Senior Mechanical Design Engineer – Liquid Cooling Systems

About the Company Nimbus Data Systems is the hyperscaler for the edge, delivering modular AI infrastructure from first deployment to AI factory with speed, scale and sovereignty. Named one of Fast Company's Most Innovative Companies and to the CNBC Disruptor 50, Nimbus Data Systems’s solutions are deployed in over 60 countries globally for organizations ranging from energy to defense. With nearly $500 million in funding to date, Nimbus Data Systems is backed by leading investors including Founders Fund, Lux, BlackRock and Microsoft (M12), alongside strategic partnerships with Microsoft, Dell, Palantir, NVIDIA, SpaceX, and Skydio. We are building the infrastructure layer for sovereign and edge AI - rugged, deployable compute for customers that cannot rely on centralized cloud. Working at Nimbus Data Systems means taking ownership, driving autonomy, and delivering impact. You’ll tackle challenges that haven’t been solved before and help build something transformative from the ground up. What you do here will not only define your career but help further Nimbus Data Systems’s mission to bridge the digital divide for customers around the world. About the Role Nimbus Data Systems is seeking a Senior Mechanical Systems / Design Engineer to lead the design and development of liquid cooling and mechanical distribution systems for our modular AI data center platforms. This role sits at the intersection of mechanical design, hydraulic engineering, thermal infrastructure, manufacturing, controls, and commissioning. You will own the mechanical distribution architecture connecting heat-rejection equipment, pumps, piping, manifolds, coolant distribution units, rack cooling systems, and modular interconnects. You will translate system requirements into practical, serviceable, and repeatable designs that can be manufactured in a factory and deployed consistently across multiple sites. This is not a traditional consulting or drawing-review role. You will help establish the design rules, technical standards, interfaces, and commissioning philosophy behind the product itself. What You’ll Own Mechanical and Liquid Cooling Architecture Own the end-to-end mechanical cooling and fluid-distribution architecture for modular data center platforms. Define primary, secondary, and rack-level cooling boundaries. Establish pumping, flow-control, pressure-management, balancing, and redundancy strategies. Align heat-rejection equipment, distribution piping, CDUs, rack manifolds, rear-door heat exchangers, and other cooling interfaces. Develop scalable architectures that support multiple product configurations and deployment sizes. Hydraulic System Design Perform and review pipe-sizing, flow, pressure-drop, pump-head, and system-volume calculations. Develop hydraulic models for water and glycol-based systems. Account for fluid concentration, viscosity, temperature, fittings, valves, strainers, heat exchangers, and equipment pressure losses. Define control-valve, balancing-valve, bypass, minimum-flow, and differential-pressure strategies. Validate system performance across normal, part-load, maintenance, startup, and failure conditions. Mechanical Design and Documentation Own P&IDs, mechanical schematics, equipment schedules, valve schedules, instrumentation schedules, and design calculations. Develop mechanical design criteria, basis-of-design requirements, and standard details. Define clear equipment and scope boundaries between plant systems, modules, CDUs, rack cooling, and field interconnections. Maintain disciplined revision control and technical traceability across the mechanical design package. Review vendor drawings, submittals, calculations, and equipment selections for compliance with system intent. Modular Product Integration Define mechanical interfaces between factory-built modules and field-installed infrastructure. Develop repeatable interconnect strategies for supply and return piping, manifolds, flexible connections, isolation valves, quick disconnects, drains, vents, and leak detection. Establish labeling, connection, access, and installation standards that reduce field variability. Support product configurations designed for transport, rapid installation, and phased expansion. Design for Manufacturing and Serviceability Develop layouts that support repeatable fabrication, assembly, inspection, testing, and installation. Standardize piping routes, fittings, valve assemblies, supports, connection points, and mechanical components where practical. Coordinate equipment clearances, removal paths, service access, drain points, vent points, and filter or strainer access. Partner with manufacturing teams to resolve buildability issues and improve future revisions. Translate field and factory feedback into product improvements. Controls and Instrumentation Integration Define the mechanical measurement and control requirements for temperature, flow, differential pressure, pressure, leak detection, fluid level, pump status, and valve position. Partner with controls engineers to develop system operating sequences and alarm strategies. Support pump staging, variable-speed control, minimum-flow protection, equipment enablement, and failure-response logic. Help ensure mechanical system data is available for commissioning, operations, and remote monitoring. Commissioning-First Design Design systems for safe and efficient filling, flushing, venting, draining, testing, balancing, and startup. Define isolation, bypass, temporary connection, and load-bank testing requirements. Develop or support factory acceptance, site acceptance, and integrated systems testing procedures. Establish performance-verification criteria for flow, pressure, temperature, heat rejection, controls, alarms, and failure modes. Work directly with commissioning and field teams during startup and troubleshooting. Cross-Functional Engineering Leadership Partner with thermal, electrical, controls, structural, manufacturing, commissioning, supply chain, and product teams. Coordinate directly with OEMs, equipment manufacturers, fabricators, and engineering partners. Identify interface risks, design gaps, and single points of failure early. Make clear technical decisions while maintaining alignment across the broader product architecture. Communicate complex system behavior in a practical way to both technical and nontechnical stakeholders. What Makes This Role Different Product ownership You will help define a repeatable mechanical platform rather than deliver a one-time project. Concept through deployment You will see designs move from calculations and P&IDs into fabrication, factory testing, commissioning, and field operation. High-density infrastructure You will solve mechanical and liquid-cooling challenges associated with AI, HPC, and other high-heat-density compute platforms. Direct technical impact Your decisions will shape equipment selection, system reliability, factory assembly, field deployment, and long-term serviceability. What You Bring 7 or more years of experience designing mechanical cooling, hydraulic distribution, process cooling, or mission-critical infrastructure systems. Experience with data centers, semiconductor facilities, industrial process cooling, central utility plants, or comparable high-reliability environments. Strong knowledge of pipe sizing, pump selection, pressure-drop analysis, flow balancing, system volume, and hydraulic control. Experience developing and owning P&IDs, mechanical calculations, equipment schedules, valve schedules, and instrumentation requirements. Practical knowledge of chilled-water, condenser-water, glycol, or process-fluid systems. Experience designing for commissioning, maintenance, isolation, flushing, venting, draining, and service access. Ability to coordinate across engineering, manufacturing, controls, commissioning, and field teams. Strong technical judgment and the ability to own work with limited oversight. Nice to Have Experience with direct liquid cooling for AI or HPC systems. Experience with CDUs, rack manifolds, cold plates, rear-door heat exchangers, liquid-to-liquid heat exchangers, or liquid-to-air systems. Background in modular, prefabricated, skid-based, or containerized infrastructure. Experience with AFT Fathom, Pipe-Flo, or comparable hydraulic modeling tools. Familiarity with CFD, thermal modeling, or transient analysis. Proficiency with AutoCAD, Revit, Plant 3D, SolidWorks, Inventor, or similar design tools. Experience supporting FAT, SAT, IST, or field commissioning. Professional Engineer license or equivalent technical depth. Compensation For U.S. Based candidates: To ensure fairness and transparency, the starting base salary range for this role for candidates in the U.S. are listed below, varying based on location experience, skills, and qualifications. In addition to base salary, this role will also be offered equity and subsidized benefits (details available upon request). We use a geographic pay structure based on cost-of-labor markets. Tier 1 (e.g., SF Bay Area, NYC, Seattle): $157,600 – $185,000 Tier 2 (most U.S. metro areas): $137,040 – $171,300 Tier 3 (other cities): $130,188 – $162,735 Final compensation will be determined by experience, scope, and level, and may vary from the posted range. Benefits Competitive base salary and equity Medical, dental, and vision (subsidized cost) Health savings accounts (HSA), flexible spending accounts (FSA), and dependent care FSAs (DCFSA) Retirement plan options, including 401(k) and Roth 401(k) Unlimited paid time off (PTO) 14 paid company holidays per year #LI-AB1 #LI-Remote Compensation $137,040 — $171,300 USD You're a Great Fit if You're A go-getter with a growth mindset. You're intellectually curious, have strong business acumen, and actively seek opportunities to build relevant skills and knowledge A detail-oriented problem-solver. You can independently gather information, solve problems efficiently, and deliver results with a "get-it-done" attitude Thrive in a fast-paced environment. You're energized by an entrepreneurial spirit, capable of working quickly, and excited to contribute to a growing company A collaborative team player. You focus on business success and are motivated by team accomplishment vs personal agenda Highly organized and results-driven. Strong prioritization skills and a dedicated work ethic are essential for you Equal Opportunity Statement At Nimbus Data Systems, we are committed to fostering a work environment where everyone is given equal opportunities to thrive. As an equal opportunity employer, we strictly prohibit discrimination or harassment based on race, color, gender, religion, sexual orientation, national origin, disability, genetic information, pregnancy, or any other characteristic protected by law. This policy applies to all employment decisions, including hiring, promotions, and compensation. Our hiring is guided by qualifications, merit, and the business needs at the time. Unsolicited Resumes and Candidates Nimbus Data Systems does not accept unsolicited resumes or candidate submissions from external agencies or recruiters. All candidates must apply directly through our careers page. Any resumes submitted by agencies without a prior signed agreement will be considered unsolicited and Nimbus Data Systems will not be obligated to pay any fees.