Data Center Handbook, 2nd Edition

34DATA CENTER AIR MANAGEMENT

Robert Tozer and Sophia Flucker

Operational Intelligence Ltd, London, United Kingdom

34.1 INTRODUCTION

Data center energy consumption has continued to grow due to the increasing intensity with which businesses and individuals use IT. Current efforts to reduce energy consumption focus on the operation of the IT equipment and cooling systems and include expansion of the operating temperature ranges for IT equipment [1] and the raising of cooling system set points. Liquid cooling is used in some high density applications, however most facilities are air cooled; air management problems, solutions, and metrics are the focus of this chapter. In order to increase operating temperatures and optimize cooling unit fan speeds, it is important to first ensure that data center airflow is properly managed to ensure the continued reliability of IT equipment.

In legacy facility designs, data halls are flooded with cold air without much thought about managing airflow. With low load densities this was not a problem as this did not result in hot spots and energy efficiency was less of a concern, but as densities have increased, the need to manage air and reduce energy consumption has become more apparent. Traditional cooling systems in legacy data centers supply cold air from CRAH (computer room air handling) units located on the perimeter of the room to IT equipment via a raised floor. Air exhausted from the rear of IT equipment returns to the CRAH unit having mixed ...