GC: n

CT: WEATHER systems, as the world has recently been reminded, have awesome power. The energy released by a large hurricane can exceed the energy consumption of the human race for a whole year, and even an average tornado has a power similar to that of a large power station. If only mankind could harness that energy, rather than being at its mercy. Louis Michaud, a Canadian engineer who works at a large oil company, believes he has devised a way to do just that, by generating artificial whirlwinds that can be controlled and harnessed. He calls his invention the “atmospheric vortex engine”.
His idea works on a similar principle to a solar chimney, which consists of a tall, hollow cylinder surrounded by a large greenhouse. The sun heats the air in the greenhouse, and the hot air rises. But its only escape route is via the chimney. A turbine at the base of the chimney generates electricity as the air rushes by. A small solar chimney was operated successfully in Spain in the 1980s, and EnviroMission, an Australian firm, is planning to build a 1,000-metre-high example in New South Wales. But the efficiency of such a system is proportional to the height of the chimney, notes Mr Michaud, which is limited by practical considerations. His scheme replaces the chimney with a tornado-like vortex of spinning air, which could extend several kilometres into the atmosphere
This vortex would be produced inside a large cylindrical wall, 200 metres in diameter and 100 metres tall. Warm air at ground level enters via tangential inlets around the base of the wall. Steam is also injected to get the vortex started. Once established, the heat content of the air at ground level is enough to keep the vortex going. As the air rises, it expands and cools, and water vapour condenses, releasing even more heat. This is, in fact, what powers a hurricane, which can be thought of as a heat engine that takes in warm, humid air at its base, releases cold, watery air at the top of the troposphere, about 12 kilometres up, and liberates a vast amount of energy in the process. (Just as water requires heat to make it boil, it releases heat as it condenses back into a liquid.).

S: TE – http://www.economist.com/node/4455446 (last access: 7 December 2014)

N: 1. 1650s, “whirlpool, eddying mass,” from Latin vortex, variant of vertex “an eddy of water, wind, or flame; whirlpool; whirlwind,” from stem of vertere “to turn”. Plural form is vortices. Became prominent in 17c. theories of astrophysics (by Descartes, etc.). In reference to human affairs, it is attested from 1761. Vorticism as a movement in British arts and literature is attested from 1914, coined by Ezra Pound.
2. A mass of fluid (as a liquid) with a whirling or circular motion that tends to form a cavity or vacuum in the center of the circle and to draw toward this cavity or vacuum bodies subject to its action.
3. Any flow possessing vorticity; for example, an eddy, whirlpool, or other rotary motion.

S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=vortex&searchmode=none (last access: 7 December 2014). 2. MW – http://www.merriam-webster.com/dictionary/vortex (last access: 2 December 2014). 3. GDT – http://www.granddictionnaire.com/ficheOqlf.aspx?Id_Fiche=8415324 (last access: 7 December 2014).

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CR: rotor , wind energy, [wint turbine (1)].