Thermal System Engineer - Longmont, CO

About ErthSearch

ErthSearch is a recruitment agency specializing in placing top talent at ClimateTech startups and scaleups in the US. 

We believe the need for the right people is core to building a successful venture, and failure is not an option in the climate fight. 

The challenge: recruitment fees are often prohibitive. We are here to change that. Our cost model is transparent and affordable, so you can get the best talent on the market without it costing you an arm and a leg. 

Reach out if you want a genuine hiring partner – not another mercenary.

About Our Client

ErthSearch is working with OptiGrid, a venture-backed startup revolutionizing EV infrastructure. They build battery-based energy storage systems that provide ultrafast charging and resilient power alternatives, decentralized from the traditional grid to accelerate sustainable electrification.

The Role

As a Thermal System Engineer at OptiGrid, you’ll be the architect behind the thermal systems that manage next-generation battery and power electronics platforms. This is a hands-on role where you will drive designs from concept and early prototype testing to production with manufacturing partners. Your expertise will directly influence product performance, reliability, and customer satisfaction—opening new markets and driving technology forward.

What You’ll Do

• Drive V2 Development: Own the thermal architecture for our next-gen battery and power conversion platforms.
• Simulation & Validation: Perform (or oversee) high-level thermal modeling and CFD to predict performance, followed by rigorous physical testing to validate results.
• SME Leadership: Collaborate with mechanical and electrical teams to ensure thermal considerations are integrated early in the design cycle.
• Production Readiness: Ensure all designs are optimized for real-world manufacturing, taking ownership of the product through the UL certification process.
• Field Support: Occasionally travel (approx. 10%) to the field to troubleshoot or evaluate performance in real-world environments.

Qualifications & Skills

Core Requirements

• Battery Thermal Experience: Proven track record of implementing thermal management systems for battery packs (BESS, EV, or similar high-capacity systems).
• Power Electronics Expertise: Direct experience managing thermal loads for high-power electronics (kilowatt-scale) and power conversion systems.
• Manufacturing Intuition: You have moved designs from R&D into volume production. You possess a "visceral understanding" of how design decisions impact the manufacturing floor.
• Technical Tools: Proficiency in 3D CAD—ideally PTC Creo—and experience with PLM tools like Arena for production documentation.
• Education & Experience: A minimum of 5 years in thermal engineering; 10+ years is preferred.

Who You Are

• A Collaborative Communicator: You enjoy working with others to solve complex problems and can translate technical thermal data into actionable insights for the broader engineering team.
• Flexible & Ego-Free: While you are the expert, you are flexible in your thinking. You listen to ideas, navigate trade-offs, and prioritize the best path forward for the product over being "right."
• Hands-On: You are as comfortable at a computer running simulations as you are in the lab testing hardware.

Benefits

• Comprehensive Health, Dental, and Vision Insurance
• Short-Term and Long-Term Disability Insurance
• Life Insurance
• Competitive PTO package
• Dog-friendly office environment

Application

If you are interested in this role and believe you are a good fit (i.e., have experience designing complex thermal management systems for power electronics) apply today.

If you have any problems applying, you can reach out to Silas@erthsearch.com with your updated resume and reason for interest.