# Numerical analysis of advanced thermal management for metal hydride reactors using heat pipes

Oussama Rejeb, Christophe Vial, Abdelmajid Jemni, Tarik Kousksou, Nour-Eddine Fenineche, Maamar Bettayeb, Chaouki Ghenai

► To cite this version:

Oussama Rejeb, Christophe Vial, Abdelmajid Jemni, Tarik Kousksou, Nour-Eddine Fenineche, et al. Numerical analysis of advanced thermal management for metal hydride reactors using heat pipes. 15th International Conference on Hydrogen Production (ICH2P-2024) ICH2P, Dec 2024, Sharjah, United Arab Emirates. hal-04859709

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https://hal.science/hal-04859709v1

Submitted on 30 Dec 2024

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# Theoretical analysis of advanced thermal management for metal hydride reactors using heat pipes

¹ Oussama Rejeb¹, Christophe Vial¹, Abdelmajid Jemni², Tarik Kousksou³, Noureddine Fenineche⁴, Maamar

Bettayeb ⁵,⁶, Chaouki Ghenai ⁷,⁸*

1. Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut Pascal, F-63000, Clermont-Ferrand, France

2. Université de Monastir, Ecole Nationale d'Ingénieurs de Monastir (ENIM), LESTE, LR99ES31, 5000, Monastir, Tunisia.

3. Laboratoire SIAME, Université de Pau et des Pays de L'Adour/E2S UPPA, EA4581, 64000 Pau, France

4. ICB-PMDM UMR 6303, CNRS, Université Bourgogne Franche-Comté, UTBM, Belfort, F-90010, France

5. Department of Electrical Engineering, University of Sharjah, Sharjah, United Arab Emirates.

6. Center of Excellence in Intelligent Engineering Systems (CEIES), King Abdulaziz University, Jeddah, Saudi Arabia.

7. Department of Sustainable and Renewable Energy Engineering, College of Engineering, University of Sharjah, Sharjah, United Arab Emirates

8. Sustainable Energy Development Research Group, Research Institute for Science and Engineering (RISE), University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates.

<figure><img src="image_3.png" /></figure>

## Context

<table><thead><tr><td>Hydrogen Storage Mode</td><td>Conditions</td><td>Advantages</td><td>Disadvantages</td></tr></thead><tbody><tr><td>Compressed</td><td>150 to 700 bars</td><td>Simple, fast refuelling, compact</td><td>High pressure risks, energy for compression</td></tr><tr><td>Liquefied</td><td>-253 °C and 1 atm</td><td>High energy density, stable storage</td><td>Energy loss, cryogenic risks, complex insulation</td></tr><tr><td>Solid (Hydride)</td><td>25 °C</td><td>Safe, stable, less energy loss</td><td>Limited efficiency, slower refuelling, thermal management needed.</td></tr></tbody></table>

## Contribution

* Safe hydrogen storage: solid storage ensures safety

* Heat pipe thermal management chosen for its efficient, passive, reliable, temperature control.

* Developed a Dynamic Model for the LaNi5 material with a cylindrical reactor coupled with heat pipe

## System Description

<figure><img src="image_4.png" /><figcaption>LaNi5 cylindrical reactor coupled withs heat pipe</figcaption></figure>

## Mathematical Part

### Kinetics Reaction

$$ \frac{dX_{abs}}{dt} = Cst_{abs}\ln\left(\frac{P}{P_{eq,abs}}\right)\exp\left(-\frac{E_{act}}{RT_{abs}}\right)(X_{lim,abs} - X_{abs}) $$

### Energy equation

$$ (C_{p,can}m_{can} + C_{p,MH}m_{MH})\frac{dT_{abs}}{dt} = -Cst_{x}\frac{\Delta H}{MW_{H2}}\frac{dX_{abs}}{dt} - \frac{(T_{eva} - T_{abs})}{R_{abs,eva}} $$

### Evaporator

$$ 0 = \frac{(T_{abs} - T_{eva})}{R_{abs,eva}} + \frac{(T_{cond} - T_{eva})}{R_{cond,eva}} $$

### Condenser

$$ 0 = \frac{(T_{ex} - T_{cond})}{R_{ex}} + \frac{(T_{eva} - T_{cond})}{R_{cond,eva}} $$

## Validation

<figure><img src="image_5.png" /></figure>

Validation: Comparing the results provided by the numerical model with experimental data available in the literature.

## Results

<figure><img src="image_6.png" /></figure>

The variation in hydrogen storage capacity (%wt) for parabolic fins, rectangular fins, and triangular fins.

## Conclusions

**Model Development:** A lumped transient model for a heat pipe LaNi5 cylindrical reactor integrates kinetics, energy, and mass transfer.

**Thermal Control:** Heat pipe reduce the charging time.

**Efficiency Boost:** Heat pipe enhance the reliability of metal hydride hydrogen storage, supporting sustainable energy solutions.