Optimized Modeling and Design of a PCM-Enhanced H2 Storage

Abstract

Thermal and mechanical energy storage is pivotal for the effective exploitation of renewable energy sources, thus fostering the transition to a sustainable economy. Hydrogen-based systems are among the most promising solutions for electrical energy storage. However, several technical and economic barriers (e.g., high costs, low energy and power density, advanced material requirements) still hinder the diffusion of such solutions. Similarly, the realization of latent heat storages through phase change materials is particularly attractive because it provides high energy density in addition to allowing for the storage of the heat of fusion at a (nearly) constant temperature. In this paper, we posit the challenge to couple a metal hydride H2 canister with a latent heat storage, in order to improve the overall power density and realize a passive control of the system temperature. A highly flexible numerical solver based on a hybrid Lattice Boltzmann Phase-Field (LB-PF) algorithm is developed to assist the design of the hybrid PCM-MH tank by studying the melting and solidification processes of paraffin-like materials. The present approach is used to model the storage of the heat released by the hydride during the H2 loading process in a phase change material (PCM). The results in terms of Nusselt numbers are used to design an enhanced metal-hydride storage for H2-based energy systems, relevant for a reliable and cost-effective “Hydrogen Economy”. The application of the developed numerical model to the case study demonstrates the feasibility of the posited design. Specifically, the phase change material application significantly increases the heat flux at the metal hydride surface, thus improving the overall system power density.

Comparison of enthalpy-porosity and lattice Boltzmann-phase field techniques for the simulation of the heat transfer and melting processes in LHTES devices

“…where f + and f − are frequency scales (the inverse of the time scale that rules melting and solidification, respectively) and K + and K − are melting/solidification switch functions. Further details on the implementation of K + and K − , as well as on the forces dependence on ϕ can be found in [15] and [16].…”

“…For the setup of the LB-PF simulations of Cases B and C, the reader is redirected towards reference [16].…”

“…As such, the first goal of the present work is to assess the combined effects of the mushy zone constant and the phase change temperature range for a reference 2D melting case [13,14], including also the impact of purely numerical parameters such as grid density. In addition to that, an original lattice-Boltzmann phase field (LB-PF) formulation [15,16] is proposed for the modeling and simulation of the same class of PCM melting problems. Lattice boltzmann algorithms for fluid dynamic simulations are known to be computationally efficient and easily modifiable/extendable to incorporate additional complex physical and chemical phenomena [17,18].…”

Coolant Wetting Simulation on Simplified Stator Coil Model by the Phase-Field Lattice Boltzmann Method

“…This method has been extended to enable its use in multiphase flow solvers with various models such as the color-gradient model [ 7 ], the pseudopotential model (Shan–Chen model) [ 8 ], and the phase-field model [ 9 ]. The phase-field lattice Boltzmann method has been used in various applications such as the study of the effect of natural convection on lamellar eutectic growth [ 10 ] and the design of the hybrid phase change material-based metal hydride storage tank [ 11 ]. Our group has developed a phase-field lattice Boltzmann method with high phase conservation and precise wettability representation on complex geometries.…”

Simulation and experimentation study on the performance of metal hydride storage vessels

“…The Nusselt numbers obtained are utilized to design an improved metalhydride storage system for H 2 -based systems. 19 A triangle channel flow-field was anticipated to have higher polarization performance and a more regular velocity distribution, whereas four serpentine flow-fields for hydrogen and air had performance disparities. The pressure in the triangle channels was monitored to produce similar charts on a regular basis, and it revealed a very low pressure reduction.…”