Part of Accenture's role is to compare the test results with the projections in the EPA's report. Andrew Fanara, head of the EPA team that authored the report, said next week's findings would "complement" the EPA research and help validate its projections. Fanara said he expected to attend the summit next week, along with representatives from the Department of Energy.

Participants said the event is unique because of the cooperation from data center operators, who typically are secretive about their operations. "This level of transparency is rare in the data center industry, but it’s a sign of how committed the participants are to increasing energy efficiency," said Jim Smith, vice president of engineering at Digital Realty Trust, another of the data centers taking part.

All the technologies being tested are available today. The case studies cover basic best practices, such as improving air flow management and consolidating server equipment, as well as emerging technologies like the wireless sensor networks. They will all be published at no charge, along with Accenture's consolidated report.

Sun tested modular cooling products from five vendors, and Accenture will present a side-by-side comparison of the results, Tung said. Digital Realty Trust, Yahoo and NetApp tested air economizers, which use outside air to supplement cooling systems when the outside air is cold enough, a technique also called "free cooling."

The U.S. Postal Service is in the process of upgrading a data center in San Mateo, California, that will use high-efficiency power transformers, also called power distribution units, or PDUs, made by Powersmiths. Its case study will compare the operating losses of transformers already in place with the new high-efficiency products, said Peter Ouellette, Powersmiths' district manager for Northern California.

Not all the technologies were tested thoroughly. Only two weeks of data were collected for the free cooling equipment, so the results had to be extrapolated for the year, Tung said. But she thinks most of the data will be valuable. "In each case we've given the 'before' and the 'after,' so the before sets the baseline and the after shows what was actually saved," she said.

The summit is one of several initiatives to address energy use in data centers. Others include the Green Grid, a vendor-led effort. The Uptime Institute and McKinsey published a report on the subject in May, and the EPA is working on an Energy Star specification for both servers and data centers.

Summit organizers said the event plugs a gap between recommending energy-efficient technologies and documenting the savings from their usage.