Stulz launches data centre cooler upgrades
1st September 2026
GERMANY: Stulz has announced a fourth generation of its TelAir and WallAir cooling series to meet the growing demands of 5G, edge and critical infrastructure applications.
TelAir 4 and WallAir 4 combine the advantages of a lower GWP R454C refrigerant with integrated free cooling and a certified EN378 safety architecture.
The TelAir 4 series is designed for indoor installation, while the WallAir 4 can be mounted externally on a container wall as a space saving monobloc solution. Both are available in two standard enclosure sizes and four cooling capacity classes, ranging from 6-17kW.
In combined free cooling and mixed-mode operation, Stulz claims the TelAir and WallAir units can reduce operating costs by up to 80%.
With EC fans, the units operate across a temperature range from -20°C to 54°C for TelAir 4 and -20°C to 54°C for WallAir 4. For extreme climates, an optional winter kit extends operation down to -40°C.
Customers can choose between classic on/off systems that are equipped with a thermostatic expansion valve, or continuously modulating EC inverter compressors paired with an electronic expansion valve.
In both variants the evaporator fan is positioned at the bottom to quickly dilute and extract refrigerant gases in the event of a leak. A two-stage sensor system activates maximum fan speed and shuts down other power consumers at 10% of the lower flammability limit, while at 20% LFL the unit is fully disconnected from the power supply. An enclosed IP54 control cabinet further eliminates potential ignition sources.
In terms of airflow, the TelAir 4 series supports both downflow and displacement concepts, with optional adjustable outlet grilles for targeted horizontal or vertical air distribution without mixing cold and warm air. WallAir 4 utilises the proven displacement principle for direct cold air stratification within the room, and TelAir 4’s in-wall installation provides protection against weather and vandalism, reducing noise emissions to levels suitable for use in sensitive residential and mixed-use areas.
Stulz says it has prioritised ease of use and its E² Basic controller enables operation through integrated ethernet interface, Modbus and a wide range of inputs and outputs for seamless integration with building management and (DCIM) systems. Password protected access levels provide enhanced security, alongside dedicated inputs for monitoring fire, smoke and intrusion alarms.
