I just read a neat article in Infoworld about Data Center energy efficiency, conspicuously the article does not talk about carbon footprint or greenhouse gasses, not once, it talks about the cost of energy and how stupid it is to waste money. It talks about using human ingenuity to solve the problem and for once it spends time looking at the basics, the low cost stuff that makes an enormous difference.

I said years ago that altruism is fine as a starting point but that capitalism and price pressure will have the biggest and most significant impact on energy efficiency. Anybody want to argue?

The article suggest that putting data centers on decommissioned ships and reusing hot water from cooling systems to fill the town swimming pool are wacky ideas. Personally I think these are smart and ingenious approaches. The sea is always cool and is an infinite heat sink, so why not use it as an alternative to refrigeration? I have used the large underground lake in Milan, Italy (7C, 45F year around) to cool a data center very effectively so why not the sea? Dumping hot air out of heat exchangers into the air is dumb, why not heat the town swimming pool and reduce our taxes or admission prices?

Another neat idea is that one large health-care center is looking at reusing hot water expelled by its cooling systems to do its laundry. Alternatives are heating glasshouses for horticulture.

A hosting company in the USA is freezing water overnight, when the cost of electricity is cheaper, and then blowing air over the ice during the day to provide cold air for cooling systems. BT did this in London over 20 years ago.

The article addresses the basics when it states that one of the most effective approaches is better air-flow management, so that cold air pumped in to cool equipment doesn’t mix with hot exhaust air coming out.

Many data centers use alternating hot and cold aisles to keep warm and cold air separate, but that method is only partially effective because the air mixes in the spaces above the aisles.

Oracle tested “hot-aisle containment” at a data center in Austin, Texas, which involves building an enclosure around server racks so that the hot exhaust can be siphoned off. Why cool heated air when you can cool fresh air?

Yahoo tested cold-aisle containment, and then installed a wireless sensor network to monitor temperature and humidity around the room. The sensor network allowed Yahoo to gradually increase the temperature in its data center without creating heat spots that could damage equipment. The set-up can reduce cooling energy costs by 25 percent. This approach only works with fresh air cooling.

The containment systems must not interfere with sprinkler systems. Yahoo used flame-retardant PVC connected to the racks with “fusible links” that would collapse at 130 degrees Fahrenheit in the event of a fire, allowing the sprinklers to operate.

Another case study looked at air-side economizing, which is basically just a fancy name for opening the windows and using outside air for cooling. We call it Fresh Air Cooling here on The Hot Aisle because that is what it is.

Dean Nelson of Sun said data centers should consider raising their overall temperatures. Sun tested modular cooling systems on five-year-old servers and they operated without any problems even when aisle temperatures reached 85 degrees Fahrenheit. ”It makes me wonder,” he said, “why are we running our cold aisles at 65 degrees?”  The Hot Aisle wonders why it has taken so long for common sense to catch up and when are Sun and the other vendors going to come out and stand behind us operating their equipment at higher temperatures?

Accenture is publishing the results from the case studies on its Web site, along with an overview that compares their effectiveness.