Greening up data center cooling got a lot of discussion over the past week, ranging from using more smarts to cool air to using water and oil (but not mixed together) to keep servers running at peak efficiency.

Nanyang Technical University (NTU) and Toshiba are testing a combination of free-air cooling in containerized data center rack modules and virtualization software to optimize server cooling and usage, according to Data Center Dynamics.  The configuration is being tested in Singapore, with Toshiba providing the containerized modules and NTU adding smart software.   The smart cooling system  brings in air outside of the data center when the outside air temperature is lower than inside the data center, rather than simply recirculating air (and adding to the power bill) on a fixed path around the clock.   NTU's software moves multiple applications from different servers onto one serve, than puts freed-up servers into sleep mode until needed.   Current data shows energy savings of up to 40 percent when compared to conventional data center configurations in Japan.

Water cooling is back in vogue at the U.S. Department of Energy's National Renewable Energy Lab (NREL).  HP and Intel are teaming up to build a $10 million energy-efficient high performance computer (HPC) system for NRELs energy R&D work - putting greener servers to make more green energy technologies. Waste heat from the computer system will be captured with water and used as the primary heat source for offices and lab space.

Finally, Intel  has been working with Green Revolution Cooling on a year-long trial of Green's fluid-submersion technology. Green Revolution says its tech reduces cooling energy usage by 90 to 95 percent while also reducing server power by 10 to 20 percent.   In addition, the company says on its website (www.grcooling.com) that a from-scratch installation cost is significantly lower than comparable air-cooled systems and retrofit paybacks are low as one year and typically below three years.

I tend to be a little squirmy when it comes to liquid cooling since water and electrical gear don't really mesh that well if the plumbing breaks somewhere in the machine room or at a server.  I'm also not sure if I'd be comfy with the Green Revolution solution; it uses a non-conductive mineral oil optimized for cooling data center hardware, so you're talking about an oil spill instead of water.  (Can you say slippery floors and clothing stains?) Swapping parts is also a bit more troublesome, since you have to pull the server out of the oil bath, let it drain, and then swap in a new board or other part.

While you can use off-the-shelf hardware with some modifications (don't need a fan, do need to seal the hard drive from oil leaking in), Intel is looking at building customized hardware specifically for oil-based immersion cooling.  It will be interesting to see if Intel will combine oil-based cooling with ideas coming out of the Open Compute initiative, building an power and maintenance optimized design for big data center players like Facebook.  Since Intel has a representative on the Open Compute board, it's possible that we may see some significant compute-per-watt and overall data center energy usage numbers in a couple of years.