Experimental evaluation of dynamic operating concepts for alkaline water electrolyzers powered by renewable energy

Brauns, Jörn; Turek, Thomas

doi:10.1016/j.electacta.2021.139715

Cited by 35 publications

(18 citation statements)

References 56 publications

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“…reached in 0.24 ms. Both tests demonstrate that the specific electrolyte conductivity is suitable to meet dynamic performance, as required when connecting alkaline electrolyzers to intermittent green energy sources such as RES [36]. Finally, a test with dynamic solicitations has been performed to highlight the performance of the studied alkaline electrolyzer.…”

Section: Static and Dynamic Operationmentioning

confidence: 99%

“…As reported in [44], the HRI electrolyzer membrane resistance made of Zirfon material of 0.5 mm thickness is given in Equation ( 36) as: R mem = 0.060 + 80• exp(T/ 50) 10000•S mem (36) where S mem (cm 2 ) is the membrane surface, T ( • K) is the temperature. After analyzing the semi-empirical and empirical models, the next subsection allows introducing the dynamic modeling of alkaline electrolyzers that has to be considered when coupling them with intermittent energy sources.…”

Section: Membranementioning

confidence: 99%

“…Indeed, in both cases, the steady-state cell voltage operation is reached in 0.24 ms. Both tests demonstrate that the specific electrolyte conductivity is suitable to meet dynamic performance, as required when connecting alkaline electrolyzers to intermittent green energy sources such as RES[36].…”

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confidence: 97%

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A Comprehensive Survey of Alkaline Electrolyzer Modeling: Electrical Domain and Specific Electrolyte Conductivity

et al. 2022

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Alkaline electrolyzers are the most widespread technology due to their maturity, low cost, and large capacity in generating hydrogen. However, compared to proton exchange membrane (PEM) electrolyzers, they request the use of potassium hydroxide (KOH) or sodium hydroxide (NaOH) since the electrolyte relies on a liquid solution. For this reason, the performances of alkaline electrolyzers are governed by the electrolyte concentration and operating temperature. Due to the growing development of the water electrolysis process based on alkaline electrolyzers to generate green hydrogen from renewable energy sources, the main purpose of this paper is to carry out a comprehensive survey on alkaline electrolyzers, and more specifically about their electrical domain and specific electrolytic conductivity. Besides, this survey will allow emphasizing the remaining key issues from the modeling point of view.

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Section: Static and Dynamic Operationmentioning

confidence: 99%

Section: Membranementioning

confidence: 99%

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A Comprehensive Survey of Alkaline Electrolyzer Modeling: Electrical Domain and Specific Electrolyte Conductivity

et al. 2022

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“…Tt = (T stack,t + T sep,t )/2 (6) in which i is the current density, U rev is the reversible voltage, T is the average temperature, and r 1 , r 2 , t 1 , t 2 , t 3 , s are parameters. The heat loss to the ambient Q dis,stack is composed of thermal convection and radiation:…”

Section: Heat Exchangementioning

confidence: 99%

“…Since the electrolysis reaction is exothermic at room temperature, cooling devices are equipped to maintain the system temperature at the rated temperature [3]. Temperature affects both system efficiency and security: temperatures lower than the rated temperature hinder the electrolysis reaction and lead to low efficiency [4]; on the other hand, high temperatures beyond the upper limit can harm and shorten the lifetime of the materials of the stack by decreasing the corrosion resistance [5][6][7]. A consequence of corrosion is that the diffusion of gas molecules through the diaphragm increases, negatively impacting the gas purity [7,8].…”

mentioning

confidence: 99%

Thermal Modelling and Controller Design of an Alkaline Electrolysis System under Dynamic Operating Conditions

Qi¹,

Li²,

Lin³

et al. 2022

Preprint

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Thermal management is vital for the efficient and safe operation of alkaline electrolysis systems. Traditional alkaline electrolysis systems use simple proportional-integral-differentiation (PID) controllers to maintain the stack temperature near the rated value. However, in renewable-to-hydrogen scenarios, the stack temperature is disturbed by load fluctuations, and the temperature overshoot phenomenon occurs which can exceed the upper limit and harm the stack. This paper focuses on the thermal modelling and controller design of an alkaline electrolysis system under dynamic operating conditions. A control-oriented thermal model is established in the form of a third-order time-delay process, which is used for simulation and controller design. Based on this model, we propose two novel controllers to reduce temperature overshoot: one is a current feed-forward PID controller (PID-I), the other is a model predictive controller (MPC). Their performances are tested on a labscale system and the experimental results are satisfying: the temperature * These authors contributed equally.

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Erzeugung von Wasserstoff durch Elektrolyse

Bockelmann,

Becker,

Stypka

et al. 2023

Chemie in nserer Zeit

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ZusammenfassungIn diesem Übersichtsbeitrag berichten wir über die Grundlagen und den erreichten technischen Stand der Herstellung von grünem Wasserstoff durch Wasserelektrolyse. Für diese nachhaltige Produktion von Wasserstoff wird lediglich gereinigtes Wasser und erneuerbare elektrische Energie benötigt. Wegen der großen Stabilität des Wassermoleküls ist der Energiebedarf der Elektrolyse allerdings sehr hoch. Wir zeigen, dass es bereits drei technisch verfügbare Technologien (alkalische, PEM‐ und Hochtemperatur‐Elektrolyse) mit jeweils spezifischen Vor‐ und Nachteilen gibt. Zukünftige Entwicklungen konzentrieren sich auf die Senkung der Investitionen für Elektrolyseanlagen sowie auf die Verringerung der Verluste bei der Wasserspaltung, beispielsweise durch alkalische Membranelektrolyse mit einer eleganten Kombination der Eigenschaften von alkalischer und PEM‐Elektrolyse.

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Experimental evaluation of dynamic operating concepts for alkaline water electrolyzers powered by renewable energy

Cited by 35 publications

References 56 publications

A Comprehensive Survey of Alkaline Electrolyzer Modeling: Electrical Domain and Specific Electrolyte Conductivity

A Comprehensive Survey of Alkaline Electrolyzer Modeling: Electrical Domain and Specific Electrolyte Conductivity

Thermal Modelling and Controller Design of an Alkaline Electrolysis System under Dynamic Operating Conditions

Erzeugung von Wasserstoff durch Elektrolyse

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