Google Inc. announced that it has filed a patent for a "water-based data center" that uses the motion of waves to power on-board computers and the ocean’s water to cool them. The patent was submitted in February 2007, but was spotted in the U.S. Patent & Trademark office’s electronic filings and publicized online in the last week.
The floating data centers would be located 3 to 7 miles from shore, in 50 to 70 meters of water. If perfected, this approach could be used to build 40MW data centers. Standard shipping containers would house racks of computers that could be transported by truck and placed onto a boat by crane. The company says the data center containers could be stacked two or more high, so that each data barge could hold "12 or more" containers.
A wave-power generator would be the primary source of electricity. However, wind turbines could also be used to power water pumps and a tidal power generator could be used in rivers.
The Google design incorporates the Pelamis Wave Energy Converter units, which use the motion of ocean surface waves to create electricity and can be combined to form "wave farms." The largest existing project uses seven Pelamis units to generate about 5MW of power. According to diagrams included in the patent application, the company plans to combine 40 or more Pelamis units to produce 40MW of power. A British company, Pelamis Wave Power, is operating a prototype in Scotland and intends to install one off Portugal.
The company speculates that an array of pontoons spread over a square kilometer could produce 30MW of electricity, enough to operate a single system. Also envisioned is equipment to use the direct current electricity to run dc-capable computers.
Server makers and data center operators are already circulating water to cool computing gear. The patent documents describe a cooling system based on sea-powered pumps and seawater-to-freshwater heat exchangers.
