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Despite myriads of mathematical and experimental studies using various heat exchanger-metal hydride assemblies, an adept comparison of reactors on standard performance defining parameters, i.e., reactor weight, external energy utilization, and alloy material, are not studied or reported for industrial storage containers and onboard applications. This lacuna is a critical barrier in developing efficacious hydrogen storage reactors for various applications. This article chronicles the 3-D design and optimization of three basic heat exchanger setups of solid-state hydrogen storage systems (shell and tube, spiral tube, and tubular) on critical parameters. For 5 kg LaNi 5 , a tubular design with small tube diameters has resulted in a shorter reaction time (120 s) for 90% saturation at 303 K and 15 bar inlet conditions; however, the reactor's gravimetric density was exceptionally high. In contrast, the reactor with three spiral tubes accomplished an exemplary reaction rate at a reasonable gravimetric density. This spiral arrangement became the base for developing a novel reactor that integrated heat pipes to reduce the sorption time. The proposed design achieved a specific output energy rate of 527 W/kg for 90% saturation in 366 s at a supply pressure of 15 bar, which is 23.7% higher than the reactor without heat pipes. [Display omitted] [ABSTRACT FROM AUTHOR]

• Solved two–point boundary value problem using novel integral technique. • Developed technique is adopted for cooling tower transfer characteristics prediction. • Proposed analytical model acts a tool to predict optimal cooling tower performance. • Quantified thermal mass of the packed column with height of the cooling tower. • Emphasized importance of heat and moisture difference ratios variation with tower height. In the present study, a novel integral technique based on a two-point boundary value problem for the evaporative cooling process occurring across the mechanically driven counter flow cooling tower is structured and solved numerically. The developed technique is validated with the experimental data reported in the literature by choosing thermal load and vaporization rate as thermal performance evaluation parameters and observed the maximum deviation to be ± 13.5%. Moreover, the effect of inlet parameters on thermal load and vaporization rate is evaluated, and it is observed that water inlet temperature and air-specific humidity has a substantial influence on the performance of the cooling tower. Unique dimensionless parameters such as characteristic thermal mass of the packed column with tower height, heat difference ratio and moisture difference ratio along the height of the packed column, and number of heat-transfer units are introduced for assessing the performance as well as transfer characteristics of the cooling tower considering air as the cooling medium and water as the working fluid. The influence of various parameters such as Lewis number, number of heat and mass transfer units, fluid flow ratio, dimensionless thermal mass of the packed column with tower height, and moisture difference ratio on cooling tower efficiency is analyzed and observed that fluid flow ratio and moisture difference ratio have a significant impact on the thermal performance of the cooling tower. Further, for the given operating range, optimal values of number of heat transfer units, fluid flow ratio, and characteristic height of the cooling tower are predicted and found to be 0.87,0.35, and 0.8 m, respectively. [ABSTRACT FROM AUTHOR]