Sr. Systems Engineer - Mechanical

Fleet Data Centers designs, builds and operates mega-scale data center campuses. Fleet provides its customers with flexibility and predictability to meet their upside demand forecasts, addressing a key need in the market as traditional leased models are struggling to keep pace with the demand for new Cloud and AI infrastructure. Fleet is led by a team of industry veterans that have already made a lasting imprint on the evolution of global digital infrastructure and are committed and uniquely capable of upleveling data center development scale and operations in the face of rising demand. Fleet is well positioned to bring in-house design, engineering and operational capabilities to collaborate with customers on tailored solutions for campuses of 500MW+. This unique model enables Fleet to provide the world’s largest and most sophisticated customers with a seamless extension of their own data center fleets with constant access to design innovation. Fleet is headquartered in Denver, Colorado, with satellite offices in Seattle, WA and Arlington, VA. Position Overview: We are seeking a Senior Systems Engineer – Mechanical to own the detailed design validation, analysis, and ongoing optimization of Fleet’s data center cooling topology from campus level through the rack. This role requires a deep understanding of Fleet data center cooling topology, including air-side and liquid-side systems (fan walls, CRAHs/CRACs, chillers, dry coolers, pumps, heat exchangers, distribution manifolds, in-rack cooling components), and how these components interact under a variety of operating and failure scenarios. The ideal candidate will pair strong mechanical engineering fundamentals with practical data center cooling experience, ensuring that the air-to-liquid mix and cooling configuration for each deployment match rack layouts and rack SKUs, that CFD and failure-mode simulations are routinely used to de-risk deployments, and that cooling system behavior is well understood and systematically improved. This role is accountable for end-to-end thermal system integrity, including aisle-level optimization, fan wall octet configuration, failure-mode simulations (e.g., CRAC outage, dry cooler outage), and impact assessment for infrastructure upgrades and expansions, with the goal of optimizing uptime SLAs and minimizing cooling stranding. We have a hybrid policy, and candidates can sit in Seattle, WA, Denver, CO, Austin, TX, or Alexandria, VA. Responsibilities Cooling Topology Ownership & Rack-Level Alignment Develop and maintain a deep understanding of Fleet data center cooling topology, including: Air-side systems: fan walls, CRAHs/CRACs, air handlers, ducting, containment, filters. Rack-level solutions: liquid-cooled cold plates, rear-door heat exchangers, in-rack manifolds, hybrid air/liquid configurations. Determine the air-to-liquid mix needed to support a given rack layout, accounting for: Rack SKUs and thermal design power per rack/cluster. Liquid-cooled vs.air-cooled SKUs and their specific inlet temperature, flow, and ΔT requirements. Aisle-level and room-level constraints (supply/return temperatures, pressure, containment). Ensure that for each deployment: The selected cooling topology supports the planned rack densities and layouts. Air and liquid paths are balanced to avoid local under-supply or over-supply conditions. Design assumptions are documented and traceable back to rack SKUs and IT deployment plans. Rack SKUs, Cooling Requirements & Data Accuracy Understand the air and liquid cooling requirements for each rack SKU, including: Inlet temperature and humidity ranges. Liquid flow, pressure, and temperature ranges for cold plates and rear-door heat exchangers. Allowable gradients across the rack and between front/rear or supply/return. Maintain a structured mapping between rack SKUs and required cooling configuration, including: Airflow requirements per rack and per aisle. Liquid flow per rack, per manifold, and per loop. Any special constraints (e.g., high ΔT, mixed air/liquid in same aisle, hot aisle / cold aisle rules). Ensure all cooling-related specifications and quantities (fan wall modules, CRAHs/CRACs, CDUs, pumps, valves, manifolds, piping sizes, coil sizes) are: Accurate and complete. Captured in standardized BOMs and drawings. Provided to capacity planners and procurement with enough detail to plan and procure infrastructure. CFD & Thermal Analysis Perform CFD analysis at room and aisle level to: Validate that planned rack placement does not create hot spots. Confirm that airflow patterns, pressure profiles, and temperature distributions are within allowable limits. Identify and mitigate cooling stranding, where cooling capacity exists but cannot be effectively delivered to IT load because of placement or topology. Use CFD and thermal modeling tools to: Evaluate different rack arrangements and containment strategies. Test sensitivity to changes in IT load, fan speeds, supply temperatures, and air-to-liquid mix. Quantify margin to thresholds (e.g., maximum rack inlet temperature, maximum component temperatures). Translate CFD results into actionable design rules, placement constraints, and deployment guidelines for capacity planners and operations. Aisle-Level Optimization & Fan Wall Configuration Optimize cooling for each aisle based on: Actual and forecasted IT load distribution. Air-to-liquid split for the racks in that aisle. Containment strategy (cold aisle, hot aisle, full containment, partial containment). Recommend fan wall octet configurations (and other fan wall module configurations) per deployment to: Meet airflow and pressure requirements for current and planned density. Maintain redundancy and margin for failure and maintenance scenarios. Minimize fan energy use while preserving required thermal headroom. Work with operations to tune setpoints (supply temperature, fan speeds, differential pressure, chilled water temperatures, etc.) in a way that: Supports uptime SLAs. Minimizes cooling stranding and unnecessary over-provisioning. Maintains or improves site PUE. Failure Mode Simulations & Uptime Optimization Conduct failure mode simulations and analyses for mechanical systems, including at minimum: Dry cooler outage or degraded performance scenarios. Pump failures, valve failures, and partial loss of liquid loops. Loss of containment or unplanned bypass conditions. For each scenario, evaluate: Transient and steady-state temperature excursions at the rack and component level. Time-to-threshold (how long before violating safe temperature limits). Impact on redundancy, load shedding requirements, and achievable uptime. Use results to: Recommend design improvements (additional redundancy, loop segmentation, capacity rebalancing). Define operational responses and MOPs (e.g., load shedding priorities, setpoint changes). Optimize uptime SLAs while minimizing cooling stranding, especially in mixed air/liquid deployments and high-density aisles. Cross-Functional Collaboration & Documentation Partner with capacity planners, rack design teams, site operations, facilities engineering, and procurement to ensure: Cooling design and capacity assumptions are aligned with rack deployment plans and SLAs. Air-to-liquid decisions are integrated into forecast models and program timelines. Mechanical constraints are visible and respected in planning and operations. Produce and maintain clear design guides, reference one-lines, piping schematics, and airflow diagrams for: Standard Fleet cooling topologies and variants. Site-specific implementations and exceptions. High-density / AI-specific deployments. Contribute mechanical content to internal standards and playbooks covering: Cooling topology design rules. CFD analysis methodologies and acceptance criteria. Failure mode simulation procedures and reporting standards. Support design reviews, incident reviews, and vendor evaluations from a mechanical systems standpoint. Required Qualifications Bachelor’s degree in Mechanical Engineering or a closely related engineering discipline. 6+ years of experience in data center mechanical engineering, mission-critical HVAC design, or thermal systems engineering for large industrial or technology facilities. Demonstrated deep understanding of data center cooling topologies, including both air-cooled and liquid-cooled architectures (fan walls, CRAHs/CRACs, chillers, dry coolers, pumps, heat exchangers, CDUs, manifolds, containment systems). Hands-on experience performing and interpreting CFD analysis for data halls or similar mission-critical environments, with a track record of using CFD results to drive design changes and rack placement decisions. Proven ability to: Determine appropriate air-to-liquid mix for given rack layouts and densities. Assess and optimize thermal performance at rack, aisle, and room levels. Identify and remediate hot spots and cooling stranding. Experience designing or analyzing failure modes for cooling systems (e.g., CRAC/CRAH outage, dry cooler/chiller degradation, pump or valve failures) and translating results into design and operational mitigations. Strong analytical and problem-solving skills, with the ability to connect thermal and mechanical design decisions to uptime, SLA performance, and site efficiency (PUE, water usage). Clear written and verbal communication skills, including the ability to document complex cooling concepts and present analyses to engineering and operations stakeholders. Preferred Experience in hyperscale or colocation data centers, especially supporting high-density AI/GPU clusters and advanced liquid cooling (direct-to-chip, rear-door heat exchangers, in-rack manifolds). Proficiency with industry-standard CFD and thermal analysis tools and familiarity with integrating results into DCIM/BMS or capacity planning workflows. Familiarity with data center efficiency metrics (e.g., PUE, WUE) and how cooling design decisions influence them. Experience with DCIM, BMS, and monitoring systems for tracking and optimizing thermal performance in production environments. Knowledge of relevant mechanical and building codes and standards as applied to mission-critical facilities. Prior experience conducting infrastructure upgrade or expansion impact analyses in live data centers, including development of MOPs and risk mitigations. Required Traits and Skills Integrity and Ethical Standards: Make safety- and reliability-focused decisions in all cooling design and operations work, especially in live critical environments. Effective Communication: Clearly explain complex cooling and CFD concepts, tradeoffs, and risks to both technical and non-technical audiences; comfortable presenting findings to engineering, operations, and leadership teams. Operational Paranoia: Anticipate mechanical and thermal risks, identify vulnerabilities in cooling topology and controls, and proactively implement mechanisms to prevent and minimize disruptions and safeguard safety, security, availability, and scale. Strategic & Systems Thinking: Understand how local cooling decisions (e.g., air-to-liquid ratios, fan wall octet configurations, CDUs placement) affect the behavior of the entire thermal system and overall uptime SLA. Critical Thinking & Analytical Ability: Use data, telemetry, CFD, and empirical testing to drive decisions; evaluate cost, risk, and performance tradeoffs for alternative cooling designs and operating strategies. Collaboration & Relationship Management: Build strong working relationships with capacity planners, site operations, facilities engineers, vendors, and other partners to drive aligned outcomes across power, cooling, and IT. Leadership & Mentorship: Provide technical leadership within the mechanical engineering domain, mentor peers and junior engineers, and help establish Fleet’s best practices for high-density cooling. Expected Salary Range $120,000 - $150,000 Salary + Bonus Fleet Data Centers Employment Fleet Data Center employees enjoy competitive compensation and comprehensive benefits, including 100% employer-covered medical, dental, and vision insurance, a 401K program, standard paid holidays, and unlimited PTO. NOTE: This job description is not intended to be all-inclusive. Employees may perform other related duties as assigned to meet the organization’s ongoing needs. Fleet Data Centers is proud to be an Equal Opportunity Employer. Qualified applicants are considered for employment regardless of age, race, color, religion, sex, national origin, sexual orientation, gender identity, disability or veteran status. If you need assistance applying for any of our open positions, please contact us at View email address on click.appcast.io. #J-18808-Ljbffr Fleet Data Centers