Lead Mechanical Engineer, Data Center Design

About this role

ABOUT FLUIDSTACK

We exist to make humanity more free. For most of human history, you farmed or you starved. Technology gave people more time for the things they wanted to do, instead of things they had to do. Powerful AI will be the biggest lever for human choice we've ever built - but only if models are aligned with what humanity actually wants. There are groups building AI who don't share these goals. Whoever deploys frontier compute infrastructure fastest will decide whether AI expands human freedom or shrinks it.

We're singularly focused on delivering 10 to 100s of GWs of compute faster than anyone else, rethinking every layer of the stack. We acquire power, design and build data centers, and operate them - with teams spanning hardware and software. Speed and scale are our key differentiators. Come be a part of building civilization-scale infrastructure for AI.

We hire people who care deeply about this problem space. If that is you, please apply!

ABOUT THE ROLE

The Lead Mechanical Engineer is a senior technical leader within FluidStack’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 FluidStack 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.

RESPONSIBILITIES

Mechanical Strategy & Standards

- Define and own FluidStack’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.

Modular Construction & Prefabrication

- 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 800VDC 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.

Multi-Project Design Delivery

- 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.

Team Leadership & Vendor Management

- 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 FluidStack’s mechanical interests in cross-functional forums with electrical, controls, construction, operations, and customer engineering teams.

- Interface with customer technical teams on cooling requirements, thermal specifications, and rack-level integration for GPU and TPU deployments.

BASIC QUALIFICATIONS

- B.S. in Mechanical Engineering or equivalent technical discipline.

- 10+ years of experience designing mechanical/cooling systems for data centers, with significant exposure to hyperscale or high-performance computing facilities.

- Deep technical knowledge of chilled water systems, air-cooled and water-cooled chillers, direct liquid cooling, and heat rejection plant design.

- Experience leading or managing a mechanical engineering team and directing external MEP consultants through a full design lifecycle.

- Working comm

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