Thermofluids & Heat Exchanger Engineer

Fluidstack; Austin (TX); On-site; USD 120,000 - 180,000; Full time

Job summary

Fluidstack is seeking a highly skilled engineer for the Thermofluids R&D Team in Austin. You will define machine cycle models, size heat exchangers, and design the fluid system including piping and relief paths to support gigawatt-scale compute infrastructure.

You will simulate cycle performance, calibrate models against datasheets and test data, and report gaps clearly. The role emphasizes holding open questions, and working across heat transfer challenges in a fast-paced environment.

Qualifications

• You’ve built a thermodynamic cycle model from fluid properties.
• You’ve sized real heat exchangers against published correlations.
• You’ve calibrated a model against a machine datasheet or test data and reported the gap honestly.
• You’ve written the analysis that changed a design decision.
• You’ve sized a relief path and signed off that the system was protected.
• You’ve held a result open when it was still open, instead of closing it early to be helpful.

Responsibilities

• Define the machine cycle model and set working fluid, pressures, temperatures, and flows.
• Design heat exchangers with very large surface areas and arrange the fluid system accordingly.
• Develop piping, valves, headers, relief and isolation sizing to meet pressure-drop budgets.
• Run trades on air-side temperature rise, face velocity, and subcooling; derive operating points from exchanger ratings.
• Take cycle predictions to the test stand and reconcile with measured COP.

Skills

Thermodynamic modeling

Heat exchanger sizing

Fluid systems design

Two-phase flow

Data center cooling

Tools

CoolProp

REFPROP

Cavallini

Gnielinski

Wang

Job description

Fluidstack is seeking a highly skilled engineer for the Thermofluids R&D Team in Austin. You will define machine cycle models, size heat exchangers, and design the fluid system including piping and relief paths to support gigawatt-scale compute infrastructure.

You will simulate cycle performance, calibrate models against datasheets and test data, and report gaps clearly. The role emphasizes holding open questions, and working across heat transfer challenges in a fast-paced environment.