Senior Mechanical Engineer - Thermal & Fluids Systems

• Define system requirements, interfaces, and performance targets related to mechanical structures and fluid systems
• Develop and maintain system-level architecture for mechanical and fluid subsystems
• Perform trade studies to evaluate mechanical configurations, flow architectures, and their impact on system performance and cost
• Integrate components such as pumps, piping networks, valves, heat exchangers, and rotating machinery into the overall system design
• Design structural support hardware for multiple components and sub-systems
• Perform hand calculations using first principles to size components, determine flow rates, estimate stresses, etc.
• Perform finite element analysis (FEA) to evaluate structural integrity of components and subsystems
• Identify opportunities to optimize plant layout to increase construction efficiency, minimize cost, and improve maintainability
• Identify, outline, design, and support component-level and sub-system testing required for risk mitigation
• Assist in the development of test plans and instrumentation strategies to validate mechanical and fluid performance
• Analyze experimental data to refine and improve system design
• Generate technical documentation including system specifications, modeling reports, design trade studies, test analysis reports
• Develop and manage relationships with third-party vendors
• Support Field Ops teams with technical expertise and advice after product delivery and accept feedback on possible design improvements
• Other related tasks as defined by your supervisor that add value to the design needs

Required qualifications

• Bachelor's degree in mechanical engineering or related field, or equivalent experience
• 5+ years of proven experience in systems engineering or highly related role, with a strong portfolio of projects involving diverse and integrated machinery
• A solid understanding of and the ability to apply first principles of core mechanical engineering principles, including structural and fluid mechanics, thermodynamics, and material science
• Experience with a modern CAD package and a willingness to immediately self-teach proficiency in Siemens NX
• Excellent analytical and critical thinking skills
• Highly self-motivated with effective communication and team-working skills

Basic experience

• Experience with components and sub-systems common to power generation or process plants, like heat exchangers, pumps, turbines, valves, piping, fittings, sensors, and fluid management systems
• Understanding of thermodynamic cycles (e.g., Rankine, Brayton)
• Experience generating 3D models and managing assemblies in CAD while ensuring proper fit and function
• Building 1D models of thermo-fluid systems using commercial software (e.g., Aspen, Dymola)
• Proven experience using Python or another coding language to build thermal and/or fluid models
• In-depth knowledge of the design and operation of heat exchangers and how to select the appropriate type for a given application
• Understanding of the applicable codes, compliance, and regulations pertaining to development, deployment, and commissioning processing or power generation hardware
• Experience with computational fluid dynamics (CFD) using commercial software (e.g., ANSYS CFX, ANSYS Fluent, Numeca)
• You have worked with other engineering disciplines (such as Aerodynamics, Turbomachinery, Dev Test, Materials, and Manufacturing) to optimize designs for performance, reliability, and manufacturability
• You are effective and respectful in communicating with other engineers even when it is controversial or regarding errors that you have observed or have been observed in your work
• Experience creating and maintaining comprehensive design documentation including design reviews and component and system specifications

• Experience with components and sub-systems common to power generation or process plants, like heat exchangers, pumps, turbines, valves, piping, fittings, sensors, and fluid management systems
• Strong intuition for optimizing the layout of a complex system of machinery
• Experience generating 3D models and managing assemblies in CAD while ensuring proper fit and function
• Experience with FEA using commercial software (e.g., ANSYS Mechanical, NASTRAN, Catia)
• You have worked with other engineering disciplines (such as Aerodynamics, Turbomachinery, Dev Test, Materials, and Manufacturing) to optimize designs for performance, reliability, and manufacturability
• You are effective and respectful in communicating with other engineers even when it is controversial or regarding errors that you have observed or have been observed in your work
• Experience creating and maintaining comprehensive design documentation including design reviews and component and system specifications

• Base salary ranges from $140-200k per annum
• Equity options
• 100% company-covered Platinum or HD/HSA (with company contribution) medical
• 100% company-covered dental and vision
• Daily catered lunch
• Several annual social and team building outings

Actual base salary offered will be determined by: experience, skills, and work location. This range is for base salary, our total compensation includes equity and benefits. We welcome you to apply even if your expectations are outside our listed range.

Company description

Critical Energy is an innovative, early-stage, venture-backed cleantech company on a mission to accelerate the global energy transition through abundant, low-cost clean energy. Founded by an ex-SpaceX engineer, Critical Energy designs and manufactures factory-built, modular power plants. These rapidly deployable systems convert heat into electricity using a closed-loop thermodynamic cycle and can be installed in just weeks.

Critical Energy’s technology delivers high-efficiency, 24/7 power for geothermal applications and waste heat recovery (including from data center gas turbines), making clean energy practical and cost-effective for demanding sectors like AI hyperscalers and data centers. Backed by top climate and technology investors, Critical Energy is scaling rapidly.

Our mission

To build an abundant, low-cost, 100% clean energy future through groundbreaking geothermal innovation.

We are a team of passionate engineers, designers, and visionaries building cutting-edge solutions to meet the world’s energy needs with 100% clean energy. We are in the initial stages of development and building our team. This is your chance to join on the ground floor of something big! If you are ready to work at a fun, fast-paced, groundbreaking organization that is positioned to revolutionize geothermal energy, apply today!