Stulz-ATS, a manufacturer of computer room air conditioners that recently received the Frost & Sullivan 2008 Award for North American Datacenter Cooling Solutions Growth Strategy Leadership, introduces the upflow versions of its CyberAir precision air-conditioning series, which is now complete.

With a diverse range of options, the CyberAir 2 series offers flexible solutions for the air conditioning of large and medium-sized data centres. Precision A/C units are now available with seven different cooling systems. The cooling capacity ranges from 18.6 kW to 197 kW. The units are also available in six sizes, from 1000 mm to 2900 in width with a depth of only 890 mm. Stulz supplies its CyberAir 2 units with a choice of refrigerants: standard types R407C and R410A, or high-temperature refrigerant R134a. All parts requiring maintenance can be accessed from the front of the unit for greater convenience. In addition, in the CyberAir 2 the positions of the connecting pipes and base plate have been standardised to facilitate planning and installation of the units. In the CyberAir 2 series, Stulz uses electronic expansion valves (EEV) as standard.

According to the company’s press release, with Dynamic Free Cooling, or DFC for short, developed specially for the CyberAir 2, Stulz can boast a unique, energy-efficient solution for the air conditioning of data centres. The electronically controlled hybrid cooling system combines dynamic compressor cooling and free cooling in four stages. DFC automatically selects the best operating mode, depending on the outside temperature and heat load in the data centre. For units with DFC, Stulz has developed an external pump station in identical design for indoor installation. Five pumps with different outputs are available. Stulz has also modified the internal C7000 microprocessor and control terminal. The controller can be configured and operated either using a service laptop or the C7000 Advanced user interface. Use of the C7000 Advanced is improved by optimised navigation. The controller permits up to 20 A/C units to be combined in one bus system. For inter-unit communication, Stulz utilises the high transmission rates and excellent reliability of the RS485 bus system.