CRAC Units vs. CRAH Units

Maintaining proper temperature in data centers is critical. At one time, computer room and data center managers relied on conventional air conditioning systems to manage temperature. As systems were expanded with additional servers, managers simply added more air conditioners. 

The technology of today has necessitated larger data centers with much higher server densities. Computer room and data center applications require highly specialized equipment to optimize air circulation for more effective cooling and environmental regulation. 

Among the most widely used systems for computer room and data center cooling are Computer Room Air Conditioning (CRAC) and Computer Room Air Handler (CRAH) units. Each type of system uses raised floors, which circulate cool air under the floor through perforated floor tiles to ensure adequate air distribution. 

They also allow warm air from equipment to circulate through computer room air handling units. While CRAC units can be self-contained, CRAH units require chilled water and under floor plumbing to feed water to the system. 

Computer Room Air Conditioning (CRAC) Units

Computer Room Air Conditioning (CRAC) units are designed for applications where close control, high precision air conditioning is essential. Examples of these applications include data center cooling, medium and low-density server environments, telecom switching stations, medical operating theaters, and clean room environments.

Computer room air conditioners maintain air temperature, circulation, and humidity level in data center computer rooms. CRAC units generate cooling by blowing air over a coil filled with refrigerant. A compressor within the unit enables the refrigerant to maintain its cool state. Excess heat is ejected using a glycol mix, water or ambient air. 

CRAC Units: 

  • Use refrigerants and compressors
  • Have a simpler function
  • Are harder to adjust for computer room needs

Computer Room Air Handler (CRAH) Units

Like CRAC units, computer room air handler (CRAH) units are installed in data centers to manage the heat generated by computer equipment. Unlike CRAC units that employ mechanical refrigeration to cool data center air, a CRAH uses fans, cooling coils, and a water chiller system to displace heat.

Computer room air handler units operate like the chilled water air handling units installed in multi-story buildings. CRAH units provide cooling by blowing air over a cooling coil filled with chilled water, which is usually supplied by a chiller, or a chilled water plant. They regulate fan speed to maintain a set static pressure, ensuring the humidity levels and temperature remain stable.

CRAH Units: 

  • Use chilled water and control valves
  • Use a more efficient cooling cycle
  • Have greater heat removal capabilities

Not sure which type of system is right for your data center? Level Solutions has the experience and expertise to help you find the appropriate system to meet your needs. Contact us to discuss your needs.

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