Effects of fluctuating thermal sources on a shell-and-tube latent thermal energy storage during charging process

摘要

The fluctuating and intermittent nature of industrial heat sources is a crucial technical barrier limiting the implementation of heat recovery energy systems. Latent Thermal Energy Storage (LTES) has the potential to overcome these issues by maintaining a Waste Heat Recovery (WHR) system within designed operation conditions to achieve effective and efficient operation. However, the dynamic heat transfer characteristics of LTES under fluctuating heat sources need to be studied further to better understand the effects of thermal fluctuation. In this work, the charging performance of a shell-and-tube LTES under fluctuating and steady heat source has been investigated and analysed. The effects of period and amplitude for the fluctuating heat source, as well as the Stefan number, are investigated in detail. Results indicate that large-period fluctuating heat sources can considerably reduce the total melting time but also reduce the energy storage capacity, whilst small-period fluctuating heat sources have almost no effect on the melting process of LTES. For the effects of fluctuating amplitude, both the total melting time and energy storage capacity decline at a decreasing rate with an increase of fluctuating amplitude. These results can bridge the knowledge gap needed for future designs of shell-and-tube LTES for fluctuating heat sources used with heat recovery applications.