Airborne wind energy
[1] However, semantically HAWP might also include wind energy conversion systems that are somehow positioned at a large height from the ground or sea surface.
Various mechanisms are proposed for capturing the kinetic energy of winds such as kites, kytoons, aerostats, gliders, gliders with turbines for regenerative soaring,[2] sailplanes with turbines, or other airfoils, including multiple-point building- or terrain-enabled holdings.
Energy generated by a high-altitude system may be used aloft or sent to the ground surface by conducting cables, mechanical force through a tether, rotation of endless line loop, movement of changed chemicals, flow of high-pressure gases, flow of low-pressure gases, or laser or microwave power beams.
Energy can be captured from the wind by kites,[10] kytoons, tethered gliders,[11] tethered sailplanes, aerostats (spherical as well as shaped kytoons), bladed turbines, airfoils, airfoil matrices, drogues, variable drogues, spiral airfoils, Darrieus turbines, Magnus-effect VAWT blimps, multiple-rotor complexes, fabric Jalbert-parafoil kites, uni-blade turbines, flipwings, tethers, bridles, string loops, wafting blades, undulating forms, and piezoelectric materials,[12] and more.
[13] When a scheme's purpose is to propel ships and boats,[14][15] the objects tether-placed in the wind will tend to have most of the captured energy be in useful tension in the main tether.
[17][18] The mechanical energy of the device may be converted to heat, sound, electricity, light, tension, pushes, pulls, laser, microwave, chemical changes, or compression of gases.
Even a family of free-flight airborne devices are represented in the literature that capture the kinetic energy of high-altitude winds (beginning with a description in 1967 by Richard Miller in his book Without Visible Means of Support) and a contemporary patent application by Dale C. Kramer, soaring sailplane competitor, inventor.
A research on airborne wind turbine technology innovations reveals that the “Kite type AWTs” technique, the most common type, has high scope of growth in the future; it has contributed for about 44% of the total airborne wind energy during 2008–2012.
The “Carousel” configuration several kites fly at a constant height and higher altitudes, pulling in rotation a generator that moves on a wide circular rail.
[20] One method of keeping working HAWP systems aloft is to use buoyant aerostats whether or not the electric generator is lifted or left on the ground.
In case of productive winds the aerostats are typically blown down by the aerodynamic drag applied on the wide and unavoidable Reynolds surface excluding them de facto from the HAWP category.
The first period had a high focus on pulling carriages over the lands and capturing atmospheric electricity and lightning for human use.
[30] The second period was in the 1970s and 1980s when research and investment flourished; a drop in oil price resulted in no significant installations of HAWP.
The tension in the lofted devices performs the work of lifting and pulling body parts and things.
