
Direct Free Cooling
Potential savings with Direct Free Cooling
In temperate climes north and south of the equatorial zone, the energy-saving advantages of the STULZ CyberAir 3PRO CW with Direct Free Cooling can be exploited to the full.

Regions suitable for Free Cooling
Direct Free Cooling
With Direct Free Cooling, the CyberAir 3PRO CW air conditions data centers up to 90 % more economically than conventional compressor cooling systems. The prerequisite for this is data centers with wider temperature and humidity tolerances. Direct Free Cooling exploits the potential of outside temperatures to air condition the data center using the cool outside air. Via the CyberAir 3PRO CW, the outside air, which has been treated by filter systems, gets directly into the server room.
Special solution for small to medium-sized data centers: Direct Free Cooling with FreeCool Plenum
To exploit huge potential savings in smaller data centers, too, and when modernizing existing cooling systems, CyberAir 3PRO CW units with downflow air conduction can be equipped with the FreeCool Plenum Free Cooling box. With this option, Free Cooling is automatically combined with the chiller system's compressor cooling in three variable stages, to suit the outside temperature and cooling needs, ensuring that maximum savings are always exploited to the full:
1. Free Cooling
- The outside air damper opens
- Outside air is conveyed through the filter of the FreeCool Plenum directly into the unit, then into the data center
- The compressor of the chiller system remains off, completely saving the cooling energy normally required
2. Mixed mode
- As 1, plus:
- The compressor of the chiller system is additionally switched on for support
- When the outside air damper is open, the compressor of the chiller system runs in partial load mode
3. DX mode
- The CyberAir 3PRO CW cools exclusively using the chiller system's compressor
- The outside air damper remains closed, and no outside air is used for cooling
- Return air damper open 100 %
The FCP design with the dampers on top is a flexible construction that takes up no extra space.