Sr. Systems Engineer – Mechanical

Position Overview:

We are seeking a Senior Systems Engineer Mechanical to own the detailed design validation analysis and ongoing optimization of Fleets 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.
  • Liquid-side systems: chillers dry coolers pumps CDUs heat exchangers headers/manifolds valve trains.
  • 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 -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:
• • CRAC/CRAH outage scenarios (single unit or multiple simultaneous failures).
  • 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.

Infrastructure Upgrades & Expansion Impact Analysis

• Lead or support infrastructure upgrades and expansion impact analyses for cooling systems including:
• • Adding or resizing fan walls CRAHs/CRACs dry coolers chillers pumps CDUs and distribution headers.
  • Increasing liquid cooling fraction as AI-heavy racks grow in share.
  • Changing setpoints or operating modes (e.g. different supply temperatures economization strategies).
• Quantify for proposed changes:
• • Effect on current and future thermal capacity and headroom.
  • Changes in aisle-level and room-level airflow / liquid flow distribution.
  • Impact on PUE water usage and operating costs.
• Provide mechanical engineering input into MOPs and risk assessments for any cooling system change that could impact live IT load.

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

• Bachelors 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 Fleets best practices for high-density cooling.

Expected Salary Range

$120000 - $150000 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 organizations 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.

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Required Experience:

Senior IC