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Data Center Power Efficiency Changes Available, Yet Not Often Used
With the consistently increasing amount of data produced, consumed and stored by companies throughout the world, there is also an increase in the amount of data center power that must be used to manage the capacity. In fact, data centers today can consume as much as 87600 MWHr of energy, or more. As a result of this demand on the grid, power companies and data center managers needed to make a change.
A recent white paper by Server Technology (News - Alert) focused on this increase in data center power and the changes that came as a result of this consumption. To reduce the transmission losses along the line from the distribution substation, a transformer is often put in place to step down the voltage to a level of 480VAC that is entering the building. The result is a much more usable working voltage for an efficient data center.
Once this power is brought inside the typical data center, this data center power is often converted down yet again to reach the 208V 3-phase power/120V single-phase in a configuration that is either Wye or Delta. When this transformation of power takes place, losses in the form of waste heat are often produced, according to Server Technology.
The conventional topology of the data center power shows that there is a double-conversion once the power enters the data center. The first transformation will take place at the UPS, while the second occurs at the end of the row PDU. Both instances put the heat load inside the data center, which increases the demand for additional cooling technology.
The conversion from the 480V to 208V end-to-end efficiency tends to peak at just below 88 percent when measured between the 40-60 percent load. Over time, there have been incremental improvements in efficiency that have been made possible in the data center power by the UPS and end of row PDU/autotransformer manufacturers.
When auto-ranging AC to DC power supplies are put in place, the input power is transformed one more time. The IT load at the higher end of the input voltage range can deliver an efficiency benefit of 2-3 percent over operating at the low end. When removing the PDU or autotransformer, however, the losses result in a lower capital expense for the power transmission process, while operating expenses are also reduced with the associated power losses of that particular transformation. Some manufacturers claim the elimination of the PDU transformer can produce a 2 percent efficiency gain.
Most data centers, however, do not select paths that reduce their power utilization. In fact, many will use the same size copper and more than double the available power sent to the cabinet. This enables the data center to take an immediate jump in compute density for the equivalent space. In essence, data centers generally use all of the power coming in and often need more. A complete analysis of the power consumed and the potential efficiency gains could help change this trend.
Susan J. Campbell is a contributing editor for TMCnet and has also written for eastbiz.com. To read more of Susan’s articles, please visit her columnist page.
Edited by Carrie Schmelkin
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