Chris Page, Director of Climate & Energy Strategy at Yahoo! spoke at the 2010 Data Center Efficiency Summit and presented Yahoo! Compute Coop Design.

The primary attributes of the Yahoo! design are: 1) 100% free air cooling (no chillers), 2) slab concrete floor, 3) use of wind power to augment air handling units, and 4) pre-engineered building for construction speed.

Chris reports the idea to orient the building such that the wind force on the external wall facing the dominant wind direction and use this higher pressure to assist the air handling units was taken from looking at farm buildings in the Buffalo, New York area. An example given was the use of natural cooling in chicken coops.

Chiller free data centers are getting more common (Chillerless Data Center at 95F) but the design approach is still far from common place. The Yahoo! team reports they run the facility at 75F and use evaporative cooling to attempt to hold the server approach temperatures down below 80F using evaporative cooling. A common approach and the one used by Microsoft in the chillerless datacenter at 95F example is install low efficiency coolers for those rare days when they are needed on the logic that low efficiency is cheap and really fine for very rare use. The Yahoo! approach is to avoid the capital cost and power consumption of chillers entirely by allowing the cold aisle temperatures to rise to 85F to 90F when they are unable to hold the temperature lower. They calculate they will only do this 34 hours a year which is less than 0.4% of the year.

Reported results:

· PUE at 1.08 with evaporative cooling and believe they could do better in colder climates

· Save ~36 million gallons of water / yr, compared to previous water cooled chiller plant w/o airside economization design

· Saves over ~8 million gallons of sewer discharge / yr (zero discharge design)

· Lower construction cost (not quantified)

· 6 months from dirt to operating facility

Chris’ slides: (the middle slides of the 3 slide deck set)

Thanks to Vijay Rao for sending this my way.


James Hamilton



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