Network Communications News (NCN) August 2016 - Page 26

F E AT U R E IT load Data centre operators need a better understanding of how IT equipment operates and how its reliability is impacted at high temperatures. Congestion Edge computing is an inevitable consequence of vastly increased data traffic which requires more sophisticated traffic management. With the Internet of Things expected to comprise 50 billion devices connected worldwide by 2020, network latency and speed of response will require data transactions to be contained, as far as possible, within regional networks, to remove some of the congestion from global networks. Much effort has already been directed towards the challenge of using energy more efficiently in data centres. Vendors of data centre infrastructure equipment such as cooling, air conditioning, power supply and containment products have produced reference designs that allow highly predictable installations to be constructed. They make widespread use of metrics such as PUE to validate how efficiently a data centre’s power can be delivered to the IT equipment it contains. However, PUE is limited in terms of managing the overall energy consumption of a data centre, measuring only the relative difference between power consumed on IT equipment and that consumed on IT and infrastructure combined. So although it is now easier to build data centres with confidence that a low PUE rating will be achieved, it doesn’t automatically mean that overall energy consumption will be reduced. One strategy recommended by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) to reduce overall energy consumption is to arrange a data centre so that the ambient temperature inside can be allowed to rise. If a data centre can operate effectively at higher temperatures, the initial thought was that cooling equipment such as chillers can operate in economy mode and will not need to be deployed as frequently, resulting in a lower energy requirement. However, this technique has not been widely adopted for a variety of reasons. Apart from a natural conservative reluctance among engineers to change an approach that has been seen to work effectively, the results of allowing temperature to rise have been mixed. Although allowing chillers to operate in economiser mode for a greater part of the year produces immediate energy savings these are offset by the greater burden placed on other parts of the cooling infrastructure. Dry coolers must operate when the chillers are in economiser mode. Furthermore, there is an increase in the energy expended by fans both in the server racks t