Experimental study on a channel-embedded sensible thermal energy storage unit with the heat storage body immersed in heat-conducting oil

In order to study the feasibility of a liquid working medium working in a solid heat storage body, this paper experimentally studied a novel pilot-scale sensible thermal energy storage unit (STESU) with a channel-embedded solid thermal energy storage body (STESB). The material of the body with fluid channels is corundum castable, and the heat-conducting oil works as a heat-transfer medium. While working, the heat-conducting oil flows through the fluid channels of the solid thermal energy storage body, and the oil submerges the body for convection heat exchange in the unit. The charging experiments under different flow rates were carried out to evaluate the thermal performance of the heat storage unit, including temperature, power, and efficiency. The results indicate that the unit's thermal energy storage capacity is about 1.054 x 10(6) kJ. When the flow rate increases from 2.0 kg center dot s(-1) to 2.8 kg center dot s(-1), the heat storage power increases from 71.90 kW to 90.58 kW, the total heat transfer area and heat transfer coefficient increases from 3.29 to 3.60 W/K, and the working efficiency of the charge-discharge cycle is 95.6%, which indicates that the thermal performance of the unit is better than that of heat storage unit which uses air as the heat transfer working medium.