CoolAir

Abstract

Despite its benefits, free cooling may expose servers to high absolute temperatures, wide temperature variations, and high humidity when datacenters are sited at certain locations. Prior research (in non-free-cooled datacenters) has shown that high temperatures and/or wide temporal temperature variations can harm hardware reliability.In this paper, we identify the runtime management strategies required to limit absolute temperatures, temperature variations, humidity, and cooling energy in free-cooled datacenters. As the basis for our study, we propose CoolAir, a system that embodies these strategies. Using CoolAir and a real freecooled datacenter prototype, we show that effective management requires cooling infrastructures that can act smoothly. In addition, we show that CoolAir can tightly manage temperature and significantly reduce temperature variation, often at a lower cooling cost than existing free-cooled datacenters. Perhaps most importantly, based on our results, we derive several principles and lessons that should guide the design of management systems for free-cooled datacenters of any size.

Thermal Management of Data Centers Under Steady and Transient Conditions

“…Substantial energy savings are obtained if chillers are not employed and ambient air is directly used for heat removal. This circumstance is often known as free cooling and has been of considerable interest due to the reduced costs and simplifications involved (Goiri et al, 2015). A consideration of the heat input due to the electronic system, possible hot spots and effectiveness of the circulating flow would allow the determination of when chillers are needed to ensure satisfactory performance of the data center (Tschudi, 2003;Litner, 2010).…”