Energy....

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Energy....

Post  Shelby on Tue Oct 20, 2009 9:09 am

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Note since writing what is below, it has occurred to me that a mirror reflector for a Stirling Engine probably isn't going to be practical due to storms (plus the tracking hardware will add cost). I doubt any one (even in poor countries) wants to have to remember to protect their parabolic reflector every time a strong wind comes. The only way solar powered stirling engines can competes with solid-state solar panels, is if one can use hot boxes (but these add cost also) and then route the hot liquid to the stirling engine, but then you will give up some of your efficiency on the hot liquid pump.

What we really need is for companies to copy what http://nanosolar.com ($1 per watt claimed, also First Solar) is doing and bypass govts which are taxing the heck out of solar panel imports. The motivation behind a homemade solution, is the govt is bypassed. However, I am think that $1 per watt is a govt subsidy lie, because that is apparently (Wikipedia "First Solar") only the manufacturing cost (not including any profit, distribution cost, marketing cost, etc) and all panels are pre-sold to large institutions that get bank financing and tax credits. Afaik, we can't buy First Solar nor Nano Solar in the retail market. So I continue to think the real cost of solid-state solar panels (including the inverter and shipping, not including tax credits), is more in the realm of $4 - $5 per watt in USA and higher in developing countries due to import taxes and low volume lack of economy-of-scale.
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Note there is already a commercial unit obtaining near 30% efficiency for 35W output:

http://www.sunpower.com/lib/sitefiles/pdf/publications/Doc0083.pdf

I wonder how hard can it be to learn how to make these (they include the linear alternator) in a developing world machine shops for less than the $5+ per watt cost of retail solar cells in developing world (which does not include the DC-to-AC inverter)? Figure this could be scaled up to maybe 100W, and the metal + alternator components involved is probably only cost < $20, then you've only got labor involved. The parabolic mirror can be made with aluminum foil, but I do not yet have a good idea how to minimize the cost of the substrate. Could use a plastic tank for the cool end water cooled, will need a large hink sink fins which will increase metal working and cost. My rough calculation is need about 1.5 years to recapture capital cost for each $1 per Watt on 20 cents per KWHour electric grid cost comparison.

Apparently we can end this energy crisis and defeat TPTB right now. The key epiphany is to not try to use the photoelectric effect, but rather use macro heat engine effect (which scales better with our homemade capabilities). Just modern medicine can be superceded by Vitamen C (yes I cured a terminal liver cancer patient with 500mg of VitC per hour), the PTB can not make solar better than we can with simple things God gave us. I will need to do some more research on the exact instructions and costs involved, but here is the preliminary info (and maybe some of you can help me work out the exact instructions and calculations?):


http://www.fieldlines.com/story/2004/6/28/64740/2752

Re: Homemade Photovoltaics (3.00 / 0) (#9)
by thunderhead on Fri Jul 02, 2004 at 07:18:04 AM MST

If what you're looking for is some kind of way to cheaply turn sunlight into electricity, the two options that I think have the most mileage are thermocouples and Stirling engines. A thermocouple is remarkably cheap to make (you can buy copper and constantan wire from your local electronic shop), or a Stirling engine using the heat from a conventional solar panel ought to deliver quite a reasonable amount of power: possibly 100W for every 1kW of thermal energy.

For a copper/constantan thermocouple the voltage at a 30C temperature difference is about 1.2mV. So if you wanted to charge a 12v battery you'd want at least 12,000 junction pairs to get 14.4v. Arranging them into a panel by twisting or soldering them together either side of an insulating plate should be possible. On one side you want to cool them with some sort of circulating water, and on the other side paint them black and glaze them.

For a Stirling engine using air at atmospheric pressure, the power available is going to be something around 10W per litre of working volume per revolution per second. So if you can get up to 1500rpm and you have a litre of volume, that'll give you about 250W. But to drive it you'd need 2500W of heat - maybe four to six square metres of panel where I live.

In both designs, it should be possible to use a heat store and double the energy on starry nights. Both thermocouples and Stirling engines are reversible, and a solar panel staring at the night sky will get cold.

If the designs are cheaper than silicon photovoltaics probably depends on how much your time costs: the materials for the thermocouple version would be dirt cheap, and the materials for a Stirling engine not much more expensive. Both have the advantage of being not beyond the home constructor, which silicon panels certainly are!


Contrast this against inefficient, useless homemade solar cells designs:

http://worldwatts.com/homemade_solar_cell/homemade_solar_cell.html

With regard to the Stirling engine approach, realize that in one example, 131 degrees of heat can be collected in a simple, homemade hot box when the ambient temperature is only 80 degrees:

http://www.wonderhowto.com/how-to/video/how-to-harvest-the-sun-with-a-homemade-solar-panel-198274/

Homemade stirling engine (convert heat to motion, which can be attached to electric generator):

http://www.google.com/#hl=en&q=homemade+stirling+engine

http://www.prlog.org/10318904-make-homemade-solar-panel-or-is-the-stirling-solar-engine-worth-try.html

...One of the most effective ways to use solar energy as a heat source for the Stirling engine is by way of a parabolic dish which concentrates solar radiation onto the cylinder to create the necessary temperature differential.

Stirling solar generators are generally much more effective in converting solar energy into electricity than solar photovoltaic panels, and can reach efficiencies of 24% - 30%, nearly double that of certain solar cells.

The attraction for many homeowners who have some workshop experience is that a solar powered Stirling engine can be built for much less than the cost of a full solar panel system installation which often runs to over $20,000. A single 3-kilowatt Stirling engine can be enough to power an energy efficient home...


One of the big design constraints of Stirling Engines that mitigates their advantages:

http://en.wikipedia.org/wiki/Stirling_engine#Analysis

is the need to dissipate the heat on the cool side of the engine-- the higher the temperature difference between cool and heated ends, then the higher the efficiency. One possible solution to this is to have a large enough body of water (i.e. pool) to immerse the cool end into, then also have your water heater for free:

http://www.google.com/#hl=en&source=hp&q=water+cooled+stirling+engine

Math of Stirling Engines:

http://www.ent.ohiou.edu/~urieli/stirling/me422.html
http://www.ssrsi.org/sr2/Heat/stirling.htm

Types:

http://www.ent.ohiou.edu/~urieli/stirling/engines/beta.html

Beale estimated 23% efficiency in 1978 issue of Popular Mechanics (has since patented and gone commercial with sunpower.com):

http://books.google.com/books?id=jAAAAAAAMBAJ&pg=PA74&lpg=PA74&dq=william+beale+stirling&source=bl&ots=Q3hYL6HRK7&sig=jGZzKd2yIcPK9CsoqPnD5zO0Vwo&hl=en&ei=hJHdSqu3HZDe7APA0qScDg&sa=X&oi=book_result&ct=result&resnum=9&ved=0CCQQ6AEwCA#v=onepage&q=william%20beale%20stirling&f=false

http://www.amazon.com/Next-Great-Thing-Stirling-Engine/dp/0393036197




Regarding the thermocouple electric generation option, I note that the 1 peso (2 cents) cupro-nickel coins in Philippines have 75% copper, 25% nickel, maybe could be used to make a cheap and non-ideal substitute for constantan:

http://en.wikipedia.org/wiki/Cupronickel

Those are about 2 cents for about what is currently roughly 5 cents of metal, and readily available.

http://books.google.com/books?id=G1i8tzrJ1nMC&pg=PA264&lpg=PA264&dq=silver+thermocouple&source=bl&ots=3K5n5C1Hbn&sig=NefzpMBD7ZLdXStUayPLdkZZZuU&hl=en&ei=15zdSvf5HISG6AOc5bGrDg&sa=X&oi=book_result&ct=result&resnum=9&ved=0CCUQ6AEwCA#v=onepage&q=silver%20thermocouple&f=false (scroll down)


Note that thermocouples will have lower efficiency than Stirling Engines, except if theoretically combined conductors in the IR light sprectrum:

http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator#Efficiency

http://en.allexperts.com/q/Electrical-Engineering-1356/kind-electric-generator-work.htm

..."The voltage produced by thermocouple junctions is strictly dependent upon temperature. Any current in a thermocouple circuit is a function of circuit resistance in opposition to this voltage (I=E/R). In other words, the relationship between temperature and Seebeck voltage is fixed, while the relationship between temperature and current is variable, depending on the total resistance of the circuit. With heavy enough thermocouple conductors, currents upwards of hundreds of amps can be generated from a single pair of thermocouple junctions! (I've actually seen this in a laboratory experiment, using heavy bars of copper and copper/nickel alloy to form the junctions and the circuit conductors.)"

"Thermocouples, however, can be built from heavy-gauge wire for low resistance, and connected in such a way so as to generate very high currents for purposes other than temperature measurement. One such purpose is electric power generation. By connecting many thermocouples in series, alternating hot/cold temperatures with each junction, a device called a thermopile can be constructed to produce substantial amounts of voltage and current:"...

...Answer:

...The thermocouple is also inefficient, but it is a lot better than a VG generator. In fact, thermocouple piles were used by the military in the second world war for local power generation. They used a gasoline powered torch to heat one half of the junction, and the other half was to be immersed into water. This power was used for operating radios, lights, etc. I think it was at 12 volts...

More on limitations of thermocouple generation:

http://en.wikipedia.org/wiki/Thermogenerator
http://scitoys.com/board/messages/1/5598.html?1231354067
http://en.wikipedia.org/wiki/Energy_harvesting#Thermoelectrics

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All lies

Post  Shelby on Wed Oct 21, 2009 3:39 pm

Hydrogen (nor H20) is not an energy source, rather it is one of the worst energy carriers because of the very low density of the gas (and in compressed form it is a bitch). Hydrogen has been promulgated by the mass media in order to cause us to waste enormous time and resources. Uranium and nuclear energy are the correct replacement for declining carbon fuels. The new mini nuclear reactors are extremely safe, reliable, no liquids and can be buried in your backyard.

Homemade anything is not economical in scale. It will cost you $1000s in your time just to make something that won't generate 100W. You can buy 100W solar panel for $600 in Philippines.

The problem with solar is the energy is not dense enough. Uranium is extremely dense.

Maybe Stirling Engine with a focusing mirror would be about equivalent in cost to a commercial solar panel. Solar will never compete with coal nor uranium. The $1 per watt lies for Nanosolar.com and first Solar are just govt subsidy lies that are like H20 designed to bankrupt us, when we should be doing nuclear in a big way.

I urge you to read the "Global Warming Nonsense" thread in the Economic discussion forum for more...

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Regenerating dinasour birds could castrate the banksters

Post  Shelby on Tue Nov 03, 2009 7:05 pm


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Do-It-Yourself Passive Solar refigeration, water purification, and air conditioning

Post  Shelby on Sun Nov 22, 2009 7:50 pm

Passive means no moving parts!


1) Passive solar refigeration is a simple do-it-yourself matter:

http://www.rexresearch.com/cummins/cummins.htm



2) Passive solar water purification is very simple, just collect the steam on glass or plastic and let it drip down into your collector, e.g. here is a 5 minute project to make purified drinking water from urine or saltwater (in case you get lost at sea!):

http://www.instructables.com/id/Uncle-Johns-portable-solar-water-distiller-Fo/

However the solar purifier does not boil the water, thus does not kill bacteria, so you can simply place your purified water in a 0.999 silver container to kill the bacteria, or you can produce the silver ions with 9V battery (as long as your keep the ion level to the required 0.1 PPM, your skin should not turn blue over years of use).

And then your water will taste better than boiled distilled water. 1 gallon per 8 sq.ft per day.

Actually it is possible to boil water with concentrated solar power, even do cooking.



3) Passive solar air-conditioning can be done with a solar chimney:

http://en.wikipedia.org/w/index.php?title=Solar_chimney&oldid=325515385#Solar_chimney_and_sustainable_architecture
(note do not waste your time with the Solar Updraft towers generators, as I studied the calculations and they are impractical)

I did some rough calculations:

http://intraweb.stockton.edu/eyos/energy_studies/content/docs/FINAL_PAPERS/4B-7.pdf (see page 5)

That paper basically says that 1 sq.meter area of chimney (at 45 degree angle) can move per hour, between 100 - 200 cu.meter of air volume, and that is for a chimney with considerable mass on the collector to store up energy to keep it running at night. That is for a day with roughly 800 W per sq.meter solar power, note the desert and tropics will be up 2400 W per sq.meter. The relative day and night flow rate can be adjusted by increasing or decreasing the collector mass and its specific heat (e.g. water stores the most heat), so that you can choose to get a higher day flow rate with lower night flow rate, or vice versa.

To give some rough idea of sizing, I estimate that a large box fan will move no more than 1 cu.meter of air volume per second (pi x 0.25m x 0.25m x 5 m/s). So that is 3600 cu.meter per hour. So you would need roughly 18 - 36 sq.meters of solar chimney to give same flow rate (or in the desert or tropics maybe only 1/3 of that). You would control the air speed, by adjusting the distance between the chimney's back plate collector and its front plate of glass or glaze. Alternatively by using a sealed room, and adjusting the portal to the source of incoming air to the otherwise sealed room. In either case, you may also have to factor in friction if you use small portals into the chimney from the room you are drawing the air, or small portal for the incoming air to the sealed room.

For the design to be economically competitive (in terms of time to get return on capital) with electric cooling, an integrated design with the construction of the house will be necessary. One of the general design factors is that the flow rate will be proportional to the equivalent horizontal collector area x equivalent height of the exit tower (see page 2 below equation 9). For example (and this could retrofit most existing houses) you could make the roof the nearly flat collector, then have an updraft tower in the center. The roof could be covered with raised plastic, and even the updraft tower could be walled with plastic sheathing. The incoming area would flow from the inside of the house to the outer edge of the roof then flow over the surface of roof to the updraft tower. So a typical small house with 64 sq.meter roof, the in tropics you could be looking at about equivalent to 5 box fans of cooling. Figure maybe you would need to invest about $500 - $1000 (in low price labor region), but that would offset the price of 5 fans (about $150) and the $50 per year in fan electricity, plus you would have cooling that runs into the night and which can be design to flow air more diffusely (not as focused as fan), thus being more comfortable and healthy (less sinus effects). Also it would be nearly silent. Typhoon and high wind prone areas would need a more sturdy design and might not be cost competitive.

Another idea for a design would be to make the roof the walls (teepee design) for the house, but this would only collect sun intensely on one side of the roof for each half of the day.


Last edited by Shelby on Mon Nov 23, 2009 8:10 pm; edited 1 time in total

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Will Solar Panels reach Grid Parity in Next decade?

Post  Shelby on Mon Nov 23, 2009 2:43 am


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Transportation fuel (battery)

Post  Shelby on Mon Nov 23, 2009 5:15 pm

Forget the electric battery for transportation applications! The current best commercial electric battery is Lithium-Ion (the silver-zinc battery promises to be 40% better) or for high power NiMH, but in any case, this chart shows that Lithium-Ion (and others) are orders-of-magnitude worse than hydro-carbon fuels, in terms of both mass and volume per energy stored. Even nanowire advances for electric batteries will not close the orders-of-magnitude difference.

Also note on that chart, that as compared to oil and diesel, Aluminum has 250% better volume density and 67% of the weight (mass) density.

Diesel/gas can be made from methane natural gas or coal (both of which we have 100+ year supply, methane is even renewable as crops convert from CO2) using some catalysts and input energy (e.g. electric energy from burning coal, nuclear or recent advances in solar). Aluminum is the most abundant metal on earth, and the 3rd most abundant element on earth after oxygen and silicon, and is produced from ores, or from recycling, of aluminum oxide and input electrical energy. When aluminum is consumed as a fuel, the waste product is aluminum oxide. Thus, both of these fuels are portable forms of stored electrical energy, with orders-of-magnitude better volume and weight (mass) density than the electrical batteries. Note also there is even science for simulating what crops do, and directly convert CO2 back to renewable energy (see also and this).

Thus, the two best renewable transportation fuels are gas/diesel and aluminum, or think of them as batteries that generate combustion instead of electricity. Any one who says the EROEI is less than 1, does not know what they are talking about. There need not be an energy crisis, if society is not discentivized economically from producing energy. In short, transportation fuels are renewable, and this is what the governments (kings) had to hide from society (as 1 Samuel 8 promised they would do).

Here is a do-it-yourself project for using aluminum is a jar to double the fuel mileage of your gas vehicle (press Ctrl+F, then search for "albee" in the comments). Others have reproduced this.

Note, that nuclear reactions have orders-of-magnitude better energy densities, than the above best transportation fuels. And thus mini-nuclear reactors are best when price is not the objective (e.g. submarines, battleships). However, note that there is commercial reality towards producing smaller, less expensive, safely self-contained mini-reactors.

Btw, here is an interesting link of potentially suppressed technologies.

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Artificial photosynthesis?

Post  Shelby on Thu Mar 11, 2010 8:39 pm

http://www.silverbearcafe.com/private/03.10/catalyst.html

I am still studying this to to understand its efficiency.

Apparently the breakthrough is to split the oxygen more efficiently (less input energy):

http://www.sciencemag.org/cgi/content/abstract/321/5892/1072

Thus apparently it may make a more efficient battery? I do not yet see how this increases the efficiency of the collection of energy from the sun. I think not. I think this is just a way to more efficiently get hydrogen and oxygen, but not the most efficient battery.

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Stirling engine + hot box?

Post  Shelby on Fri Mar 12, 2010 5:27 am

ADD: I found $1.20 per watt solar panels (thin film too so are superior in low light and hot climates):

http://sunelec.com/

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The basic idea is as follows, then the justification follows that.

A stirling engine is in practice up to about 35% efficient (in real world) at converting heat to mechanical (kinetic) energy, whereas current solar panels are about 8 - 15% efficient at converting solar radiation to electrical (potential) energy.

A good explanation of how Stirling engine works:

http://www.sesusa.org/types.htm
http://en.wikipedia.org/wiki/Stirling_engine

Unlike combustion engines, Stirling engines are simple devices, and can probably be build in a garage machine shop.

Apparently the main challenge for using Stirling engine for solar power generation, is the focusing of the solar energy to the hot side of the heat exchanging requiring large mirrors and complex tracking device, and then the fact that cold side needs to sink a lot of energy as the efficiency is proportional to how cold it is.

My prior research revealed that a home-made hot box can produce 131 degrees with 80 degrees ambient temperature:

http://www.wonderhowto.com/how-to/video/how-to-harvest-the-sun-with-a-homemade-solar-panel-198274/
http://goldwetrust.up-with.com/technology-f8/energy-t119.htm#2089

That isn't ideal differential, as that will only achieve a theoretical efficiency of 40% (so real world maybe 20%). Maybe there is some way to produce a more intense heat from using simple fixed mirror (aluminum foil or used cdroms) focused into large area of a hot box (as opposed to tracking motorized, narrow focusing on tip of hot side of Stirling heat exchanger), and especially here in tropics where I am the sun is maybe 3x more intense.

But my idea gets more interesting. I am thinking the Stirling engine itself can be used to both drive a load (generator, inverse stirling engine for refrigeration, etc) and to mechanically pump the hot liquid from the hot box in a closed loop. Then place the cold side of the Stirling heat exchanger in the ocean water which is I think around 65 degrees (7100 island, longest coastline in world here in this small country). So then we can get closer to the 30% efficiency and do not need complex mirror tracking costs. Or even immerse the cold side in a tank so you get hot water (85 degrees? supplement with valve from the super hot water side) as a free side effect. At least decreases the cost of the cold side heat sink.

Do you think this is easy to build and would it be cost competitive to solar panels which are selling for $6.80 per watt here in Philippines (as low as $3 per watt in USA, before S&H)?

The urgent reason for this is that the reflation of the Western debt is causing the Asian countries to boom so fast that they are outstripping their generation capacities, and we are suddenly thrust into 5 hours per day brownouts due to the El Nino, but even when rains return, the growth is outstripping power supply and so power rates will have to skyrocket in order to ramp up diesel barges quickly, or more likely we will be suck with brown outs for years.

http://goldwetrust.up-with.com/health-f5/living-in-other-countries-after-the-us-collapses-t87-15.htm#2801

Not only that, the affordable land in Asia is outside the cities, but at least here in Philippines, the power supply outside the cities is spotty and unreliable. And the cheapest land are the innumerable mountains where electricity will not be forth coming any time soon.

There seems to be an opportunity here to cut off the TPTB's energy monopoly. I think solar panels are headed for $1 per watt in a few years, as I detailed on my forum (due to nanosilver prisms on top of thin films and other advances), and I am thinking that perhaps this stirling concept can get down to that price point. Which at 20 cents per KWH, means 1.5 years ROI which is excellent and re-empower the individual against TPTB.


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ADD: an advantage of using a hot water resevior for the heat, means it could function as an integrated battery and thus the engine could continue to run after run went down, thus decreasing the amount of external battery storage needed, which eliminates a major cost and maintenance headache in solar panel systems. Also the stirling engine can directly drive a stirling engine cooler, thus much more efficient for refrigeration.


==============
ADD: interesting links:

http://www.popularmechanics.com/science/research/4288743.html
http://www.solarbuzz.com/ModulePrices.htm
http://www.popularmechanics.com/science/research/4306443.html
http://www.popularmechanics.com/science/research/4306162.html
http://www.popularmechanics.com/science/earth/4253464.html

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