Energy Storage Science and Technology ›› 2025, Vol. 14 ›› Issue (8): 3185-3193.doi: 10.19799/j.cnki.2095-4239.2025.0110

• Energy Storage System and Engineering • Previous Articles    

Experimental investigation of thermal performance in a solid sensible heat storage device for medium-high-temperature flue gas waste heat recovery

Jiulin CHEN(), Xiaodi XUE(), Li WANG, Zhijue XING   

  1. SiACT Power Co. , Ltd. , Xi’an 710075, Shaanxi, China
  • Received:2025-02-06 Revised:2025-02-18 Online:2025-08-28 Published:2025-08-18
  • Contact: Xiaodi XUE E-mail:jlchen_sust@163.com;xiaodi_xue@126.com

Abstract:

To improve the low utilization efficiency of industrial flue gas waste heat caused by high dust content and significant temperature fluctuations, a novel horizontal flue gas–solid sensible heat storage device employing high-temperature concrete as the thermal storage medium was developed. A pilot-scale system was designed and constructed for the recovery and storage of waste heat from steel sintering ring-cooled flue gas. Experimental investigations were conducted to analyze the temperature distribution, flow resistance characteristics, instantaneous energy efficiency, thermal efficiency, and exergy efficiency of the storage device. The results revealed the formation of thermoclines along the axial direction during charging and discharging, with higher temperatures near the charging inlet and a relatively uniform radial temperature distribution. The device exhibited a low pressure drop, with a gradual pressure increase during charging and a corresponding decrease during discharging. Both the instantaneous energy efficiency and heat transfer power declined over time. Lower flue gas flow rates yielded more stable instantaneous efficiency, extended heat exchange duration, and reduced pressure drop, though at the cost of decreased heat transfer power. Therefore, the optimal flow velocity should be selected according to application requirements. During stable operation, the system achieved a heat storage capacity of 1376 kWh, with thermal and exergy efficiencies of 93.02% and 91.7%, respectively. The parallel-plate heat exchange structure enabled efficient heat transfer between the solid storage unit and dusty flue gas while effectively mitigating ash deposition and channel blockage. These findings provide an experimental foundation for the scale-up and application of flue gas-solid sensible heat storage systems.

Key words: flue gas waste heat, solid sensible heat storage, thermocline, thermal performance, experimental study

CLC Number: