Issue link: https://www.e-digitaleditions.com/i/1132978
60 I ICT TODAY Managing capacity includes how to optimize and maximize utilization of the existing capacity and the ability to plan and forecast for future needs. Additional savings can also be achieved by balancing the power, airflow and pressure increasing ventilation. There are significant energy savings related to bringing 415V to the rack. It is estimated that by using a smaller isolation transfer that goes from 480V to 415V (in comparison to a larger isolation transformer which take the incoming voltage of 480V to 208V), approximately 2 percent in energy losses can be saved. In addition, when considering IT rack equipment power supplies, the end user can realize even more efficiencies. It is estimated that IT equipment switching power supplies run at approximately 80 percent efficiency at 100V all the way up to 91 percent 11 efficiency at 240V. 415V rack PDU outlets supply 240V to the attached IT equipment; the equipment can run as much as 11 percent more efficiently than the same piece of equipment running on 120V. Bringing 415V to the rack is also beneficial as it helps in lowering infrastructure costs. In reference to the precious energy savings discussion, using smaller isolation transformers are not only smaller, but they are also more cost effective than their larger counterparts (480V to 208V) per transformer deployed. Next, there are additional savings that can be achieved in regard to power cables. Considering what was learned from the increased power capacity section, a 60A 208V three-phase rack PDU has equivalent power capacity to a 30A 415V three-phase rack PDU (i.e., 17,292 VA (60A x .8 x 208V x 1.732) and 17,250 VA (30A x .8 x 415V x 1.732) accord- ingly. The AWG required to carry 30 Amps is 10 AWG in comparison to the AWG required to carry 60 Amps which is 6 AWG. Taking a look at the market costs of the two AWG, there is an approximate savings of $0.28 per foot. Accordingly, when considering the amount of power cables that are installed into a data center, these can provide additional savings to the data center owner. The cost of outages can be substantial, since it can damage equipment, cause loss of productivity, loss of business and in some cases loss of reputation. Outage risks can be reduced with warning alarms triggered when overload or potential hot spots are detected. They can also be reduced by logging power trends for anticipating overloading, since power has a transient behavior that needs to be monitored over time to detect and predict anomalies. Should an outage occur, intelligent rack PDUs enable the gradual powering-up of the equipment in the data center avoiding uncontrolled power up that can create a power surge resulting in continuous outages. Another benefit is capacity management by finding best fit and stranded capacity while being able to forecast remaining capacity and future needs. Low, compact PDUs help to reduce rack space. Air flow and ventilation are improved, thereby contributing to reduction in energy costs. Quality, reliability, and safety are paramount considerations when selecting the right intelligent rack PDU supporting high density power applications. As the voltages are increased so is the inherent increased risk for arc flash. Safety features to look for include 10KAIC (Ampere Interrupting Capacity) breakers as well as magnetic- hydraulic breakers with stable trip characteristics at extreme temperatures. These breakers provide double the AIC rating of what would be found in a standard 208V rack PDU which typically has 5 KAIC breakers, increasing the safety level of the PDU. The AIC rating indicates the maximum fault current that the breaker overcurrent protection device will safely clear when a fault is applied at the load side of the breaker. In addition, utilizing an IP67 waterproof plug with pin and sleeve provides secure and reliable connections. Selecting a 415V PDU provides a great deal of benefits with regard to capacity and savings in both energy