Gábor Dobos Owner and Managing Director
Chemotronik Kft. Május 1. út 2. 3078 Bátonyterenye Hungary dg@ifo-energy-unlimited.com www.ifo-energy-unlimited.com www.chemotronik.hu
Identified Flying Object – IFO: an Untethered Airborne Wind Energy System
Gábor Dobos Chemotronik Kft. The characteristic feature of our AWE-system concept is
the use of un-tethered flying devices [1]. Today, the ”flag-ships” of this emerging industry choose to use tethered ones. This fact may have several causes, among others the doubts regarding the technical feasibility as well as the theoretical background of this technology [2]. The presentation begins with the theoretical principles of IFO-gliders and their demonstration with a simple time-domain simulation as well as some existing ”proofs of concept”. The most critical problem of the idea is that har-vested energy has to be stored temporarily on-board the IFO. The presentation discusses some of the possibilities. IFOs apply a special technique of flight called Dynamic Soaring. This way the flying device can capitalise on the energy of wind shears by increasing its own airspeed to several times that of the gradient. Since winds do not stay in place, the flying devices need to follow them. Tethered devices obviously cannot do so. Their untethered com-petitors (e.g.: IFOs, guided by their LIDAR) are free to rise into and travel with winds that would maximise the con-tinuous yield from an energy extraction aircraft. Most tethered devices work today near the upper end of the planetary boundary layer, that is: at about 500 m alti-tude. Summarising wind power data that are
characteris-tic for the parcharacteris-ticular device and altitude (see figure), one can state that the tethered and conventional types have insurmountable handicaps compared to the IFO. Characteristic wind power data of wind power plants [3]
Type Heigth (m) Wind Speed (m/s) Wind Power Density (W/m2) Conventional 100 4 38 Tethered 735 7.3 224 Un-tethered IFO 10000 140∗ 411000
∗Airspeed of the IFO
These first results show that un-tethered flying energy harvesting devices deserve more attention in the future than they had until now.
References:
[1] Dobos G.: Un-tethered autonomous flying wind power plant. PCT patent application WO2010106382A3, Hungarian patent: HU000227468B1
[2] Harrop P.: Biomimetic aircraft snatch power aloft. Energy Har-vesting Journal. 31 October 2012.
http://www.energyharvestingjournal.com/articles/4862/ biomimetic-aircraft-snatch-power-aloft
[3] Archer C. L.: An Introduction to Meteorology for Airborne Wind Energy. In: Airborne Wind Energy. Springer (2013)
