Mechanical Engineer, Thermofluids

The role

This person will design and build machines for large scale heat rejection. They will own cycle models, design heat exchangers, and design fluid systems including piping and valves.

What you will do

• Define the machine by owning the cycle model for working fluid, pressures, temperatures, and flows.
• Design heat exchangers with surface areas running into millions of square meters.
• Design the fluid system including piping, valves, headers, relief, and isolation.
• Run trades to decide the machine including air-side temperature rise, face velocity, and subcooling.
• Derive operating points from coupled exchanger ratings.
• Take cycle predictions onto the test stand and reconcile them against measured COP.

Required qualifications

• 10+ years of experience in thermofluids engineering, including thermodynamic cycle modeling, heat exchanger design, and high-pressure fluid system design.
• Experience building a thermodynamic cycle model from fluid properties up.
• Experience sizing real heat exchangers against published correlations.
• Experience calibrating a model against a machine datasheet or test data.
• Experience writing analysis that changed a design decision.
• Experience sizing a relief path and signing off that the system is protected.
• Comfortable with regular travel of 25% or more.

Nice to have

• Vapor-compression and transcritical cycles (chillers, heat pumps, refrigeration)
• Propulsion and cryogenic fluid systems (feed systems, regenerative cooling, two-phase transport)
• Piping and relief design for high-pressure fluid systems
• Real-gas properties and two-phase heat-transfer correlations (CoolProp, REFPROP, Cavallini, Gnielinski, Wang)
• Data center thermal architecture (CDUs, dry coolers, direct-to-chip)

About the company

Fluidstack acquires, designs, builds, and operates data centers to deliver compute for AI. They focus on speed and scale to build civilization-scale infrastructure.