The Impact of Active and Passive Thermal Management on the Energy Storage Efficiency of Metal Hydride Pairs Based Heat Storage

Abstract

Two-tank metal hydride pairs have gained tremendous interest in thermal energy storage systems for concentrating solar power plants or industrial waste heat recovery. Generally, the system’s performance depends on selecting and matching the metal hydride pairs and the thermal management adopted. In this study, the 2D mathematical modeling used to investigate the heat storage system’s performance under different thermal management techniques, including active and passive heat transfer techniques, is analyzed and discussed in detail. The change in the energy storage density, the specific power output, and the energy storage efficiency is studied under different heat transfer measures applied to the two tanks. The results showed that there is a trade-off between the energy storage density and the energy storage efficiency. The adoption of active heat transfer enhancement (convective heat transfer enhancement) leads to a high energy storage density of 670 MJ m−3 (close to the maximum theoretical value of 755.3 MJ m−3). In contrast, the energy storage efficiency decreases dramatically due to the increase in the pumping power. On the other hand, passive heat transfer techniques using the bed’s thermal conductivity enhancers provide a balance between the energy storage density (578 MJ m−3) and the energy efficiency (74%). The utilization of phase change material as an internal heat recovery medium leads to a further reduction in the heat storage performance indicators (142 MJ m−3 and 49%). Nevertheless, such a system combining thermochemical and latent heat storage, if properly optimized, can be promising for thermal energy storage applications.

Dehydrogenation of Metal Hydride Reactor-Phase Change Materials Coupled with Light-Duty Fuel Cell Vehicles

“…The multi-physics governing equations are solved in COMSOL using the linear solver PARDISO (parallel direct solver). The flowchart of the selected modules and procedures was given in a previous study [42]. The implicit backward Euler algorithm is used to discretize the time-dependent differential equations, where the default time step of ∆t = 0.01 s is adopted.…”

“…where the permeability K eff of the porous bed depends on the averaged particle size and the bed porosity through the relation of Kozeny-Karman [42] and µ g is the dynamic viscosity of hydrogen gas. The ideal gas law gives the relationship between the pressure and density of the gas:…”

Thermal Energy, Process, and Transport Intensification - A Brief Review of Literature in 2021 and Prospects

“…used a PCM (RT41) and a porous material to improve thermal performance of a solar water heater. The weather data corresponding to the installation location was adopted under three different PCM placement modes: 1) horizontally in the center of the tank, 2) under the absorber plate, and 3) as a cylindrical tube in the center of the storage tank.Metal hydride material-based thermal energy storage systems have gained tremendous interest of research and their performance depends on selecting and matching the metal hydride pairs and the thermal management adopted Nyamsi and Tolj (2021). investigated the impact of active and passive thermal management on the energy storage efficiency of metal hydride pairsbased heat storage systems for concentrating solar power plants or industrial waste heat recovery.…”