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Cooling Strategies for Server Rooms

Experience tells us that a cooling strategy is only rarely implemented in small to medium sized data centre environments. Cooling strategy and implementation is common-place in the larger Enterprise however it is only as the result of poor performance, unsatisfactory downtime or, worse still, repeated hardware failure that cooling is considered in the SME.

on365 design and install cooling solutions for any size of room or space. We recognise that data hardware is often located in spaces not originally designed to contain hi-tech devices and with the advances in performance and introduction of new technologies such as VOIP there is an increasingly substandard level of cooling available.

Most IT hardware has a minimum and maximum operating temperature guide printed on their product and this helps establish the ideal operating temperature for a specific customer environment. It is worth noting that although a maximum temperature is given, all equipment will perform significantly worse than at cooler temperatures. Typically the ideal recommended operating temperatures are between 70°F (21°C) and 75°F (24°C)70deg. Even more attention must be given to wiring environments where a UPS is deployed. Any increase in temperature has a far greater and more significant effect on battery devices than other IT hardware. Lifetime of the product can be halved in extreme cases.

To consider cooling as the removal of heat, rather than supply of cold air, is the first step to understanding the problem. Heat, if not removed, accumulates and ambient temperature naturally rises. Heat can be removed from an office space or wiring closet in five different ways, all of which differ in effectiveness and cost. These methods are:
  • Conduction: Heat escapes through the walls of the space
  • Passive Ventilation: Heat flow is caused by effect of cooler air on the other side of a vent or grill
  • Fan-assisted Ventilation: Heat is physically removed by a grille with air-moving device.
  • Comfort Cooling: Heat is dissipated by a buildings ambient temp air conditioning system
  • Dedicated Cooling: Heat can be removed by a dedicated wiring closet air conditioner.

It is now common practice to ensure up-time and business critical availability through deployment of distributed UPS systems. These UPS systems are generally sized to provide back-up availability for the racked IT hardware but should also be capable of operating the cooling system suring sustained periods of power outage. on365 understand this requirement and can recommend a solution to ensure that the air conditioning and fan systems continue to control temperatures that would otherwise rise to unacceptable levels. Air conditioning requires UPS performance for higher than a fan assisted solution and this, coupled to cost, makes fan assisted ventilation the most popular solution.

A well designed and implemented passive ventilation system is effective for lower power levels, just a grille in the wall will suffice however for those environments with high power VoIP routers, servers and multiple Ethernet switches then fan-assisted ventilation is recommended. When the closet power level for critical closets is over 2000 watts (4500 watts for non-critical closets), or the ambient air outside the closet is hot, uncontrolled, or contaminated, dedicated air conditioning is the most appropriate solution. Relying on the use of the buildings air-conditioned ventilation is not recommended because it will almost always result in wide closet temperature fluctuations.

The suggestions and observations made by on365 on this page are for guideline purposes only. For a more detailed appraisal of your cooling needs you should call us and one of our trained experienced engineers wil lvisit and advise the most appropriate solution for you.


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