h a l f b a k e r yRenovating the wheel
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[sorry, I had the whole thing written wrong with piezo electrics and all, so reposting corrected version]
[May 2008: changed name to Thermal Electricity, from Thermo-Electric]
In large scale thermo-electric systems it seems much more energy can be caught than with photo-voltaic systems. For instance
the Luz program which produces megawatts of electricity in the Mojave desert (see link) is all thermo-electric. A few years ago at Klil a village in northern Israel there was an experiment for rigging up the whole village to photo voltaic cells which turn light into electricity. Although a lot of money was spent ($150K on every roof) it was hardly enough to run a PC and a few lights. Not to speak of a washing machine or refridgerator. (They ended up using wind power, and even selling back to the electric company).
So my point is that the same size of thermo-electric receivers is more efficient and gives much more energy than the PV cells (those "electricity from light cells ") you see on calculators and lamp posts).
Scaling down is a sure way in nature and in science to increase efficiency. And I propose a scaling down of thermo-electric power, and making tiny cells, each which receives heat from the sun and turns it into electicity. So now these solar cells will be even more efficient than the large panels connected to big electricity producing machinery.
Each micro or very small panel will trap heat and convert it into electricity, for example by using a tiny steam engine to run a tiny electric generator (implementation is in the other half of the bakery). Of course selling millions of these will bring down the cost of the cells.
example from google search for "efficiency in biology"
http://www.bath.ac..../pdf/63_Forbord.pdf
But almost any of the results will do. True for insects, enzyme reactions, farming, muscle tissue usage and almost every field [pashute, Oct 04 2004, last modified Oct 21 2004]
Luz
http://lsa.colorado...eet/texts/solar.htm
Scroll down to Solar Thermal Energy (section 5 part 2) [pashute, Oct 04 2004, last modified Oct 21 2004]
Photovoltaic cells
http://www.mrsolar.com/
(if you don't know what they are) [pashute, Oct 04 2004, last modified Oct 21 2004]
affirmation of my thoughts
http://www.solarpaces.org/stepowgen.htm
although they are not making miniature "pv" like cells [pashute, Oct 04 2004, last modified Oct 21 2004]
[link]
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Sorry rodsTiger, 7thOf8, Phoenix and Lurch. |
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I just got the whole idea so badly across and the remarks almost nothing to do with my idea. |
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If you want I can repost your remarks (saved them) along with fishbones... :-( |
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"a scaling down of thermo-electric power, and making tiny cells": |
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I'm still not exactly sure what the complete idea is. Is it to just increase the efficiency of the process by shrinking the cells and thereby increasing the density of cells in a panel so that an equivalent sized panel puts out more energy? Or is it to just make teeny tiny panels and put them everywhere on everything? Or is it something else entirely? |
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I'm not doing well at reading between the lines on this one so I'm not voting yet. |
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"Scaling down is a sure way in nature and in science to increase efficiency" - wrong. |
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"Of course selling millions of these cells will make the cells become low cost" - another bizarre, misstated theory. |
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And what the heck is a Magwatt? Something from Star Wars 3 ? |
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Scaling down: Examples - reversible energy efficiency in thermodynamics thru almost infinitely small steps of heating/cooling. Biological phenomena such as "assimilation efficiency" and more. Search google for "efficiency and science" or any field of science and you will find that slow small steps, small amounts and small sizes are all part of efficiency. |
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Low cost: What is bizzare about that? The price of PV cells went down when millions bought them, and these cells which will be the same size or smaller but much more efficient will go down in price when bought. |
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Magwatt: I assume you never make spelling mistakes. And your mother tongue is English yes? [fixed anyways] |
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DrCurry: usually not so harsh on halfbaker ideas. |
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Half: Equivalent size of the new TE panel will put out much more energy than a common PV panel (These are "electricity from light" panels like the ones you have on calculators). The only problem is they only work in the sun, and not in a room. So they are good for recharging a battery on a lamp post etc. Giving much more power than current panels give (and so stronger light possible or longer periods). |
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Are you *sure* you are talking about thermoelectric panels? The Luz link refers to a steam turbine generation setup. Pick one - turbine or TE - and we'll go over it. |
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I really don't see the relevance of the Forbord paper. Would people be willing to pay more for a personally-crafted kilowatt of power than for a generic mass-produced kilowatt? |
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"Efficiency in biology" refers to those things which consume power, not generate it. Of course it makes sense for power consumption to be as low as possible for a thing that has to provide its own fuel, but that's not what you're talking about. When it comes to energy production economies of scale apply so generally larger = more efficient. |
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"...selling millions of these will bring down the cost ..."
Again, not true. Selling millions does nothing to the cost of production. You may be able to lower the price if you can afford to make less on each unit, but that's not the same thing. To lower the cost of production, you need more efficient manufacturing processes, cheaper materials, cheaper labor, etc. |
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Well I will give [pashute] a croissant just for going to the trouble to reformat and repost then idea in a more coherent way. |
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Large area PV-cells are more efficient than smaller ones. I'm not sure about Seebeck-effect thermoelectric convertors. But there is the germ of a good idea here. |
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Other than being curious as to how the proposed cells perform the conversion without some sort of heat engine cycle, I have one other comment. |
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Scaling down is not always an efficient way to go; it depends on the application, because of the proportionally increased amount of overhead necessary. For instance: a large, smoky diesel bus is more efficient than several small cars in terms of pollution, both in manufacturing and operation per mobile person, simply because the bus carries more passengers. Economy of scale at work. |
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I actually meant any thermal to electricity process. Common TE is actually done by a "thermo-couple" of materials: typically metal, but sometimes liquid and gas. These have typical efficiencies of 5% but are very reliable (no moving parts) AND - still give more electricity per cost and per size compared to pv cells. Also they can be connected to a heat storage source (hot water tank) which is usually cheaper than a battery, and also possibly needed in addition to the electric system.[see new link] |
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I was also thinking about chemical storage type (http://www.sunergy.com) very small steam motors,
http://www.spacedaily.com/news/nanotech-01l.html or some sort of efficient heat-pump energy generator like a stirling motor http://www.globalcooling.com/stircoolunit.html |
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Solar thermal electricity generation can be much less expensive than photovoltaics. |
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Unfortunately, this seems not to be the case for TE (Seebeck effect) devices. The cost per Watt peak of the TEs (at least at Hi-Z.com) is higher than PV. You still have to add the cost of the concentrator (if any) and absorber and ev. tracking mechanism.
Maybe i'll try Peltier Elements in reverse operation. Please tell me if you find a source for less expensive devices. I plan to build a prototype this summer:-) |
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Solar thermal plants with thermodynamic devices are a different issue. Dish/Stirling engines even exceeded peak efficiencies of 25%. The parabolic trough systems have lower peak efficiencies (about 15%) but are the most cost effective for really large plants (see kjcsolar.com). |
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Four years later, added another sentence to the idea. Towards the end I wrote about the tiny steam engine. Basically what I'm getting at is to try and get electricity from the sun's heat and not from the sun's light (although it seems that most of vegetation in nature uses only the light and avoids the heat). |
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