Performance investigation and optimization of latent heat storage exchangers with sandwiched tree-channels

• Published in: International journal of heat and mass transfer 2022-02, Vol.183, p.122161, Article 122161
• Main Authors: Huang, Yongping, Chen, Donglian, Zheng, Yi, Liu, Xiangdong
• Format: Article
• Language: English
• Subjects: Algorithms; Channels; Enthalpy; Fractal geometry; Fractals; Heat exchangers; Heat storage; Latent heat; Latent heat storage exchanger; Melting; Melting enhancement; Optimization; Response surface method; Response surface methodology; Sandwiched tree-channels; Thickness
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2021.122161

•A latent heat storage exchanger (LHSE) with sandwiched tree-channels is designed.•Sandwiched tree-channels are optimized by the response surface method.•An innovative LHSE with sandwiched tree-channels shortens melting process by 51.5%.•Optimal fractal level, thickness and length fractal dimensions are 5, 2.89 and 1.99. The inefficient thermal transport of latent heat storage exchangers (LHSEs) restricts its engineering applications. To address this challenge, we design an innovative shell-and-tube LHSE with sandwiched tree-channels. The numerical approach using an enthalpy-porosity algorithm is conducted to research the melting performance of innovative LHSEs, focusing on comparisons with traditional LHSE units. Moreover, the response surface method (RSM) is adopted for structure optimizations of innovative LHSE units. The results indicate that the inherent high-efficiency thermal path of sandwiched tree-channels enhances the melting rate, while their fully extended spatial layout improves the temperature uniformity level. Compared with traditional ones, the innovative LHSE unit shortens the melting duration by 51.5% and improves the temperature uniformity by 21.1%. Interestingly, the melting convection of vertical directions is more intense than horizontal directions during the middle stage, and the overall melting performance depends heavily on the late stage. RSM results show that structural parameters of sandwiched tree-channels contribute to melting performance in the order of branch level, thickness fractal dimension, and length fractal dimension. To minimize the melting duration of LHSE units, fractal level, thickness fractal dimension, and length fractal dimension of 5, 2.89, and 1.99 are recommended for engineering applications meeting the dimensional range herein.