Design and optimization of longitudinally finned embedded tube-type hydride reactor based on standardized responses using MO-desirability-based technique

Abstract

The current research comprehensively investigates a longitudinal finned LaNi5 hydride-based hydrogen storage device. The design factors, namely the heat fin's thickness and height, are selected for optimization. The employed Central Composite design formulated eight cases when design factors varied between 2–5 mm fin heights and 1–2 mm thicknesses. The investigation emphasized the influence of the contact area between the copper fin and LaNi5 hydride on output responses such as 90 % and 100 % saturation time, thermal power, and alloy weight ratio. The optimal design for the longitudinally finned hydride reactor is determined using a quadratic regression model and a multi-response desirability technique. The desirability approach indicated a final design archetype for a capacity of 5 kg LaNi5 (assuming 20 % expansion volume) comprising a fin thickness of 1 mm and a height of 5 mm, yielding a combined desirability of 0.737. The simulation results of the optimum design show response values of 131 s, 612 s, 0.572, and 233.39 W/kg for 90 % saturation, 100 % saturation, weight ratio, and thermal power, respectively, against the regression model predicted values of 129.5 s, 609.33 s, 0.572085, and 233.587 W/kg with an overall deviation less than ±1.5 %. Additionally, a comparative study against the reactor designs reported in the literature revealed the modeled design's betterment, and henceforward, scaling up the present design improved the weight ratio without much hampering the absorption time and thermal power. Subsequently, a sensitivity study is performed to evaluate the means by which different operational conditions impact system performance.