{"schemaVersion":"jobsearcher.job.v1","id":"08dd19ab65561dfb5e6ca155","url":"https://jobsearcher.com/jobs/08dd19ab65561dfb5e6ca155","canonicalUrl":"https://jobsearcher.com/jobs/08dd19ab65561dfb5e6ca155","title":"Mechanical Engineer, Thermofluids","description":"Location\n\nAustin, TX; Los Angeles; CA; San Francisco, CA\n\nEmployment Type\n\nFull time\n\nLocation Type\n\nHybrid\n\nDepartment\n\nDevelopment\n\nCompensation\n$210K – $260K • Offers Equity\n\nTo provide greater transparency to candidates, we share base pay ranges for all US-based job postings. Our compensation package includes base salary, equity for all full time roles, benefits, and, for applicable roles, commissions plans.\n\nThis range reflects a good-faith estimate based on the applicable pay scale, the range previously established for this role, the compensation of individuals currently in equivalent positions, and/or the budgeted amount for the position. Actual compensation may vary based on experience, qualifications, and other factors.\n\nWe welcome compensation discussions if this range doesn't meet your requirements. Outstanding candidates may be eligible for adjusted terms, plus meaningful equity that ensures you benefit directly from the company's long-term performance.\n\nTotal compensation may also include equity in the form of restricted stock units.\nAbout Fluidstack\n\nWe 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.\n\nWe'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.\n\nWe hire people who care deeply about this problem space. If that is you, please apply!\n\nHow We Operate\n\nBe a barrel. Full autonomy. Own things end to end, take on scope without being asked, no permission required to operate outside your core role.\n\nInsane urgency. We drive everything forward as fast as possible.\n\nReason from first principles. Challenge every assumption. Zero analogy thinking, no egos, the best idea wins.\n\nLove of the game. The frontier of AI is the most interesting problem of our time. We put in long hours at high intensity to push the frontier forward.\n\nBuild something that actually matters. If you're going to spend your time, spend it on something that matters to the world.\n\nThe Thermofluids R&D Team\n\nExamples of key problems the team is working on\n\nReject 10s of GW of heat, starting now. Fluidstack is targeting 10s of GW of compute over the next two years. Every watt of it becomes heat that has to go somewhere, and no cooling team has ever been asked to open at that scale rather than grow into it.\n\nDesign and build the machines, because nobody can supply them. The merchant compressor market cannot deliver at this rate, and the vendor base behind today’s chillers will not scale to gigawatts. We are taking compressor and chiller design in house, working on machine architectures nobody sells today, and going from blank sheet to production faster than this industry thinks is possible.\n\nOwn every thermofluids problem behind the fleet, not just the chiller. Working fluid and cycle architecture, heat exchangers at a scale that dominates the cost of the plant, two-phase heat transfer at the chip, and thermal energy storage. All of it is open, and whatever this team lands gets built thousands of times.\n\nRole Scope\n\nDefine 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.\n\nDesign heat exchangers with surface areas running into millions of square meters, among the largest single drivers of a data center’s physical footprint.\n\nDesign 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.\n\nRun 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.\n\nTake the cycle predictions onto the test stand and reconcile them against measured COP, then say plainly where the model was wrong.\n\nWhat We're Looking For\n\nThe below is a starting point. We always make space for exceptional people, so if you don't fit this role exactly, tell us where you would.\n\nYou’ve built a thermodynamic cycle model from fluid properties up and defended its assumptions to someone actively trying to break it.\n\nYou’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.\n\nYou’ve calibrated a model against a machine datasheet or test data and reported the gap honestly rather than tuning until it disappeared.\n\nYou’ve written the analysis that changed a design decision, in a form that people who never ran the code could read and act on.\n\nYou’ve sized a relief path and been the one who signed off that the system was protected.\n\nYou’ve held a result open when it was still open, instead of closing it early to be helpful.\n\nBonus: 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).\n\nWe are committed to pay equity and transparency.\n\nFluidstack is an Equal Employment Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, sexual orientation, gender identity, disability and protected veterans’ status, or any other characteristic protected by law. Fluidstack will consider for employment qualified applicants with arrest and conviction records pursuant to applicable law.\n\nYou will receive a confirmation email once your application has successfully been accepted. If there is an error with your submission and you did not receive a confirmation email, please email careers@fluidstack.io with your resume/CV, the role you've applied for, and the date you submitted your application- someone from our recruiting team will be in touch.\n\nCompensation Range: $210K - $260K","company":"FluidStack","rawCompany":"fluidstack","city":"Austin","state":"TX","isRemote":false,"isActive":false,"createdAt":"2026-09-24T06:40:12.680Z","occupations":[{"code":"17-2141.00","title":"Mechanical Engineers","slug":"mechanical-engineers"},{"code":"17-2199.00","title":"Engineers, All Other","slug":"engineers-all-other"},{"code":"49-9021.00","title":"Heating, Air Conditioning, and Refrigeration Mechanics and Installers","slug":"heating-air-conditioning-and-refrigeration-mechanics-and-installers"}],"industries":[{"code":"513210","title":"Software Publishers","slug":"software-publishers"},{"code":"541330","title":"Engineering Services","slug":"engineering-services"},{"code":"333415","title":"Air-Conditioning and Warm Air Heating Equipment and Commercial and Industrial Refrigeration Equipment Manufacturing","slug":"air-conditioning-and-warm-air-heating-equipment-and-commercial-and-industrial-refrigeration-equipment-manufacturing"}],"jobPosting":{"@context":"https://schema.org","@type":"JobPosting","title":"Mechanical Engineer, Thermofluids","description":"Location\n\nAustin, TX; Los Angeles; CA; San Francisco, CA\n\nEmployment Type\n\nFull time\n\nLocation Type\n\nHybrid\n\nDepartment\n\nDevelopment\n\nCompensation\n$210K – $260K • Offers Equity\n\nTo provide greater transparency to candidates, we share base pay ranges for all US-based job postings. Our compensation package includes base salary, equity for all full time roles, benefits, and, for applicable roles, commissions plans.\n\nThis range reflects a good-faith estimate based on the applicable pay scale, the range previously established for this role, the compensation of individuals currently in equivalent positions, and/or the budgeted amount for the position. Actual compensation may vary based on experience, qualifications, and other factors.\n\nWe welcome compensation discussions if this range doesn't meet your requirements. Outstanding candidates may be eligible for adjusted terms, plus meaningful equity that ensures you benefit directly from the company's long-term performance.\n\nTotal compensation may also include equity in the form of restricted stock units.\nAbout Fluidstack\n\nWe 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.\n\nWe'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.\n\nWe hire people who care deeply about this problem space. If that is you, please apply!\n\nHow We Operate\n\nBe a barrel. Full autonomy. Own things end to end, take on scope without being asked, no permission required to operate outside your core role.\n\nInsane urgency. We drive everything forward as fast as possible.\n\nReason from first principles. Challenge every assumption. Zero analogy thinking, no egos, the best idea wins.\n\nLove of the game. The frontier of AI is the most interesting problem of our time. We put in long hours at high intensity to push the frontier forward.\n\nBuild something that actually matters. If you're going to spend your time, spend it on something that matters to the world.\n\nThe Thermofluids R&D Team\n\nExamples of key problems the team is working on\n\nReject 10s of GW of heat, starting now. Fluidstack is targeting 10s of GW of compute over the next two years. Every watt of it becomes heat that has to go somewhere, and no cooling team has ever been asked to open at that scale rather than grow into it.\n\nDesign and build the machines, because nobody can supply them. The merchant compressor market cannot deliver at this rate, and the vendor base behind today’s chillers will not scale to gigawatts. We are taking compressor and chiller design in house, working on machine architectures nobody sells today, and going from blank sheet to production faster than this industry thinks is possible.\n\nOwn every thermofluids problem behind the fleet, not just the chiller. Working fluid and cycle architecture, heat exchangers at a scale that dominates the cost of the plant, two-phase heat transfer at the chip, and thermal energy storage. All of it is open, and whatever this team lands gets built thousands of times.\n\nRole Scope\n\nDefine 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.\n\nDesign heat exchangers with surface areas running into millions of square meters, among the largest single drivers of a data center’s physical footprint.\n\nDesign 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.\n\nRun 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.\n\nTake the cycle predictions onto the test stand and reconcile them against measured COP, then say plainly where the model was wrong.\n\nWhat We're Looking For\n\nThe below is a starting point. We always make space for exceptional people, so if you don't fit this role exactly, tell us where you would.\n\nYou’ve built a thermodynamic cycle model from fluid properties up and defended its assumptions to someone actively trying to break it.\n\nYou’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.\n\nYou’ve calibrated a model against a machine datasheet or test data and reported the gap honestly rather than tuning until it disappeared.\n\nYou’ve written the analysis that changed a design decision, in a form that people who never ran the code could read and act on.\n\nYou’ve sized a relief path and been the one who signed off that the system was protected.\n\nYou’ve held a result open when it was still open, instead of closing it early to be helpful.\n\nBonus: 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).\n\nWe are committed to pay equity and transparency.\n\nFluidstack is an Equal Employment Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, sexual orientation, gender identity, disability and protected veterans’ status, or any other characteristic protected by law. Fluidstack will consider for employment qualified applicants with arrest and conviction records pursuant to applicable law.\n\nYou will receive a confirmation email once your application has successfully been accepted. If there is an error with your submission and you did not receive a confirmation email, please email careers@fluidstack.io with your resume/CV, the role you've applied for, and the date you submitted your application- someone from our recruiting team will be in touch.\n\nCompensation Range: $210K - $260K","datePosted":"2026-09-24T06:40:12.680Z","dateModified":"2026-09-24T06:40:12.680Z","hiringOrganization":{"@type":"Organization","name":"FluidStack","sameAs":"https://jobsearcher.com"},"jobLocation":{"@type":"Place","address":{"@type":"PostalAddress","addressLocality":"Austin","addressRegion":"TX","addressCountry":"US"}},"identifier":{"@type":"PropertyValue","name":"JobSearcher","value":"08dd19ab65561dfb5e6ca155"},"url":"https://jobsearcher.com/jobs/08dd19ab65561dfb5e6ca155"}}