Data centers use about 1.3 percent of the world’s power. According to Stanford University, facilities like those operated by Amazon and Facebook gobbled around 250 billion kilowatt-hours in 2010, and around half that energy isn’t used for computing tasks at all. Instead, it powers the fans and chillers used to cool down computer chips. As rising electrical bills become an environmental and business concern, Technology Review identified five creative ideas for recycling waste heat.
Green computing: A rack of University of Notre Dame servers (at rear) heats an enclosed botanical garden at the South Bend Conservatory in South Bend, Indiana. Air drawn from outdoors cools the computers; hot air is released into the greenhouse. The servers are connected to the university’s main computing cluster and are given more processing tasks if higher temperatures are needed. Paul Brenner of Notre Dame’s Center for Computing Research says the prototype could lower heating costs for the conservatory while cutting the school’s annual electric bill.