Design of metal hydride reactor with embedded helical coil using optimization methods

Abstract

Metal hydride offers an efficient and cost-effective method to store hydrogen. In this study, Taguchi method coupled with grey relational analysis was used to optimize the design parameters i.e., diameter of helical tube (dh), major diameter of helical tube (dm), number of turns of helical tube (N) and velocity of heat transfer fluid ( V f ) for the helical tube heat exchanger embedded inside metal hydride bed to achieve minimum desorption time (td) for 80% desorption and minimum outlet temperature (T0) of heat transfer fluid (HTF). The performance of all experiments in the orthogonal array used for Taguchi and Grey relational analysis was evaluated by 3-D numerical simulations performed in commercial software COMSOL 5.3a. This stepwise methodology is significantly computationally efficient as the number of required simulations reduced by 90% as compared to the traditional parametric study-based methodology. Further, this methodology enables to estimate an optimized level of the parameters by considering all the objective functions (td, T0) simultaneously. Later, the performance of the optimally designed systems was compared with the orthogonal array experiments and it was found out that the optimized system designs have better performance in terms of the objective parameters i.e., td and T0 when compared with the other experiments of orthogonal array. These optimized systems will then be used for refrigeration and cooling applications.

Numerical and Theoretical Evaluation of Coupled Metal-Hydride-Based Thermal Storage System with Embedded Helical Tubes

“…The above model is a combination of two reactors that are validated individually in previous articles of other authors. 27,28 The individual models are closely matching with the experimental studies with a maximum variation of 5.24% and 2.4% for Mg 2 Ni−H 2 and LaNi 5 −H 2 respectively. Since these two validated models are used further for the combined system, it is expected that the present model gives a good approximation.…”

“…The water is used as HTF in this reactor as the temperature of reactor is below boiling point of water. The dimension of Reactor B and geometrical parameters of helical tube was optimized by Taguchi analysis and Grey relational analysis in the previous article . The design and dimensions correspond to minimum time for hydrogen desorption is selected and given in Table .…”

“…The helical tube arrangement is used inside metal hydride reactors for the flow of HTF. The geometrical parameter of helical tube for HTMH and LTMH reactors were optimized by Taguchi method and grey relational analysis and presented in earlier articles. , Further, the performance of this metal hydride thermal storage system is investigated based on discharging cycle and effect of various parameter on the outlet temperature of HTF from a helical tube embedded inside the HTMH reactor is studied. Finally, the thermal analysis of the system (energy balance) is analyzed based on the temperature variation of HTF and of the reactors.…”

Machine learning modelling and optimization for metal hydride hydrogen storage systems

“…Recently few scientic literature studies have been published on the implementation of the Taguchi method and Grey relational analysis for optimal system design with different enhancement techniques. [42][43][44] It was found that the Taguchi method and Grey relational analysis have limitations in terms of the selection of parameters and their levels, wherein global optimization with large sets of parameters is difficult to attain. 45,46 Nowadays machine learning along with various optimization techniques is at the forefront in various disciplines to optimize large datasets with a higher number of parameters.…”

Review of thermal management technology for metal hydride reaction beds

“…6a) are also essential factors affecting the effect of the MHR with spiral tubes thermal management besides the parameters of number, size, and position. 48,[65][66][67][68][69][70] The major radius reects the distance from the center of the MHB to the spiral tubes, and the axial pitch is dened as the distance between similar positions on consecutive turns of the spiral tubes. The reaction rate is accelerated by growing the major radius and the number of spiral tube turns, whereas a rise in axial pitch has the reverse effect on H 2 absorption.…”