Cool your chips: What's ahead in energy management

Computerworld - There are already ways to add liquid to your existing rack server, and cooling the chips themselves is a logical next step, some believe. Various technologies are at different stages of commercialization.

"There is going to be a return to liquid-cooled electronics like the old mainframe days," said Terry Rodgers, a consultant at Syska Hennessy Group Inc. "A lot of the newer products out there today are very effective in getting heat out of a rack and allowing data centers to remain in operation, but they are not saving energy. The move to direct-component cooling is going to be needed if we are going to create truly more efficient systems."

Liquid is 3,500% more efficient than air, said Patchen Noelke, director of marketing at Spraycool, a division of ISR Inc. With many companies now embracing cabinet-level cooling (see related story), "it's only a short step to putting liquid inside the server, where the benefits are enormous for power savings," Noelke said.

Spraycool has two commercial products. The M-Series is a direct chip-cooling technology in which a module is attached to the surface of a processor or other system component. Inside the module, liquid is sprayed across a cold plate on top of the processor, removing as much as half the heat. Spraycool also sells the G-Series, used primarily in defense contracts, which sprays nonconductive fluid directly across an entire motherboard.

The M-Series modules are being evaluated by a range of businesses and labs, and the next major step in commercialization will be to get server makers to begin offering platforms that incorporate the technology. One partner in this effort is Smart Modular Technologies Inc. (SMT), a provider of memory subsystems that in February announced it would begin offering a family of DIMMs that combine the Spraycool modules with its own flexible circuit-board technology.

"This is a complete shift in how to design systems," said Arthur Sainio, senior marketing manager at SMT. "But it's really a no-brainer. It will be hard for [resellers] to dispute better performance, lower power and lower operating costs."

The Pacific Northwest National Laboratory (PNNL) is entering its third phase of cooling tests designed to evaluate and measure the effectiveness of the Spraycool technology. In the first two phases, the lab used Hewlett-Packard Co. servers with Itanium 2 processors to test the modules. The lab is now testing the modules on IBM servers using quad-core Xeon processors.

Stephen Elbert, associate division director for computational sciences and mathematics at PNNL, said the lab will need new cooling technologies by the end of the decade as it deploys hotter next-generation servers. The current tests are expected to yield metrics that can be used to justify further deployment of chip-level cooling techniques.