Principal Thermal Engineer

OptiCool; Town of Webster (NY); On-site; USD 180,000 - 260,000; Full time

Job summary

OptiCool is seeking a highly experienced Principal Engineer to lead the design, development, and optimization of CDU systems for hyperscale data centers in the United States. You will push heat extraction capacity per footprint and volume, enabling next‑generation liquid cooling for AI and high-density compute.

You will champion refrigerant-based and CO₂ cooling approaches, lead end‑to‑end architectures, and collaborate with hyperscale customers to scale innovative cooling solutions from concept

Qualifications

• 10+ years of experience in thermal-fluid systems, including liquid and/or refrigerant-based cooling.
• Demonstrated experience with two-phase heat transfer, refrigeration cycles, or advanced cooling technologies.
• Strong understanding of heat transfer, fluid dynamics, and thermodynamics in both single-phase and two-phase systems.
• Experience designing for high heat flux and space-constrained environments.
• Proven ability to innovate and bring new thermal management concepts from idea to prototype.
• Proficiency with CAD and advanced simulation tools (CFD, two-phase modeling where applicable).

Responsibilities

• Lead end-to-end design of CDU systems supporting hyperscale deployments, including primary/secondary loop architecture.
• Define system requirements aligned with hyperscaler priorities: maximum kW removed per CDU footprint, rack density scaling, and floor space efficiency.
• Design and integrate high-performance components: pumps, compact heat exchangers, manifolds, filtration systems, and controls.
• Optimize CDU designs for maximum heat transfer per square foot (kW/ft²) and per unit volume (kW/m³).
• Drive innovation in advanced heat extraction technologies, including two-phase cooling systems, transcritical and subcritical CO₂ cooling, and hybrid liquid–refrigerant architectures.

Skills

Thermal-fluid systems

Two-phase heat transfer

CFD

Heat transfer

Refrigeration cycles

High heat flux

CAD

Education

Bachelor’s or Master’s degree in Mechanical, Thermal, or Chemical Engineering

Tools

CAD

CFD

Job description

We are seeking a highly experienced Principal Engineer to lead the design, development, and optimization of Coolant Distribution Units (CDUs) for hyperscale data center environments. This role is central to enabling next-generation liquid cooling solutions for AI and high-density compute, with a strong emphasis on maximizing heat extraction capacity per unit footprint and volume.

A key focus of this role is to innovate and develop new heat extraction approaches, including the application of refrigerant-based and CO₂-based cooling technologies, to push beyond the limits of traditional water-based CDU systems.

Key Responsibilities

• Lead end-to-end design of CDU systems supporting hyperscale deployments, including primary/secondary loop architecture
• Define system requirements aligned with hyperscaler priorities: maximum kW removed per CDU footprint, rack density scaling, and floor space efficiency
• Design and integrate high-performance components: pumps, compact heat exchangers, manifolds, filtration systems, and controls
• Optimize CDU designs for maximum heat transfer per square foot (kW/ft²) and per unit volume (kW/m³)
• Drive innovation in advanced heat extraction technologies, including:
  • Two-phase cooling systems (boiling/evaporative heat transfer)
  • Transcritical and subcritical CO₂ cooling systems
  • Hybrid liquid–refrigerant architectures for ultra-high heat flux applications
• Evaluate and implement phase-change cooling strategies to significantly increase heat transfer coefficients and reduce system footprint
• Lead feasibility studies comparing water vs. dielectric fluids vs. refrigerants vs. CO₂ for performance, safety, cost, and scalability
• Address system challenges including pressure management, leak mitigation, safety compliance, and material compatibility for refrigerant/CO₂ systems
• Conduct advanced thermal and fluid modeling (including two-phase flow and phase-change dynamics)
• Optimize system-level tradeoffs between heat extraction capability, energy efficiency, and mechanical complexity
• Develop CDU concepts capable of supporting 100–300+ kW per rack and future scaling beyond
• Ensure compliance with evolving environmental and regulatory considerations (low-GWP refrigerants, sustainability goals)
• Collaborate with hyperscale customers and partners to align next‑generation CDU architectures with future infrastructure roadmaps
• Lead prototyping and validation of novel cooling architectures, including lab-scale and full-scale demonstrations

Required Qualifications

• Bachelor’s or Master’s degree in Mechanical, Thermal, or Chemical Engineering (or related field)
• 10+ years of experience in thermal-fluid systems, including liquid and/or refrigerant-based cooling
• Demonstrated experience with two-phase heat transfer, refrigeration cycles, or advanced cooling technologies
• Strong understanding of heat transfer, fluid dynamics, and thermodynamics in both single-phase and two-phase systems
• Experience designing for high heat flux and space‑constrained environments
• Proven ability to innovate and bring new thermal management concepts from idea to prototype
• Proficiency with CAD and advanced simulation tools (CFD, two-phase modeling where applicable)

Preferred Qualifications

• Experience with refrigerants (e.g., HFOs, HFCs) and CO₂ (R-744) cooling systems in industrial or data center applications
• Familiarity with ASHRAE standards (including refrigerant safety classifications) and Open Compute Project liquid cooling initiatives
• Knowledge of direct‑to‑chip, immersion cooling, and hybrid cooling architectures
• Experience addressing regulatory, safety, and environmental constraints (pressure systems, refrigerant handling, low‑GWP requirements)
• Background in system controls for managing dynamic thermal loads and phase‑change systems
• Experience working with hyperscalers or next‑gen data center infrastructure providers

• Innovation in next‑generation thermal management technologies
• Systems‑level thinking across mechanical, thermal, and refrigeration domains
• Strong analytical capability in multi‑phase heat transfer and system optimization
• Ability to evaluate emerging technologies and translate them into scalable products
• Leadership in cross‑functional, R&D‑driven engineering teams

Success Metrics

• Heat extraction density (kW per CDU footprint and volume)
• Demonstrated advancement of next‑generation cooling concepts (refrigerant/CO₂ adoption, prototypes, patents)
• Maximum supported rack density (kW/rack), including next‑gen AI workloads
• Thermal efficiency and system COP improvements
• Reduction in total cost of ownership (TCO) at hyperscale
• Reliability and safety performance of advanced cooling systems

Why Join Us

• Lead innovation at the frontier of data center cooling evolution beyond water‑based systems
• Work on breakthrough technologies enabling future AI infrastructure
• Influence industry direction toward higher efficiency and sustainable cooling solutions
• Collaborate with leading hyperscalers and technology innovators