Who Are We? XNRGY Climate Systems is a North American leader in sustainable HVAC solutions and advanced manufacturing of custom air treatment systems. We design and manufacture energy-efficient climate systems for applications including data centers, healthcare facilities, industrial buildings, and other mission-critical environments. Position Overview Reporting to the Manager, CPQ Tools & Selection Software, the Senior Performance Engineer, Thermal Modeling owns the physics behind our selection tools, developing and validating the performance models that determine how our equipment is selected, rated, and represented to customers. You’ll work across cutting-edge chiller and data center cooling technologies, from compressor and refrigerant-cycle modeling to chilled-water coils, psychrometrics, fan arrays, and acoustics. This is a hands-on role working directly with test data, build and improve engineering models, and see your work move from the test stand into commercial selection tools, partnering closely with stakeholders to ensure what the tool predicts matches what the equipment actually delivers. The role is based in Mesa, AZ with hybrid flexibility and occasional travel to test facilities, supplier test sites, and customer or consultant meetings. An Overview of your Responsibilities! • Performance Modeling: Develop and maintain thermal and performance models for chiller and air-side systems, incorporating real-world equipment behavior and operating conditions. • Model Validation: Compare model predictions against test data, identify discrepancies and root causes, and improve model accuracy and robustness. • Test & Correlation: Work closely with Testing & Labs to define test requirements, analyze results, validate models, and establish certified operating envelopes. • Selection Logic: Translate engineering models and test results into reliable selection logic, including off-design conditions, part-load operation, and coupled product performance. • Standards & Ratings: Support AHRI, ASHRAE, and AMCA ratings, certifications, performance documentation, and standardized model outputs. • Technical Support: Serve as the technical performance expert for stakeholders, helping resolve complex selections and performance questions and supporting customer-facing requirements. What you’ll need, among other things! • Bachelor’s degree in Mechanical Engineering, Thermal Engineering, or a related engineering discipline. • 7+ years of experience in HVAC, refrigeration, turbomachinery, or related performance engineering. • Experience developing and validating empirical or semi-empirical performance models against test data, with strong knowledge of thermodynamics, heat transfer, and psychrometrics. • Deep expertise in either air-side or refrigerant-side performance modeling, with working knowledge of the other; Air-side experience with data center cooling is strongly preferred. • Experience with performance testing, test data analysis, measurement uncertainty, and model-to-test correlation, with proven judgment around data quality. • Proficiency with technical computing tools such as Python, MATLAB, or equivalent, and experience working with engineering data and property libraries such as CoolProp or REFPROP; Familiarity with SQL and Git is a plus. • Ability to travel approximately 20% of the time, including trips to test facilities, supplier test sites, and customer or consultant meetings. Why Choose XNRGY? At XNRGY Climate Systems, you’ll be part of a fast-growing organization helping transform the climate systems industry through sustainability, innovation, and advanced manufacturing. You’ll have the opportunity to lead and develop a growing Supplier Quality Engineering team, influence supplier performance and operational excellence, collaborate with talented cross-functional teams, and play an important role in supporting XNRGY’s continued growth.