Three Options for Energy-Efficient Data Centers

by | Apr 21, 2010

The best options for cost-effective data center retrofits that significantly reduce energy consumption include electrical equipment upgrades, server virtualization and cooling optimization, according to an article written by Coy Stine, director of Data Center Services for Bluestone Energy Services for Data Center Knowledge.

As an example, replacing UPS and PDU equipment delivers less electrical loss and less waste heat to remove. While efficiency gains depend on the age of the equipment being replaced, a five percent gain in UPS efficiency can lead to a 10 to 60 percent reduction in annual operational costs, said Stine. The drawbacks: high capital costs, potential IT downtime and complex electrical work.

With server virtualization, companies can achieve substantial energy savings by eliminating redundant server hardware. However, migrating applications and data to virtualized platforms requires technical expertise for both the initial transition and ongoing software maintenance. Stine recommends gradual implementation, starting with new server systems.

The cooling infrastructure offers the best choice for cost reduction with up to 40 percent of cooling costs cut by making simple modifications, said Stine. In many cases, cooling optimization may allow one or more computer room air conditioners (CRACs) to be switched off entirely or placed in standby mode. Most approaches will result in fewer fans, re-heaters, humidifiers, compressors and heat-ejection equipment requiring power.

Most of these retrofits maintain 100 percent uptime of IT equipment during installation, and the payback is typically less than two years. In addition, electric utilities typically provide incentives for these projects, typically covering between 15 to 70 percent of the cost, since they offer huge cuts in energy use.

A new EPA study indicates that a data center’s uptime has no impact on its energy efficiency. Some of the biggest factors that have a larger impact on a data center’s energy efficiency or power unit efficiency (PUE) include idle capacity and the type of equipment used, according to Uptime Institute.

The Green Grid, together with several global government and industry groups including the EPA, recently agreed to global data center energy-efficiency metrics centered on the PUE rating.

Energy-efficient data centers also lead to fewer emissions. As an example, communications services provider Elisa is planning a new data center in Espoo, Finland, that is expected to reduce carbon dioxide emissions by about 7,500 tons annually. The new data center will also use the heat generated by the servers for district heating.

The data center will also leverage cloud computing, which uses more efficient server resources, while reliability and ease of use will be provided by the UPS and stand-by supply systems included in the solution.

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