What’s a computer room air conditioning (CRAC) unit?

What’s a computer room air conditioning (CRAC) unit?

A computer room air conditioning (CRAC) device is an unit that monitors and keeps the heat, air distribution and humidity for a data center, networking or maybe server room. CRAC units change the air conditioning units applied to the past to cool data centers. By comparison, CRAC devices have far better air filtration, better moisture control systems and/or higher airflow than normal Ac systems.

CRAC units help stop low water and humidity vapor from forming. Humidity that is low is able to lead to static electricity buildup, that may damage electronics, and water vapor buildup, which could cause short circuits and corrode equipment.

CRAC units function through a refrigeration cycle wherein air is blown over a cooling coil loaded with refrigerant. Refrigerant in the cooling coil is kept cool by a compressor. Excessive heat is expelled as air, water or maybe a glycol mixture. Older CRAC units are only able to switch on and off, while new units allow different airflow variations.

You will find a number of ways that CRAC devices could be situated. A very common CRAC setup is experiencing cooling air dispensed through an elevated floor. Additionally known as raised floors, the cooled air increases through the perforated floor sections, forming chilly aisles. The cool air moves through the racks, wherever it picks up heat before leaving out of the back of the racks. The bright exit air forms warm aisles behind the racks, and the warm air returns to the CRAC intakes, that are positioned above the floor.

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A good example of a raised floor airflow Raised floor cooling in data centers forces cool airflow upward throughout the floor, up previous servers and right into a CRAC consumption in which the atmosphere is cooled.

CRAC devices are the following components:



This’s a substance compound which can be used as a coolant in CRAC and air conditioners.

Cooling coils.

Additionally known as evaporator coils, refrigerant moves from the cooling coils to cool the atmosphere.


This will keep the refrigerant running throughout the coil cool.
Air filters. These help capture the accumulation of dirt or maybe debris which travels by way of a

CRAC product.

Electronically commutated (EC) fans. EC fans blow air that is cool while creating less heating with high efficiency.

Dehumidifiers and humidifiers.

Even though these’re elective in CRAC systems, humidifiers increase the quantity of moisture in the environment, while dehumidifiers clean water vapor out of the atmosphere.

What exactly are the differences between CRAH and CRAC units?

Computer room air handler (CRAH) devices are one more data center cooling device. The primary difference between CRAC and CRAH units is the way they cool the surrounding environments of theirs. CRAC units utilize both refrigerants and compressors, while CRAH units utilize cold water and balance valves.

The CRAH units use fans to blow air over the cooling coils. Rather than the coils being loaded with refrigerant, nonetheless, they are full of chilled water. Air that is warm from the information center room is pulled again into the CRAH unit, passing over the cold water coils. The heat transfers from the environment to the water, the place that the water then comes back to a chiller.

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Because CRAH units do not need a compressor, they normally use less energy and tend to be more effective in comparison with CRAC units. This makes CRAH units much more appropriate for renewable data centers.

CRAC units are perfect for data centers with electric loads of 200 kilowatts (kW) or even less. Meanwhile, CRAH devices are created for data centers with electric loads of 200 kW or even more. CRAH units can also be perfect for environments with increased availability requirements.


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