Data Center Cooling : Air-cooled Design Parameters and Influences

icon-time 5 min

The increase amount of data center cooling generated needs to be stored in the well-known Data Center facilities. That big amount of data is stored in computing systems such as servers, consisting of processors, memory slots, network cards, power supply and integrated fans.

There are three (3) main sources of component temperature: Self heating, air heating and system ambient.

According to the ASHRAE Thermal Guidelines, the recommended temperatures range from 18 degC up to 20 degC, although the most common temperatures range is 18 degC to 27 degC.

There are some allowable degrees of reliability recommended by ASHRAE, each one depending on the different applications and components design chosen.



Figure 1
Figure 1 ASHRAE Recommended and Allowable Temperature and Humidity Ranges

The recommended envelope shown in red, gives a recommendation to data center operators in terms of high reliability and the allowable envelope (A1,A2,A3,A4) refers to where the IT manufacturers test their equipment and assuring the acceptable performance depending on the environmental boundaries.

Short-term displacement outside the recommended charts as shown above, may not cause severe damages, but prolonged ones my cause negative variations in terms of reliability and durability:

  • Humidity deviation: Affects IT Reliability and enhances corrosion.
  • Temperature deviation: Affects IT reliability, DC Airflow and Transient Response.

How’s the typical arrangement?

The important specification to meet for data center cooling systems is the air inlet to datacom equipment. The most common rack arrangement is the hot-aisle/cold-aisle, where the cold/hot air are not mixed due to separate air-flows.

 

Figure 2
Figure 2 ASHRAE Typical arrangement recommendation 

There are also three recommended air-flow patterns through the racks that allows us to redistribute properly the cold/hot air-flow through the racks and corresponding aisles.

Figure 3