Combining liquid-cooled & air-cooled load banks for effective data center commissioning
As data centers grow in scale and thermal intensity, traditional commissioning approaches are evolving to reflect modern cooling architectures. Many hyperscale and colocation facilities are now starting to utilize both air and liquid cooling strategies to support high-density IT loads. In parallel, commissioning engineers are turning to a hybrid approach—using both liquid-cooled and air-cooled load banks—to properly simulate live operating conditions. This article explores how integrating both types of load banks supports accurate, reliable, and scalable data center commissioning.
Understanding Load Banks in Data Center Commissioning
Load banks are essential tools for simulating real-world power and cooling demands in a new or upgraded facility. They validate system integrity, redundancy, and thermal behavior before live IT hardware is deployed. Load banks are used to test:
Electrical infrastructure (UPS systems, PDUs, switchgear, back-up diesel generators)
Mechanical systems (CRACs, chillers, pumps, liquid cooling loops)
Controls, failovers, and backup sequences
Historically, air-cooled load banks have been the norm. However, the emergence of liquid cooling in new in high-performance data centers requires liquid-cooled load banks (LCLBs) for full validation testing.
The Role of Air-Cooled Load Banks
Air-cooled load banks discharge heat into the surrounding environment and are ideal for simulating traditional server racks. During commissioning, they:
- Validate airflow management strategies (hot aisle/cold aisle containment)
- Test the hall cooling capacity and distribution
- Offer easy setup and mobility
They are typically used during early commissioning phases or in areas where traditional air cooling remains in use.
The Role of Liquid-Cooled Load Banks
Liquid-cooled load banks are purpose-built to test liquid-cooled environments, which are increasingly common in high-density compute and AI/ML workloads. LCLBs are connected to the facility’s cooling distribution system and:
- Simulate the thermal load of liquid-cooled servers
- Verify pump performance, flow rate, delta-T, and heat rejection capacity
- Stress-test cooling loops and backup modes
- Identify commissioning bottlenecks such as air locks, low flow, or thermal lag
Because liquid-cooled systems discharge heat into the liquid, using air-cooled load banks alone will not reveal how the liquid cooling infrastructure behaves under real load.
A Combined Approach
In modern facilities where both liquid and air-cooling technology is utilized, deploying both liquid and air-cooled load banks offers the most complete test environment in the commissioning phase.
| Requirement | Air-Cooled Load Bank | Liquid-Cooled Load Bank |
|---|---|---|
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Simulates air-cooled racks |
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Simulates liquid-cooled racks |
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Tests HVAC Systems |
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Tests CDU/RCU and liquid coops |
|
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Verifies total power and heat rejection |
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Supports phased commissioning |
|
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By placing air-cooled load banks in legacy rack zones and liquid-cooled load banks in high-density zones, commissioning teams can validate true mixed-mode operations. This reflects the real diversity of cooling demands seen in production. The data center operators can have complete confidence both types of cooling infrastructures will perform effectively in real world operation.
Networking & Common Control
A hybrid load bank network enables centralized control of both air-cooled and liquid-cooled load banks, providing commissioning teams with a unified interface to simulate and monitor diverse thermal and electrical loads across the facility. By integrating both types of load banks into a single control platform—whether via a wired or wireless control system—operators can coordinate test sequences, ramp loads in tandem, log performance data, and respond to system behavior in real time. This centralized approach is particularly valuable in hybrid-cooled data centers, where maintaining synchronized testing across traditional and high-density liquid-cooled zones is critical. Hybrid network control enhances efficiency, reduces human error, and supports more comprehensive data capture during commissioning and integrated systems testing (IST).
Utilizing a common control system for both air-cooled and liquid-cooled load banks significantly enhances commissioning efficiency by streamlining operations, reducing manual intervention, and enabling synchronized load testing across diverse cooling zones. A unified interface allows operators to monitor, control, and sequence all load banks from a single workstation—eliminating the complexity of managing separate systems. This integration supports faster test execution, coordinated ramp-up/down cycles, and comprehensive data logging for compliance and reporting.
This level of integration—particularly when it comes to liquid cooling—requires deep expertise and robust engineering capabilities that not all providers are equipped to offer. Suppliers may offer only air-cooled solutions or provide liquid-cooled units with limited control capabilities, forcing commissioning teams to piece together systems from multiple vendors. This fragmented approach increases setup time, complicates troubleshooting, and can introduce delays—especially problematic under the tight project timelines typical of hyperscale and colocation buildouts.
In contrast, leading data centers prioritize reliability, repeatability, and expert support—making a single-vendor solution that offers fully networked, hybrid-capable load banks highly valuable. A one-stop shop for both air and liquid-cooled load banks ensures not only interoperability, but also access to experienced engineering teams, field support, and commissioning services that can adapt to evolving site requirements. This is critical for minimizing risk and meeting go-live deadlines with confidence.
Conclusion
As data centers become more complex, load bank strategies must evolve accordingly. Air-cooled load banks continue to play a vital role, but they cannot replicate the demands of liquid cooling systems. A hybrid commissioning plan that integrates both technologies is essential for verifying high-density infrastructure, maximizing uptime, and ensuring the long-term success of mission-critical environments.
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