Nasa launches Press Release endorsing new generator. http://www.nasa.gov/press/2013/dece...-soon-power-american-households/#.Us0LoNJdUrW I am confused as to its operation technology at present as I have not had much time to research it. Please Register or Log in to view the hidden image! This noiseless 60 lb unit can run in a kitchen as easily as a basement. Anybody know how this works? Sounds fun.
Try reading the link: it is a cogen plant, and a bad one: Total efficiency of 90% is fine, but not that exciting - a good gas turbine or diesel cogen plant will do it, but electrical efficiency of 12% is absolutely horrible. It is 1/3 to 1/4 the efficiency of other types of cogen plants. Other than being quiet (a fuel cell is quiet too...), I see no benefit to this.
Elastic waves Consider a volume V which is home to a continuous medium, is essoun gas, liquid or solid at rest. There are various sizes and properties of the medium, such as temperature, pressure, density, which may have different values diversipunti the medium. Suppose that, while varying from point to point, these values remain unchanged over time. Now, if somehow we introduce unaperturbazione pressure and density (or both, for example in gas these two quantities are related, thus varying the other one was also varies), if the medium has a certain elasticity, disturbance propagates in the middle. In other words, the pressure (and / or density), as well as vary dapunto up, will also change over time. A disturbance that propagates in half due to the elasticity of the same elastic wave is called. The sound A vibrating body immersed in it in the air produces the ondeelastiche giving rise to the phenomenon that is called sound. For this elastic waves are called acoustic waves or sound waves. The acoustics is part of physics that studies the acoustic waves. The easiest way to produce a sound is to place a vibrating body, such as, for example, the string of a guitar or a membrane of a drum. We begin the study of sounds with the sounds simple. Consider a cylindrical tube surrounded by air, with a free end, while the other is inserted a piston that vibrates with sinusoidal motion, ie, if x (t) indicates the depth of the piston inside the cylinder at t, we have where indicates the frequency of vibration of the piston. This, in its motion, compresses the air around the cylinder piston that increases its density, and when the piston goes back on it produces rarefaction, ie, the density decreases, due to the elasticity of air changes densities will propagate into the cylinder as a sine wave having the same frequency of vibration that produces it. The propagation speed depends on the medium and its temperatura.Nel our case, where the medium is air, the speed is 331.4 meters per second at 0 degrees ° C. The following table gives the values of the speed of sound in varimezzi. What we have just seen is an example of a simple sound. A sound that is simple if sinusoidal. Let us now examine the characteristics of a simple sound. [video=youtube;r2GIY2ZmXPY]http://www.youtube.com/watch?v=r2GIY2ZmXPY&feature=player_embedded[/video] http://www.youtube.com/watch?v=r2GIY2ZmXPY&feature=player_embedded http://www.google.com/url?sa=t&rct=...WGnYAo&usg=AFQjCNH3W9i6kgtO4B14KKGkqQV5bB1q0w http://www.google.com/url?sa=t&rct=...WGnYAo&usg=AFQjCNHMr-DzOGLAZzy3wbMyWku6Px2aEw
I suppose the advantage is its silence. But you are quite right that to be economic, one would have to have a situation where the amount of electricity needed was about 10% of the heat required. In a domestic setting, maybe in the depths of winter, but at other times of of year very wasteful of heat - or if run to generate only the heat required, incapable of contributing much to electric power needs. It seems to be a curious feature of NASA these days that it devotes so much time to promoting more or less wacky general research ideas. I begin to wonder if it is losing its way, to be honest.
Why the heck aren't they promoting the free piston Stirling engine co-generator that is more like 25% efficient for electrical power?
Sounds more like a space-oriented program that a private company (Nirvana) is trying to tout as a household power source. Note that NASA is not working directly on this; all they are doing is "assisting Nirvana to integrate the NASA technology into TAPS."
@ Billvon, Thank you for explaining this to me. I find the topic interesting and would love to have one to dissect. I did not realize this was possible. Xerox originated the device. What a company that is.. Brought us copiers, then windows software/mouse (despite it was all copied/Stolen by Steve Jobs and Bill Gates.), and they are still innovating. If one Executive was on the ball during the Microsoft Era, Xerox would hold the Microsoft Fortune.
I'll mostly give them the benefit of the doubt on this one. The design constraints for a spacecraft power supply are vastly different from those of a house. So it may make sense. This includes, potentially: -Lower weight -Less vibration -Consistent electricity/heat demand ratio -Use of hydrogen fuel What I don't like is that NASA is promoting it for home use, but they may just be doing their industry partner a solid.
That's what I mean. It's clear this may be suitable in space, but pretending it has a domestic application seems almost like a scam. They may damage their credibility if they do too much of this sort of promotional stuff.
I think it is the improvement in this important technology that is worth notice. Someone said this unit only does 12% efficiency in converting, but for a tiny 35' unit that runs silently that is pretty decent for a cogenerator. I believe even the superior nuclear generators run at only 30-40%. My sister was without power in her home on Christmas, 3 days after an Ice Storm. If she had this then her Kids might have enjoyed Christmas at home. It is an alternative. They claim it is cheaper then regular power, but who knows. Portable battery AC power is already in many homes, so this will simply be another option. I do not see how using this would could be compared to a scam as last poster claims. It is just an alternative in a growing list.
I think it might. The other application I've seen is thermophotovoltaics. You surround the flame source in your furnace/water heater with TPV cells and generate a moderate amount of power for emergency uses/grid support. It's effectively cogeneration.
It's based on acoustics, specifically the esoteric knowledge of thermoacoustics. In a nutshell, it turns out that if you construct some kind of closed configuration of pipes (tekkies speak of waveguides, cavities, resonators - that sort of thing) and apply heat in one spot, the air inside will rush through the pipes to equalize the pressure. Now if you do this very carefully, esp. applying some of the more rigorous science involved, you can come up with a network of pipes that will oscillate to the natural frequency of that pipe arrangement. An example of natural resonance is the pipe of a pipe organ. Change the length of the pipe, and the pitch changes. Since what's oscillating in the device is waves of pressure, we can use them to do what engines do - convert energy from one form to another. Hence the term "thermoacoustic heat engine". Once the air - or whatever "working fluid" is used - begins to oscillate, those pulses of pressure can be coupled to a transducer which converts the vibrations into electricity. A microphone is such a device. It converts the acoustic waves coming from the voice into small electric currents. The type of transducer used here will need to generate larger amounts of electrical power so it's designed for that. The simple type is a coil of wire attached to a diaphragm, which is a kind of piston. The coil is free to slide back and forth over concentric magnetic pole pieces, as the force of the acoustic wave drives the diaphragm into sympathetic vibration. The result is an alternating current which in this case serves as an electric power source. Ouila. We got electricity directly from heat, with no moving parts - except the coil. But it's not a load-bearing friction - the opposing force due to the electrical load is mostly longitudinal, not radial, with respect to the magnet, and with a light flexible support that friction can practically be eliminated, leaving just the friction of flexing in that support as the only appreciable mechanical loss during the conversion. And it's negligible. Hence the appeal of this kind of apparatus. No load-bearing moving parts means it will not break down for a very long time. Unlike a typical engine it's silent, so it's good for use indoors. You're referring to cold fusion, khwilborn's other pet topic. In the technology it's of course completely different but you might find some other comparisons. Unlike e-cat this uses more energy to produce less work. This is fairly well understood and practical, even fairly primitive, and several working prototypes can be found. Plus they're done by hobbyists and as science projects. The key to perfecting it has been to get the efficiency higher. I think that's been achieved well enough for some entrepreneur, like the company described here, to give it a shot. No moving parts offers the possibility of a low manufacturing cost. What ought to happen is that investments are made in arriving at the lowest cost optimal design, and then it's a matter of taking it on as new challenge for some reasonably optimistic manufacturer, as often happens in China. If it caught on, the unit price could drop just like the price of phones, PCs & electronics. It's hard to say how the company that's pursuing this will fare as far as cost of production is concerned. But they seem to be saying they are close to making it happen. Yeah, that makes it ideal for indoor use. I think they are hoping to achieve around 30%. That's true - it may be more appealing to folks in the higher and lower latitudes. What would be a little better would be to generate electricity from the heat lost through the walls, although I guess that competes with the idea of having better insulation. But such an approach might be made reversible, so that for either extreme of temperature the gradient between indoor and outdoor heat is exploited. Or, avoiding the counterproductive side of that, it might be applied in solar collectors and geothermal wells. I'm not sure they're in this line of work anymore. They did a software CAD tool in 1994 which was used in 2004 to develop a prototype. A larger scale device was built at Los Alamos somewhere in that timeframe. And there have been a few papers they contributed. But it looks like it was maybe just a few key investigators who would have been doing other work in acoustics if not for this. I would call this an improvement on that idea. Here you do better than free-piston as far as reducing moving parts. They're effectively gone altogether. I think they are expecting to get 30% efficiency, which is what LANL reported, and there is at least one paper under funding of Chinese academies of science which also claims 30%. That's also consistent with Nirvana borrowing ideas from a power supply designed for space flight and reengineering it for home use. I'm reminded of how the fuel cell also had its genesis at NASA, even though it looks like Li-ion batteries have left them on the back burner. You might like to the idea behind this paper: Loudspeaker-driven thermo-acoustic refrigeration, Ph.D. Thesis, Technische Universiteit Eindhoven, (2001). Also you might enjoy some of the science projects at YouTube under the search heading of "thermoacoustic Stirling engine". I think the general theory of operation has been in the public domain ever since acoustics were first explained by the likes of Rayleigh, Kirchoff, folks from the 19th c. The focusing of the theory into the applied sciences probably goes to a 1979 paper in one of the acoustics journals titled A pistonless Stirling engine—The traveling wave heat engine. As for working models, it looks like the success in prototyping mainly goes to NASA and Los Alamos with assistance from some contractors like Northrup Grumman. Incidently that author I mentioned above also holds this 1986 patent which at least gives you some idea of the niche of science that companies like Xerox would need to embrace to succeed at this. I think the 2002 decision by Xerox to shed the Palo Alto Research Center (where the innovations you mentioned took place) might be a step away from this, but I suppose that has its own story. In fact the designers were assuming a small plutonium source might be available. I'm not sure. There have been some recent papers of Chinese authorship that might indicate some foreign competition is motivating the government agencies to nudge the fledgling US entrepreneurs forward into the fray. Just a guess. It would be interesting to know the actual motives behind the press release. I suggested the foreign competition angle, but who knows? It even occurred to me that since the two main milestones in this at NASA were in 1994 and 2004 maybe this is a 10th/20th anniversary tribute to the contributors. Just a wild guess. I did get the sense though that there might have been some disappointment that the 2004 project was not funded for an investigation of design optimization, and, if so, based on the atrocities the Bush administration was inflicting on science at the time, it would not surprise me if it were dumped prematurely. For anybody interested here is the 2004 paper from NASA.
@Aqueous Id, thanks for explaining this as clearly as you did. I have not had time to delve into Billvons links yet. Resonance technologies are awesome. I recently recalled hearing a young girl invented a land mine detector using sound to get the mines to resonate and give up their location. I was intrigued by that also, and have wondered of other resonant applications. [video=youtube;4TR3Pxc-zBc]http://www.youtube.com/watch?v=4TR3Pxc-zBc[/video]
any idea how much it cost? If you want quiet generator then this fuel cell would be beter imo www.efoy.com In my area we have natural gas thats very cheap but if the power goes down,the furnace wouldnt run..I could probably still heat the house using the stove not very safely,though as its open flame..wish that someone could invent gas furnace that wouldnt need electric power to run..
@ Scorpius, I think the point of this thread is that they have found a cheap way to run your furnace off its own energy (gas). At 35" and 13" in Diameter this unit is fairly small. I think it would be less complicated in Construction than many Dollar Store Items I see, so I imagine the cost will be based more upon unfair demand in the beginning.
