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 filters
- Develop and maintain a deep understanding of liquid-side systems including chillers, dry coolers, pumps, CDUs, heat exchangers, headers/manifolds, and valve trains
- Develop 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 configurations
- Determine the air-to-liquid mix needed to support a given rack layout and density, considering rack SKUs, aisle configuration, containment, and site constraints
- Ensure 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 ranges
- Understand liquid flow, pressure, and temperature ranges for cold plates and rear-door heat exchangers
- Maintain structured mapping from rack SKUs to required airflow per rack and aisle
- Maintain structured mapping from rack SKUs to required liquid flow per rack, manifold, and loop
- Maintain structured mapping from rack SKUs to special constraints such as mixed air and liquid aisles and maximum delta T
- Ensure 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 spots
- Perform CFD analysis to 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
- Use CFD and thermal modeling tools to test sensitivity to changes in IT load, fan speeds, supply temperatures, and air-to-liquid mix
- Quantify margin to thresholds such as maximum rack inlet temperature and 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: