Intelligent rack PDUs meter power, in some cases at the individual outlet level. Metering can include current, voltage, power (kVA, kW) and consumption (kWh). Ideally, kWh should be measured at +/- 1% billing-grade accuracy. Intelligent rack PDUs can also support environmental monitoring at the rack. Ideally, the rack PDU should support optional plug-and-play environmental sensors, such as temperature and humidity, which then don’t require additional network connections or hardware.
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends placing temperature sensors on the cool air inlet side of a rack at the bottom, middle and top. An intelligent rack PDU should also support monitoring temperature with user-adjustable high and low temperature thresholds. When the thresholds are crossed, alerts are sent so the temperature can be lowered if too hot or raised if too low, thereby wasting power by overcooling. Monitoring humidity is also important but since it doesn’t change much with respect to location on a rack, one humidity sensor per rack is sufficient.
Recently, ASHRAE raised the high end of the allowable inlet temperature range to 27° C (81° F). IT equipment vendors ensure that with this inlet temperature, IT equipment will operate safely. By raising the ambient temperature in a data center, IT managers can reduce the energy consumed by air-conditioning.
As a global vendor of rack power distribution units, Raritan provides a very large range of product configurations that accept 400V input. While 400V distribution is relatively new in North America, Raritan has deployed 400V systems in Australia and in many European countries where it is the nominal standard.