17 February 2026
STULZ has launched an upgraded version of its pioneering CyberRack Active Rear Door, building on the success of the previous model. This advanced rear-mounted heat exchanger features electronically commutated (EC) fans that efficiently capture heat directly at its source, offering a space-saving solution for high-density data center cooling.
Designed for both air and liquid-cooled environments, the new CyberRack Active Rear Door boasts improved performance, increased flexibility, and simplified integration. Equipped with integrated sensors that continuously monitor return and supply air temperatures within individual server racks, the system adjusts cooling output automatically to match fluctuating server heat loads. This ensures consistent, efficient, and reliable operation even during workload spikes.
Valeria Mercante, product manager at STULZ, explained that the surge in high-performance computing (HPC) and artificial intelligence (AI) has pushed server power densities higher than ever, creating significant heat management challenges. “With data center space often limited, the CyberRack Active Rear Door is engineered to deliver maximum cooling capacity within a compact footprint of just 274mm depth. Capable of providing up to 49kW of chilled water cooling through large heat exchanger surfaces and EC fans, it supports higher water temperatures and can extend free cooling hours, thereby reducing energy consumption and operational costs,” she said.
Thanks to its compact size, the system can be installed without repositioning racks, making it an ideal retrofit solution or suitable for environments with limited floorspace. Custom adaptor frames enable seamless integration with a wide range of rack sizes, supporting standalone operation, supplemental precision cooling, or hybrid configurations alongside direct-to-chip liquid cooling solutions.
Ease of maintenance is another key feature. The CyberRack Active Rear Door opens more than 90° via a two-step process, providing access to fans and coils. Hot-swappable axial fans with plug connectors facilitate quick servicing, minimizing downtime. The system’s differential pressure control precisely adjusts fan speeds to match server airflow needs, ensuring operational reliability while maintaining low noise emissions.
Central to the system’s user-friendly operation is STULZ’s E² intelligent control system. Featuring a 4.3-inch touchscreen with unified menu logic, the E² controller manages advanced functions such as redundancy, cross-unit parallel operation, standby modes, and seamless integration with building management systems (BMS).
Valeria Mercante summarized the company’s commitment: “The updated CyberRack Active Rear Door exemplifies our dedication to delivering innovative, intelligent, and energy-efficient cooling solutions. Whether space is tight, heat loads are high, or there’s no raised floor, these units provide highly effective cooling regardless of server workload. Our team is always ready to assist with tailored advice to find the right solution for your data center needs.”
