International Journal of Energy Research, Vol.45, No.2, 1836-1856, 2021
Design and analysis of metal hydride reactor embedded with internal copper fins and external water cooling
Hydrogen is considered as a viable alternative fuel source for many domains. The main challenge in hydrogen technology is its storage. The most efficient form of storing hydrogen by volume is to adopt solid-state storage. This is achieved by gas-solid interaction using metal hydrides (MH). But, to achieve the full storing potential of MH, the heat management of the reactor is the critical factor. MHs having inferior thermal conductivity prove a challenge and thus, several kinds of research have gone into developing efficient MH reactors with features trying to enhance the heat transfer rate. In the view of this, in the present work, an MH reactor is designed and numerically (finite volume method) analyzed its heat transfer characteristics during hydrogenation and dehydrogenation of La(0.9)Ce(0.1)Ni(5)at 293 K. Besides, to achieve improved heat transfer rates, new internal copper fins, and external water jackets are provided. The objective of the present work is to achieve high heat transfer rates with minimum reduction in MH mass within the reactor. Also, a parametric study is carried out to identify the optimized fin design by varying number fins, fin height, and fin thickness, which results in the optimum fin structure of 12 numbers, 12 mm, and 2 mm, respectively. The CFD simulation of MH reactor with and without fins results in improved heat transfer rates and reaction kinetics with internal copper fins. The maximum temperature rise during absorption is reduced by 22.3 K, and during desorption, the drop in bed temperature is reduced by 6.8 K, using optimized copper fins. The obtained results are compared with previous work and observed that the implementation of internal copper fins with external water cooling provides better heat transfer. The proposed reactor + fin arrangement can be efficiently used for the development of MH based thermodynamic devices.