Thermo Mechanical Engineer

Thermo Mechanical Engineer Overview

Fractile is at the forefront of AI technology, developing silicon, systems, and software to run the world’s most advanced models at unprecedented speeds and lower costs. Our team, comprising experts in hardware and software, is rapidly expanding to meet the growing demand for our innovative products.

We are currently looking for a Thermal Engineer with extensive experience in data centre or high-density system design. The ideal candidate will have a strong background in thermal design or mechanical engineering, with the ability to lead design direction and work hands-on with suppliers, prototypes, and test rigs. We are open to hiring either contractors or permanent staff, prioritizing candidates who can provide valuable expertise and help shape robust, production-ready cooling solutions.

The Role

You will be responsible for leading the design of an advanced cooling system for a high-density AI accelerator system intended for data centre deployment. This role involves developing the complete cooling architecture, including Direct-to-Chip (D2C) liquid cooling and rack-level thermal management solutions. You will work closely with mechanical engineers, chip and board designers, and third-party suppliers to define requirements, review designs, and ensure that all components meet performance, reliability, and manufacturability standards. Your role may also include leading or advising on the creation of a thermal test platform to validate solutions under real-world conditions.

Key Responsibilities

• Lead the design and specification of an advanced cooling solution for dense AI hardware systems.
• Collaborate with third-party suppliers to define thermal and mechanical requirements and review proposed solutions.
• Contribute to mechanical system design by specifying chassis interfaces, manifold routing, fittings, and integration details.
• Model and simulate thermal performance at cold plate, chassis, and rack levels.
• Develop and/or oversee a test platform to validate cooling concepts and final implementation.
• Support the design of Direct-to-Chip (D2C) liquid cooling systems, cold plates, CDUs, and hybrid liquid-air chassis.
• Drive design reviews, evaluate trade-offs, and ensure solutions are manufacturable and reliable.
• Liaise with system, hardware, and data centre teams to ensure the cooling architecture integrates seamlessly into overall system design.

Skills & Experience

• Essential: Bachelor’s Degree in Mechanical Engineering.
• At least 7 years of experience in developing hardware products with thermal design liquid cooling systems for high-performance computing, data centres, or equivalent high-density hardware.
• Expertise with D2C liquid cooling, cold plate design, and CDU/rack-level systems.
• Hands-on experience with thermal modelling and simulation tools.
• Experience taking designs through prototyping, testing, and production.
• Strong collaboration skills, comfortable working across disciplines and with suppliers.
• Familiarity with thermal-fluid analysis, materials selection, and system reliability principles.
• Desirable: Experience with AI accelerator or HPC hardware.
• Background in mechanical engineering to support mechanical chassis design and integration.
• Experience working directly with data centre operators or hyperscale infrastructure teams.
• Awareness of liquid handling and serviceability considerations in deployed environments.

How We Work

At Fractile, we value ownership and execution, allowing you to drive your work forward. We encourage rapid iteration, working directly with top leadership to transition from ideas to hardware on ambitious timelines. Our teams engage fully across hardware, software, silicon, and modelling to create products with generational impact. We maintain an optimistic and pragmatic approach, committed to achieving our goals through hard work. A team player mentality is essential, as we believe the mission is greater than any individual, and we strive to see the best ideas come to fruition, regardless of their origin.

About Us

Founded in 2022, Fractile has grown to a team of over 70 members and continues to expand rapidly. Our modern, open offices are located in London and Bristol, fostering a collaborative and problem-solving culture built on deep curiosity, entrepreneurial initiative, and technical fluency.

Note: Certain roles may involve working on technologies subject to export restrictions. Applicants may need to undergo additional eligibility checks to ensure compliance with applicable laws.

Degree Requirement: Bachelor’s

Visa Sponsorship May be