updated 10:03 pm EDT, Mon May 21, 2012
Applying knowledge of cooling to buildings
Some details revealed about how Apple intends to make its Maiden, North Carolina data center almost entirely powered from renewable-energy sources have come to light, showing a combination of solar and fuel-cell technology and practical energy-saving policies. The plans show that the company behind the iMac are also applying some cooling lessons learned from computers to the buildings, such as variable-speed fans.
Apple plans to implement two solar farms of approximately 100 acres each, along with a biogas-based fuel cell installation that will go online later in the year. Between the two, the company will already be generating roughly 60 percent of the data center's energy needs (about 45 megawatts) by the end of 2012, but Apple says it will make the remainder renewable "through sourcing arrangements with local and regional clean-energy sources," according to its environmental website.
These plans, reports ZDNet, have been in the works for years and are not a reaction to Greenpeace's recent pressure campaign against Apple, which is really targeting the company's use of mostly coal-based Duke Energy, which provides electricity using coal, oil and nuclear power to a sizeable portion of the US southeast. The company also operates some hydroelectric power plants in Brazil.
Apple is currently one of Duke Energy's biggest single customers, but a shift by Apple to demanding renewable sources for its data center's power could pressure the company to compete more aggressively with renewable-energy investments, such as solar or wind power. Apple plans to register the renewable energy generated by its own solar and fuel-cell installations with the North Carolina Renewable Energy Tracking System (NC-RETS) in order to address complaints about transparency on its energy use.
Apple's data centers already engage in conservation measures typically employed in data centers around the world, such as using motion sensors so that unused parts of the building are kept dark, power-distribution systems that spread electricity around at higher voltages, LED lighting and a white "cool-roof" design. In addition, the Maiden facility will employ a chilled-water storage system to improve AC chiller efficiency, which helps shift consumption of air-conditioning power to off-peak hours.
Also incorporated into the design of the facility is "free-air cooling," which allows cool air outside the buildings to be drawn in and used to remove generated heat, an idea also employed in some of Apple's computers such as the iMac, which uses convection cooling to minimize the use of fans. Likewise, the Maiden facility employs variable-speed fans with sensors to help them automatically handle demand for cooling. These measure are estimated to handle the data center's cooling needs for up to 75 percent of a typical day, particularly during the cooler parts of the year.
Apple has said publicly that it plans for its Newark, California and forthcoming Prineville, Oregon data centers to also shift to more clean power through sourcing relationships and other measures. The new center in Prineville is planned to be as energy-independent and use renewable resources on the same scale as the Maiden facility. [via ZDNet]
Apple's Maiden NC data center