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Steps to Ease Data Center Cooling – Number 1

by Dave Cappuccio  |  March 23, 2012  |  1 Comment

Cooling with the data center has become our achilles heal in many cases. Historically the folks in IT had relatively nothing to do with heat or cooling management, this was strictly under the purview of the facilities team (after all, if it wasn’t IT gear, it didn’t count). In todays world though the IT team has to get involved, since they are the ones that need to live with (and fix) the problem.

Well the good news is that in most older data centers (older being 10+ years), there are plenty of low hanging fruit to choose from when deciding what project to undertake in order to develop a more efficient cooling environment within the data center.

Over the next few posts I’ll posit 10 of the easy steps you can take to solve, or mitigate the cooling issue at your site.

1. Hot Aisle/Cold Aisle
As one of the oldest techniques in data center efficiency, placing rows of racks back to back and front to front is a simple method to redirect some of the hot air exiting the back of your racks into a common area. Without this configuration the hot air will exit the rack and be pulled into the front of the adjoining row, thus creating hot spots and very poor distribution of cool air. Creating hot and cold aisle configurations can improve air flow and cooling efficiency by as much as 10%.

2. Variable Speed Drives – Variable Frequency Drives
One of the largest consumers of electricity in data centers are the air handlers and/or air conditioners (CRAH’s and CRAC’s). These units have very powerful fans which need to move large amounts of air across the data center floor to the IT equipment. On many older units the fans spin at a continuous rate and the airflow remains continuous, regardless of how much is actually needed (e.g. a mostly empty data center would get the same airflow as a nearly full data center). Unless IT or Facilities teams are diligent, these fans are normally left on one speed all the time, creating a very inefficient environment. Newer CRAHs and CRACs have variable speed drives which can automatically sense temperature variations on the floor and therefor modulate the airflow, and fan speed, accordingly. Sophisticated units allow the synchronization of many units across a data center so the optimal fan speed, air flow, and energy consumption can be achieved. Implementing variable speed drives, synchronized, can reduce energy consumption by up to 15%. Example vendors; Emerson, Schneider Electric, Stulz.

Category: data-center-design  data-centers  food-for-thought  green-it  power-and-cooling  

Tags: cooling  data-center  design  

David J. Cappuccio
Research VP
6 years at Gartner
41 years IT industry

David J. Cappuccio is a managing vice president and chief of research for the Infrastructure teams with Gartner, responsible for research in data center futures, servers, power/cooling, green IT, enterprise management and IT operations. Read Full Bio


Thoughts on Steps to Ease Data Center Cooling – Number 1


  1. William Collier says:

    I don’t know about others, but I’m way overdosed on the issue of Hot Aisle/Cold Aisle configuration. However, one may want to be aware that the front-to-front configuration isn’t the only method for laying out equipment and achieving optimal energy efficiency. Although it’s more costly (cabinet cost and flexibility) there is the use of face-to-back configurations where the back of the cabinet is equipped with an exhaust chimney.

    Regarding VSD/VFDs it’s not necessarily correct to state that CRACs “have very powerful fans,” that is unless you are comparing them to a propeller fan in an in-row cooler. The fans in CRACs units aren’t very powerful especially in older equipment, they’re only capable of pushing air about 30′ and with a VERY low static pressure. Recently there have been some improvements in these units, but still not what could be called powerful–in comparison to other methodologies. VFDs have been around for a long time and only recently made their way into the data center industry, however, they’re only capable of being backed off their operating level IF air is actually covering the entire zone and then sending a signal that all temperature requirements are satisfied. Ideally your comment is correct, however, there’s not many ideal data centers.



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