Lead Thermal Design Engineer (Austin, TX)

Exowatt is revolutionizing the energy landscape for the AI era with our groundbreaking P3 system that captures solar energy, stores it as heat, and generates electricity on demand. Founded in 2023 and backed by leading investors including Andreessen Horowitz, Sam Altman, and Felicis, we're committed to providing clean, modular, and scalable power that meets the rapidly growing demands of AI infrastructure. Our mission is to make sustainable renewable energy always available and almost free, enabling technological advancement while protecting our planet.    We are seeking a Lead Thermal Design Engineer to lead the design, development, and optimization of solar thermal receivers for our energy systems. In this role, you will own the engineering of components that absorb and transfer high-flux solar radiation into our thermal storage systems. You will work at the intersection of heat transfer, materials science, and optical engineering to push the boundaries of receiver efficiency, durability, and cost-effectiveness.   This position is based in Austin, TX. If hired for this role, relocation to Austin, TX is required. We provide relocation assistance. Key Responsibilities • Own the solar thermal receiver end to end architecture, design, analysis, prototyping, and qualification for a first-of-its-kind energy product, with direct influence on system-level cost and performance targets • Set the technical direction for receiver development: define requirements, drive design reviews, and make the calls on architecture trade-offs (cavity, external, tubular, particle-based) that determine how much of the sun we capture • Build and validate thermal and optical models, flux distribution, heat transfer efficiency, thermal stress, and use them to iterate designs in days, not quarters • Select and qualify materials that survive 600°C–1000°C+, extreme thermal cycling, and concentrated solar flux, working hands-on with ceramics, refractory metals, and advanced alloys • Design, run, and learn from high-flux prototype testing and accelerated life evaluation, and you'll see your hardware tested under real sun, not just in simulation • Partner closely with the solar collection, controls, heat exchanger, and thermal storage teams to optimize aiming strategies, flux distribution, and downstream integration as one system • Drive design-for-manufacturing from day one so the receiver scales from prototype to mass production at a cost the grid has never seen • Shape the receiver roadmap by tracking and pulling in advances in selective absorbers, high-temperature coatings, and receiver technology, and grow the team around you as we scale Required Qualifications • Bachelor's degree in Mechanical Engineering, Aerospace Engineering, Materials Science, or a related field, or equivalent demonstrated engineering depth • 7+ years designing high-temperature thermal hardware — solar receivers, heat exchangers, combustors, furnaces, propulsion components, or comparable systems operating at extreme heat flux • Deep command of heat transfer (conduction, convection, radiation), thermodynamics, and fluid mechanics, and the judgment to know when a hand calc beats a week of simulation • Proficiency with thermal and structural simulation tools (ANSYS, COMSOL, SolarPILOT, or equivalent), grounded in physical intuition rather than dependent on it • Hands-on experience with high-temperature materials like ceramics, refractory metals, advanced alloys up to and including selection, qualification, and failure analysis • A track record of taking hardware from concept through prototype testing into production, and the scars to prove it Preferred Qualifications • Advanced degree (MS/PhD) in a relevant discipline • Direct experience designing solar thermal receivers • Experience with molten salt, liquid sodium, or particle-based heat transfer media • Knowledge of selective absorber coatings and high-temperature surface treatments • Familiarity with optical modeling and ray-tracing tools for flux analysis, or solar field aiming-point optimization • Publications or patents in solar thermal or high-temperature receiver technology • Experience thriving in an early-stage, fast-iteration hardware environment where you set the standard rather than follow one What We Offer: Competitive salary and equity options. Comprehensive benefits package, including health, dental, and retirement plans. A dynamic work environment that fosters creativity and innovation. Opportunities for professional growth and development in a rapidly evolving industry. Relocation assistance.