CDU: Core Hub of High-Density Liquid Cooling for AI Data Centers
With the rapid growth of AI models, supercomputing and high-density server cabinets, single-rack power density in data centers has reached 80kW, 100kW and beyond. Restricted by low efficiency, high noise and excessive energy consumption, traditional air cooling can no longer support high-power computing hardware. As a result, liquid cooling has become the preferred cooling solution for modern intelligent computing centers. As the core hub connecting the entire cooling loop, the CDU determines the efficiency, stability and service life of liquid cooling systems, making it essential for liquid-cooled data centers. The air liquid CDU cooling unit enables seamless upgrades from legacy air cooling to liquid cooling, delivering reliable, low-energy heat dissipation for high-density computing scenarios.
CDU (Coolant Distribution Unit) is the core control and heat exchange device for cold plate liquid cooling systems, acting as the heart and brain of liquid-cooled data centers. It integrates heat exchange, circulation, filtration, temperature and pressure regulation, and intelligent monitoring into one compact unit, widely used in AI computing centers, supercomputing facilities and large-scale liquid cooling data centers. The CDU physically isolates the facility-level primary cold source and server-level secondary cooling loop, precisely distributing low-temperature coolant and stabilizing the operating status of all liquid-cooled IT devices. High-purity server cooling liquid circulates in closed independent loops, ensuring efficient heat transfer while avoiding cross-contamination and equipment corrosion.
A high-performance CDU consists of precision collaborative modules, including brazed plate heat exchangers, 1+1 redundant variable-frequency pumps, filtration and degassing units, pressure-stabilizing expansion tanks, high-precision sensors and intelligent control systems. The plate heat exchanger achieves over 95% heat transfer efficiency and isolates dual loops to protect server cold plates and pipelines. Redundant pumps support uninterrupted operation and dynamic flow adjustment according to real-time computing loads. Filtration and degassing modules eliminate impurities and air bubbles, while the expansion tank stabilizes loop pressure and liquid volume. Full-range sensors and intelligent control realize real-time monitoring and fault protection. All components jointly ensure stable and efficient operation of the complete data center air liquid CDU, meeting 7×24-hour high-availability operation requirements.
The CDU operates with two physically isolated but thermally connected closed loops for fully automated cyclic cooling. Low-temperature chilled water from the facility cold source enters the primary-side heat exchanger, while the secondary-side coolant circulates through server cold plates to absorb heat from CPUs and GPUs. Heated secondary coolant transfers heat to the primary chilled water through counter-flow heat exchange, then cools down and recirculates to the cabinets. The warmed primary water returns to the facility cooling system for re-chilling. The CDU dynamically adjusts flow, temperature and pressure to match fluctuating computing loads. The integrated rack air liquid cooling CDU realizes cabinet-level precise cooling, shortening pipelines, reducing flow resistance and lowering liquid leakage risks for high-density racks.
CDUs deliver outstanding advantages in cooling performance, energy saving, system stability and intelligent O&M. They easily support 80kW–200kW per rack cooling capacity, eliminating overheating and computing throttling for high-power AI and HPC devices. Intelligent frequency conversion and precise temperature control reduce data center PUE below 1.1, significantly cutting refrigeration energy consumption and operational costs. Dual-loop isolation and multi-dimensional protection modules prevent pipeline blockage, corrosion and pressure anomalies, while redundant hardware ensures zero service interruption. Full-data monitoring and remote diagnosis simplify large-scale O&M. Paired with auxiliary cooling equipment such as the rear door liquid heat exchanger, CDUs effectively optimize overall thermal management during incremental upgrades of traditional computer rooms.
Industry mainstream CDUs are categorized into cabinet-mounted, in-row and centralized types to suit different project scales. Cabinet-mounted CDUs feature compact size and flexible deployment for small and medium-sized liquid cooling rooms and edge computing nodes. In-row CDUs provide larger cooling coverage and stronger heat exchange capacity, ideal for medium and large AI intelligent computing centers. Centralized modular CDUs offer ultra-high cooling power and centralized management, perfectly matching hyperscale supercomputing bases and large-scale AI clusters. For heat-intensive AI training scenarios, the customized AI GPU rack rear door heat exchanger serves as an efficient supplementary cooling solution to stabilize GPU cluster operation under full loads.
Driven by computing iteration and low-carbon policies, CDU technology presents four major development trends: high integration and lightweight design for compact high-density layouts; AI adaptive temperature and flow regulation for further energy reduction; full redundant hardware design to support non-stop maintenance; and standardized, universal specifications to improve equipment compatibility. In traditional computer room renovation projects, the high-efficiency high density server rear door heat exchanger effectively solves high-power heat dissipation bottlenecks, lowering the threshold for enterprises to upgrade from air cooling to liquid cooling.
Liquid cooling is the optimal solution for high-density computing heat dissipation, and CDU acts as the core lifeline of the entire cooling system. Beyond simple water conveyance, it integrates heat exchange, power circulation, safety protection and intelligent scheduling to stabilize cold volume distribution, heat transfer and system operation. With the booming development of AI computing power and green data center construction, continuous CDU technological upgrades will drive liquid cooling infrastructure toward higher efficiency, lower energy consumption and stronger stability. Custom cold plate solutions further improve energy efficiency and reduce maintenance costs across data centers, new energy and industrial scenarios, empowering reliable and eco-friendly operation of the complete data center liquid cooling system.
With a comprehensive portfolio that spans CDUs, cold plates, manifolds, and piping, EXTRCOOL delivers an all-in-one liquid cooling infrastructure. You can opt for off-the-shelf models or have them fully customized to your specific site conditions. Our thermal engineering delivers superior heat extraction, lowers energy consumption, and helps minimize your environmental footprint. Trusted for reliable performance at gigawatt-class data centres around the globe, EXTRCOOL provides the continuous cooling you can count on.
Explore all offerings or obtain a customised quotation at: https://www.extrcool.com/
