Power Generation Idea
Overclocked, Mon Oct 29 2007, 04:15AMIn the recent Months Ive become Intrested in Power Generation (alternative mind you). So Far, there are various ways to generate Power Using Various Sources Around us (excluding Coal, and Oil. Nuclear power FTW IF its used right) such as Wind, Solar, and in some spots, geothermal. Ive heard there are Generators That will use the tides of the ocean in the works, and I myself have been thinking of some idea to use the oceans waves to generate power. However, There is one Form we dont take advantage of.
Thermoelectric Energy, ie, Heat. Sure we can use it to boil water for our hot water heaters, But why not use something to generate power? Im thinking a homemade thermocouple. I have some Forrest M. Mimms Books that show how to make one and which materials one could use. Im thinking if you can get a bunch of these, Put them in the sun OR snow (since they generate power via a difference in temperature) hooked up in series, you could probably get enough voltage to power a battery.
I think they were made of Copper and Steel...err or It was a steel paper clip and 2 copper wires. I Know My idea will work, But will it be Practical? Are the bill of materials just so expensive, that its cheaper to go solar? Still, If there is Heat or cold, there has to be a way to put it to use. Hmm dont diodes or most semiconductors produce a voltage if heated or cooled?
On A side note, I do know there are things such as Peltiers, and I have a couple, But Ive heard pelts arent really a good way to generate electricity from heat.
Re: Power Generation Idea
..., Mon Oct 29 2007, 04:38AM
Face it, converting heat back into usable energy just isn't easy.
You will never be able to get any appreciable amount of power using thermcouples, even with pielters you can't recover more than a few precent of the energy.
Really the only way that exists currently to create large amounts of usable energy from heat is to boil something, and then use a turbine and generator to turn a motor.
..., Mon Oct 29 2007, 04:38AM
Face it, converting heat back into usable energy just isn't easy.
You will never be able to get any appreciable amount of power using thermcouples, even with pielters you can't recover more than a few precent of the energy.
Really the only way that exists currently to create large amounts of usable energy from heat is to boil something, and then use a turbine and generator to turn a motor.
Re: Power Generation Idea
Coyote Wilde, Mon Oct 29 2007, 05:37AM
All of the technologies you 'excluded' are thermoelectric, technically (along with geothermal and some solar) -- they convert heat to electricity.
They don't use peltiers/thermocouples, because thermocouples suck. Peltiers are thermocouples run in reverse, and the ones you have are way more efficient than anything you could make with metals like iron and copper. But compared to a rankine cycle steam system, like the excluded technologies, there's absolutely no contest.
If your Tmax is too low to boil water, you can use another fluid instead of water, or switch to the sterling cycle. A small sterling engine is probably your best bet to work from a small differential, but it still won't work well.
You NEED a heat difference. The bigger, the better.
Also, putting something in the sun to heat up is technically solar power. Use some sun-tracking mirrors and you can get some righchously high temps, plenty to boil water with. An newspaper in Revolutionary France (IIRC) actually powered its printing presses with solar-thermal-steam. It's name? The Sun, of course. (well, translated)
But no, what you want to do is not practical. If you want to leave semiconductors in the sun to get power, get PV.
Since somebody is going to counter my "thermocouples suck" with NASA's use of them in RTGs, it's only because they have no moving parts and won't wear out on a decade-long mission like the Pioneer probes, Voyagers, Galileo, Cassini, or New Horizons. NASA has been looking very hard for alternatives to better use the available power, and have an impressively efficient free-piston sterling generator in testing now.
Coyote Wilde, Mon Oct 29 2007, 05:37AM
All of the technologies you 'excluded' are thermoelectric, technically (along with geothermal and some solar) -- they convert heat to electricity.
They don't use peltiers/thermocouples, because thermocouples suck. Peltiers are thermocouples run in reverse, and the ones you have are way more efficient than anything you could make with metals like iron and copper. But compared to a rankine cycle steam system, like the excluded technologies, there's absolutely no contest.
If your Tmax is too low to boil water, you can use another fluid instead of water, or switch to the sterling cycle. A small sterling engine is probably your best bet to work from a small differential, but it still won't work well.
You NEED a heat difference. The bigger, the better.
Also, putting something in the sun to heat up is technically solar power. Use some sun-tracking mirrors and you can get some righchously high temps, plenty to boil water with. An newspaper in Revolutionary France (IIRC) actually powered its printing presses with solar-thermal-steam. It's name? The Sun, of course. (well, translated)
But no, what you want to do is not practical. If you want to leave semiconductors in the sun to get power, get PV.
Since somebody is going to counter my "thermocouples suck" with NASA's use of them in RTGs, it's only because they have no moving parts and won't wear out on a decade-long mission like the Pioneer probes, Voyagers, Galileo, Cassini, or New Horizons. NASA has been looking very hard for alternatives to better use the available power, and have an impressively efficient free-piston sterling generator in testing now.
Re: Power Generation Idea
Bjørn, Mon Oct 29 2007, 07:51AM
First we need to find the teoretical maximum efficiency obtainable. e = 1 - (Tcold / Thot), temperatures in kelvin. Imagine you have smelting snow and an air temperature of 10 deg C. e = 1 -(273/283) = 3.5% efficiency, then you subtract any losses in your system and you are left with hardly a measurable efficiency.
Peltiers are as good as anything for very small generators, I have seen several peltier power generators, I have never seen a small strirling or other mechancal type that is in actual practical every day use. Peltiers can give more than 10% efficiency without moving parts but it is very difficult since you need high temperature differences and you are very close to destroying the peltier. I have reached 10% conversion efficiency using a candle as the power source and used it to power LEDs that made more light than the candle itself. Fun but perfectly useless since other light sources than candles would be a lot more efficient.
Your first step would be to replace all heating of air and water with solar heat and heat pumps. Then reduce your energy use in general as much as possible. Then you have significant savings without spending more than you save. Then look at hydroelectric, solar and wind power. Then look at other forms. The exception would be if you use gas, oil, wood or other sources of high temperature for heating, then you can in theory do very well in combining those with a thermoelectric generator.
Bjørn, Mon Oct 29 2007, 07:51AM
First we need to find the teoretical maximum efficiency obtainable. e = 1 - (Tcold / Thot), temperatures in kelvin. Imagine you have smelting snow and an air temperature of 10 deg C. e = 1 -(273/283) = 3.5% efficiency, then you subtract any losses in your system and you are left with hardly a measurable efficiency.
Peltiers are as good as anything for very small generators, I have seen several peltier power generators, I have never seen a small strirling or other mechancal type that is in actual practical every day use. Peltiers can give more than 10% efficiency without moving parts but it is very difficult since you need high temperature differences and you are very close to destroying the peltier. I have reached 10% conversion efficiency using a candle as the power source and used it to power LEDs that made more light than the candle itself. Fun but perfectly useless since other light sources than candles would be a lot more efficient.
Your first step would be to replace all heating of air and water with solar heat and heat pumps. Then reduce your energy use in general as much as possible. Then you have significant savings without spending more than you save. Then look at hydroelectric, solar and wind power. Then look at other forms. The exception would be if you use gas, oil, wood or other sources of high temperature for heating, then you can in theory do very well in combining those with a thermoelectric generator.
Re: Power Generation Idea
Avalanche, Mon Oct 29 2007, 06:27PM
I had a go at making my own thermoelectric generator a while back. I can't remember if I posted it here or on another forum, but here it is, just for interest... It's a 70 watt peltier cooler sandwiched between two heatsinks, on top of a lamp.
I know the open circuit voltage in the photos proves nothing, but the output impedence is quite low. Short circuit current was well over an amp, and by experimenting with different loads I managed a power output of about 3 watts IIRC.
I originally intended to use it for recharging phones and cameras remotely, where the lamp could run for 12 hours overnight on one fill.
I gave up in the end, I never actually used the thing. It sort of worked, you had to run the fan as well to stop the module overheating.
Avalanche, Mon Oct 29 2007, 06:27PM
I had a go at making my own thermoelectric generator a while back. I can't remember if I posted it here or on another forum, but here it is, just for interest... It's a 70 watt peltier cooler sandwiched between two heatsinks, on top of a lamp.
I know the open circuit voltage in the photos proves nothing, but the output impedence is quite low. Short circuit current was well over an amp, and by experimenting with different loads I managed a power output of about 3 watts IIRC.
I originally intended to use it for recharging phones and cameras remotely, where the lamp could run for 12 hours overnight on one fill.
I gave up in the end, I never actually used the thing. It sort of worked, you had to run the fan as well to stop the module overheating.
Re: Power Generation Idea
Coyote Wilde, Mon Oct 29 2007, 11:21PM
That's actually pretty cool, Avalanche. Too bad it didn't quite work >_>;
I seem to recall the Soviets at one point producing a similar kerosene-lamp/thermal-generator for use in remote Siberia, but they had purpose-made thermocouples to take the heat.
Okay, I'll concede Bjorn's point... but like I said, you use peltiers where the moving parts of a sterling or rankine cycle engine are going to be a problem. I can see that being smallness.
Though small Stirlings are used, just not commonly-- example here, a power-cooler:
A similar size to what they started to fit peltier modules into a few years ago... this is at once way more efficient and more expensive, probably due to those fine machining tolerances. No idea if how well the Stirling unit would work ripped out and run in reverse, however.
Coyote Wilde, Mon Oct 29 2007, 11:21PM
That's actually pretty cool, Avalanche. Too bad it didn't quite work >_>;
I seem to recall the Soviets at one point producing a similar kerosene-lamp/thermal-generator for use in remote Siberia, but they had purpose-made thermocouples to take the heat.
Okay, I'll concede Bjorn's point... but like I said, you use peltiers where the moving parts of a sterling or rankine cycle engine are going to be a problem. I can see that being smallness.
Though small Stirlings are used, just not commonly-- example here, a power-cooler:
A similar size to what they started to fit peltier modules into a few years ago... this is at once way more efficient and more expensive, probably due to those fine machining tolerances. No idea if how well the Stirling unit would work ripped out and run in reverse, however.
Re: Power Generation Idea
Steve Conner, Tue Oct 30 2007, 09:45AM
Avalanche, did it take more power to run the fan than what you got out of the Peltier? :(
Steve Conner, Tue Oct 30 2007, 09:45AM
Avalanche, did it take more power to run the fan than what you got out of the Peltier? :(
Re: Power Generation Idea
Avalanche, Tue Oct 30 2007, 07:32PM
The power output from the peltier would have probably been about right to run the fan, taking into account conversion losses from having to step up the output to 12v for the fan. That's why I never bothered taking the project any further. If I really cooked the peltier it would produce a bit more, but not for long!
To make it worthwhile on a small scale a fanless approach is definitely the way forward
Avalanche, Tue Oct 30 2007, 07:32PM
The power output from the peltier would have probably been about right to run the fan, taking into account conversion losses from having to step up the output to 12v for the fan. That's why I never bothered taking the project any further. If I really cooked the peltier it would produce a bit more, but not for long!
To make it worthwhile on a small scale a fanless approach is definitely the way forward
Re: Power Generation Idea
Overclocked, Tue Oct 30 2007, 11:40PM
Crap, I kinda figured that it wasnt practical. Oh well, I guess theres always generators.
I did do a little experiment and found that Blue LEDs Do give a lot of voltage when exposed to light, appr 500 mV. Not bad considering Solar Panels give the same. But I wouldnt know how much current it would be able to supply. By the time you a lot of money of LEDs, you can just get surplus solar panels from electronics goldmine.
Overclocked, Tue Oct 30 2007, 11:40PM
Crap, I kinda figured that it wasnt practical. Oh well, I guess theres always generators.
I did do a little experiment and found that Blue LEDs Do give a lot of voltage when exposed to light, appr 500 mV. Not bad considering Solar Panels give the same. But I wouldnt know how much current it would be able to supply. By the time you a lot of money of LEDs, you can just get surplus solar panels from electronics goldmine.
Re: Power Generation Idea
Conundrum, Fri Nov 02 2007, 09:07PM
or use solar cells directly, they are mostly sensitive to red light which an alcohol burner flame provides in quantity.
-A
Conundrum, Fri Nov 02 2007, 09:07PM
or use solar cells directly, they are mostly sensitive to red light which an alcohol burner flame provides in quantity.
-A
Re: Power Generation Idea
Coyote Wilde, Mon Nov 05 2007, 02:53AM
Yeah, solar cells are going to give more bang for your buck as solar cells than LEDs will. The LEDs probably benefit from having the clear dome on them-- focus sunlight onto the die. Focused solar-cells heat up and degrade faster, though, is my understanding. But one can always connive some cooling arrangement.
Most alcohol burner flames I've seen have been blue, but I suppose your mileage may vary... Modern Mechanix has the Soviet kerosene lamp thermocouple here:
Coyote Wilde, Mon Nov 05 2007, 02:53AM
Yeah, solar cells are going to give more bang for your buck as solar cells than LEDs will. The LEDs probably benefit from having the clear dome on them-- focus sunlight onto the die. Focused solar-cells heat up and degrade faster, though, is my understanding. But one can always connive some cooling arrangement.
Most alcohol burner flames I've seen have been blue, but I suppose your mileage may vary... Modern Mechanix has the Soviet kerosene lamp thermocouple here:
Re: Power Generation Idea
Bjørn, Mon Nov 05 2007, 03:31AM
He probably meant infrared light, that would make more sense.
I have managed to get more than 2mA from a LED, a very high power density considering the very small size of the chip. Silicon semiconductors does not do very well in high temperature and they degrade much faster at elevated temperatures. Specially designed semiconductors can do very well at high temperatures.
Bjørn, Mon Nov 05 2007, 03:31AM
He probably meant infrared light, that would make more sense.
I have managed to get more than 2mA from a LED, a very high power density considering the very small size of the chip. Silicon semiconductors does not do very well in high temperature and they degrade much faster at elevated temperatures. Specially designed semiconductors can do very well at high temperatures.
Avalanche, did it take more power to run the fan than what you got out of the Peltier?I have seen people getting 10W out of single peltiers when used on wood stoves. There are still people that live places where it is not possible to get electricity and where it is not enough sunlight to use solar power. Wind power would work but a peltier is much cheaper when you only need to power a radio and charge some small batteries. If the peltier elements were cheap enough it should be possible to get 500W or more out of a wood stove.
Re: Power Generation Idea
..., Mon Nov 05 2007, 04:09AM
Actually, if Emcore (or any of the other solar companies for that matter) has anything to do with it, solar power is going to be made by a triple junction (or once we can make them, 4 5 6 junction cells) solar cells, which are essentially several cells made of different materials (Si GaAs, Ge, etc) stacked on top of each other. The top cell absorbs from 400nm+ the middle from 600-400nm, and the bottom on anything up to 600nm (very roughly) . These cells produce about 30% sun->electricity efficiency, and we are planned to be up to 50% in the next few years.
Of course these cells cost $$$$$ to make, so we are running them at about 1000x concentration. Cooling really isn't that big of of problem, since the overall assembly doesn't get more than 1sun worth of energy, so we just use have the cells bolted to an Al block painted black.
We have complete modules ready to be bolted down to a concrete pad for sale if you are interested. Or you can buy just a piece of solar cell soldered to a copper block ready for your own concentrator. We are actually working with a bank to allow us to give you a panel, and then you pay it back by selling electricity back into the grid
..., Mon Nov 05 2007, 04:09AM
Actually, if Emcore (or any of the other solar companies for that matter) has anything to do with it, solar power is going to be made by a triple junction (or once we can make them, 4 5 6 junction cells) solar cells, which are essentially several cells made of different materials (Si GaAs, Ge, etc) stacked on top of each other. The top cell absorbs from 400nm+ the middle from 600-400nm, and the bottom on anything up to 600nm (very roughly) . These cells produce about 30% sun->electricity efficiency, and we are planned to be up to 50% in the next few years.
Of course these cells cost $$$$$ to make, so we are running them at about 1000x concentration. Cooling really isn't that big of of problem, since the overall assembly doesn't get more than 1sun worth of energy, so we just use have the cells bolted to an Al block painted black.
We have complete modules ready to be bolted down to a concrete pad for sale if you are interested. Or you can buy just a piece of solar cell soldered to a copper block ready for your own concentrator. We are actually working with a bank to allow us to give you a panel, and then you pay it back by selling electricity back into the grid
Re: Power Generation Idea
Overclocked, Mon Nov 05 2007, 04:08PM
Wouldnt it just be easier to boil water to turn to steam to run a generator?
Overclocked, Mon Nov 05 2007, 04:08PM
Bjørn Bæverfjord wrote ...
He probably meant infrared light, that would make more sense.
I have managed to get more than 2mA from a LED, a very high power density considering the very small size of the chip. Silicon semiconductors does not do very well in high temperature and they degrade much faster at elevated temperatures. Specially designed semiconductors can do very well at high temperatures.
He probably meant infrared light, that would make more sense.
I have managed to get more than 2mA from a LED, a very high power density considering the very small size of the chip. Silicon semiconductors does not do very well in high temperature and they degrade much faster at elevated temperatures. Specially designed semiconductors can do very well at high temperatures.
Avalanche, did it take more power to run the fan than what you got out of the Peltier?I have seen people getting 10W out of single peltiers when used on wood stoves. There are still people that live places where it is not possible to get electricity and where it is not enough sunlight to use solar power. Wind power would work but a peltier is much cheaper when you only need to power a radio and charge some small batteries. If the peltier elements were cheap enough it should be possible to get 500W or more out of a wood stove.
Wouldnt it just be easier to boil water to turn to steam to run a generator?
Re: Power Generation Idea
Bjørn, Mon Nov 05 2007, 04:31PM
In theory a steam engine is far more efficient, it is not very hard to reach 50% efficiency even for a small one. You just can't buy one for $30 like a peltier, probably not even for $3000.
Bjørn, Mon Nov 05 2007, 04:31PM
Wouldnt it just be easier to boil water to turn to steam to run a generator?No, not on a small scale. Everything that has to do with water and steam is a huge pain to get working reliably and safely. On a small scale it would be a more expensive too. A large part of the reason is that there are no small small mass produced generators. Just try e-bay for a small steam engine and see what the prices are. And they are mostly not up to continious use.
In theory a steam engine is far more efficient, it is not very hard to reach 50% efficiency even for a small one. You just can't buy one for $30 like a peltier, probably not even for $3000.
Re: Power Generation Idea
Avalanche, Mon Nov 05 2007, 09:35PM
Don't rule out the peltiers yet, I was just demonstrating that it can work to generate usable power - but to make it worthwhile it would need to be a lot more thought out than my crappy attempt above. Like I said if I 'cooked' the peltier, I got a much larger output for the short duration that the large temperature differential could be maintained, but the fan couldn't keep up (eventually the output would drop to what it was before - similar overall temperature differential, but with the whole thing just 'hotter'. Hope this makes sense!
A better approach might have been for me to mount the thing sideways, so the hot air rising out of the lamp didn't directly heat the top heatsink! Also a much larger top heatsink would have helped.
Avalanche, Mon Nov 05 2007, 09:35PM
wrote ...
Crap, I kinda figured that it wasnt practical. Oh well, I guess theres always generators.
Crap, I kinda figured that it wasnt practical. Oh well, I guess theres always generators.
Don't rule out the peltiers yet, I was just demonstrating that it can work to generate usable power - but to make it worthwhile it would need to be a lot more thought out than my crappy attempt above. Like I said if I 'cooked' the peltier, I got a much larger output for the short duration that the large temperature differential could be maintained, but the fan couldn't keep up (eventually the output would drop to what it was before - similar overall temperature differential, but with the whole thing just 'hotter'. Hope this makes sense!
A better approach might have been for me to mount the thing sideways, so the hot air rising out of the lamp didn't directly heat the top heatsink! Also a much larger top heatsink would have helped.
Re: Power Generation Idea
Bjørn, Mon Nov 05 2007, 11:02PM
I mounted the peltier almost vertical with a small heatsink on the hot side and a large heatsink on the cold side. It worked fairly well. It is all about maintaining as large a temperature differential as possible.
It is a significant problem to regulate the temperature accurately. If it gets too hot the solder melts, not hot enough and the efficiency suffers badly.
Bjørn, Mon Nov 05 2007, 11:02PM
I mounted the peltier almost vertical with a small heatsink on the hot side and a large heatsink on the cold side. It worked fairly well. It is all about maintaining as large a temperature differential as possible.
It is a significant problem to regulate the temperature accurately. If it gets too hot the solder melts, not hot enough and the efficiency suffers badly.
Re: Power Generation Idea
Overclocked, Fri Nov 09 2007, 01:59AM
After looking on google using the right terms, seems Im not the only one who had the same idea..However, There was one article I came across that Solar cells would start to be used in the IR range, ie, heat.
Hmm, Technically, If I got a solar cell, and used red filim on it, I could <theoretically> generate power from heat. But from what Ive heard, solar cells dont like Too much Heat. Ive heard that they best perform at 70C (or was it 70F?)
Overclocked, Fri Nov 09 2007, 01:59AM
After looking on google using the right terms, seems Im not the only one who had the same idea..However, There was one article I came across that Solar cells would start to be used in the IR range, ie, heat.
Hmm, Technically, If I got a solar cell, and used red filim on it, I could <theoretically> generate power from heat. But from what Ive heard, solar cells dont like Too much Heat. Ive heard that they best perform at 70C (or was it 70F?)
Re: Power Generation Idea
Electroholic, Fri Nov 09 2007, 02:28AM
the colder the better, for every degree C increase, eff decreases by 0.5%. for silicon cells anyway.
Electroholic, Fri Nov 09 2007, 02:28AM
the colder the better, for every degree C increase, eff decreases by 0.5%. for silicon cells anyway.
Re: Power Generation Idea
marchse, Fri Jun 11 2010, 01:00PM
But even though solar power is a reliable one.. There has to be some source as a alternative one at night times.
Power Plant Development
marchse, Fri Jun 11 2010, 01:00PM
But even though solar power is a reliable one.. There has to be some source as a alternative one at night times.
Power Plant Development
Re: Power Generation Idea
IntraWinding, Fri Jun 11 2010, 02:25PM
Kerosene Radio
Made in Moscow for use in rural areas, this all-wave radio is reportedly powered by the kerosene lamp hanging above it. A group of thermocouples is heated internally to 570 degrees by the flame. Fins cool the outside to about 90 degrees. The temperature differential generates enough current to operate the low-drain reciever. Regular listeners may want fur lined union suits, though: it works best in a room with open windows
And scroll down about half way here
Kerosene Lamp Powers Radio
REMOTE areas of Siberia and China use thermoelectric generators like the one shown here to convert heat from a kerosene lamp into electricity for radios.
The 20-lb. device is being studied by scientists at the Martin Co., Baltimore, Md., where similar direct conversion principles have been applied to nuclear heat sources. They paid $56 for the Russian-built device.
A series of thermocouples is arranged around the upper portion of the lamp. As each set of elements is heated at one end by the lamp, a small amount of electricity flows through the pair. Metallic fins remove the excess heat.
IntraWinding, Fri Jun 11 2010, 02:25PM
Kerosene Radio
Made in Moscow for use in rural areas, this all-wave radio is reportedly powered by the kerosene lamp hanging above it. A group of thermocouples is heated internally to 570 degrees by the flame. Fins cool the outside to about 90 degrees. The temperature differential generates enough current to operate the low-drain reciever. Regular listeners may want fur lined union suits, though: it works best in a room with open windows
And scroll down about half way here
Kerosene Lamp Powers Radio
REMOTE areas of Siberia and China use thermoelectric generators like the one shown here to convert heat from a kerosene lamp into electricity for radios.
The 20-lb. device is being studied by scientists at the Martin Co., Baltimore, Md., where similar direct conversion principles have been applied to nuclear heat sources. They paid $56 for the Russian-built device.
A series of thermocouples is arranged around the upper portion of the lamp. As each set of elements is heated at one end by the lamp, a small amount of electricity flows through the pair. Metallic fins remove the excess heat.
Re: Power Generation Idea
radiotech, Fri Jun 11 2010, 03:43PM
You could make a rain powered generator. Small scale paddle wheel or cup wheels turning a series of small generators made out of permanent magnet DC motors-(battery powered hand tools are a good source.) Calculate how much energy is in falling rain over an area.
Also consider if you overhaul the load (reverse the shaft torque) in an AC washing machine motor) you can make your electricity meter slow down or actually turn in reverse (feed the grid). These generators are known as induction generators and are used in industry to recover energy in certain situations.
radiotech, Fri Jun 11 2010, 03:43PM
You could make a rain powered generator. Small scale paddle wheel or cup wheels turning a series of small generators made out of permanent magnet DC motors-(battery powered hand tools are a good source.) Calculate how much energy is in falling rain over an area.
Also consider if you overhaul the load (reverse the shaft torque) in an AC washing machine motor) you can make your electricity meter slow down or actually turn in reverse (feed the grid). These generators are known as induction generators and are used in industry to recover energy in certain situations.
Re: Power Generation Idea
Sulaiman, Fri Jun 11 2010, 05:35PM
For "green" energy I have two 5W solar panels that will probably never pay for themselves but on eBay there are relatively cheap individual cells that I calculated could pay for themselves in c3 years.
I use them to recharge or 'float charge' VRLA batteries for a transceiver that I'm building, it's just that amateur radio is independant of communications infrastructure so I want it independant of the power infrastructure too.
Bio-mass seems the next easiest, either to ferment to alcohol or dry and burn.
Small wind turbines look practical.
For peltiers etc. a Freznel lens or a concave mirror/reflector (old satellite dish?) would up the power per unit.
How about a small turbine on the house water system so every time you use water you get electricity ?
Sulaiman, Fri Jun 11 2010, 05:35PM
For "green" energy I have two 5W solar panels that will probably never pay for themselves but on eBay there are relatively cheap individual cells that I calculated could pay for themselves in c3 years.
I use them to recharge or 'float charge' VRLA batteries for a transceiver that I'm building, it's just that amateur radio is independant of communications infrastructure so I want it independant of the power infrastructure too.
Bio-mass seems the next easiest, either to ferment to alcohol or dry and burn.
Small wind turbines look practical.
For peltiers etc. a Freznel lens or a concave mirror/reflector (old satellite dish?) would up the power per unit.
How about a small turbine on the house water system so every time you use water you get electricity ?
Re: Power Generation Idea
Mattski, Sat Jun 12 2010, 06:38PM
One of the senior projects at my school this year was a thermoelectric generator. It was a big box with a fresnel lens focusing on a black absorber. Then absorber -> copper heat spreader -> thermoelectric device -> heat sink with fan.
The whole box was sun tracking, based on a lookup table of location and time of day. It would wake up every now and then for a quick reorienting. In full sunlight it supposedly produced about 2W above the power usage, since the reorienting circuitry spent most of its time asleep.
Mattski, Sat Jun 12 2010, 06:38PM
One of the senior projects at my school this year was a thermoelectric generator. It was a big box with a fresnel lens focusing on a black absorber. Then absorber -> copper heat spreader -> thermoelectric device -> heat sink with fan.
The whole box was sun tracking, based on a lookup table of location and time of day. It would wake up every now and then for a quick reorienting. In full sunlight it supposedly produced about 2W above the power usage, since the reorienting circuitry spent most of its time asleep.
Re: Power Generation Idea
Crunchy Frog, Sun Jun 13 2010, 09:55PM
This reminds me, I read a while back about satellites generating power by extending a long (like a few km) wire or loop of wire into space, but I can't find anything about it now because I can't remember what it's called.
Does anyone know what I'm talking about?
Crunchy Frog, Sun Jun 13 2010, 09:55PM
This reminds me, I read a while back about satellites generating power by extending a long (like a few km) wire or loop of wire into space, but I can't find anything about it now because I can't remember what it's called.
Does anyone know what I'm talking about?
Re: Power Generation Idea
Bjørn, Sun Jun 13 2010, 10:43PM
You will find it here:
Bjørn, Sun Jun 13 2010, 10:43PM
You will find it here:
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