Contact UsWhy Cooling Matters More Than Ever
As data centers continue to scale in size and complexity—driven by the explosive growth of AI and cloud computing—the demand for efficient cooling systems has never been greater.
Data centers can range from 1,000 to over 100,000 square feet and consume up to 150 megawatts of power. In fact, as of last year, they accounted for 1.5% of global electricity consumption, and that figure is expected to double by 2030. With such massive energy use, effective cooling isn’t just a technical necessity. It’s a sustainability imperative.
Understanding Chiller Yards
Chiller yards are outdoor installations of air-cooled chillers that remove heat from a fluid, typically air or water, using a refrigeration cycle. These systems rely on fans to draw ambient air through condenser coils, dissipating heat into the environment. However, poor layout or environmental factors can lead to hot exhaust air being re-ingested into the system, reducing cooling efficiency.
Data Center Cooling Simulation: Visualizing Chiller Inlet Airflow with Reverse Pathlines
Reverse pathlines are a powerful visualization tool in Ansys Fluent that trace the origin of airflow entering a specific region—in this case, the condenser inlets of chiller units. By seeding pathlines at the inlets and coloring them by temperature, engineers can clearly identify whether incoming air is ambient or recirculated exhaust.
In this simulation, reverse pathlines revealed complex three-dimensional flow behavior and confirmed significant hot air re-ingestion in downstream chillers. This insight was instrumental in evaluating mitigation strategies such as canopy installation, which effectively redirected airflow and reduced inlet temperatures.
Mitigation Strategies for Reducing Hot Air Recirculation
One of the most critical challenges in chiller yard design is the re-ingestion of hot exhaust air into condenser inlets, which can significantly degrade cooling performance. Whether you are optimizing chiller placement before construction or diagnosing and improving existing installations, Ansys Fluent, one of the most robust tools for data center cooling simulation available today, allows you to model a real-world chiller yard scenario while accounting for things like wind direction, ambient temperature, and airflow patterns to identify areas of hot air recirculation.
There are several design interventions that may help reduce this hot air recirculation:
- Relocating Chillers: Physically moving chillers to a different location on the site to avoid prevailing wind patterns or wake zones, while effective, can be very costly if you are working with an already established chiller yard. This tactic would be best suited for clean-sheet designs where layout flexibility exists.
- Elevating Chillers: Raising chillers above ground level—either on platforms or rooftops—to reduce exposure to recirculated exhaust air can help in wind-shadow scenarios and reduce interaction with low-level recirculation zones.
- Adding exhaust stacks: Extending the vertical ducting of exhaust fans to push hot air higher above the chiller yard is useful for creating mechanical separation between exhaust outlets and condenser inlets. This tactic offers relatively low cost compared to relocation or elevation and can be implemented on existing chillers.
- Installing canopies: This tactic involves adding horizontal barriers above the chillers to block downward recirculation of hot exhaust air. This is a practical and cost-effective solution for both new and existing installations and can help significantly reduce re-ingestion.
Mitigating Re-ingestion with Canopy Installations
Among the various mitigation strategies explored and outlined above, installing a canopy proves to be one of the most effective and cost-efficient solutions for reducing hot air re-ingestion.
A canopy is typically added above the chiller yard at the height of the exhaust ducts, which allows it to successfully block recirculated exhaust from being drawn back into the condenser inlets.
After implementing a canopy in a design experiencing significant hot air re-ingestion in downstream chillers, with inlet temperatures rising up to 133°F, 23°F above ambient, the results showed a dramatic reduction in inlet temperatures across most chillers, with only the final unit experiencing minor recirculation due to the canopy ending too early—a fixable issue by simply extending the structure.
Overall, the canopy introduced a 7% reduction in fan flow rate, providing a near-total elimination of thermal performance degradation.
Optimize for Peak Performance: Data Center Cooling Simulation
Optimizing chiller yard design with CFD simulation enables data centers to maintain peak thermal performance while minimizing energy costs and operational risks. By identifying airflow inefficiencies and testing mitigation strategies virtually, engineers can avoid costly redesigns and ensure reliable cooling from day one. The result is a streamlined design process that supports scalable, high-performance infrastructure.
Need help with a chiller yard design? SimuTech Group empowers engineers to tackle complex cooling challenges with advanced Ansys simulation tools and expert consulting. Contact us today to start designing and optimizing your data center cooling strategy.
Watch the Data Center Cooling Simulation Webinar
Want to see data center cooling simulation in action? Watch our latest webinar: Smarter Cooling for Data Centers: How CFD Simulation Enhances Chiller Yard Design and Optimization
