to-medium temperature range, and to establish an experimental platform to investigate the heat storage and release processes. The analysis of temperature distribution and device efficiency during thermal energy storage and release is based on empirical data obtained from experimental investigations. The results indicate that the heat storage uniformity reached 73.55%, the heat storage efficiency achieved 87.17%, the heat release uniformity attained 86.04%, and the heat release completion rate reached 81.43%, placing it at a relatively high-performance level among solid heat storage devices. When heat transfer oil transpires at a flow rate of 3.86–4.32 m³ /h, temperature fluctuations are restricted to a range of 0.06–0.36°C, with the stability of the heat load maintained within 9.93–10.76 kW. The study verifies the feasibility of improving the efficiency of solid heat storage devices via heat transfer oil, delineates key operational parameters and structural design elements, and provides both theoretical and experimental support for the engineering development of a high-efficiency solid heat storage system.