Numerical model for studying axisymmetric thermal energy storages based on granular phase change materials with gaseous heat transfer fluid

• Published in: Computers & mathematics with applications (1987) Vol. 112; pp. 138 - 153
• Main Authors: Fetsov, Sergey S., Lutsenko, Nickolay A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15-04-2022; Elsevier BV
• Subjects: Energy storage; Finite difference method; Heat conductivity; Heat loss; Heat transfer; Heat transfer coefficients; Mathematical models; Numerical analysis; Numerical methods; Numerical models; One dimensional models; Parameters; Phase change material; Phase change materials; Porous media; Thermal conductivity; Thermal energy; Thermal energy storage; Two dimensional models; Upper bounds; Porous media; Thermal energy storage; Finite-difference method; Phase change material
• ISSN: 0898-1221; 1873-7668
• DOI: 10.1016/j.camwa.2022.03.001

•Novel numerical model of gas flows in TES based on granular PCM is proposed.•Convergence analysis of the proposed method is carried out by means of resolution tests.•Applicability of 1D approach for modelling TES with lateral heat losses is studied.•1D approach isn't accurate at high lateral heat losses and low PCM thermal conductivity.•1D approach at large lateral heat losses cannot provide lower or upper bound for sought parameters.
A mathematical model and novel numerical method are proposed for calculating flows of gaseous heat transfer fluid in axisymmetric thermal energy storages (TES) based on granular phase change materials (PCM). The developed computational technique is based on finite difference method and uses a combination of explicit and implicit schemes. Using the resolution tests, the detailed convergence analysis of the numerical method is carried out. The efficiency of the developed model is demonstrated by simulating the processes of heating, energy storage and cooling of the TES taking into account the lateral heat losses at various values of heat loss intensity and PCM heat conductivity. A comparison of the solutions obtained by 1D and 2D models is carried out, and the applicability of commonly used 1D approach for simulating processes in the axisymmetric TES with lateral heat losses is analyzed. It is shown that the ability of the 1D model to predict the averaged parameters decreases not only with increasing heat transfer coefficient, but also with decreasing PCM heat conductivity. The use of the 1D approach at large lateral heat losses does not provide guaranteed lower or upper bound for the sought parameters.