Lead Mechanical Engineer, Data Center Design

About The Role

The Lead Mechanical Engineer is a senior technical leader within Fluid Stack’s Design and Engineering team. You will define the mechanical cooling strategy and own the programmatic design from chip to chiller across a multi-site, multi-state portfolio of some of the world’s largest AI data centers.

This is an owner/developer role. You will set the technical direction for how Fluid Stack cools tens of thousands of GPUs – spanning air‑cooled and liquid‑cooled architectures, chilled water systems, heat rejection, and in‑row/in‑rack thermal management.

You will define the requirements for modular, prefabricated mechanical assemblies designed around rapid deployment and compute‑refresh flexibility. You will manage a growing mechanical engineering team and coordinate across electrical, controls, structural, and construction disciplines to deliver cooling infrastructure at unprecedented speed and scale.

We recently announced a $50 billion computing infrastructure partnership with Anthropic, building custom data centers in New York and Texas with more sites to come. This role will shape the mechanical systems that make that possible.

• Define and own Fluid Stack’s mechanical cooling strategy across the portfolio – from chip-level thermal interfaces through CDU/coolant distribution, chilled water plants, and heat rejection to atmosphere.
• Develop and maintain the mechanical basis of design, master specifications, standard drawings, and sequence of operations for all cooling systems.
• Drive key architectural decisions: coolant chemistry (e.g. clean PG25 circuits), chiller topology (air‑cooled vs. water‑cooled centrifugal), CDU elimination strategies, and medium‑voltage chiller integration.
• Lead innovation on energy efficiency – free cooling, water‑side economizers, waste‑heat reuse – targeting best‑in‑class PUE and WUE across all sites.
• Establish thermal and hydraulic design criteria for high‑density GPU deployments (75–150+ kW/rack) spanning direct liquid cooling, rear‑door heat exchangers, and hybrid air/liquid architectures.
• Drive innovation and technology development across the mechanical and cooling discipline.

• Define the requirements for modular, prefabricated mechanical assemblies – including hot‑aisle containment cooling units, chiller skids, pump packages, and piping modules – designed for rapid site deployment with minimal field interfaces.
• Collaborate with manufacturing and procurement to evaluate emerging cooling technologies and manufacturing partners – including 800
  
  VDC chiller platforms, CO₂‑based systems, and integrated chiller/dry‑cooler packages.
• Work with BIM and structural teams to ensure prefab mechanical modules integrate cleanly into the base‑build design, with fabrication‑ready models and coordinated BOMs.

• Own mechanical design delivery across multiple concurrent data center programs – from concept through IFC, coordinating with external MEP consultants and internal discipline leads.
• Review and enforce mechanical deliverable quality at 30/60/90/IFC milestones; manage RFIs, design changes, and value engineering during construction.
• Produce and maintain project‑specific mechanical documentation: P&IDs, equipment schedules, valve schedules, piping plans, cooling yard layouts, and pump room arrangements.
• Support factory acceptance testing, site quality inspections, and commissioning of mechanical systems including chilled water loop flushing, passivation, and hydraulic testing.
• Conduct CFD modeling and thermal capacity planning to validate airflow, pressure drop, and temperature targets for each deployment.

• Build and manage a mechanical engineering team – set priorities, mentor engineers, and create a culture of technical rigor and speed.
• Manage relationships with chiller, pump, dry cooler, and coolant distribution vendors; drive competitive procurement and hold suppliers accountable on lead time, quality, and performance.
• Represent Fluid Stack’s mechanical interests in cross‑functional forums with electrical, controls, construction,…