Optimizing data center energy efficiency via ambient-aware IT workload scheduling

Energy consumption in data centers has increased over the years. A significant percentage of the total energy required by data centers may be consumed by cooling equipment. To decrease cooling cost, incorporation of air-side economization, or "free" cooling, which utilizes locally available outside air to augment or replace the cooling capacity provided by traditional data center cooling infrastructure, has been explored in recent years. However, little work has been done on exploiting the diurnal nature of outside air conditions by integrating the active management of cooling and IT workload scheduling. In this paper, we estimate the savings obtained by using this concept of integrated management in a containerized data center that implements a micro-grid of cooling resources consisting of outside air, conditioned air using DX (Direct Expansion) units, and a combination of both. For such a data center, a previously developed energy model is utilized to estimate the annual savings obtained by scheduling workload according to the variable cost of cooling resource generation and delivery. The impact of data center location and allowable IT inlet air temperature range on savings is also studied. The results show that the integrated management can decrease the cooling cost by up to 50% depending on location of the data center, the types of IT workload and total IT resources available in the data center.