h a l f b a k e r yOn the one hand, true. On the other hand, bollocks.
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How about keeping energy in its mechanical state, changing to electricity results in huge energy loss -
Employing windmills, waterwheels, stationary bikes to raise a weight into high storage mode, maybe up a nearby tree, then, as it falls on demand, it turns a central axel, or pulls a longer extenstion
cable turning pulleys , like the old belt driven factory systems, that turn individual motors, with the various set of gears for the required speeds of refrig. compressors, whole house vaccum system, home ventilation fans, workshop tools ...
Especially for country dwellers near streams.
Mechanical Power Distribution
Mechanical_20Power_...ribution#1162866997
[xaviergisz, Dec 31 2007]
see annos by [zen_tom] for spinning/gravity effects
Global_20ceiling
[4whom, Dec 31 2007]
Friction oven
Windmill_20powered_20friction_20oven
Prior art [8th of 7, Dec 31 2007]
Combined cycle power plant
http://en.wikipedia...wiki/Combined_cycle
[ldischler, Jan 03 2008]
[link]
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It is well known, around the 'bakery, that spinning causes gravity, see link for further details. Perhaps if you could erect a windmill or watermill that doesn't spin or even spins the other way this would allow you to manipulate gravity to store your potential energy. |
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Happy New year to all, may 2008 bring all that you wish for. |
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This is quite baked--eg, grandfather clocks, hydroelectric dams. You could also use springs and flywheels. In nineteenth century factories, a waterwheel would drive an overhead shaft, and long leather belts would transfer power down to rows of machines. In cities, compressed air was piped under the streets. |
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Completely baked, the only part I like is the belts running ceiling fans. I seen this a few times in bars and I've always wanted to do it in my house. You don't even want to do this with a fridge. the great thing about electrical compressors is that you don't need rotary seals, just glue in around the electrical wire. |
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There is a valid point here, in that whenever energy is converted from one form to another, there are losses. |
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Thus, it makes more sense to burn one cubic metre of methane in a domestic heater than to burn it in a power station, convert the energy into electricity (with all the iron and copper losses that implies), transmit the electrical energy (more losses) and then convert it back into heat for space heating. |
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There is a valid case for avoiding conversions. Windmills convert rotational energy into electrical energy; the same is true of wave-power schemes. |
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If the intermittent output of renewable sources can be harnessed directly as mechanical energy with minimal transmission losses, all well and good. |
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The problem has always been storing mechanical energy. A large (very large) flywheel spinning in vacuo is a possibility .... |
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//Thus, it makes more sense to burn one cubic metre of methane in a domestic heater than to burn it in a power station, convert the energy into electricity (with all the iron and copper losses that implies), transmit the electrical energy (more losses) and then convert it back into heat for space heating.//
On the other hand, it's far more efficient to convert it to electricity in a power plant and use the electricity to power a heat pump in a home. |
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[M-C] - most of the systems you describe involve pretty heavy frictional losses, orders of magnitude higher than any electrical losses for equivalent systems. |
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Also a bit curious about your statement //changing to electricity results in huge energy loss// |
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'cause it's pretty much wrong. It's the change from heat, or chemical/nuclear energy to mechanical which results in the big losses, due mostly to the big hairy entropy-monster who's hiding under your bed. Once you've got rotational energy, converting to electrical can be done at >>95%. And back again to rotational, at similar efficiency. |
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Electrical distribution is also fantastically efficient compared to mechanical storage or distribution. |
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I dunno, I mean, given how long they've been working at it, and market forces, maybe all those engineers and such have gone and went and evolved a relatively efficient system, y'know? |
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[ldiscler] I disagree, I think it's Honda that is now selling home axial turbine generators for those connectd to gas lines. I think it would be more efficient than heat pumps for the simple reason that all the "waste" heat of the motor/gen heats the house. The only waste is whatever heat can't be scavenged from the exhaust, which should be small because you have little size or weight limitations in a home installation. |
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Heat pumps have gotten very efficient. Some operate with COP's as high as 5.0. By comparison, the best gas heater has a COP of 1.0.
Of course, that doesn't factor in the generation and transmission losses, but even so, the heat pump is more efficient, not to mention that it can be used for cooling as well.
I don't know about the Honda product--which is apparently something different from the simple heater 8th of 7 was talking about--but you could burn the gas in an engine and drive a heat pump. You could use the waste heat for heating that way, instead of dumping it, and with no electrical transmission losses. On the downside, you'll be paying more for gas than the power station. |
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FIAT used to have a device called the TOTEM: It was a small internal combustion engine, where the waste heat was used for space heating, and the rotational energy was used for electric genenration. It's out there on the web somewhere, bvut the capital costs were very high..... |
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//heavy frictional losses, orders of
magnitude higher than any electrical
losses for equivalent systems.// If an
electrical system loses 2%, and frictional
losses are orders of magnitude higher,
then we're talking 200% losses? |
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No, but 20% isn't out of the question. |
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Or even 63%, which is 1.5 orders of magnitude. |
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Oh, shutup, you know what I mean. lots higher. |
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Look, it's funny, but impractical for the broad range of applications suggested, ok? |
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Thanks for your responses. I'd always heard there was 90% energy loss in generating electricity. -8th of 7- seems to be of the same belief. If not, this idea is practically worthless, until we lose the grid and have been 'bombed back to the stone age.' Can you give us some impressive source to set us straight, ol' custardguts? |
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Another inspiration of this proposal was the beauty of a well built clockwork at a large scale, with large, perfectly lathed wheels or gears on extremely accurate bearings. Kind of a celebration of precision. Maybe run the sparkling power axel exposed down the full length of one's linear, partially underground house. |
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One thing about mechanical generation - it seems that a water wheel might be a little less efficient than simply filling up a series of one ton barrels that are strategically hooked to the power axel, which turns various gear arrangements. It seems to me that a one ton barrel falling one or two feet, hooked to a very small dia. wheel (yielding high RPM, low torque) should be enough energy to run the whole house central vaccum cleaner for 20 minutes. Interesting exercises for the math proned. I'd think a drop of 1 ' should run the refrigerator all night. Just guessing.
Actually, I'm intuitively guessing according to how much of my own energy I'd use to spin, say, a salad spinner and how much I'd use to lift a heavy object. |
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A combined cycle power plant can get 50-60% eff., and in the case of cogeneration, 85%. |
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It's a size thing. Size IS important. |
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The plant has to be sized to give efficient district heating in its distribution footprint. it has to balance thermal and electrical load. It has to balance a lot of factors ..... this argument has been continuing for decades and there's no one-size-fits-all solution. |
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Those figures are optimised for minimum cost, as well, ie 7.3% losses are cheaper, than using 50% more copper and going down to ~5% losses, etc. |
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My point was that once you have rotational energy, it's more efficient to transport it as electricity, not shafts/belts/wire rope, etc. |
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Don't get me wrong, I mean as a mech eng, I'd love to see a piece of practical art in this form. It'd be a masterpiece of modern manufacturing excellence to see a house/building/monument that was powered solely by mechanical means. I'd really go to town, and would be satisfied to devote a few years designing this thing. Just don't expect it to ever be commercially viable on any large scale, that's all. |
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on that note, here, have this idea's first bun. |
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Thanks for the link to the already baked -MechPwrDistr.- I looked around but didn't see it to or would have started from there. Have a croissant, they're fattening, the French avoid them. But a countrywide grid is asking alot of Willy Wonka. |
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Not yet delved into the fructeuse pregnant promise of -Spinning gravity effects-. |
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Thanks for the bun and thanks for the numbers.
Though aren't they for extremely large power plants? |
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I've heard of stationary bike powered generators that seem extremely inefficient, that you have to pedal hard and fast just to fire up the tele. or light an incandescent bulb (not too soon to be obsolete). That's what inspired this idea. |
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I'd be nice for rural homes to be able to stay off the grid and avoid lines to the house. Using elec. solor panels to run the IT products, sun water heaters and seasonal solar heat masses with south facing windows with thermal shutters and insulation, gas cooking (my own should suffice), then a 100% mechanical system for things that turn. |
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As carpenter, I know the big difference in energy between working with your hand and elbow, and working with your arms, shoulder and body. So that doing some full body manuever (like sculling) should be able to crank up some appreciable energy, perhaps equal to a 1000watt radial saw, if more than half wasn't wasted being transferred into elec. |
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More art/machines:
-1- a pedal system built super solid and precise and embedded in the concrete floor giving the sensation of solidity and accuracy.
-2- an ergonomic (nice grabbable handle) 3' lever sticking out of the wall, secured and connected perfectly solid with tight machined bearing, that lets you pump more energy into the suspended weight storage (lift it a few ".)
-3- Any exercise machine that let's you wind up the house. Rowing machine, tight as hell bearings,what a physical work of art to do all that motion with zero jiggle, no squeaks.
-4- If you lived by a cliff, simply pile some rocks into a suspended bucket (connected to the power axel) and let it descend a few hundred meters. Once it reachs bottom, start another. Not too sexy for the cliff, though.
-5- If a tree must come down anyway, attach a cable up top, running to ye old hypothetical power axle. As the tree slowly falls you might get a years worth of clothes washing. |
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Anyone have some classic mechancical energy formulas and conversions at hand? |
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Baked perhaps, but sound [+] |
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I'm beginning to doubt the usefulness of efficiency as an idea, beyond the most obvious immediate sense of basic sane parsimony. Much more important, I think, is the effect on the entire complex of interrelated systems in which a device operates, that is, the "Why does cow dung burn if natural things are so efficient?" question. |
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Diversifying energy sources and energy forms tends to have beneficial systemic effects, whatever the loss in "efficiency". |
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// Why does cow dung burn // |
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So that Australians can save money on tobacco .... |
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// if natural things are so efficient // |
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They're not "efficient" in any absolute sense; they are 'sufficently' efficient to survive and prosper in their own evolutionary niche. |
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The tubeworms that live around deep sea vents may have horrendously inefficient metabolisms, but since there are no competitors (of a different species) or predators, they survive and reproduce. |
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Things don't have to be efficient, they only have to be sufficent - natural selection does the rest. |
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