Thermal Systems Digital Twin Engineer

Do you long to apply your academic expertise to an impactful and engaging business problem that will reduce energy consumption of the building sector?

About PassiveLogic®

PassiveLogic is the first fully autonomous platform for buildings. We’ve reinvented the fundamental principles of automation to democratize technology, optimize buildings, and reduce the world’s carbon footprint. We are a team of technologists, engineers, and creatives dedicated to making a sustainable impact through real-world solutions.

We are looking for team members who have a passion for technology and want to work on cutting-edge problems with real-world solutions. Our culture is built on bringing together the most talented engineers, thinkers, and creatives—backed by the world’s leading investors—working together to make the future a reality.

About the Role

This is a career-defining opportunity to play a crucial role in a hyper-scale AI company that is transforming the future of autonomous systems, energy, and the built environment.

The Thermal Systems Digital Twin Engineer will develop a library of physics-based models of building and HVAC components, equipment, assemblies, systems, buildings, and entire campuses. These models will support simulation, validation, and testing across teams. Validated models are used by our AI and Equipment Inferencer engine to optimize building system control.

What you’ll do

Component template development: Defines and develops fundamental component templates, in addition to managing the component template evolution process.

Mathematical and system modeling: Develop mathematical models for equipment, thermo-physical systems, and building simulation.

Model standardization and validation: Standardize and validate physics-based models for use by the PassiveLogic control engine for optimized autonomous control of buildings.

Software and model development: Contribute to both model development and software implementation.

What you’ll bring

If your experience does not meet all our posted requirements below, we’d still love to hear from you. We are looking for practitioners who are passionate about understanding people, committed to lifelong learning, and driven by the love of what they do. If that’s you, please apply!


You must have

• Proven experience:
• Master’s or Ph.D. in Mechanical Engineering, Aerospace Engineering, Chemical Engineering, Applied Physics, or a related field, with a focus on thermal-fluid sciences.

• Strong understanding of thermodynamics, heat transfer, and fluid dynamics.
• Hands-on experience in first-principles (physics-based) modeling of thermodynamic, thermo-chemical, or thermo-mechanical devices (as opposed to curve-fitted models or off-the-shelf FEA usage).
• Experience with object-oriented simulation tools such as Modelica (or Dymola), Simscape, etc.

• Understanding of buildings, mechanical systems, and process control.
• Strong skills in numerical methods, mathematical modeling, and data analysis.
• Interest in (or preferably, experience with) computer programming and/or software development.

• Exceptional communication skills: strong desire to be an outstanding teammate with a collaborative and interpersonal communication style.
• Organizational and strategic mindset:ability to establish clear workflows for developing and refining models, as well as a structured approach to validating them, ensuring consistency and accuracy.
• Collaborative mindset: openness to participating in a feedback-driven work process to guide improvements and drive growth.
• Adaptability: comfortable in a fast-paced startup environment; eager to learn, iterate, and innovate.
• Problem-solving orientation: you own this role. When issues arise, be the empowered force that solves them—rolling up your sleeves and taking initiative.

You should have:

• Modeling experience: Good analysis and problem-solving skills; experience with FEA modeling techniques.
• Fundamental building knowledge: Knowledge of the fundamentals of building energy and/or HVAC systems.
• Strong programming skills: Including but not limited to: Swift, Matlab, C++, C, etc.

It’s helpful to have

• Fundamental building knowledge: Knowledge of the fundamentals of building energy and/or HVAC systems.
• Experience in HVAC Systems modeling.
• HVAC Equipment Modeling experience: Heat pump, boiler, storage tank, solar thermal panels etc.
• Strong programming skills: Including but not limited to: Swift, Matlab, C++, C, etc.
• Experience in git version control.
• Experience/familiarity with: 
• Graph theory and Bond Graph modeling approaches.
• EnergyPlus.
• Swift language development experience (S4TF even better).
• Heuristic, statistical, or machine learning methods.
• Working in a startup.

Compensation, Benefits & Perks:

• Competitive compensation
• Generous equity share package
• Medical, dental and vision coverage
• Disability and life Insurance options
• Flex PTO
• Team-building events
• Free catered lunch in the office Monday — Friday
• Free ski pass (We are at the base of Big Cottonwood Canyon)
• Free National Park pass

When applying, include:

• A cover letter telling us why you're the perfect candidate for PassiveLogic
• A resume
• Extra mile — include a description of a project (of any type) you personally created, devised, built, managed, organized, or designed that was of your own self-initiative

Diversity and inclusion

Diversity, inclusion, and belonging is woven into our values and everything we do. We welcome all—come as you are and bring your whole self. We are proud to be an Equal Opportunity Employer. We celebrate diversity every day by maintaining a safe and inclusive environment for our employees at every stage of their careers.