Senior Mechanical​/Thermal Engineer

Orien Energy is an early‑stage climate tech startup developing advanced sorption heat pumps that convert low‑grade waste heat from water or humid air into high‑temperature steam. Initially focused on enhancing energy efficiency of the energy‑intensive industrial drying, we are now expanding into data center waste heat reuse. Our mission is to unlock industrial‑scale energy efficiency and decarbonization across both industrial processes and data centers.

We are backed by leading energy & climate programs/investors, including the Activate Fellowship, Harvard Climate Circle Incubator, and the Massachusetts Clean Energy Center.

We are seeking a highly motivated Senior Mechanical / Thermal Systems Engineer to join our founding team. This role will lead the prototyping of our benchtop heat pump system, spanning both modeling and experimental efforts. On the modeling side, you will refine an existing heat and mass transfer model in MATLAB to guide experimental design and system optimization. On the experimental side, you will design and fabricate heat exchangers, integrate the full‑loop system, and lead testing to characterize key performance metrics, including coefficient of performance and energy recovery ratio.

You will work closely with other founding team members to develop prototypes, generate critical data, and advance the system toward pilot deployment.

This role offers a clear path to senior technical leadership, with the potential to grow into a CTO‑level position.

• Design and develop thermofluid systems and components (heat exchangers, heat pump cycles, vacuum systems)
• Build and test prototypes
• Analyze experimental data and iterate on designs
• Support scale‑up from lab to pilot systems
• Collaborate with industrial partners on system integration
• Document results and contribute to technical reports and presentations

• PhD in Mechanical Engineering or at least 5 years of engineering R&D experience in related fields
• Strong background in heat transfer, thermodynamics, and fluid mechanics
• Experience with experimental design and prototyping
• Hands‑on experience in lab or industrial settings
• Strong problem‑solving and communication skills
• Mentoring experience
• Being able to work onsite at Greentown Labs in Somerville

• Experience with sorption heat pumps
• Experience with vacuum systems
• Startup or fast‑paced R&D environment experience

Competitive salary ($110,000–$150,000 depending on experience) and equity package (significant ownership as a founding engineer).

• Health insurance coverage
• 401(k) plan
• Flexible PTO policy
• Access to Greentown Labs, CIC Cambridge, and other world‑class entrepreneurial programs

Somerville, MA (Greentown Labs)

Please send a cover letter and your resume to Dr. Yajing Zhao (yjzhaorgy) directly!