Performance Measurements and Modelling of a Low Cost 1 Kw Alkaline Electrolyzer Prototype to Test Electrogenerator
Authors: Mandin Philippe , Rabillard Lilian , Thappily Praveen 
Published: December 2024

This work will demonstrate the performances of an alkaline electrolyzer prototype realized and assembled to match the characteristics of an industrial electrolyser (5 kW of electrical power) with low-cost materials and reduced maintenance. This project was made possible by the Region Bretagne, in collaboration with the KOHLER SDMO team in Brest. The initial goal is to produce valuable chemicals, hydrogen, during electro generator tests of electricity production. One difficulty is to avoid or to limit the spikes which occur during electro genrators tests, for example when power pass from 50% to 75%. These spikes are not acceptable for commercial electrolyzers. And the goal is a low cost solution to valorise the usually lost electricity produced during theses tests.
The necessity to use affordable materials led us to choose Stainless Steel 316L or nickel plates as electrodes substrates and Zirfon as membrane for the prototype. This work will explain the different steps to realize a stack with a power of 1 kW with those materials, and then the usage of 5 stacks to reach the 5 kW objective fixed. To this intend, this work will put the light on the exploration of mechanical parameters such as the surface of the electrodes, electrical parameters like cell tension steps, and chemical parameters (composition of electrolytes, dissolved species and percentage of weight of each to match the correct properties). [1]
To determine the performances of the electrolyser, this work will focus on the measurement of parameters. Regarding the objective of 1 kW per stack, the main parameters that are needed to be observed are the electrical ones. Therefore, current density and intensity spikes will be the fundamental parameters to measure. After reaching our objectives, it is also needed to measure other parameters regarding the hydrogen produced and its purity. The remaining measured parameters are related to the evaluation of the prototype during the experiment, such as temperature of plates and gas produced, and pressure in the electrolytes and gas pipes. [2 – 3]
To validate these experimental measurements, a theoretical modeling of the electrolyzer is proposed. Because this is a multiphysical system, this work mainly focus on electrical and thermal modeling. [3]

Table 1. Explored parameters, their units, and extremum values.

Physical properties

Symbol

Units

Maximum values

Minimum values

Cell tension

Ucell

V

1,5

3

Surface of electrodes

Awork

cm²

400

825

Chemical species

-

NaOH

KOH

Mass fraction

Yk
a

%w

1

5

a For k the chemical species used

Table 2. Measured parameters.

Physical properties

Symbol

Units

Nominal intensity

In

A

Intensity spikes

Γ

%In
a

Current density

j

A.cm-2

Gas flow rate

Qm

kg.s-1

Purity of H2

%HR, %O2, %H2

-

Gas pressure

Pgas

PSI

Temperature of plates, gas and electrolytes

Tplates, Tgas, Telectrolyte

°C

a Ratio between maximum Intensity (Imax) and nominal intensity (In)
Fig. 1. Industrial setup in Brest at KOHLER SDMO

Acknowledgement

These works were carried out within the Brittany Regional Council funding and the KOHLER valuable collaboration.

References

Damien Le Bideau, Philippe Mandin, Mohamed Benbouzid, Myeongsub Kim, Mathieu Sellier, International Journal of Hydrogen,
2019
Volume 44, pp4553-4569

Zhibo Ren, Jinyi Wang, Zhiyong Yu, Chang Zhang, Shiwang Gao, Pengjie Wang, Journal of Power Sources,
2022
Volume 544

Damien Le Bideau. « Étude de l’amélioration de la production d’hydrogène par le procédé d’électrolyse de l’eau alcaline : simulation avec mécanique des fluides numérique et optimisation génétique. »
2021.

Figure 1