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Hot Vs Cold: Which Aisle Containment Is Best For Servers?
April 18, 2022
by Bentec Editor

As many businesses may already know, data centre solutions are key assets that draw a significant amount of power to operate, primarily from the cooling equipment that keeps the electronic equipment it houses at optimal levels. Due to the high energy costs associated with operating a data centre, companies continually search for better and more innovative solutions to solve this issue.

One such innovative system that continues to deliver on this promise while increasing cooling capacity is the aisle containment structure, which can be configured as a hot or cold aisle containment system. To know which is more suitable for your data centre, let us first understand the differences between these two containment systems and the pros and cons of each.

Cold aisle containment (CAC)

CAC comprise of doors at both ends of the aisle covered by a type of partition or roof. They serve as a physical barrier that contains the supply of cold airflow. Essentially, the cold air enters from beneath the raised floor of the aisle and exits as hot air outwards after cooling the equipment placed on either side. This structure is typically more common as compared to hot aisle containment due to its simpler implementation and lack of additional airflow pathways, making it less expensive. Here is a summary of the main pros and cons of cold aisle containment.

Pros of CAC

  • Easier implementation
  • Enables greater surface area for ‘cold sinks’ in case of power outages
  • Simpler to retrofit into older data centres thanks to its ease of installation
  • More cost-effective

Cons of CAC

  • Lower the delta T by increasing the mixing of return air
  • Cold air leakages could arise from the openings under the equipment and the raised floor itself, reducing the efficiency of the overall system
  • Higher room temperature also means potential obstructions to the fire detection system of the overall data centre space

Hot Aisle Containment (HAC)

HAC is similar in structure to cold aisle containment but with an additional physical barrier or ductwork that guides hot exhaust air back to the AC return, taking full advantage of the natural tendency for warm air to rise. As a result, HACs increase cooling capacity while saving energy at the same time. It doubles this capacity by isolating the exhaust air and preventing it from mixing with the cold air as it returns to the AC coil. Below is a summary of the main pros and cons of hot aisle containment.

Pros of HAC

  • Cold air leakages become a non-issue as they will eventually cool the containment from the outside
  • Generally better cooling effectiveness
  • Performs well in most data centre environments
  • Standard fire detection solutions can still be used

Cons of HAC

  • Higher upfront costs
  • Requires additional ductwork or contained path that directly funnels exhaust air back to the AC units
  • Higher temperatures inside the hot aisle may prove uncomfortable for personnel

The verdict

Studies from theoretical and on-field studies have proven that hot and cold aisle containment are both equally efficient if they are done well. With that said, not all data centres are made and set up equally, so there are plenty of considerations to take into account to ensure your organisation makes the right choice.

Many might lean towards HACs as preferable based on the points established above. However, that does not mean there is no place for CACs. Depending on your data centre setup, a CAC may be the better option. Therefore, it is crucial to fully understand the kind of data centre you have first before committing to one.

If you are looking for sever rack cooling solutions, Bentec Digital Solutions has got your back. We offer both hot and cold aisle containment, as well as other cooling options such as rack-based cooling, in-row cooling and more. We also provide other data centre solutions such as quality server racks, uninterruptible power supply, Intelligent PDU, Electronic Locks, and leak detection. Reach out to us today for a non-obligated consultation and we would be happy to assist you in any way we can.