Part 2: How HVAC Economizers Can Help Data Centers Meet Energy Codes, Energy Star Ratings And ASHRAE Standards
How HVAC Economizers Can Help Data Centers Meet Energy Codes, Energy Star Ratings And ASHRAE Standards
By Loren Snyder January 2014 - Data Centers
Increasingly, international energy codes, Energy Star, and ASHRAE standards are advocating the use of outside air to help cool data centers; this is done via HVAC economizer modes. Results of economizers will vary depending upon mechanical equipment and geographic location or climate zone, but some ballpark estimates exist.
“The total energy use of the mechanical system can be reduced by as much as 50 to 60 percent, depending on the mechanical system,” says Brett Griffin, senior associate mechanical engineer for mission critical facilities at Environmental Systems Design, Inc. “In addition to that, raising the space temperatures by 5 degrees can result in as much as 1,000 extra hours of economizer operation per year, again depending on the mechanical system and the local climate.”
Sometimes referred to as “free cooling,” economizer mode bypasses the mechanical cooling system and draws outside air into the conditioned space when outside air is cool enough. This can be done via direct fresh air, heat exchangers, or heat wheels.
Role of IT
Regardless of where a data center is located, Cassiliano says, data centers may be able to save energy by taking a hard look at redundancy. He notes that critical applications are required to have redundancy; however, in most cases, less critical applications do not require the same level of redundancy, and secondary equipment isn’t genuinely needed. That principle applies to both data center infrastructure and to IT equipment.
“If you don’t need it, don’t use it,” says Cassiliano, who is also president and CEO of Business Information Services, Inc. (BIZ).
Technology managers can also help reduce power use, Cassiliano says. For example, most modern IT equipment has power management features designed to minimize energy use. Cassiliano advocates understanding and using power management features to reduce energy use. He also notes the importance of virtualizing servers.
“Most data centers are using less than 15 percent of server capacity,” he says. By virtualizing servers, data centers can achieve greater energy efficiency.
“These days, most sophisticated data center operators are reducing energy loss due to data center infrastructure,” Cassiliano says. “But now the focus also needs to be on IT equipment use: maximize utilization of available servers, use power-management features, and shut down idle equipment.”