Researches at the University of Rochester have devised a process in which a special high-power laser etching on the surface of silicon makes liquid flow vertically upward along the silicon surface, overcoming the pull of gravity, without pumps or other mechanical devices.
 Dr. Chunlei Guo holds a piece of black metal created in his lab. Treated silicon is similar in appearance. Credit: Press Office at University of Rochester |
I've had a few people contact me about a technology announced at the University of Rochester in which a special high-power laser etching on the surface of silicon makes liquid flow vertically upward along the silicon surface, overcoming the pull of gravity, without pumps or other mechanical devices.
Perpetual Motion Machine?
Of course as soon as we hear about water flowing uphill freely, our imagination jumps to the next step which would be to harvest that energy as the fluid flows back downhill, converting the potential energy into kinetic energy.
My guess was that the laws of conservation of energy would kick in somewhere in this process, arguing against such a system.
I phoned Alan Blank, who wrote the article at the University of Rochester News, and he explained that what causes the water to climb the silicon in the first place is that the fluid molecules have a greater affinity for the etched substrate than for the other molecules around them in their fluid state, so they adhere to the etched substrate, climbing upward. And that same principle that causes them to climb upward would also make it difficult to extract that fluid from the substrate, so the idea of a free ride up a hill to then jump off to go down the hill is uncertain here.
Dr. Chunlei Guo, the professor who is heading the research at the University of Rochester, said: "Water going up and back down in perpetual motion is not possible, but one may do two beneficial things together: cooling down a hot surface while moving liquid up and down at the same time."
Evaporative Cooling
Meanwhile, I got a phone call out of the blue from the father of a guy who runs one of the largest data centers in the world, wondering if I had any suggestions about possible technologies to use in both providing reliable renewable power for the data centers as well as for the cooling issues they have in the data centers.
While talking to him, I got a returned phone call from Dr. Guo. He mentioned that one of the main applications of the technology would be for cooling computers. He envisions a closed loop system using methanol or acetone, which would climb up the etched silicon substrate, then evaporate off, creating a cooling effect. That vapor would then be run through a condenser where the resulting liquid would then be returned to the chamber from which it would then run up the etched silicon substrate again. He proposes that you would want to use this method to target the key components of the computer system which tend to heat up the most. He thinks this system would be very efficient resulting in "huge energy savings."
Such a system has not yet been built or tested, but all the technology has been developed and just needs to be engineered for these kinds of applications.
Photon Capture
The grooved surface also has the property of trapping photons, making the surface appear pitch-black. In the cooling application, dark surfaces radiate heat better than lither ones. However, this might have an application in the opposite extreme – solar thermal energy collection surfaces.
Imagine, for example, using this etching process on a surface that would be collecting solar thermal energy -- since black absorbs better, and pitch black even better still. So a solar thermal panel thus etched would gather more energy from the sun. It may be a question of economics, though, since I would imagine the etching process is not cheap.
Earlier research by Dr. Guo showed that an etched tungsten filament in an incandescent light bulb gave out more light, and used half as much energy to produce the same amount of light. (Ref.) This may seem counterintuitive, but it is the same principle, if I understand correctly.
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Comments
I'm not sure etching tungsten filiments results in the same principle. By logic, I would think etching it would reduce the amount of physical material in the light's element, resulting in increased resistance in the circuit, which would result in increased light emitted. I may have the electrical details mixed up but I tend to suspect the lighting principles involved with the light bulb are different than those in operation on the photon trapping materials.
To Mr. Alan:
Re above article: If a grooved device is slightly inclined and bent at the top away from the source of the flow , then the water at the top will be forced by the incoming flow to the other side of the device (which is not grooved). The water will drop by gravity and maybe collected at the bottom, thus a complete recirculation ensues. Depending on the amount of water that the device can handle and the height to which the water will go, a "renewable" power source becomes a reality. Of course, there will be a need to take care of the losses due to evaporation. (Just a wild opinion on one of the many potentials of the invention.)
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