A research paper from Intel shows the chip giant figured out what many apartment and home dwellers have known for years: using a fan to pull in cool air from the outside is as good as an air conditioner.
Datacenters have operated on the notion that they must be hermetically sealed from the outside, with all moisture eliminated, and the air conditioning blasting. What Intel (NASDAQ: INTC) found is in a favorable climate, a datacenter can be kept cool by using an air economizer to draw in cooler air from the outside and blow hot air out of the building.
The chip giant ran a 10-month test with a datacenter of 900 servers in New Mexico, not exactly a temperate climate, using air economizers and the outside air to keep the datacenter cool. The 900 blades and racks were run at 90 percent utilization throughout the test.
The temperature of the outside air ranged between 64 and 92 degrees. Air conditioning was used if the outdoor temperature went above 90 degrees and if it dropped below 65 degrees, the air was warmed by recirculating hot air produced by the servers.
Intel made no attempt to control humidity and applied only minimal filtering for dust. As such, humidity in the datacenter ran from four percent to 90 percent, and the servers were covered with a fine layer of dust. Sounds like the computer room in the average household.
The results? “We observed no consistent increase in server failure rates as a result of the greater variation in temperature and humidity, and the decrease in air quality,” wrote Don Atwood, a regional datacenter manager and John G. Miner, a senior systems engineer with Intel. “This suggests that existing assumptions about the need to closely regulate these factors bear further scrutiny.”
A 74 percent reduction in energy consumption
With the economizer instead of air conditioning, the power draw was reduced from 111.78 kilowatts to 28.6 kilowatts, a 74 percent reduction in energy consumption. The server failure rate was 4.46 percent, not much worse than the 3.83 percent with air conditioning.
Based on that 74 percent decrease in power consumption, and being able to use air economizers for 91 percent of the year (weather conditions permitting), Intel estimates it could save approximately 67 percent of the total power used annually for cooling. That would translate into $143,000 for a small 500-kilowatt datacenter, or $2.87 million for a 10-megawatt datacenter.
As it turns out, Intel is not exactly ahead of the curve on this one. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) came to a similar conclusion last December.
Sun goes deep underground
Also, one of the most notable deployments of Sun Microsystems’ mobile datacenter, the MD S20, is deep underground in an abandoned Japanese mine, where the natural ambient temperature was a key element to the placement of the servers, which are housed inside a standard shipping container.
