Airflow management and thermal management in data centres

Airflow management and thermal management in the data centre

Airflow management and thermal management are increasingly common and effective solutions used in data centres to achieve cost reductions, energy efficiencies, and extended server and IT equipment life. In this article, we will examine thermal management and airflow management systems independently, and the methods used to implement these data centre systems effectively, alongside similarities and differences. We will also look at the individual benefits and how data centre operators can use airflow management and thermal management practices to obtain best results.

Airflow management systems used in data centres

What is airflow management? Airflow management involves using an airflow system, such as cold aisle or hot aisle containment, which directs airflow and blocks conditioned and server exhaust air, therefore managing volumetric flow rate within a data centre. Airflow management systems improve or maintain intake air temperatures to server and IT equipment in your data centre so the flow rate of conditioned air is reduced as much as possible alongside the highest intake air temperatures, ensuring all intake temperatures are significantly lower and more even. By facilitating control of thermal management, airflow management systems drive better efficiency and increased capacity in your data centre.

There are two common data centre airflow management systems known as aisle containment systems. The most well-known airflow management system, cold aisle containment, restricts the loss of cold air while preventing mixing of cold air and hot server exhaust air, therefore optimising data centre efficiency. A cold aisle containment system works by lining up the network and server cabinets in alternating rows so that hot air exhausts and cold air intakes face in opposing directions. The data centre benefits you can expect to see for cold aisle containment include: improved power usage effectiveness (PUE), reduced hot spots, cost savings, favourable return on investment (ROI), reduced carbon footprint and emissions, and extended server and IT equipment life.

The other airflow management system is hot aisle containment. Hot aisle containment systems ensure the hot exhaust air from racks is contained within the data centre aisle, which allows the rest of your data centre to become a reservoir of cold air. By creating a separate pathway for exhaust air to take back to the air conditioning unit intake without mixing with cold air, hot aisle containment systems facilitate the removal of hot air through either a ceiling plenum or by using large ducts that connect to the computer room air handler (CRAH) unit.

Another popular hot aisle containment approach to data centre cooling is otherwise known as in-row cooling, where computer room air conditioning (CRAC) units are built into the actual cabinet rows. Typically, the hot aisle will then have a flat roof on the aisle with no requirement to install a hot air plenum. The cooling from this type of hot aisle containment system is more granular with in-row CRAC fan speeds controlled separately.

Thermal management in data centres

Thermal management is all about controlling the temperature to achieve optimum temperature levels for your servers, usually through cooling, as IT equipment will generate excess heat. Thermal management has benefits such as maximising rack population and IT footprint, preventing premature failure, and improving the overall reliability of equipment. There are two different approaches to thermal management, detailed below.

The passive approach to data centre thermal management makes use of natural airflow as vent openings are installed in top and bottom sections of an enclosure, and the hotter equipment is placed lower in the rack, allowing hot air to rise. You can use passive thermal management in your data centre to prevent the mixing of hot and cold air, to isolate and redirect flow of air from side-vented equipment, and to open airflow to equipment. The data centre system provides natural cooling without requiring any additional fans.

Active approaches to thermal management utilise forced air through fans to achieve optimal temperatures. This type of thermal management is adopted when equipment inside the location produces too much heat for the passive approach to work in providing sufficient ventilation. For active thermal management to be successful, you’ll need to use top-mount fans in your data centre with no venting in the upper racks/towards the top of the enclosure.

Airflow management and thermal management in data centres: conclusion

You can choose to use airflow management systems or thermal management independently in your data, but studies have shown that these systems produce best results when they are used as a combined tool to combat data centre efficiency issues. To achieve best practice, you should implement the airflow management system (such as cold aisle containment) first, followed by thermal management, as thermal management maximises the existing benefits of airflow management. Implementing both these energy efficient systems in your data centre will increase capacity/efficiency of cooling units while also reducing operating costs.

Cross-Guard has over 20 years of experience in designing, manufacturing and installing the perfect fit physical IT solutions to help data centres across the globe. The company provides bespoke hot and cold aisle containment systems that are highly versatile. The aisle containment systems can be easily modified to suit a client’s changing requirements.

Cross-Guard’s premium aisle containment systems combine the often conflicting requirements of security, energy saving, fire safety, and data centre efficiency. Aisle containment solutions are designed and manufactured to last, can be retrofitted to any type of server cabinet, and will generate excellent return on investment for your data centre.

If you’d like more details on airflow management, aisle containment, and achieving data centre energy efficiency, please contact us on +44 (0)20 8108 9328 or email sales@cross-guard.com.

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