5 Ways to Optimize Data Center Airflow Efficiency

A simple and effective way to reduce data center energy costs is to improve airflow efficiency. The easier it is for air to move through the equipment within the data center, the more effective traditional HVAC systems are at keeping the equipment cool.

1. Leakage in sealed equipment
We’ll start with probably the most obvious way to improve airflow, sealing leaks that allow cold air to move in a different direction than where you want it to flow. For example, if you are trying to cool a server cabinet, holes or gaps on the outside of the cabinet may reduce the efficiency of the air cooling system.

We may not be able to seal all gaps or holes, some are unavoidable due to requirements such as having to run cables to the equipment. However, leaks should be found and repaired whenever possible to improve airflow efficiency.

2 Target data center equipment
Another simple but critical way to improve airflow is to make sure your cooling system is targeted at the equipment you want to cool. Rather than filling the entire data center with cold air, or blowing cold air in the general direction of servers and other heat-generating equipment, aim the cold air source as directly as possible at the equipment you want to cool.
Implementing this strategy may require running more ductwork and may require the installation of additional HVAC equipment to carry targeted air over greater distances. But those upfront costs will be well worth it if they translate into greater energy efficiency.

3. Install a larger capacity fan for cold air delivery

Even if cold air within the data center is already effectively targeted, increasing the capacity of the fans or blowers that move the cold air can improve airflow efficiency.

Of course, larger capacity fans require more power to operate. But the power required to spin the fan is much less than the power needed to cool the air. This means that if more powerful fans allow cold air to be distributed more efficiently within the data center, greater overall energy efficiency will be achieved.

The caveat here is that if cold air is already being distributed efficiently, or if room temperature air is being blown instead of cold air, in which case the electrical cost of the fan may outweigh the efficiency savings from distributing the air more efficiently. It’s also important not to think of higher fan speeds as a cheap solution to a situation of poor airflow efficiency; it’s better to address the root cause of inefficient airflow than to buy a bigger fan. However, when combined with other measures to optimize the use of cold air, higher fan speeds can provide the power to help ensure that the air within the data center moves in the most efficient manner.

4. Are the server cabinets facing each other?

The rear of a server cabinet is typically where the most heat is generated. This makes it difficult to cool servers in an efficient manner if the back of one server cabinet is facing the front of another server cabinet. In this case, you end up blowing cold air along the server aisle, with one side of the aisle being hotter than the other, resulting in less efficient overall airflow.

A better approach is what is called a hot aisle/cold aisle configuration. Under this approach, data center operators place server cabinets in rows, with the front of one row facing the front of another row, and similarly, the back of each row facing the back of the other row.

In this way, maximum capacity of cold air can be delivered to the channels on both sides of the server cabinet and maximum utilization of air can be achieved. Frontal channels can take in less air because they have less heat to dissipate.

5. Sky box

To achieve the highest possible airflow efficiency in your data center, make sure air never flows where it’s not meant to.

This means installing barriers above the server cabinets to ensure that all air flows through the servers and not into the space above. Any other parts of the data center such as storage or staging space that do not contain IT equipment should also be sealed so that valuable air is not wasted in these areas.

In other words, the goal should be to create a box around the device that needs to be cooled and restrict airflow into the box.

Summary: Making the Most of Airflow

Almost all data centers rely at least partially on moving air to prevent IT equipment from overheating. But some data centers do this more efficiently than others. To get the most out of your airflow, be sure to eliminate inefficiencies that can cause air to end up where it’s not needed, while taking steps to direct air where it will have the greatest impact.

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