According the EPA Data Center Report to Congress published in August of 2007, “up to 30% improvement in data center energy efficiency can be obtained from improved airflow management”. A measurement that was not called state-of-the-art or a best practice but just an ordinary operational improvement.
Improving airflow in a traditional data center is all about separating and containing cold and warm air, and free airflow underneath raised floors isn’t it? But this common knowledge isn’t a common practice. Even for companies that use and run big data centers. Data center Knowledge placed a blog entry about big savings for Facebook by redesigning the airflow in one of its existing data centers in Santa Clara, California as presented on the Data Center Energy Efficiency Summit 2010
By using computational fluid dynamics (CFD) software they discovered that the cold air entering the room didn’t reach the servers. So they installed a cold aisle system (doors at the end, roof panels, blanking plates, …). By this a cascade of other improvements became operational. They could reduce the number of CRAC units, reduce server fan energy by lowering their speed, raising the air temperature with 9 degrees Fahrenheit, also they could raise the water temperature of the supply water coming from its chillers, requiring less energy for refrigeration.
But wait a minute where did I hear a similar story? It was on the Power and Cooling conference in London, two weeks ago, where Jeremy Hartley of eCool Solutions told a similar story about a data center of Yahoo and where similar actions led to a 15% reduction in power usage.
So is this energy-saving good news or is it bad news? These actions to improve cooling and thereby creating big energy and money savings are not really rocket science. So what is the reasons that this isn’t done earlier? EPA told it already in 2007. Who will send the message to the CIO: “Green your data center by improving airflow management and get big savings”?