Senior Thermofluids Engineer for High-Impact Data Centers

Fluidstack; San Francisco (CA); Hybrid; USD 210,000 - 260,000; Full time

Job summary

Fluidstack is seeking a seasoned thermofluids engineer to define machine cycles, optimize heat exchangers, and design high‑pressure fluid systems for data-center scale cooling.

You will size exchangers, model cycle performance, and validate predictions against test data. The role requires traveling about 25% and supports a hybrid setup, with a strong preference for Austin, TX, but open to other locations for the right candidate.

Qualifications

• 10+ years of experience in thermofluids engineering, including thermodynamic cycle modeling, heat exchanger design, and high-pressure fluid system design.
• You’ve built a thermodynamic cycle model from fluid properties up and defended its assumptions to someone actively trying to break it.
• You’ve sized real heat exchangers against published correlations, and you’ve caught a case where the correlation belonged to a different geometry than the one in front of you.
• You’ve calibrated a model against a machine datasheet or test data and reported the gap honestly rather than tuning until it disappeared.
• You’ve written the analysis that changed a design decision, in a form that people who never ran the code could read and act on.

Responsibilities

• Define what the machine has to be, owning the cycle model that sets the working fluid and the pressures, temperatures and flows the compressor, turbine and exchangers are designed against.
• Design heat exchangers with surface areas running into millions of square meters, among the largest single drivers of a data center’s physical footprint.
• Design the fluid system around the machine: piping, valves, headers, relief and isolation, sized against the pressure-drop budget the cycle can afford and the pressures the fluid actually runs at.
• Run the trades that decide the machine: air-side temperature rise, face velocity and subcooling. Derive the operating points from coupled exchanger ratings rather than asserted approach temperatures, so infeasible designs get caught in the model instead of in hardware.
• Take the cycle predictions onto the test stand and reconcile them against measured COP, then say plainly where the model was wrong.

Skills

Thermofluids engineering

Thermodynamic cycle modeling

Heat exchanger design

High-pressure fluid systems

Model validation against data

Tools

CoolProp

REFPROP

Cavallini

Gnielinski

Wang correlations

Job description

Fluidstack is seeking a seasoned thermofluids engineer to define machine cycles, optimize heat exchangers, and design high‑pressure fluid systems for data-center scale cooling.

You will size exchangers, model cycle performance, and validate predictions against test data. The role requires traveling about 25% and supports a hybrid setup, with a strong preference for Austin, TX, but open to other locations for the right candidate.