Numerical analysis of discharging stability of basalt fiber bundle thermal energy storage tank

In this paper, a new thermal energy storage (TES) scheme of basalt fiber bundles is proposed. This basalt fiber bundle TES tank adopts two-stage runner arrangement to increase the specific surface area and improve the heat exchange effect. Based on this, a variable flow rate and preheating control scheme is proposed to enhance the discharging stability. The results when the air initial flow rate is 1m/sshow that the two methods of automatically controlling the flow rate change and using two tanks in series to make full use of the waste heat can significantly increase the stable discharging time of the TES tank. The increase in the stable discharging time reached 115% with variable flow rate scheme. And the simultaneous use of variable flow and preheating control schemes can extend the stable discharging time to 166% of the constant flow scheme. This TES tank can provide a wide heating power range and the maximum discharging power per unit area reaches 1.005MW±1% when the initial flow rate is 1m/s. However, it is difficult for honeycomb and packed bed to achieve such output under the same flow rate. In short, this new scheme can realize the coexistence of high thermal energy storage density, strong stable discharging, small volume and high discharging power, and can be used in mobile thermal energy storage system to meet user groups with significant differences in heating demand.