High-performance and low-cost packed bed latent thermal energy storage system based on spray technology

Abstract

Packed bed latent thermal energy storage (PBLTES) strategy can contribute to the comprehensive performance of the integrated industrial systems. To address issues associated with the excessive initial investment in oil-based packed bed, a novel cascaded spray-type PBLTES (ST-PBLTES) system is proposed, and the corresponding numerical model is constructed in this paper. Besides, a comprehensive energy, exergy and economic analysis methodology is applied to examine the thermal transport performance and economic cost of cascaded ST-PBLTES system under various parameters from a comparative point of view. Finally, cascade ST-PBLTES system is analyzed under different operating conditions using a comprehensive objective evaluation method to evaluate the merits and demerits. The study reveals that the Energy density (EnD) and Exergy density (ExD) in cascaded ST-PBLTES system are increased respectively up to 17.21 % and 26.98 % if the inlet temperature rises. With the increasing of the set HTF outlet temperature, the thermal storage performance of the ST-PBLTES system is significantly improved, and the EnD and ExD are increased by 70.13 % and 82.83 %, respectively. When the HTF outlet temperature is set at 463 K, the capacity cost of cascaded ST-PBLTES system can be reduced by 1/3 compared to traditional full-fill PBLTES system and have the approaching thermal storage performance. The work provides a reference and valuable insights for further improvement of PBLTES system.