Yes yes, for their phone-sized receiver. If you change the receiver size or transmitter size, you can change the power delivered.. If you fix the distance and take away the requirement to track a moving object, you can reliably send more power as well.. Adding battery capacity to a TV that's used 4 hours per day effectively cuts the power requirement to 1/6th. Lights that are used for a few hours each night are in the same range. Why does everyone's creativity suddenly disappear when the hivemind has decided to attack a company?
I'll run some better numbers tomorrow for a fixed distance / size, but intuitively, eliminating the "tracking a phone from 5M away" requirement dramatically expands the use cases.
Keep in mind that you still need to obey the laws of thermodynamics. Those are rules startups can't ever break.
The writeup I linked has a good argument against the feasibility of wireless power for a TV:
> A typical large, flat-screen TV (eg. [42]) will draw about 60 watts. Since a TV is usually mounted in one place, some of the limitations get easier, but not all - if the TV is two feet (60 cm) from the wall, and the receiver is 40% efficient, that's still about 80% losses. To transmit 300 watts at 0.3 W/cm^2, one has to have a 1,000 cm^2 transmitter, a bit over a foot on each side (31.6 cm). One could make the transmitter smaller (100 cm^2, or 4 inches/10 cm across) by increasing the intensity to 165 dB, a level that causes burns "almost instantly" (from Question #7), but that seems unwise. Since most power outlets are near the floor, and the TV probably isn't, one would still have to run a cord to the transmitter. And uBeam takes 240 watts of electricity, about a dozen light bulbs' worth, and dumps it into the air for no real reason. That's not good for the environment. Or the power bill. Or the air conditioning - all that heat makes the room hotter.
What people often forget is that the second law of thermodynamics only applies to a closed system.
So, a startup in a closed system with no product or source of revenue will dissolve into entropy. But a startup with continual funding from VCs can remain as long as the influx of cash continues.
I'm not moved by that post.. Didn't you know Google wasted $100M by investing in D-Wave which has been proven to be no faster than a laptop?
Anyway, there's nothing about thermodynamic limitations in the section about the TV. The author is making several exaggerated statements that are easily refuted to make the TV suddenly possible... Let's focus on the wasted energy (240W or a dozen light bulbs!) to make the point:
* Assume a 48" LED[1] that uses 31W and suddenly you're only wasting 120W.
* His 80% loss figure is a holdover from his calculations about the phone -- cut this in half and you're at 60W of waste heat. (You should be able to achieve a nearly perfect perpendicular 'connection' between transmitter/receiver for a fixed TV).
So far, we're delivering 30W of power and wasting 60W as heat -- not ideal
* If you plan for a worst-case of 8-hrs straight of watching TV and plan on a battery backup, you could get away with delivering 10W to the TV and only wasting 20W as heat which is eminently reasonable.
The "physically impossible" claims are greatly overstated (for non-phone charging use cases).
Your battery solution for the TV doesn't reduce the energy waste, it just spreads it out in time. It's now 20W wasted 24 hours a day instead of 60W for 8 hours a day. Same difference.
Until our houses are powered by 100% renewable energy, any technology that sacrifices more than half the input energy just so someone doesn't have to see an extension cord should be banned by law.
Additionally -- how big is the room in which you want to mount your TV? The loss coefficient for ultrasound in air varies with frequency, temperature and humidity, but it's about 1dB/meter in this range, give or take. If you have a three meter wide room, and you have the transmitter and receiver mounted on opposite walls as you recommend, then you lose 3dB = HALF of the power through the air, and there's nothing you can do about it. To get to your 33% total efficiency number, all of the other losses, including conversion from DC to ultrasound and back and transducer losses at both ends, would have to amount to another 15% at most -- highly unlikely, though maybe not impossible -- though these are all well known numbers that someone skilled in the field could write down for you.
There's a big difference between 30% efficient now and 90% efficient in the future, and "it's never going to get any better than this"
Those are good ideas, but, and this is quite important, they're not what uBeam are saying they're going to make. There are definitely use cases where wireless power transmission would be brilliant. That alone is not enough to support uBeam - we can only judge them by what they say (and demonstrate), not be what we imagine they might do if they succeed.
Actually, I take it back. That's not fair -- according to their investors they don't have any intention of only making phone chargers;
> And the truth is that Team uBeam doesn’t want to stop at phones. With the explosion of “wearables’ wouldn’t it be nice if you didn’t have to charge your watch, fitness tracker or noise-canceling headphones? What about if elderly people never had to ask a relative or healthcare worker to change the batteries on their hearing aids? The practical uses for uBeam technology is limitless.
Or the company themselves;
> With wires virtually eliminated, TVs can sit in the middle of a room cord-free and light fixtures will become “stick-on” without the need for routed power.
<--Original post-->
That's fair, but it sure seems like the obvious path to getting cell phone charging to work is to get a fixed object charging to work -- at which point, if they'd hired any bizdev people, they'll sell the hell out of the fixed object systems to anyone and everyone.
It's just striking to recollect the many complaints about only easy, derivative ideas being funded when a hard idea with tons of applications is being derided in such an intense fashion.
I'd rather they fund 10 uBeams that could yield useful insights or pivots than 0.
Ambition is great, but it doesn't really mean much unless they can show current, visible results that demonstrate they might actually get there. When Elon Musk says he's launching a rocket to Mars in 2 years time we all get pretty excited because he's already launched a rocket to transfer orbit today. He's demonstrated that he can bring a similar thing to the market. If I had $80m I could pay SpaceX to launch something in to space.
When uBeam say they're going to make wires a thing of the past, I will remain skeptical until they have a product on a shelf that I can buy. Until then I am as excited about their wireless power transmission as I am by any other startup in the same space - it's a great idea, but it needs to be seen.
Agreed, and I have no inside info at all -- they'll probably fail even, but it seems like there's a gulf between cautious optimism and whatever is going on here. As for the SpaceX comparison, if they do indeed send a mission to Mars in 2018, it will have been 16 years since the company was first founded with Elon's intention to go to Mars and 10 years after they first achieved orbit.. Hard things take time!
I'll run some better numbers tomorrow for a fixed distance / size, but intuitively, eliminating the "tracking a phone from 5M away" requirement dramatically expands the use cases.