New-Tech Europe Magazine | Feb 2017

Figure 3. By profiling power demand and employing battery storage it is possible to manage peak demand using power stored during low utilization periods

facilities to supplement their utility supply, akin to how power utilities ramp up and down their generating capacity throughout the day to meet expected demand from consumers and business. Unfortunately, the use of generating sets does not address the problem of peaks arising from more dynamic CPU utilization that is characterized by a higher peak to average power ratio, which is of shorter duration and occurs with a higher frequency. For this the solution is to provide battery power storage. The principle here is simple, the batteries supply power when demand peaks and are recharged during periods of lower utilization. This approach, referred to as peak shaving, is illustrated by figure 3, which shows how a server rack that would normally require 16kW of power can operate with 8-10kW of utility power. Indeed, if utility power is constrained, the

Figure 4. CUI’s rack-mount ICE hardware for intelligent power switching and battery storage

also included. Unlocking underutilized power supply capacity The peak versus average-power consumption issue discussed above clearly locks up considerable power capacity. Where peaks occur at predictable times and have a relatively long duration, data centers typically use local power generating

the supply system and causing power outages. This leads planners to add additional capacity to provide a safety buffer. Consequently it is not surprising to find that the average utilization in data centers worldwide is less than 40% purely by taking account of peak demand modeling plus the additional buffering - this figure drops further when redundancy provisions are

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