Optimization and control of cooling microgrids for data centers

Reliable operation of today's data centers requires a tremendous amount of electricity to power both the IT equipment and the supporting cooling facilities. As much as half of total data center electricity consumption can be attributed to the cooling systems required to maintain the thermal status of IT equipment. In order to lower the electricity usage of the cooling system and hence reduce the data center environmental footprint, alternative cooling resources, such as water and air-side economizers, are being exploited to supplement or replace the traditional chilled water based cooling schemes. The various cooling resource options, together with the mechanisms to distribute and deliver the cooling resource to IT equipment racks, constitute a cooling microgrid. In this paper, we present a holistic perspective for the optimization and control of the data center cooling microgrid. The holistic approach optimizes the sourcing and distribution of cooling resources from the site portfolio in response to real-time weather changes and site demand. The cooling microgrid optimization and control framework has been implemented in a research data center; we estimate that the framework cuts the yearly cooling costs by 30%.