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!

About the Role:

We are seeking a versatile Senior Mechanical Engineer with experience in thermal and fluid dynamics to support the design, development, testing, and optimization of clean energy power generation systems. Collaborating with engineers across the company, this Mechanical Engineer will take ownership from cradle to grave and help drive the project through completion. This role focuses on system-level modeling, thermal management, and fluid flow analysis, primarily at the 1D level, across components such as heat exchangers, turbines, pumps, cooling & lubrication loops, and other balance-of-plant subsystems.

The ideal candidate will bridge system architecture, physics-based modeling, and product development, ensuring industry-leading performance, reliability, and integration of complex energy systems.

Responsibilities

Define system requirements, interfaces, and performance budgets for thermal and fluid subsystems

Own system PFD and P&ID

Develop sub-system and system-level models to calculate steady, transient, and off-design thermal and fluid behavior using commercial analysis tools or in-house tools (e.g., Python code)

Support system trade studies evaluating performance, efficiency, and cost impacts

Support the integration of components including heat exchangers, pumps, fluid management systems, piping networks, and other auxiliary and support systems

Perform hand calculations using first principles to size components, determine flow rates, estimate component and system efficiency, etc.

Perform CFD and thermal analysis to evaluate heat transfer, pressure losses, flow distribution, and efficiency

Identify, outline, and support component-level and sub-system testing required for risk mitigation

Assist in the development of test plans and instrumentation strategies to validate thermo-fluid performance

Analyze experimental data to refine models and improve system design

Support development of control strategies related to thermal and fluid system performance

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 designing and building complex systems from 0 ->1 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 fluid mechanics, thermodynamics, and material science as it pertains to system sizing and modeling