Design And Experimental Evaluation of a Compact Alkaline Water Electrolyzer for Hydrogen Production

Int. Jr. of Contemp. Res. in Multi. PEER-REVIEWED JOURNAL Volume 4 Issue 6 [NovDec] Year 2025 7 © 2025 Dr. Getme Abhijit Sudamrao, Mohit Dongarwar, Tejas Ukey, Soham Fuktakar. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY NC ND).https://creativecommons.org/licenses/by/4.0/ Research Article Design And Experimental Evaluation of a Compact Alkaline Water Electrolyzer for Hydrogen Production Dr. Getme Abhijit Sudamrao 1*, Mohit Dongarwar 2, Tejas Ukey 3, Soham Fuktakar 4 1 Assistant Professor, Department of Mechanical Engineering, J.D. College of Engineering & Management, Nagpur, India 2,3,4 Student, Department of Mechanical Engineering, J.D. College of Engineering & Management, Nagpur, India, India Corresponding Author: * Dr. Getme Abhijit Sudamrao DOI: https://doi.org/10.5281/zenodo.17529306 Abstract Manuscript Information This study develops a compact alkaline water electrolyser for small-scale hydrogen production, utilising a transparent acrylic chamber, stainless steel electrodes, and 25% NaOH electrolyte. Experimental results confirmed hydrogen and oxygen generation at ~0.05 L/min with ~50% Faraday efficiency, limited by low current density (~20 mA/cm²). Optimisation strategies, including Ni-Mo electrodes, 30% NaOH, and 60°C operation, could enhance efficiency to ~65–70% and yield to ~0.15 L/min. Compared to proton exchange membrane (PEM) electrolysers, the system offers lower costs (~₹15,000 vs. ₹1,00,000/kW) but reduced flexibility. Hydrogen storage challenges were addressed with metal hydride and high-pressure solutions. The cost-effective, portable design is ideal for educational and renewable energy applications, with potential for industrial scalability upon optimisation. This work advances low-cost hydrogen production, supporting sustainable energy transitions. ▪ ISSN No: 2583-7397 ▪ Received: 02-09-2025 ▪ Accepted: 25-10-2025 ▪ Published: 05-11-2025 ▪ IJCRM:4(6); 2025: 07-10 ▪ ©2025, All Rights Reserved ▪ Plagiarism Checked: Yes ▪ Peer Review Process: Yes How to Cite this Article Getme AS, Dongarwar M, Ukey T, Fuktakar S. Design and experimental evaluation of a compact alkaline water electrolyser for hydrogen production. Int J Contemp Res Multidiscip. 2025;4(6):07-10. Access this Article Online www.multiarticlesjournal.com KEYWORDS: Alkaline water electrolysis, Faraday efficiency, PEM comparison, hydrogen storage, electrolyser cost 1. INTRODUCTION Hydrogen is a pivotal clean energy carrier for decarbonising industrial processes, fuel cells, and energy storage, with global demand projected to reach 150 million tonnes by 2030 [1, 14, 19]. Alkaline water electrolysis (AEL), a mature technology since Nicholson and Carlisle’s 1800 discovery, uses NaOH or KOH electrolytes to split water into hydrogen and oxygen, offering affordability over proton exchange membrane (PEM) and solid oxide electrolysers (SOEs) [2, 3, 5]. Recent advancements (2020–2025) focus on improving AEL efficiency through advanced electrodes (e.g., Ni-based alloys) and compact designs for small-scale applications [9, 16]. However, challenges like low efficiency (~50–60%), low-pressure gas Int. Jr. of Contemp. Res. in Multi. PEER-REVIEWED JOURNAL Volume 4 Issue 6 [NovDec] Year 2025 8 © 2025 Dr. Getme Abhijit Sudamrao, Mohit Dongarwar, Tejas Ukey, Soham Fuktakar. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY NC ND).https://creativecommons.org/licenses/by/4.0/ production, and storage difficulties limit adoption in resourceconstrained settings [4, 7]. This study addresses these gaps by developing a compact AEL designed in Fusion 360, featuring a transparent acrylic chamber and stainless-steel electrodes. Objectives include demonstrating gas production, calculating Faraday efficiency, comparing with PEM systems, and proposing optimisations (electrode materials, storage, operating conditions). Costing ~₹15,000, the system targets educational and renewable energy applications, contributing to sustainable hydrogen production [6, 18, 20]. 2. MATERIALS AND METHODS 2.1 Design Objectives • Effective hydrogen/oxygen production via AEL. • Compact, cost-effective design (~₹15,000 target). • Observable operation and Faraday efficiency >50%. • Optimisations for electrode materials and storage. 2.2 System Design Designed in Fusion 360: • Chamber: Acrylic (200 mm height, 150 mm diameter). • Electrodes: Stainless steel (100 cm², 2 mm thick). • Electrolyte: 25% NaOH (1 L). • Diaphragm: Porous polymer. • Power: 12 V DC battery (2 A). • Storage: 500 mL tank with plastic tubes. Figure 1: Schematic of the electrolyser 2.3 Basic Principle of Alkaline Water Electrolyser Alkaline water electrolysis uses electrical energy to split water into hydrogen and oxygen in an alkaline electrolyte (NaOH/KOH) [3, 6]. Two electrodes (anode, cathode) are immersed in the electrolyte, separated by a porous diaphragm to prevent gas mixing while allowing OH⁻ ion conduction. A DC power source (e.g., 12 V battery) drives the reactions: • Cathode (Reduction): 2𝐻2𝑂 + 2𝑒−→ 𝐻2(𝑔) + 2𝑂𝐻−(E⁰ = -0.83 V vs. SHE) • Anode (Oxidation): 4𝑂𝐻−→ 𝑂2(𝑔) + 2𝐻2𝑂 + 4𝑒−(E⁰ = 0.40 V vs. SHE) • Overall: 2𝐻2𝑂(𝑙) → 2𝐻2(𝑔) + 𝑂2(𝑔)(E_cell ≈ 1.23 V theoretical, 1.8–2.0 V practical due to overpotentials) [14]. The electrolyte (25–30% NaOH) enhances conductivity (~0.30.5 S/cm at 25°C), and stainless steel/nickel electrodes minimise corrosion [6, 9]. The diaphragm ensures >99.9% gas purity [3]. Operating at 60–80°C and 0.2–0.5 A/cm² optimises efficiency, with a typical Faraday efficiency of 50–80% [14, 15]. The setup produces low-pressure H₂ (<0.1 bar), collected via tubes to a storage tank [7]. 2.4 Experimental Setup • Filled chamber with 25% NaOH. • Electrodes 10 mm apart, powered by 12 V/2 A. Tested for 30 min at 25°C; gas observed visually. Figure 2: Design of electrolyser Figure 3: Schematic view of a Portable alkaline electrolyser 2.5 Performance Metrics • Gas rate: Bubble observation. • Faraday efficiency: Calculated via Faraday's laws. • Stability: Consistent operation. 3. RESULTS AND DISCUSSION 3.1 Performance Results Hydrogen/oxygen bubbles formed within 5 min. Hydrogen rate: ~0.05 L/min at <0.1 bar; ~100 mL in 30 min. Baseline Faraday efficiency: ~50% (detailed in 3.1.1), limited by 20 mA/cm² density and 25% NaOH. Table 1: Performance Metrics Parameter Value Hydrogen Rate ~0.05 L/min Faraday Efficiency ~50% Voltage/Current 12 V / 2 A Pressure <0.1 bar Time 30 min Int. Jr. of Contemp. Res. in Multi. PEER-REVIEWED JOURNAL Volume 4 Issue 6 [NovDec] Year 2025 9 © 2025 Dr. Getme Abhijit Sudamrao, Mohit Dongarwar, Tejas Ukey, Soham Fuktakar. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY NC ND).https://creativecommons.org/licenses/by/4.0/ 3.1.1 Faraday's Efficiency Calculations Faraday efficiency (η_F) measures charge utilisation for desired reactions, accounting for losses like gas crossover. It is calculated as: ηF=n ⋅ F ⋅ VH2 I ⋅ t ×100% Where: • n = 2(electrons per H₂ molecule), • F = 96485C/mol (Faraday constant), • VH2= measured H₂ volume (L), converted to moles via ideal gas law (Vm=22.4 L/mol at STP), • I= current (A), t= time (s). For the setup (I = 2 A, t = 1800 s, V_{H_2} = 0.1 L ≈ 0.00446 mol): ηF=2 ⋅ 96485 ⋅ 0.00446 2 ⋅ 1800 ×100% ≈50% Theoretical H₂ (100% efficiency): ~0.0089 mol (0.2 L). Losses (~50%) stem from crossover and side reactions at low density. Higher current (4 A) could raise η_F to ~70%. 3.2 Electrode Material Advancements Stainless steel overpotential reduced efficiency. Ni-Mo alloys lower it by 100–200 mV, boosting η_F by 5–10% [9, 16]. Nanostructured Ni coatings increase density to 40 mA/cm², yielding ~0.1 L/min H₂ [10, 11]. 3.3 Hydrogen Storage Solutions Leakage in the 500 mL tank limited collection. High-pressure tanks (5–10 bar) store ~1–2 L H₂ [7]. Metal hydrides (LaNi₅) absorb ~0.5 L/kg at low pressure [12, 17]. MOFs/adsorbents enable moderate-pressure storage [13]. 3.4 Electrolyser Efficiency Optimisation Strategies quantified: 1. Electrode Area: 200 cm² at 4 A: H₂ rate = 4⋅96485⋅1800 2⋅22.4⋅1000 ≈ 0.103L/min; η_F ~60%. 2. Electrolyte: 30% NaOH reduces losses by 20%, η_F ~60%. 3. Temperature: 60°C doubles conductivity, η_F +15% (~65%). 4. Spacing: 5 mm lowers resistance, η_F +5% [10]. Combined: ~0.15 L/min H₂, ~65–70% η_F . 3.5 DISCUSSION The AEL's affordability suits education [7]. Optimisations align with industrial AELs (~60–80% η_F) [4, 6]. PEM comparisons follow. 3.6 PEM Electrolyser Comparison PEM electrolysers use a solid polymer membrane for H⁺ conduction, contrasting AEL's OH⁻ in liquid electrolyte [2, 18]. Table 2: AEL vs. PEM Comparison Parameter Alkaline (AEL) PEM Efficiency (η_F) ~50–70% (baseline 50%) [14] ~70–80% [2, 18] Current Density 0.2–0.5 A/cm² 1–2 A/cm² [18] Operating Temp. 60–80°C 50–80°C [2] Durability/Lifespa n 50,000–80,000 h 20,000–40,000 h [18] Cost (per kW) ₹50,000–₹80,000 [20, 21] ₹1,00,000– ₹1,50,000 [20] Flexibility Low (slow response) High (rapid load changes) [18] H₂ Purity 99.9% 99.999% [2] Suitability Large-scale, steady power Intermittent renewables [18] PEM excels in purity and flexibility but costs more due to iridium catalysts [18]. AEL is better for cost-sensitive, stable-grid applications [20]. Recent 2024 data show PEM scaling challenges in large projects (>20 MW) [10]. 3.7 Cost Analysis in Indian Rupees The setup's cost (~₹15,000, 2025 estimates) ensures affordability for small-scale use [20, 21]. Breakdown (based on Indian suppliers, e.g., acrylic ₹500/kg, stainless steel ₹200/kg): Table 3: Cost Breakdown (INR) Component Quantity/Material Cost (INR) Acrylic Chamber 1 kg 500 Stainless Steel electrodes 0.5 kg 100 NaOH Electrolyte 250 g 200 Diaphragm & Tubes Polymer/plastic 300 Power Supply (Battery) 12 V, 2 A 1,000 Storage Tank 500 mL plastic 500 Connectors & Wires Clips/wires 400 Fabrication Labor Assembly 2,000 Total 15,000 Compared to commercial AELs (₹50,000–₹80,000/kW), this lab-scale prototype is ~3x cheaper, suitable for education [21]. Scaling to 1 kW could reduce costs to ₹40,000/kW by 2030 [20]. 4. Conclusion The compact AEL achieved ~50% Faraday efficiency, limited by low density. Optimisations (e.g., 200 cm² electrodes, 60°C) could reach ~65%, with Ni-Mo materials and metal hydride storage enhancing viability. PEM offers higher purity/flexibility but higher costs; AEL excels in affordability (₹15,000 setup). The design supports smallscale renewables, with industrial potential postoptimisation. 5. Acknowledgements Author’s Contributions Dr Abhijit Getme Sudamrao conceptualised/supervised, and reviewed. Mohit Dongarwar designed/tested. Tejas Ukey analysed data. Soham Fuktakar fabricated/prepared the manuscript. All revised/approved. Int. Jr. of Contemp. Res. in Multi. PEER-REVIEWED JOURNAL Volume 4 Issue 6 [NovDec] Year 2025 10 © 2025 Dr. Getme Abhijit Sudamrao, Mohit Dongarwar, Tejas Ukey, Soham Fuktakar. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY NC ND).https://creativecommons.org/licenses/by/4.0/ Funding Source Supported by J.D. 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Carmo M, et al. PEM vs. alkaline electrolysers: A 2024 review. Renew Energy. 2024;215:119012. doi:10.1016/j.renene.2023.119012. 19. Wang X. Electrolyser capex drop by 30% in 2025. BloombergNEF Report. 2024 [accessed via pvmagazine.com]. 20. Newalkar BL. BPCL-BARC collaboration on alkaline electrolysers. Moneycontrol. 2023 [cited 2025 Nov 1]. Available from: https://www.moneycontrol.com/news/business/bpcl-andbarcs-collaboration-can-halve-cost-of-alkalineelectrolysers-official-10690801.html Creative Commons (CC) License This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY 4.0) license. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. About the Authors Dr Getme Abhijit Sudamrao is an Assistant Professor in the Department of Mechanical Engineering at J.D. College of Engineering & Management, Nagpur, India. His research interests include thermal systems, renewable energy technologies, and mechanical design. He is dedicated to academic excellence, innovative teaching, and advancing sustainable engineering solutions.