Principal Engineer

Job Posting Start Date 10-16-2025 Job Posting End Date 12-01-2025

At 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.

Job Summary

JETCOOL Technologies a Flex company is a fast-moving cooling solution provider, and successful MIT-spinoff, producing game-changing cooling solutions for aerospace, electric vehicles, and data centers. We are looking for a Principal Engineer based in Littleton, Ma.

What a typical day looks like:

• Work with JetCool commercial team to adapt customer requirements into an implementation ready design.
• Advance technology maturity of new secondary system design elements (water quality, flow regulation etc.).
• Work with manufacturing partners to establish modular design specifications for fast customer implementation and deployment.
• Lead communication and technical exchange with customers, build and cultivate customer and partner relationships, focusing on behind and beyond the rack cooling infrastructure
• Work with Flex supply chain to enable vendors and ensure specifications are up to date.
• Lead technical problem solving and pull in cross functional team to provide innovative thermal cooling system solutions

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

• Bachelor (or higher) of Science (B.S. in mechanical or aerospace engineering) and 5+ years of work experience and 2+ years thermal heat rejection architecture / infrastructure experience
• Excellent first principles knowledge in mechanical engineering, fluid dynamics, thermodynamics, and system heat transfer
• Track record of delivering thermal heat rejection solutions to customers with high quality and on schedule
• Strong communication skills
• Strong problem-solving and thermal / fluid system analysis skills
• Ability to specify smart heat rejection system architectures

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

Pay Range (Applicable to Massachusetts)

$147,700.00 USD - $203,100.00 USD Annual

Job Category
Production 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: age, race, religion, color, sex, national origin, marital status, sexual orientation, gender identity, veteran status, disability, pregnancy status, or any other status protected by law. We're happy to provide reasonable accommodations to those with a disability for assistance in the application process. Please email accessibility@flex.com 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 disability assistance. To be considered for a position at JetCool, you must complete the application process first).

Client-provided location(s): Boxborough, MA

Job ID: Flex-WD207647

Employment Type: FULL_TIME

Posted: 2025-10-01T20:00:19