Senior Mechanical Systems Engineer at Tract Capital Management, LP – Mercer Island, Washington

Fleet Data Centers designs, builds and operates mega-scale data center campuses. Fleet provides its customers 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 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 such as fan walls, CRAHs/CRACs, air handlers, ducting, containment, and filtersDevelop and maintain a deep understanding of liquid-side systems including chillers, dry coolers, pumps, CDUs, heat exchangers, headers/manifolds, and valve trainsDevelop and maintain a deep understanding of rack-level solutions including liquid-cooled cold plates, rear-door heat exchangers, in-rack manifolds, and hybrid air/liquid configurationsDetermine the air-to-liquid mix needed to support a given rack layout and density, considering rack SKUs, aisle configuration, containment, and site constraintsEnsure cooling topology and capacity at room and aisle level support current and forecast rack deployments and density targets

Rack SKUs, Cooling Requirements & Data Accuracy:

Understand the air and liquid cooling requirements for each rack SKU, including inlet temperature and humidity rangesUnderstand liquid flow, pressure, and temperature ranges for cold plates and rear-door heat exchangersMaintain structured mapping from rack SKUs to required airflow per rack and aisleMaintain structured mapping from rack SKUs to required liquid flow per rack, manifold, and loopMaintain structured mapping from rack SKUs to special constraints such as mixed air and liquid aisles and maximum delta TEnsure specifications and counts for cooling components including fan wall modules, CRAHs/CRACs, CDUs, pumps, valves, manifolds, piping sizes, and coils are accurate, documented, and provided to capacity planning and procurement

CFD & Thermal Analysis:

Perform CFD analysis at room and aisle level to validate that planned rack placement does not create hot spotsPerform CFD analysis to confirm that airflow patterns, pressure profiles, and temperature distributions are within allowable limitsIdentify and mitigate cooling stranding where cooling capacity exists but cannot be effectively delivered to IT load because of placement or topologyUse CFD and thermal modeling tools to evaluate different rack arrangements and containment strategiesUse CFD and thermal modeling tools to test sensitivity to changes in IT load, fan speeds, supply temperatures, and air-to-liquid mixQuantify margin to thresholds such as maximum rack inlet temperature and maximum component temperaturesTranslate 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 distributionOptimize cooling based on air-to-liquid split for the racks in that aisleOptimize cooling based on containment strategy including cold aisle, hot aisle, full containment, and partial containmentRecommend fan wall octet configurations and other fan wall module configurations per deploymentEnsure configurations deliver required airflow and pressure with redundancyMaintain redundancy and margin for failure and maintenance scenariosMinimize energy use while maintaining thermal headroomWork with operations to tune setpoints including supply temperatures, fan speeds, differential pressure, and chilled water temperatures to support uptime SLAs and reduce cooling stranding and over-provisioning

Failure Mode Simulations & Uptime Optimization:

Conduct failure mode simulations and analyses for mechanical systems including CRAC/CRAH outage scenarios, dry cooler outage scenarios, and pump or valve failuresEvaluate transient and steady-state temperature excursions at the rack and component levelEvaluate time-to-threshold for safe temperature limitsEvaluate impact on redundancy, load shedding requirements, and achievable uptimeRecommend design improvements such as additional redundancy, loop segmentation, and capacity rebalancingDefine operational responses and MOPs including load shedding priorities and setpoint changesOptimize uptime SLAs while minimizing cooling stranding, especially in mixed air and 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 headersSupport increasing liquid cooling fraction as AI-heavy racks grow in shareSupport changing setpoints or operating modes including supply temperatures and economization strategiesQuantify effects on current and future thermal capacity and headroomQuantify changes in aisle-level and room-level airflow and liquid flow distributionQuantify impact on PUE, water usage, and operating costsProvide 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 alignment between cooling design, deployment plans, and SLAsEnsure air-to-liquid decisions are integrated into forecast models and program timelinesProduce and maintain design guides, reference one-lines, piping schematics, and airflow diagrams for baseline data halls and high-density deploymentsContribute mechanical content to internal standards and playbooks covering cooling topology design rules, CFD methodologies, and failure simulation procedures

Required Qualifications:

Bachelor’s degree in Mechanical Engineering or a closely related engineering discipline6+ years of experience in data center mechanical engineering, mission-critical HVAC design, or thermal systems engineeringDemonstrated deep understanding of data center cooling topologies including air-cooled and liquid-cooled architecturesHands-on experience performing and interpreting CFD analysis for data halls or similar environmentsProven ability to determine air-to-liquid mix, optimize thermal performance, and identify hot spots and cooling strandingExperience analyzing failure modes for cooling systems and translating results into design improvementsStrong analytical and problem-solving skills tied to uptime, SLA performance, and efficiency metricsClear written and verbal communication skills

Preferred:

Experience in hyperscale or colocation data centers supporting high-density AI/GPU clusters and liquid coolingProficiency with CFD and thermal analysis tools and integration into DCIM or planning workflowsFamiliarity with PUE, WUE, and efficiency metricsExperience with DCIM, BMS, and monitoring systemsKnowledge of mechanical and building codes for mission-critical facilitiesExperience with live data center upgrades and MOP development

Required Traits and Skills:

Integrity and Ethical Standards: Make safety- and reliability-focused decisions in all cooling design and operations workEffective Communication: Clearly explain complex cooling and CFD concepts to technical and non-technical audiencesOperational Paranoia: Anticipate risks and proactively prevent disruptionsStrategic & Systems Thinking: Understand how local cooling decisions impact the full system and uptime SLACritical Thinking & Analytical Ability: Use data, CFD, and testing to drive decisions and evaluate tradeoffsCollaboration & Relationship Management: Build strong partnerships across teams and vendorsLeadership & Mentorship: Provide technical leadership and mentor junior engineersExpected Salary Range: $120,000 - $150,000 Salary + Discretionary 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 info@fleetdatacenters.com.