The rising costs of energy and the drive to be green are resulting in greater demand to conserve energy. The energy savings potential of operating in economizer mode in certain climates makes it attractive for use in IT environments. Operating in economizer mode saves energy by utilizing outdoor air during colder months of the year allowing refrigerant-based cooling components like chillers and compressors to be shut off or operated at a reduced capacity. Up until recently, operating in economizer mode was considered an option or a secondary mode of operation but is now becoming a requirement to meet efficiency targets set by data center operators and / or standards such as ANSI/ASHRAE Standard 90.1-2010, Energy Standard for Buildings Except Low-Rise Residential Buildings. Data center operators in some climates are finding that cooling systems can operate primarily in economizer mode allowing the refrigerant-based modes (i.e. mechanical cooling) to serve as the secondary mode of operation or backup.
Although the concept of economizer mode is recognized throughout the data center industry, little has been done to standardize the terminology and its definitions leading to confusion. A significant source of confusion lies in the use of the term “economizer” to describe a component within a cooling system or a subset of a cooling system. An “economizer” is NOT an object; it IS a mode of operation.