What is the Future of Wireless Power?

mfbatzap writes "According to Firdooze, we have seen various devices that can free ourselves from wires at CES 2008. The manufactures, Wildcharge, Powercast and Fulton Innovation, came out with two different methods of transmitting power from source to the devices. Wildcharge and Fulton banked on magnetic coupling while Powercast decided to go with RF (Radio Frequency). So which technology will eventually prevail to be the future of wireless power? Or will the technological setbacks from transferring power wirelessly make it unrealistic to accomplish a wire-free world?"

is there a way

[JeanBaptiste]

to transfer power wirelessly without cooking whatever happens to pass inbetween the sender and receiver?

Out of curiousity...

[Krinsath]

Does anyone know how much power is "wasted" (if any) due to using wireless methods versus wired connections?

Off my limited knowledge, it would seem to be akin to one of the problems with biofuels...they currently take more energy to produce than they store. So will using this technology to charge a device result in taking two or three times more energy to transmit the same amount of power to the device, or is there no discernible difference between wireless and wired?

Just wondering is all...

Re:Out of curiousity...

[Abeydoun]

Here's the Wiki [wikipedia.org] I found on general wireless energy transmission.

From the wiki article

"WiPower [1] technology is a very recent example of inductive charging technology. The charging pad allow users to charge multiple electronic devices that are placed on its surface. It is insensitive to the position or orientation of the devices under charge. Unlike most inductive charging systems, the WiPower system uses air-core technology which allows the system to be integrated into very small electronic devices. The efficiency of the system actually exceeds many corded chargers which have a median efficiency of 57%."

Re:I say neither, you say neither

[farkus888]

it may not make a replacement for everything, but unless I am mistaken I have already seen electric toothbrushes that use something similar over very short distances. the advantage is they don't have to insulate any leads or connectors from the water it will inevitably be exposed to. a sealed case is always better than a sealed case with a rubber plug over the one opening where you give it power. range is not an issue because you are still dropping it into a charging dock [sitting it right on the transmitter] when the time comes to charge.

I also think another great idea would be to make the surface of a desk the transmitter, that way anyone can walk up and sit a laptop on it and their batteries never die. it would also have the nifty feature of powering you wireless mouse, or even speakers a monitor and a external keyboard on your desk at home with one power line to the wall.

omni directional power transmission?

[Original Replica]

So where does the power go, that doesn't make it into the device? In this day and age of energy efficiency and conservation, this seems a step backwards. Maybe that energy is slowly heating the room or maybe it's slowly increasing my risk for cancer, but either way if the vast majority of the power isn't going into the device it's being wasted. Tis tech might have some specific applications where the wirelessness is of true overall benefit, but everyday hand held devices aren't it. As global energy demands continue to grow using something like this to charge your cellphone will become a hallmark of bourgeois ass-hattery.

Re:is there a way

[jdray]

From what I understand, it depends on the frequency. For instance, a microwave oven operates at whatever frequency best excites a water molecule, which leads to cooking by making the water in everything hot.

There was a long-running experiment in California back in the seventies or so that transmitted kilowatts of power over a few kilometers. They were doing the test as a lead-in experiment to figure out whether or not satellite-based power generation and transmission was feasible.

I'm not confident that we know about the long term health effects of exposure to various magnetic fields. Back in the early nineties there was a discovery that sitting in front of a monitor for hours on end was causing health problems due to "ELF" (extremely low frequency) radiation. Monitor manufacturers jumped on re-tooling and shielding their CRTs to avoid the problem, and eventually all CRTs complied with a standard ("ELF-II" IIRC) that was deemed safe. I don't believe LCDs have the same issue.

Pacemakers

[Stooshie]

One thing not mentioned (particuarly with the magnetic induction system) is how pacemakers are affected.

At least with MRI scanners there are notices everywhere about people with pacemakers. If these things become widespread people with pacemakers are going to have to avoid a lot of places.

Re:Out of curiousity...

[snowraver1]

200 years ago people would never fly.
150 years ago it was impossible to talk to someone in another town
125 years ago it was impossible to own a car
50 years ago it was impossible to own a computer (except for banks, schools, and gov't)

You never know what the future might hold. Cold Fusion might prove to be possible. Zero point energy might be proved and harnessed. Maybe someone will figure out a way to take the heat out of the atmosphere and make electricity from that.

My point is, and I do have one, that nothing is impossible. There is more that we don't know then we know... Chew on that.

Re:is there a way

[Otto]

From what I understand, it depends on the frequency. For instance, a microwave oven operates at whatever frequency best excites a water molecule, which leads to cooking by making the water in everything hot.

That is incorrect, but you're forgiven because it is a common misconception that's even in a few encyclopedia's and such.

Microwaves work by producing an alternative electric field (using non-ionizing microwave radiation) that acts on molecules which have electric dipoles. Water is one of those, but so are many others, including fats and such. The process is called Dielectric Heating.

Basically, the molecule being heated is a dipole. It has a positive charge at one end, and a negative charge at the other. In an alternating electric field, it rotates as it tries to align itself with the field. This causes motion, which translates to heat. The heat spreads as the molecules hit other molecules and transfer the energy to them. Now, this process works really good on water because water is a very strong dipole, but it does not operate solely on water, and it doesn't have anything to do with water in particular.

See, the frequency doesn't actually have much to do with it. Normal kitchen microwaves operate at 2.4 Ghz or close to that. Industrial microwave devices tend to work at 915 Mhz. Also, if the frequency had something to do with it, then 2.4 Ghz would be the wrong one. The resonant frequency for water is somewhere in the 20 gigahertz range. The only reason 2.4 Ghz is used for microwaves is that it's a free bands of frequency (ISM frequency bands) that can be used worldwide.

So, there you go. Now you know.

It might not be as bad as you think, therotically.

[sectionboy]

An average laptop consumes about 50 watts. Using the back of a 15" screen as receiver (0.07 m^2), the intensity is about 50 / 0.07 = 714 watt/m^2. As a reference, "a site in Eastern Oregon receives 600 watts per square meter of solar radiation in July". http://zebu.uoregon.edu/disted/ph162/l4.html > See, it's just like walking by an unshaded window in a summer's day.

Re:Woah

[BoChen456]

Nope, they're NOT meant for anything as powerful as TVs or Computers

Magnetic coupling or RF frequency whatever, its all electro-magnetic radiation at the end of the day. Now go look at the back of your computer and see how much power it takes to run (350W?), guess what happens when you have 350W of electro-magnetic radiation blasting across your living room. I'd say "JUST BREAK A HOLE IN THE DOOR OF YOUR MICROWAVE".