A comprehensive investigation of the mathematical models for a packed bed latent heat thermal energy storage system

Abstract

The numerical simulation is effective to investigate the thermal performance of the packed bed latent heat thermal energy storage system which can provide more detailed information. There are three most commonly used numerical models developed based on the porous medium model: the continuous solid phase model, improved continuous solid phase model, and concentric dispersion model. The applicability of these models is compared by evaluating the variations of fluid temperature, temperature difference inside phase change material capsule, thermocline thickness, charging power, and computational time. The results show that the concentric dispersion model can accurately simulate the charging processes with a deviation of less than 5% between the results of the concentric dispersion model and experimental results. When the Bi is smaller than 1, the effect of the temperature gradient inside the capsule can be neglected and the continuous solid phase model shows a deviation less than 2%. When the Ste is smaller than 0.1, the sensible heat is negligible and the improved continuous solid phase model shows a deviation less than 2%.The computational time of the concentric dispersion model is generally 30% more than the other two models.

Parametric Sensitivity Analysis and Performance Evaluation of High-Temperature Macro-Encapsulated Packed-Bed Latent Heat Storage System Operating with Transient Inlet Boundary Conditions

“…The computational domain in this work is reduced to a cylindrical area and a two-dimensional cylindrical coordinate is used, as illustrated in Figure 1b. Therefore, the followings are the respective governing equations for the air and PCM [12]:…”

“…In addition to that, smaller capsules have lower thermal resistance between their centers and their walls. An increase in the heat transfer rate can also be explained by the volumetric heat transfer coefficient presented in Equation (12). As the diameter becomes smaller, h vol increases, enhancing convective heat transfer between the air and the PCM capsules.…”

“…With regards to PBLHS systems, different numerical models have been developed [11,12], with Schumman's models [13], continuous solid-phase models [14], and dispersion-concentric models [15] being the most common ones. The continuous solid-phase model was used by Lu et al [16] to explore the thermal behavior of a PBLHS system, and it was discovered that the charging efficiency rises as the melting temperature and phase change material content increase.…”

Perspectives on Low-Temperature Packed Bed Latent Heat Storage Systems

“…The HSM packing is a porous medium with a high surface-to-volume ratio at the macroscopic level, which enhances heat transfer (Yang et al, 2019;Yang et al, 2020). Heat transfer between the HSM and HTF enables the charging and discharging of the PBLHS system (Guo et al, 2021). The buoyancy effect causes the high-temperature HTF to enter the top of the heat storage tank during the charging process (Zanganeh et al, 2012).…”

Phase Engineering of Molybdenum Carbide/Oxide for Highly‐Efficient Electrocatalytic Hydrogen Production

“…The continuous consumption of fossil energy not only leads to the depletion of energy, but also causes serious pollution to the environment, and brings adverse effects on social development and people's lives. [1][2][3][4] Therefore, it is the goal of mankind all over the world to develop efficient, clean and economical energy sources, [5] and it is of great significance to achieve carbon peak and carbon neutralization. Hydrogen energy is considered as one of the ideal clean energy sources to replace fossil fuels due to its high energy density, renewability, and environment friendly.…”