SR. MECHANICAL ENGINEER Fourier is on a mission to make on-site hydrogen universally accessible. Our breakthrough architecture delivers highly modular, fully automated electrolyzer systems that scale to any capacity and optimize efficiency across all load profiles. We are building the infrastructure necessary for a purely sustainable, emission-free global energy future — and we need exceptional engineers to help us get there. ABOUT THE ROLE We are seeking a Senior Mechanical Engineer with deep hands-on expertise to lead mechanical design, analysis, integration, and validation of our commercial hydrogen production systems. This is a high-ownership role spanning all subunits and design aspects and the full balance-of-plant envelope that ties them together. This role sits at the intersection of mechanical, electrical, and manufacturing disciplines. You will co-own DFM/DFA strategy with our manufacturing partners and serve as the primary mechanical interface to our electrical and electronics engineering teams — ensuring that both high-voltage (HV) power conversion systems and low-voltage (LV) control and sensing electronics are packaged safely, thermally managed, and fully integrated into production enclosures. ROLES AND RESPONSIBILITIES * Lead concept development, design trades, and down-select decisions for all mechanical subsystems from water purification through post-production H₂ purification * Own 3D CAD design of complex parts and assemblies using SolidWorks or equivalent — including sheet metal, plastics, insulation systems, sealing methods, connectors, and fasteners * Review and develop process flow diagrams, P&IDs, and mechanical design documentation * Perform first-principles hand calculations for sizing and performance of fluid, thermal, and structural systems * Collaborate closely with the electrical and electronics engineering teams to integrate high-voltage (HV) power electronics and low-voltage (LV) control, sensing, and communications systems into mechanical enclosures * Design packaging solutions for HV electrical assemblies — including bus bars, power modules, and high-current connectors — ensuring proper insulation, creepage/clearance compliance, and thermal management * Design and validate cooling technologies (heat exchangers, forced-air systems) for thermal management of electrolyzer stacks, power electronics, and ancillary electrical components * Ensure enclosure designs meet relevant electrical safety standards (UL, IEC, NFPA) for HV systems handling DC bus voltages typical of PEM electrolysis applications * Define and manage interface control documents (ICDs) between mechanical and electrical subsystems * Partner actively with manufacturing engineering to embed Design for Manufacturability (DFM) and Design for Assembly (DFA) principles from the earliest concept phase through production release * Create and maintain full Balance-of-Plant (BoP) documentation including Bills of Materials, P&IDs, and fluid system specifications * Hands-on experience or strong familiarity with gas (hydrogen, nitrogen, oxygen) and water piping systems, including pressure ratings, material compatibility, and leak testing protocols * Develop test plans and lead laboratory test and validation activities to confirm product reliability, safety, and performance * Create and maintain PLM documentation including Bills of Materials, engineering drawings, design calculations, and FMEAs QUALIFICATIONS Required: * B.S. in Mechanical Engineering or equivalent; 6+ years of relevant experience in commercial product design and development * First-principles understanding of statics, mechanics, materials science, heat transfer, thermodynamics, and fluid dynamics — with the ability to apply these rapidly in hand calculations * Extensive experience taking mechanical designs from concept through production, including prototype builds and manufacturing release * Proven experience in DFM/DFA — working hand-in-hand with manufacturing partners to optimize designs for producibility, assembly, and reliability * Demonstrated experience packaging and integrating electromechanical systems involving both HV and LV electrical components * Proficiency in 3D CAD (SolidWorks strongly preferred) and Thermal & Structural FEA tools * Strong hands-on aptitude — comfortable in the lab, on the shop floor, and at the test rig * Experience creating GD&T-compliant 2D fabrication drawings (ASME Y14.5) Preferred: * Advanced degree (M.S. or Ph.D.) in Mechanical Engineering or closely related field * Experience with PEM electrolysis, fuel cell systems, or related electrochemical systems * Hands-on experience with hydrogen, oxygen, nitrogen, or other high-purity gas systems — including pressure management, material selection (316L SS, PTFE, PEEK), and leak testing * Experience with water purification technologies (deionization, ultrafiltration, reverse osmosis) and post-production gas purification * Multi-physics and CFD simulation experience (ANSYS Fluent, COMSOL, or similar) * Familiarity with electrical safety standards relevant to HV systems: UL 508A (industrial control panels), IEC 60204, NFPA 70E * Experience with PLM systems for BOM and drawing management WHAT WE OFFER * Fully paid Medical, Dental, and Vision coverage * Competitive salary and equity compensation commensurate with experience * Diverse and inclusive work environment * Paid sick days and vacation * In-office lunches * The opportunity to make a material impact on the global clean energy transition