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The National Snow and Ice Data Center (NSIDC), located at the University of Colorado Boulder, disseminates satellite and in-situ data globally to researchers of the cryosphere, or areas covered with snow and ice. The data, from NASA Earth Observing System satellites and both NASA and National Science Foundation ground studies, are used in Earth science and climate studies. To make its mission-essential data center more energy efficient, the NSIDC developed a retrofit project that includes virtualization of IT equipment, a unique new HVAC design, and a photovoltaic solar powered UPS.
This project was a 3-year odyssey with the usual trials and successes. Our 1600 square foot data center used half the power of the 77,000 square foot building. Datacenters are approaching the total energy use the airline industry. The irony that the tools that NSIDC used to study climate change were causing some of the climate change really bothered us. With the completion of this project datacenter power utilization was cut 70% and the cooling energy was reduced more than 90%. Our payback on the project is 29 months and we have significantly lower maintenance and increased reliability.
There were many who said this project was impossible. But in fairness to the engineers, they often have good reason. In the sciences, when you write proposals, you have to push the edge in order to get funding. In engineering the client will not fund you with a novel idea as no one wants to be first. This project is a classic case of revolutionary, not evolutionary, engineering.
Our cooling system was built to replace the existing direct expansion (DX) computer room air conditioning (CRAC) units with eight Coolerado units that use a combination of airside economization and indirect evaporative cooling. These units, can supply air that is 30°F to 40°F (16°C to 22°C) below the incoming air temperature without the use of compressors, while also producing warm, saturated air that is used to increase humidity in the datacenter on demand. The data center also includes a 50 kW roof-mounted photovoltaic (PV) array that charges a UPS to replace the need for a backup generator. The PV system generates about 75,000 kWh of electricity annually with surplus power being fed back to the grid. On sunny days the data center is energy neutral. Prior to the retrofit, the datacenter had an average PUE rating of 2.03; the retrofit project improves its PUE rating to an average of 1.15 while meeting all American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) standards.
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