At Tier 5 Systems, we seek out cutting-edge technologies that align with our mission to deliver sustainable, high-performance mechanical and HVAC solutions. That’s why we’re excited to feature Carnot’s CO₂ In-Row Cooling systems - a standout product line that brings unmatched efficiency, scalability, and environmental responsibility to data center cooling.

Why CO₂? A Natural Advantage

Carbon dioxide (CO₂ or R-744) is gaining traction as the refrigerant of the future and for good reason. With a Global Warming Potential (GWP) of just 1, CO₂ is classified as a “natural refrigerant,” making it one of the most environmentally sound options available. Unlike synthetic refrigerants such as HFCs or HFOs, which face tightening regulations due to their greenhouse gas impact or toxicity classifications (like PFAS concerns), CO₂ is non-toxic, non-flammable, and already naturally present in the atmosphere.

This means data centers utilizing CO₂ systems can confidently future-proof their infrastructure against evolving regulatory pressures - while drastically reducing their carbon footprint from day one.

Precision Cooling with In-Row Power

Carnot’s In-Row CO₂ Cooling units are purpose-built for the realities of modern data centers. Whether managing high-density racks, AI loads, or GPU-intensive applications, these systems deliver powerful performance in a compact footprint.

Each In-Row unit is designed to sit between server racks, drawing in hot air directly from the hot aisle and cooling it with precision before reintroducing it to the cold aisle. This localized approach minimizes thermal hotspots and ensures that critical equipment remains within safe temperature limits, even under intense compute loads.

Choose from two space-efficient options:

• 40 kW Unit – Just 12 inches wide, ideal for tight rack configurations or edge deployments.
• 140 kW Unit – At 30 inches wide, it offers exceptional capacity for dense, high-performance installations.

Both models integrate seamlessly between server racks, providing targeted cooling with a smaller physical footprint than many traditional systems. Carnot also has traditional CRAC units from 50kw to 175kw for modernizing more traditional server rooms and utilizing the rain cycle economization. 

The Rain Cycle™: Free Cooling Without Compromise

One of Carnot’s most compelling innovations is its patented Rain Cycle™ free-cooling design. This thermosiphon-based system utilizes a gravity-driven loop that enables economization without introducing outdoor air - an essential feature in environments where humidity control is critical.

In climates like Vancouver, where ambient temperatures allow for extended periods of economization, the Rain Cycle™ drastically reduces energy consumption by bypassing compressors and leveraging naturally cool temperatures. This not only cuts operating costs but also reduces system wear and maintenance over time. 

Key Benefits for Tier 5 Clients

• Eco-Friendly by Design: With a GWP of 1, CO₂ offers a responsible, regulation-proof alternative to synthetic refrigerants.
  
• Free Cooling with No Outdoor Air: The economizer cycle uses sealed-loop heat exchange - no need to sacrifice humidity or air quality control.
  
• Maximum Cooling Capacity: Among the highest-performing in-row units on the market, with robust specs designed for dense, high-load environments.
  
• Smaller Footprint, Greater Efficiency: The compact design and lack of oil in the data hall free up valuable space and simplify maintenance.
  
• Ready for the Future: Built-in flexibility supports both water- and CO₂-based condensing systems, ideal for scalable growth.

Seamless Integration, Thoughtful Engineering

From orbital-welded stainless-steel piping to modular controls that modulate fan speed and water flow based on real-time load, Carnot’s attention to detail sets a new standard in data center cooling. Installation follows standard industry practices (ANSI B31.5), and safety considerations such as low-mounted CO₂ sensors, ensure compliance with ventilation and detection codes.

Whether you’re retrofitting an aging facility or designing a new data center from the ground up, Tier 5 Systems can help you assess, install, and maintain Carnot’s CO₂ In-Row Cooling technology as part of a comprehensive, future-forward strategy.

Want to see if CO₂ cooling is right for your data center?

Contact Tier 5 Systems to schedule a consultation and explore how sustainable technology can support your performance and ESG goals.