Free cooling technology

We achieve top efficiency with our ABACOS systems, and that means cost savings for our customers. ABACOS stands for “air based cooling systems”.

Mode of operation

Air has a thermal capacity. For each Kelvin degree of temperature difference, it is about 335 W/h per 1,000 cubic metres of air. That is a physical fact, and it is the operating principle of our Flexibox positive pressure system.

Calculate the thermal capacity

Calculate the volumetric flow

Calculate the temperature difference

deutherm FCB 1200-DC outdoor/indoor

The new deutherm Free Cooling system

Based on years of experience, we further developed the free cooling system and set new standards in performance, noise, quality and environmental friendliness with the free cooling of mobile radio and fiber optic infrastructure.

Contact us for further information.


  • Huge energy savings
  • No environmentally harmful refrigerants
  • Complete climate control
  • Very long lifespan
  • High quality EBM-Papst™ EC fan
  • Easy installation

Flexibox 900

The Flexibox 900 is a positive pressure free cooling system for connection to a 48 VDC or 230 VAC power supply. There is an indoor version for installation in the equipment room, and an outdoor version for installation in an external shelter. The cooling capacity with the 48 V system is 814 W/K, and with the 230 V system it is 861 W/K.

With a temperature difference of 7 K as usually specified in Europe, the respective cooling capacities of the systems are therefore 5,698 W and 6,027 W.

The filtered air from the Flexibox always generates a distinct positive pressure in the equipment room, effectively preventing the entry of dirt and dust particles. G4, F5 and F7 filters are available for the Flexibox. G4 filters are typically used in base stations. They can be exchanged quickly and easily, and they are monitored by a differential pressure sensor. An alert is issued at about 70% filter fouling to allow sufficient response time. The filter can be cleaned or replaced during the next visit to the site. These filters ensure compliance with air cleanliness regulations.

Along with mounting directly on the exterior wall, the Flexibox can be mounted somewhere else and connected to the air intake through an insulated spiral duct with a length up to 20 m. Installation of fire dampers is equally easy. At locations with an especially high dust burden, such as silos, alongside farm roads or even in desert areas, the air can be pre-filtered by an air maze.

The manufacturer’s warranty is 24 months, which can be extended to as much as 5 years for a small fee, subject to periodic maintenance. The MTBF of the system components is much longer.


deutherm AirMaze Cube
deutherm AirMaze big