How Higher Chilled Water Temperature Can Improve Data Centre Cooling System Efficiency

by Paul Lin, Victor Avelar & John Bean

Download PDF

Executive summary

Alternative data centre cooling approaches such as indirect air economisation are calling into question the economic justification for using traditional chilled water cooling in new data centres, especially those in mild climates. This paper describes some innovative approaches to chilled water cooling, where the chiller is used only to boost cooling capacity on the hottest days. A capex and opex analysis describes how these approaches can save 41%-64% opex, with 13% increase in capex with assumption of using the same chiller. We also discuss the design considerations for these new technologies.


Return-on-investment analysis drives an ongoing industry effort to reduce data centre operation costs by reducing the cooling system energy consumption. A revision to ASHRAE standard TC9.9, released in 20111, encourages increasing the number of hours on economiser mode as an effective means of lowering cooling system energy consumption. In this revision, ASHRAE continued to expand the environmental range for data centres to where an increasing number of locations throughout the world are able to operate with more hours of economiser mode. In other words, reducing the number of hours in full mechanical (i.e. compressor) mode can achieve significant energy savings.

To find out more download the full pdf below:

Download PDF

Need more information?

Contact Details

Follow Us

Email Us