Numerical analysis of geometrical and process parameters influence on temperature stratification in a large volumetric heat storage tank

• Published in: Energy (Oxford) 2020-03, Vol.194, p.116878, Article 116878
• Main Authors: Kocijel, Lino, Mrzljak, Vedran, Glažar, Vladimir
• Format: Article
• Language: English
• Subjects: Cold water; Computer simulation; Diameters; Diffusers; Empirical analysis; Geometry and process parameters; Heat; Heat storage; Insulation; Large volumetric tank; Mathematical models; Model accuracy; Numerical analysis; Numerical models; Process parameters; Storage tanks; Stratification; Tank insulation thickness calculation; Temperature gradients; Thermal energy storage; Thickness; Two dimensional analysis; Velocity distribution
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2019.116878

This paper presents various numerical analyses of two-dimensional temperature and velocity fields in vertical cylindrical large volumetric heat storage tanks used in municipal heating applications. Numerical simulations were performed in order to investigate the shape impact of the heat storage tank (height-to-diameter ratio), the diffuser distance from the top of the tank, temperature difference between the warm and cold water and the volume flow variation on temperature stratification in the tank. The accuracy and precision of the numerical model was verified by comparing the numerical calculation results with the measurement results from the literature. An empirical model for the calculation of the tank wall (mantle) insulation thickness with maximum constant temperature inside the tank was also developed. The effect of reducing the insulation thickness and changing the seasons on quality of the temperature stratification and thermal losses through the tank insulation were analyzed. The financial analysis justified the possible reduction of the insulation thickness, and more flexible investment in the plant is presented. •Large volumetric heat storage tank that accumulates sensible heat is investigated.•Geometric and process parameters influence on temperature stratification is analyzed.•It is performed insulation thickness calculation of large volumetric heat storage tank.•The influence of process parameters and insulation thickness on thermal losses is presented.•Large volume tank operation can significantly differ in comparison with tanks of small volume.