CyberRack Active Rear Door

Rack-based CW cooling for optimum operating conditions

The CyberRack Active Rear Door is a heat exchanger door with EC fans for installing on the rear door of server racks. The server rack door is swapped for the CyberRack Active Rear Door, which transforms the rack into a cooled server rack that no longer discharges any heat load in the data centre.

Solutions for CyberRack Active Rear Door

  • High-Density

  • Medium-sized and large Data Centres

  • IT Rooms

  • For use in the IT sector

Application 1: Autonomous CW cooling

  • Provides comprehensive cooling capacity for the rack, with no need for additional air conditioning systems

  • Reliable cooling even without a raised floor

  • No hot return air in the IT room

Application 2: Supplementing the precision air conditioning

  • Targeted cooling of high-density racks

  • Prevention of hot spots

  • No discharge of hot return air in the IT room


Benefits: Flexibility

  • The active heat exchanger doors can be used independently of existing precision air conditioning units, or can supplement them.

Individual adapter frames make them suitable for any rack. They are available in 2 different heights and 2 different widths (42U and 48U, and 600 mm and 800 mm). Once the rack door has been replaced by the adapter frame, the CyberRack unit can be hung in the adapter frame and connected to the chilled water supply.

  • As it is mounted on the rear of the rack, there is no need to change the rack's position. This cooling solution can therefore be integrated more easily in existing data centres, regardless of whether the server racks are to be retrofitted or the rack already comes with the CyberRack.

Compact design

  • Less than 300 mm additional rack depth
  • No need to reposition the server racks
  • The servers can retain all the height units in the rack

Benefits: Efficiency

  • Optimum operating conditions: No mixing of server outlet air with the room air, because no hot return air gets into the room.

  • Maximum energy efficiency thanks to high rack inlet temperatures

  • As the servers are cooled directly in the server rack, high water temperatures are possible, considerably increasing the number of operating hours with Free Cooling.

No mixing of hot and cold air

CyberRack Active Rear Door units are installed on the rear of the rack. The active heat exchanger doors cool the server right at the source and prevent heated air from entering the room (see illustrations below).

Scheme: Airflow without CyberRack Active Rear Door

Airflow without CyberRack Active Rear Door

Airflow with CyberRack Active Rear Door

Airflow with CyberRack Active Rear Door

Integration with CyberCool 2

Solutions from STULZ are perfectly coordinated to work together, to cool your IT systems efficiently and reliably. The CyberRack unit works most efficiently in combination with the CyberCool 2 chiller.

Investments in the quality, reliability and efficiency of STULZ air conditioning and chilled water solutions pays off during operation after just a short runtime thanks to energy savings and operational reliability.

CyberCool 2 product information

Benefits: Operational reliability

  • To protect the fans integrated in the servers against overpressure, the optional differential pressure control from STULZ adapts the speed of the CyberRack fans in line with the server airflow.

  • Separate plug-in contacts enable the simple replacement of individual EC fans.

  • Worldwide service

Variety of options for CyberRack Active Rear Door

  • Uwe Kudszus, Product Manager

    "If the originally planned precision air conditioning is no longer sufficient for discharging the heat load, retrofitting the water-cooled CyberRack Active Rear Door provides targeted cooling of high-density racks. There is no need to change the position of the server racks in the data centre."



  • Return and supply air sensors ensure uniform temperature distribution under varying server load

  • EC fans for low electricity consumption

  • Targeted cooling of high-density racks

  • Less load on the room air conditioning, because the heat is discharged directly from the rack

  • For data centres with and without raised floor

  • Maintenance-friendly design

Pressure independent control valve

The pressure independent control valve (PICV) combines the functions of control, hydraulic compensation and flowrate measurement. The water flowrate required for cooling is set directly by the CyberRack control system.

• Low water-side pressure drops cut pump energy costs

• Lower investment and installation costs and faster start-up thanks to automatic hydraulic compensation

• The defined water flowrate ensures stable and precise control in all load states

• The cooling capacity of each individual server rack is recorded.


Control and monitoring           

  • C2020 controller for controlling and monitoring the air conditioning system
  • Active temperature control: The controller regulates the fan speed in accordance with the measured supply and return air values.
  • Direct connection to BMS systems via ModBus RTU protocol or Ethernet
Technical Data

Technical Data

Total cooling capacity kW19.132.7
Airflow m3/h4,8006,000
Number of fans45
Dimensions HxWxDmm2,000 x 600 x 330

Air inlet temperature 40°C / RH 20%
Water temperature: supply = 14°C, return= 19°C
Fan: external static pressure 30 Pa



Downloads Wrapper


  • STULZ CyberRack Brochure EN

    CyberRack Active Rear Door
    Rack-based CW cooling for optimum operating conditions

    • File: STULZ_CyberRack_Brochure_1805_EN.pdf

    • Type: Adobe PDF

    • Size: 1,13 MB

    • Language: English

    • Date: 2018-05-14

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