Datacenters Wasting Cooling Capacity, Report Says
In data centers, heat is an enemy that threatens to fry expensive electronics. However, a recent study suggests that many data centers are wasting a large portion of their cooling capability, which in turn means they are wasting tens of thousands of dollars a year.
According to a recent study of 45 data centers conducted by Upsite Technologies, a provider of air flow management (AFM) solutions, the average computer room is running cooling capacity that is 3.9 times the heat load. The situation is so out of whack that, in one data center, the cooling capacity was 30 times the heat load. This calculation does not take into account standby cooling capacity that was not running at the time of the assessment.
The size of the room seems to have an impact on the amount of cooling capacity a data center has over commissioned, according to the study. This is evident in the fact that the five largest sites surveyed were running only 2.4 times the actual capacity that was needed to keep things cool. That’s still twice the optimum level, as measured on Upsite’s cooling capacity factor (CCF) scale, which is 1.2 CCF.
Upsite published the results of its study in a white paper, titled “Cooling Capacity Factor (CCF) Reveals Stranded Capacity and Data Center Cost Savings,” which can be downloaded at http://whitepapers.datacenterknowledge.com/content30069. The study found the average data center had eight air conditioning (AC) units running for 7,500 square feet of raised-floor space. Ideally, a data center of that size should only have two AC units running, to achieve a CCF of 1.2.
The study also found a large number of hot and cold spots in the average data center, with 20 percent of the IT gear being significantly over-cooled (cold spots), and 35 percent being significantly under-cooled (hot spots). Hot and cold spots are critical measurements in data center cooling, Upsite says.
The biggest cause of stranded cooling capacity is bypass airflow, or air from the cooling units not passing through IT equipment before returning to the cooling units, Upsite says. There are several simple things that data center operators can do to improve airflow in their data centers, including sealing cable openings, installing blanking panels, adjusting both the number and location of perforated tiles, adjusting the position of a few cabinets, and sealing spaces where cabinets are missing in a row.
Taking these steps led to a $21,900 per-year savings in one 9,000 square-foot data center that was running eight AC units to cool 170 cabinets of IT gear. Despite a CCF of 2.2--or nearly twice the cooling capacity needed for the electric load of the IT gear--the data center was struggling to keep the gear cool. After taking certain steps, the data center was able to eliminate hot spots and turn off two of the AC units.
