Thermal Systems Engineer in , us

Energy Jobline ATTB; Théméricourt; On-site; EUR 58,000 - 81,000; Full time

Benefits offered by this job

Medical, dental, and vision plans

Life Insurance

Disability Insurance

401(k) Matching

Vacation and Sick Time

Tuition Reimbursement

Job summary

JetCool, a Flex company, seeks a Jr. Thermal Systems Engineer in Littleton, MA. You will support thermodynamic modeling, component testing, and system analysis for liquid-cooling products. This early-career role offers hands-on experience with complete cooling loops and cross-disciplinary collaboration.

The role requires a BS in mechanical/thermal fields or equivalent, 0–3 years of experience, and familiarity with lab instrumentation. CAD/CFD tools and Python/MATLAB skills are a plus.

Qualifications

• Bachelor's degree or equivalent practical experience in mechanical/thermal/aerospace.
• 0–3 years of relevant experience typical for this role.
• Strong foundation in thermodynamics, fluid mechanics, and heat transfer.
• Exposure to CFD, thermal analysis, or 1D fluid-network modeling.
• Ability to perform pressure-drop, energy-balance, pump and heat-exchanger calculations.
• Hands-on aptitude with lab instrumentation and test setups.
• Experience with analytical tools (MacroFlow, Cadence Celsius EC, Python, MATLAB) is a plus.
• Documentation and data correlation should be clear and well organized.

Responsibilities

• Support product requirements, specifications, and verification traceability.
• Develop and update 1D thermal-fluid models.
• Support CFD and conjugate heat-transfer analysis.
• Calculate pressure drop, flow distribution, thermal resistance, heat rejection, and operating points.
• Support selection and characterization of pumps, radiators, exchangers, tubing, and fittings.
• Build and instrument prototypes and thermal-fluid test loops.
• Operate flow meters, pressure transducers, thermocouples, and DAQ systems.
• Document assumptions, boundary conditions, uncertainty, results and recommendations.
• Assist in design reviews, troubleshooting and failure investigations.
• Improve reusable models, component libraries, and calculation tools.

Skills

Thermodynamics

Fluid mechanics

Heat transfer

CFD

1D Modeling

Pressure drop

Thermal analysis

Laboratory instrumentation

Python

MATLAB

Education

Bachelor's degree in mechanical/thermal/aerospace or equivalent

Tools

MacroFlow

Cadence Celsius EC

Python

MATLAB

Job description

Jr. Thermal Systems EngineerAt JetCool, a Flex company, we're at the forefront of liquid cooling innovation, delivering advanced solutions that empower our partners in AI and high-performance computing. United by a shared purpose, our teams are pushing the limits of what's possible and tackling complex challenges.A career at JetCool offers the opportunity to make a real impact by helping build smarter, more sustainable data centers. Together, we're not just advancing technology — we're redefining cooling standards to create a more sustainable tomorrow.To support our extraordinary teams who build great products and contribute to our growth, we're looking to add a Jr. Thermal Systems Engineer located in Littleton, MA.Reporting to the Product Manager the Jr. Thermal Systems Engineer will supports thermal-fluid modeling, requirements management, component characterization, testing, and system-performance analysis for liquid-cooling products. This early-career role offers significant hands-on experience with complete cooling loops and system-level engineering.

What a typical day looks like:

• Support product requirements, specifications, and verification traceability.
• Develop and update 1D thermal-fluid models.
• Support CFD and conjugate heat-transfer analysis.
• Calculate pressure drop, flow distribution, thermal resistance, heat rejection, and system operating points.
• Support selection and characterization of pumps, radiators, heat exchangers, tubing, and fittings.
• Build and instrument prototypes and thermal-fluid test loops.
• Operate flow meters, pressure transducers, thermocouples, and data-acquisition systems.
• Document assumptions, boundary conditions, uncertainty, results, and recommendations.
• Support investigation of flow imbalance, pressure drop, aeration, cavitation, coolant loss, and thermal-performance issues.
• Participate in design reviews, troubleshooting, and failure investigations.
• Improve reusable models, component libraries, and calculation tools.

The experience we're looking to add to our team:

• Bachelor's degree in mechanical, thermal, aerospace, or equivalent practical experience.
• Typically 0 to 3 years of relevant experience.
• Strong foundation in thermodynamics, fluid mechanics, and heat transfer.
• Exposure to CFD, thermal analysis, or 1D fluid-network modeling.
• Ability to perform fundamental pressure-drop, energy-balance, pump, and heat-exchanger calculations.
• Hands-on aptitude and familiarity with laboratory instrumentation., co-op, or academic experience involving thermal systems, fluid networks, electronics cooling, HVAC, or liquid cooling .
• MacroFlow, Cadence Celsius EC, Python, MATLAB, or similar analytical-tool experience is beneficial.
• Models and calculations are accurate and well documented.
• Test setups generate reliable and repeatable data.
• Analytical predictions improve through test correlation.
• The engineer assumes progressively more complex and independent assignments.

What you'll receive for the great work you provide:

• Full range of medical, dental, and vision plans
• Life Insurance
• Short-term and Long-term Disability
• Matching 401(k) Contributions
• Vacation and Paid Sick Time
• Tuition Reimbursement

Job Category: Design, Process & Technology Engineering

Is Sponsorship Available? No

JetCool is an Equal Opportunity Employer and employment selection decisions are based on merit, qualifications, and abilities. We do not discriminate based on: , , , , sex, origin, marital status, , gender , veteran status, , status, or any other status protected by law. We're happy to provide reasonable accommodations to those with a for assistance in the application process. Please email [e-mail] and we'll discuss your specific situation and next steps (NOTE: this email does not accept or consider resumes or applications. This is only for assistance.