Sun’s Colorado Consolidation Saves Millions describes how Sun used Liebert’s XD rack cooling, clear vinyl cold isle curtains and flywheels to increase the density of its data center while also reducing energy consumption. They reduced 165,000 square feet of data center space into 700 square feet while reducing their monthly power usage by one million kilowatt-hours.
When we considered the XD cooling units, there were two options: chilled water or refrigerant. In the case of chilled water, there was the question of potential water leaks in these rack-attached units. With the refrigerant option, there was the question of an increase in the number of condensers and where they would be placed and how much more maintenance would be needed. With either option, there is also an increase in the need for maintenance inside the server room amongst the servers, storage, switches, etc. The obvious benefit of the XD units is the fact that they can provide enough cooling for up to 30 kW in a single rack. Although, if I recall correctly, there is a limit to the total number of racks with the refrigerant-based version due to limits on the maximum pressure or capacity of the refrigerant in a single system.
As for the vinyl curtains, there is usually more of an objection to their aesthetics. Personally, I would like to see them installed to help keep the cold air completely contained in the cold aisle, where it is intended. Especially in raised floor environments with high velocity air flow where the cold air might be pushed outside the confines of the cold aisle without such containment.
One question about Sun’s use of the flywheel: How large are your flywheels? Flywheels generally supply on the order of ten seconds or so of power, which is usually enough time for generators to kick on but cuts it very close. What type of services run out of Sun’s Colorado facility?
