DCN August 2017 - Page 20

Cooling Active vs. Passive; what to look for and how to choose While an active system offers greater functionality than a passive system, the superiority of one over the other is contextual. Just like every runner must find what works best for them individually, knowing when to use active or passive airflow management is a decision that must be influenced by the specific needs of the data centre. An active system uses pressure sensors to discern how quickly server fans spin. If pressure is increased, the system’s fans automatically increase to match it. This helps maintain a zero- pressure environment in the cabinet to reduce the workload of the server fans. The result is electrical efficiency of the servers and minimal wear on their cooling components. As the number of servers and power consumption increase in a cabinet, so does the likelihood that airflow will become restricted and an active cooling system will be required. Since active systems scale based on server loads and their associated cold-air consumption, they also help maintain proper airflow regardless of how far the cabinet 20 | August 2017 In both active and passive configurations, the goal is the same: To get cool air to pass through critical rack equipment and move hot air into a return plenum using air containment. is from the source of cool air. This prevents problem areas that tend to occur in a passive system as the distance from the return grows. An active air system: •  Uses integrated fans at the top or rear of the cabinet •  Works well with in high-density cabinet applications •  Prefers unrestricted airflow (which is ideal), but can function without it •  Utilises automatic fan speed adjustment based on air pressure •  Should be connected to the backup power source to allow for air movement in a power outage On the other hand, the primary benefit of a passive system is simplicity. Unlike an active system, there are no additional cooling components involved in airflow management because the system relies exclusively on server fans. Fewer equipme Ёɍ͕́ɔ)ͅɕձѥݕȁɽ)̸Qȵݽɭ́)ͥٔѕɔɅљ݅ɐ)Mٕȁ́Ʌ܁ȁѼ)ѡ́ݥѡѡ͕ٕȸ)Qȁ́ѡ)ѡ͕ٕȁ́ЁȸQЁ)́ɥ͕́ѼѡɕɸՍ)ȁմѡɅɽ܁ȁɽ)ݡɔЁٕ́Յɕѕ䁄)ѕ)ͥٔȁѕ+Í͕ٕȁ́Ѽձ)ѡɽ՝ɅեЁ͠)ȁѼѡɕɸմ+\(ɭ́ݕܵͥ䁍+Iեɕ́չɕɥѕə)ɽѡЁѼѡմ+ (ɔɝ䁕аͥ)ѥ́ɔɕեɕ)5͕͔Ё) ѽ́ѡЁѕͻe)ɕѱɥȁѼѡѡȸ)фɔ́͡ձ)䁍͔ͥٔ)ѕܵͥ䁍̸)!ݕٕȰ́ѡյѥ)хɕͽɍ́ѥՕ́Ѽ)ɕ͔ͼѽݥѡɕ́ѡ)́фɕ̸́ѡ)̰фɔͥݥ)٥х͍͍ѥѡ)ȁѥٔѕ̸)Uѥѕ䰁ѡ́Ѽ)фɔѕȁٕ͕ͥ)͔׊eɔݽɥ)䁥ɕхɅ)ѵ́$٥ٕ)Ʌѡ݅ɐ)ѼѡЁ