Location & work modality: HQ Rubí (near Barcelona) / hybrid model (3 days per week at the office)

Start: ASAP

Type of Contract: Full Time / Permanent

About Submer Submer designs and delivers end-to-end AI datacenter infrastructure built around industry-leading liquid cooling.

We help organizations scale AI beyond the limits of traditional datacenters by enabling higher density, greater efficiency and lower environmental impact – accelerating time-to-AI from first deployment to full production.

What Impact You Will Have We are seeking a Mechanical Engineer to lead the design and delivery of critical mechanical systems for high-density data centers, including both conventional air-cooled facilities and direct liquid cooling (DLC) environments. This role ensures the safe, efficient, and resilient operation of cooling and mechanical infrastructure . from chillers to fan wall, CRAC/CRAH units, CDU loops and rack-level liquid cooling; enabling next-generation compute platforms and mission-critical operations. The ideal candidate brings a proven track record in mechanical design for data centers and thrives in collaborative, fast-paced, multidisciplinary projects.

What You’ll Do Mechanical System Design & Engineering

• Develop detailed designs for mechanical and cooling systems (chillers, cooling towers, CRAC/CRAH units, pumps, piping, valves, CDUs, FW, RDHx, and DLC loops).
• Define control strategies for primary and secondary cooling loops, supporting both air and DLC environments.
• Produce design documentation including schematics, layouts, hydraulic diagrams, specifications, and equipment schedules.
• Evaluate and select equipment suppliers, ensuring compliance with project performance requirements and client standards.

Thermal Performance & Analysis

• Perform load calculations, hydraulic modeling, and energy efficiency analysis.
• Optimize chilled water, glycol, and DLC systems to meet PUE and WUE targets.
• Assess redundancy schemes (N, N+1, 2N) and their impact on system performance and resilience.
• Integrate mechanical design with electrical and IT infrastructure, ensuring alignment across disciplines.

Commissioning & Delivery

• Support procurement processes, technical reviews, and submittal evaluations.
• Oversee factory acceptance tests (FATs), site acceptance tests (SATs), commissioning, and system validation.
• Lead troubleshooting and root cause analysis for thermal or mechanical issues, implementing corrective actions.

Compliance & Documentation

• Ensure designs comply with international standards, local building codes, ASHRAE, and Uptime Institute best practices.
• Develop and maintain documentation including test protocols, O&M manuals, and method statements.
• Contribute to risk assessments and ensure safety compliance for fluid handling systems.

Collaboration & Expertise

• Partner with clients, architects, electrical engineers, and IT teams to deliver integrated solutions.
• Provide subject matter expertise on high-density and DLC cooling strategies.
• Mentor junior engineers and contribute to knowledge sharing within the organization.

What You’ll Need

• Bachelor’s or Master’s degree in Mechanical Engineering (or related field).
• Minimum 4 years of experience in mission-critical mechanical design, with demonstrable data center project delivery.
• Strong knowledge of HVAC, chilled water, and liquid cooling systems (DLC, CDU, RDHx, etc.).
• Proficiency in mechanical design and analysis tools (e.g., Revit, AutoCAD MEP, HAP, Pipe-Flo, CFD).
• Familiarity with Tier certification requirements, ASHRAE guidelines, and international standards.
• Proven analytical, problem-solving, and troubleshooting skills.
• Strong communication and collaboration skills in cross-disciplinary teams.
• Ability to manage complex projects under tight deadlines in client-facing environments.

What We Offer

• Attractive compensation package reflecting your expertise and experience.
• Restaurant Pass.
• Private Health Insurance.
• Languages classes (English).
• A healthy work environment with fresh fruits to energise and an on-site gym for active breaks.
• A great work environment characterised by friendliness, international diversity, flexibility, and a hybrid-friendly approach.
• You'll be part of a fast-growing scale-up with a mission to make a positive impact, offering an exciting career evolution.

Our Inclusive Responsibility Submer is committed to creating a diverse and inclusive environment and is proud to be an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, veteran status, or any other protected category under applicable law.

From concept to deployment, we create liquid-cooled datacenters that scale smarter, run cleaner and cost less.