Retrofit Free Cooling units for indoor or outdoor installation

To considerably cut the running costs of base stations, they can be retrofitted with the STULZ Free-Air Free Cooling unit.

Solutions for Free-Air units

  • Shelter cooling

  • Direct Free Cooling

  • Installation in the shelter

  • Installation outside the shelter



  • Energy efficient Free Cooling solution that can be retrofitted in existing systems.

  • The return on investment for the retrofit is achieved especially quickly in base stations, where comfort air conditioning units are running 24 hours a day.

  • The Free-Air units are plug and play and therefore immediately ready for connection and use.

Technical Data

Cooling capacity total (kW)


Airflow volume (m3/h)






Direct Free Cooling

With Free Cooling, the units achieve savings of up to 96 % on running costs.


  • Uwe Kudszus, Product Manager

    “Many base stations still make use of comfort air conditioning systems that do not use Free Cooling. The Free-Air cooling unit can easily be integrated in systems like this, and controls the comfort air conditioning units.“

Flexible installation

The units are available in two versions for maximum versatility – FCL-IN for indoor installation and FCL for outdoor installation.

The FCL-IN is installed indoors, for when maximum protection against vandalism and adverse weather conditions is your priority

FCL-IN installation

The FCL is installed outside the container, so that the entire interior space can be used for IT equipment. Full access from the outside for maintenance purposes.

FCL installation



  • Ready for operation on the very first day – easy mechanical and electrical installation

  • Simple integration of existing comfort air conditioning units

  • Outside temperature value for Free Cooling can be defined as you wish

  • Speed-controlled EC fan

  • Full service accessibility from the front

  • Measures DC power consumption

  • G4 air filters: The FCL35/60-IN is equipped with a pocket filter, which provides a larger filter area (2 m2). This reduces pressure drops and extends service intervals

  • Insulated, powder-coated housing of galvanized sheet steel

  • The filter alarm can be triggered either by differential pressure or based on a manually adjustable fan operating time


Control and monitoring

The Free-Air units are monitored and controlled by the C102 microprocessor. Comfort air conditioning units can be integrated in the existing air conditioning system and also actuated by the C102 controller.

  • The integrated relays enable the C102 to control and monitor up to two connected comfort air conditioning units
  • It directly measures the energy consumption of the Free-Air units and records the operating hours of the comfort air conditioning units
  • It provides backup ventilation upon failure of the main power supply or a fault in the comfort air conditioning units
  • 48 VDC power supply enables it to be used for emergency backup ventilation 
  • Monitoring: ModBus onboard, further protocols via WIB 1000

WIB 1000

WIB 1000 is user-friendly and offers easy data exchange, monitoring and worldwide suitability.

  • Ongoing retrieval of data from the controller
  • Ethernet interface
  • Easy connection to existing building management system
  • Simultaneous HTTP and SNMP
  • Easy, fast configuration from a laptop
  • Compatible with all common BMS systems
  • Communication via SNMP and HTTP IP protocols





  • STULZ Telecom Line Brochure

    Air conditioning for base stations
    of cell phone networks

    • File: STULZ_Telecom-Line_Brochure_1215_en.pdf

    • Type: Adobe PDF

    • Size: 7,34 MB

    • Language: English

    • Date: 2015-12-01

STULZ Services

For this product we recommend the following STULZ services


Contact us

For sales and support inquiries, please make a selection below to find your local contact.

  • Sales
  • Service
  • STULZ GmbH


    Stulz Territories: Lower Saxony, Baden-Württemberg, Bavaria, Berlin, Brandenburg, Bremen, Hamburg, Hesse, Mecklenburg-Western Pomerania, North Rhine-Westphalia, Rhineland-Palatinate, Saarland, Saxony, Saxony-Anhalt, Schleswig-Holstein, Thuringia

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Fax: +49 40-5585-352

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