Attach a Seebeck device(thermoelectric generator) to the backside of solar cells.
Clock Loop
Posts: 2,069
I have been meaning to try this, and in light of my recent financial destruction, there is no way I can test this, perhaps someone else here, has some solar cells and Seebeck devices.
Attach a Seebeck(thermoelectric generator) to the backside of solar cells.
Combine the outputs to generate even more electricity.
Someone should try this, because I will not be doing it. Too much on my plate already.
Good luck,
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The dsp/fpga king is dead, long live the prop.
Attach a Seebeck(thermoelectric generator) to the backside of solar cells.
Combine the outputs to generate even more electricity.
Someone should try this, because I will not be doing it. Too much on my plate already.
Good luck,
TERMS OF USE: MIT License & Licensed under the TAPR Open Hardware License (www.tapr.org/OHL)
"Permission is hereby granted, free of charge, to any pers...........................
..............................OMITTED FOR FORUM............................................. ..
.................. OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. "
The dsp/fpga king is dead, long live the prop.
Comments
Just a nit pick, Thermoelectric generators are properly called Seebeck generators.
This, hybrid PV/Seebeck, has been experimented with a number of times.
Generally speaking, PV and Seebeck generators are not very compatible when using conventional silicon PV cells.
The basic problem is the Seebeck generators like high differential temperatures but silicon PV looses efficiency at higher temperatures.
Since Seebeck generators have very low efficiencies to begin with, raising the PV cell temperature looses more efficiency than gained by the thermoelectric generator gain in efficiency. It is possible to do this if exotic semiconductor PV cells, such as GalliumArsenide, and others, that can operate efficiently at higher temperatures.
Duane J
This is not "perpetual motion", just not a good way to do it.
Sunlight hits the PV cell which converts about 15% to electricity.
The rest of the light, about 85%, is converted to heat.
It's this heat that now passes through the Seebeck thermoelectric generator, 1% or a bit more, which produces more electricity.
And the left over is heat rejected to the environment.
Not perpetual motion.
The problem is the added temperature that the Seebeck generator requires to work reduces the efficiency of the PV cell.
Just because something doesn't work well doesn't mean its perpetual motion.
There are plenty of examples of perpetual motion that can never work.
This actually does work, just not well, maybe the future will find Seebeck generators that will perform better and PV cells that tolerate the higher temperatures better. Physics is not violated.
Duane J
Lower differentials can be used for low-energy apps such as wireless sensor nodes. Here is a link to a new technology that promises to use either light or heat to generate energy, using a nanomaterial based on copper sulfide.
A bit bigger and heavier than what I usually carry( MSR Pocket Rocket and a small Propane canister), but it sounds like it could boil my tea-water quicker, and the ability to recharge equipment is nice.
(Would need a USB-based charger for AAs, also, as I try to avoid equipment with specialised batteries)
I wonder if they have any European distributors...
I wonder if anyone's done the calculations to check if adding forced-air ventilation to PV cells is worth it (in terms of electrical power gained over
power to the fans)? Obviously in the diamond age PV cells would be sandwiched between slabs of diamond for efficient heat-sinking and water channels
can be in the slabs
The economics of solar cells are changing rapidly. A decade ago they were $10 a watt and now on ebay you can pick up panels for $0.75 a watt. So many of the things that used to make sense economically may not any more (eg solar trackers). I'm getting some panels for the roof soon but I'm also looking at putting some in the yard as the roof is running out of space (since I covered it with 12kw of solar hot water panels) and if one is not careful, the costs of the frame can almost be more than the cost of the panel it supports. But rather than build a metal roof then put a panel on that, I think it will be better to have an open frame so the air can get to the back of the panel and provide some wind cooling.
Ten years ago peltiers and concentrating mirrors might have been a crazy solution that worked economically but with solar panel prices falling so much, probably not any more.
FF
Give me a break. Using the Seebeck device to cool the cell would use up all the solar power. Making the device totally pointless.
I was suggesting using the Seebeck device to passively draw heat away from the back of the HOT solar panel (solar panels get HOT from the sun (like mentioned, 85% is converted to heat)
What does the solar panel do with this heat? Its radiated off in the form of air flow.
So what I am suggesting here, is attach the Seebeck device directly to the back of the solar panel. I am NOT suggesting using the Seebeck device in an active powered mode(to cool the solar panel down)
I am suggesting using it in a passive mode, the heat from the back of the solar panel, getting conducted through the Seebeck device to the LARGE HEAT SINK on the back.
I do understand with todays tech, that its very inefficient, but it WOULD produce some electricity if you purchase the right Seebeck device. (for the temp ranges)
So if a solar panel heats up to say 115 deg F in full sun.. thats pretty hot. And if you feel the backside, its much cooler. Try it with a ir thermometer.
Instead of letting the excess heat radiate away from the back of the solar cell, make it go through the seebek diode junction first.
I am NOT suggesting using the Seebeck device to do any kind of active cooling. The Seebeck device would be unpowered, and only provide minimal amounts of passive power depending on the ambient air temp, and the amount of sun hitting the solar cell.
But one can attach quite a few seebeck devices to the back of a single solar panel. Multiply that times a few solar panels, and all that extra electricity adds up. (but it does get quite expensive)
Mark my words, in the future, solar panels will integrate this effect into the design.
(P.S. WTF? a perpetual motion machine??? where did you get that from?)
NOR am i suggesting using mirrors to concentrate the sun light onto a piece of metal on the Seebeck device, you waste all those photons that could be absorbed by the PV cell.
The absorption of HEAT energy is done AFTER the solar panel has done ITS job.
Again, its only a matter of time before manufacturers steal this idea, and the original inventor gets nothing, and goes unnoticed (as usual, whoever that may be) (welcome to corporatism) (he who has the most money wins, poor people can't afford to defend patents in this corrupt system anymore) they also changed the US patent system to a first to file. This means the RICH don't even need to prove substance (only document, with a pile of money) Then they can just sit on a bajillion patents, using their money to sue anyone who challenges it with a real working prototype. Enough time hasn't passed since the law was changed for most of us in the US to see the effects, but YOU WILL. (our patent system worked fine for a century, and all of a sudden they scrap the whole thing and match the patent system that the rest of the world uses)
It is any wonder that America used to be the innovator of the world? Well, that is gone now. We now allow corporatism in our patent system.
He who has the most money for the lawyers AND filed first wins (regardless of burden of physical proof)
If you are working on an invention, and some government employee somehow gains access to your property (via warrant or something) and they see your inventions, that you haven't patented yet, they can technically just file for the patent using paperwork only (or their friend), with no physical proof now. (obviously the patent can still be challenged on grounds of being fake or perpetual motion "like")
What I am saying is the PHYSICAL PROOF, the actual invention its-self is no longer needed to win the patent.
Anything the government seems to do today is to benefit CORPORATISM. Not the individual, so if they change some laws BEWARE. They even word it all like it will help the poor inventor.
http://www.bloomberg.com/news/2011-09-16/administration-says-patent-law-change-will-spur-u-s-economy.html
(and again, where is that "SPUR"????????????) More magic, smoke and mirrors, just to protect their own corporate conglomerates from the individual.
"The legislation is the culmination of more than a decade of discussions and six years of negotiations and lobbying by every industry. It covers each step of the patent process, setting new procedures to review issued patents while curtailing some litigation. It has the support of companies including Microsoft Corp. (MSFT), International Business Machines Corp. (IBM) and a group that represents Johnson & Johnson (JNJ), Eli Lilly & Co. (LLY), 3M Co. (MMM) and General Electric Co. (GE)"
Look at all those companies that support it.. That should be a good indicator of its nature.
The individual inventor is doomed. Its a good thing earth is about to embark on a whole new era of exponential technologies that will make any attempts by controlling psychos to stop innovation pointless.
(first 3d printers, then atomic printers) Similar to how the internet DESTROYED mail, print, and telephone communication dominance.
Whos is gonna ask for permission to PRINT a patented device? No one. Eventually that situation will lead to a war on 3d printers, in the excuse that criminals can print weapons.
NEXT UP: The WAR on 3d printers. (eventaully they will be breaking your door down if you are suspected of "printing" a device that you don't have permission to print)
That will lead to making 3d printers illegal for most people. (hard to believe i know)
I don't think the economics add up but I'm happy to stand corrected, particularly if mass production has brought down prices.
First thing to do is buy one and do some experiments. That is what I did. Grab one, and get a metal tin with a metal lid. Fill that completely with warm water and put the lid on, and then put the peltier device on top with some conductive heat compound. Now put another tin with cold water in it and mount that on top of the device with more heatsink material. Now measure some volts and amps at different temperature differentials as the differential decreases.
First thing to note is that you have to move a lot of heat energy to make a little electrical energy. Ballpark figure, say you have a black surface facing the sun and you want to radiate that energy away, you might need a large cooling area - possibly 20x the heating area. So that is either a large passive heatsink (which costs money), or a fan (which consumes energy) or water cooling (which assumes you have a large store of cool water like a water tank). In many ways with heat engine design the hot part is the simpler part. It is the cooling that gets complicated. Think of the internal combustion engine where the heat is an explosion and then you need a huge radiator and a fan to keep the engine from cooking itself. If you don't keep the cool side of your peltier cool it will stop making electricity.
I did some sums and water cooling seems more practical than air cooling. So that adds weight as you need copper pipes and you need a stronger frame. It is nothing impossible though. But it all costs money.
Economists talk about the payback time. Spend x dollars and how long does it take to pay itself back. I think solar electricity cells are getting to under 3 years and that is even without the generous subsidies we have in Australia (which are being phased out). Peltiers seem a lot more than that.
Do some experiments. It is pretty cool watching electricity being produced by warm water. I reckon it cost me less than $30 for all the parts.
Or do some sums. Work out the energy output with whatever temperature differential you have and look up the peltier specifications. Like all heat engines, efficiency goes up with higher differentials but with solar panels in the sun, you might only get to 60C on the hot side and the cold might be 20C so you don't have much of a differential. Look up the Carnot cycle (and spend 10 years coming to grips with thermodynamics!).
Forget about patents. You have a good idea, build a prototype, then register your company in another country and then run like hell making your product out of China (I paid a fair bit of money once for the advice in that last sentence). But you need a working prototype and sadly, this one is not going to work. The laws of thermodynamics are working against you.
Typical of generic TEGs, the output is around 20mV per °C differential, so it takes a hot fire to generate much voltage and power. The maximum power point is determined by a fairly constant low output resistance, on the order of a few ohms.
The guys at Biolite did a huge amount of sophisticated heat flow modeling and prototyping, which subsequently directed their choice and arrangement of components for maximum energy capture and clean burning, balanced with cost factors. That is the sweat behind their patent applications and their trophy case of design awards. Lots of engineering, observation of human need, and undertaken in a giving back spirit that would be hard to match by the big corporate entities.
So it is out by an order of magnitude for solar.
Where TEGs work well is a higher temperature differential and, say, when the sun isn't shining, for example you are stuck in the dark at night and a storm has gone through and knocked out the power and all the gas stations are closed or have long queues, so you can get a fire burning with some wood or whatever and make some electricity to charge your phone to call for help.
the ROI on PV is not too shabby .
Clock I understand that some articles are not painting a good hope for Printing freedom .
however LIke the press and my laser printer .
the printer is not " reguated " so why would a 3D printer .
I have some hope that the people on Wash DC are not total air heads .
SO WHAT if then ban them ..... My mother can make one in her sleep .
what are they gonna do . BAN the sale of scanners to mod in to the drives for repraps . I doubt it .
I ll bet you can make a reprap outta legos
At the low power harvesting end, less than 10mW, they are especially of interest for powering wireless sensor nodes. That won't charge your iPhone very fast, but it is enough for a an XBee in a sleep mode. MicroPelt has chip scale TEGs in development for harvesting apps. More junctions for a higher Seeback coefficient, but the output resistance is relatively high, >100Ω, and they are still very expensive. The standard TEGs do work okay, but I sure don't see much R&D specifically for use as power sources, rather than refrigerators.
Even if you ignore the 40:1 cost failing at 40°C differential, there is a more fundamental issue :
Each degree you elevate the hot side, elevates the Soilar cell, and they drop Po at higher temperatures in the –0.44% to -.50% range.
So that 40°C adder, has cost you close to 20% of your solar output (!), already well above what your TEGS can yield - and even if it comes for free. that thermal slope is a killer.
You are better choosing the right glass that drops infrared heating, and some active cooling, than you are applying TEGS.
- and you are sure to gain some lifetime from less thermal cycling, as a bonus,
My Name is David and am new to this area of technology. I have been reading all the posts and doing alot of research on these as well as wind power and others. the trend im noticing is efficiency in all these systems, the heat lost on the solar panels while the hotter panels have energy loss if they get hotter, why is there not a simple system to catch whatever energy you can and put that back into the grid? Like per say an inexpensive solar array not to power a fridge and electric range but something to power the TV and lights. then integrate thermo electric on the stove behind the solar panels, as well as a wind turbine to not power the house but take a chunk out of the current electric bill. Just some thoughts from a noob to this area of technology.
Thnks for your time.
The electric utilities charge you a lot more for each KWH you use than they pay for any you return to the grid. Makes more sense to use what you generate for your own needs and only sell if there is an excess.
Of course, it works great for those who put in the solar panels, but the electricity company has to do something about the fact that they have to subsidise those with the panels. So our electricity charges have soared.
Not sure where we are up to today though.
The other thing is that you make solar energy during the day but most of what you use at home is during the evening. If you want to use this energy yourself, you need batteries to store it - a big cost.
David has also said that this was changed to only 6c per kWh at some time.
Germany is well known for having a huge amount of solar power going on. It certainly seemed so when travelling around Germany by train last year, one could see solar panels on roof tops everywhere. Interestingly Germany has some of the most expensive electricity in the world. Is that due to a similar subsidy system going on?
Even getting twice the price does not help if you just get 25% out.
Makes still no sense to put halogen light over the solar panels for the night.
Sad.
Mike
Nothing to see here.......