High-density racks—sometimes exceeding 30 kW per cabinet—are pushing cooling systems to their limits. Even small inefficiencies can compound into major performance issues.
Are you experiencing these issues?
- GPUs throttling due to heat
- Persistent hotspots despite increasing cooling
- Rising energy costs with no performance gains
If so, airflow—not cooling capacity—may be the problem. Without precise airflow management, even the best cooling solutions (liquid cooling, etc). won’t perform efficiently.
Why Proper Airflow Management is Critical for High-Density Racks
If you’re running 20kW+ racks, you know cooling isn’t just about adding more CRAC units—it’s about making the air work for you. But many data centers still overcool, wasting energy while hotspots persist. The complete physical separation of hot and cold air within is the first stage to maximizing cooling system efficiency.
Consider this:
- More cooling power ≠ better cooling – If airflow isn’t properly managed, conditioned air never reaches IT intake, forcing systems to overcompensate with unnecessary cooling. A poorly contained 30kW rack can require as much cooling as a properly contained 50kW rack—wasting cooling power and driving up costs.
- Hot air recirculation kills efficiency – without proper containment, CRAC/CRAH units work harder to compensate for thermal inefficiencies, increasing operational expenses and shortening equipment lifespan.
- If airflow is mismanaged, even your liquid cooling system fights itself—bypass airflow, pressure imbalances, and air leaks undermine heat dissipation, overburden auxiliary cooling systems, and reduce overall efficiency.
Before investing in costly cooling upgrades, optimize airflow first— By taking a layered approach— starting at the cabinet level and extending to room-level containment.
1. Fix Cabinet-Level Airflow First
Most airflow issues start inside the cabinet. If your cabinets aren’t sealed, you’re probably paying more than you need to and leaving performance on the table.
If you're pushing 30-50kW per cabinet-level air containment is one of the simplest and most effective ways to maintain optimal cooling efficiency.
Essential Cabinet-Level Fixes for High-Density Cooling:
- Use fully sealed cabinets – Prevents hot air from re-entering server intakes.
- Install bottom panels – Helps contain airflow within the cabinet, preventing leakage under the rack and ensuring conditioned air reaches IT equipment.
- Deploy blanking panels – Blocks unused U spaces to eliminate recirculation.
- Install air dams & grommets – Closes airflow gaps around cables and equipment.
- Use temperature and pressure sensors – Monitors real-time airflow performance.
2. Choosing the Right Room-Level Containment Strategy for Your Needs
Once cabinet airflow is optimized, room-level containment ensures heat separation at a larger scale.
What is the Best Containment Solution for High-Density Data Centers?
- Hot Aisle Containment (HAC) – Best for 20kW+ racks, HAC forces hot air into a return plenum, preventing recirculation and improving chiller efficiency.
- Cold Aisle Containment (CAC) – A practical retrofit for lower-density racks, CAC encloses the cold aisle to reduce air mixing but may struggle with high heat loads.
Not sure which is right for you? Read our blog:
Ultra-Efficient Containment Solutions
CPI offers flexible containment solutions to fit different layouts and densities.
- Creates a sealed exhaust path for hot air, directing it into a return plenum.
- Air Director & Constricted Exhaust = Faster Heat Removal—outpaces fan-based systems.
- Reduces CRAC/CRAH load, improving chiller efficiency.
- Streamlines containment by enclosing a block of cabinets, eliminating unnecessary walls between each chimney.
- Installs quickly—out of the box with just two screws.
- Telescoping design allows easy maintenance access.
- Supports mixed cabinet brands, varying heights, and irregular rows.
- Works around obstacles – Designed for columns, structural barriers, or custom layouts.
- Ideal for retrofits and facility upgrades, ensuring a seamless fit.
3. Visually Map Airflow to Find Hidden Inefficiencies
Even after optimizing cabinets and containment, hidden inefficiencies can persist. So, how do you know when your containment strategy is working?
Computational Fluid Dynamics (CFD) modeling provides a precise, data-driven analysis of airflow behavior, simulating:
- Velocity, pressure, and temperature fields
- Flow rate distribution through perforated tiles
- Rack inlet temperatures and pressure differentials
By identifying inefficiencies in real-time, CFD modeling enables proactive cooling optimization, reducing energy waste and improving thermal management—all without costly physical modifications.
Get Free Computational Fluid Dynamics Analysis from CPI
CPI offers free CFD analysis to map airflow paths, identify inefficiencies, and ensure your containment strategy is working effectively.
As part of this free service, you'll have access to a panel of onsite consultants, field application engineers and technical experts who provide a rigorous checklist of your installation's existing and planned airflow and equipment placement.
