Quote:
Originally Posted by J_Player
Hi Max,
Yes, you are right. I made a mistake calculating square meter when I should have converted from square Km. Much less power in a square meter. 
But some people have actually extracted usable power from the air. Nicola Tesla, for example. He powered a car from energy extracted from the air using an antenna, causing the car to travel easily to 90 miles per hour with an electric motor. He also put usable power in the air that caused fluorescent lights to light up 20 miles away.
Best wishes,
J_P |
Hi,
not extracting power from atmosphere: I remember Tesla made some experiment with the car that run 90miles... but that was about air (actually space... they would said "aether") as "conductor" of the energy.
That is: there was a powerful RF transmitter tower (the kind Tesla loved so much... very-high voltage Tesla coil driven if I remmeber well, kind of a metallic tower at Colorado Springs... I remember an old picture of it... with kind of a "ball" at top of it, above Tesla's lab building) then the car has a "receiver antenna" made in similar way... and a tuned circuit to get maximum efficiency in the receiving process...
The RF energy radiated by the tower was then collected at selective rf receiver at car... then converted to DC for the car-engine ...electric motor.
Indeed, it was kind of very early energy harvester thing... the radiated power (many kilowatts I guess) were collected at receiver and provide energy to the propulsion system of the car.
Due to the slight attenuation in the 90miles range from transmitter and carefully tuned rx the car was able to get enough power to run...
This was a demo of how electric energy can be translated in RF and then radiated in the space for remote powering of devices... just that happened in the kilowatts range of power!
No like RFID and the like... that indeed use very small power and get also very few from harvesting that.
Also, I think today is not possible replicate such experiments cause all modern countries have severe regulation on emission power/frequencies...
A transmitter like Tesla's one could easy swamp any RF communication in a range of 100 and maybe also 1000miles around!
There was also a kind of race for best idea in energy carring methods... like hi voltage dc vs ac etc and Tesla play a role in that along with other brilliant minds of that age.
This experiment had no real applications (till today attention to remote micropowering) cause it obviously creates huge problems to radio communications and exposure to very hi EM fields (possibly dangerous for people and environment in the megawatts/gigawatts range).
So... not power from air/atmosphere but... just using "air" as channel.
I read of experiments using air for generate power but that are really much more complex than Esteban's posted funny article... they use kind of suspended ballons (by some kevlar wire I think) at relatively high height from soil... there are that include hi-speed turbine inside... to use jetstreams and the like , hi height hi speed airflows... and other that in kind of "farms" collect charges from clouds... but I think there's nothing more than experiments and academic interest to them... not real potential of future applications if not e.g. in aerospace designs.
Kind regards,
Max