Thermal Electric Elements? | Bitcointalksearch.org

hardcore-fs

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Quote from: Foxpup on December 02, 2012, 06:44:16 PM

Quote from: ?? on ??

Funny you should say that, body fat is a better carrier of energy than oil fuels. Long had a suspicion about the farm bill and the number of liposuction clinics...

Food is a better carrier of energy than the body fat it produces. You can save a lot of energy by cutting out the middleman, so to speak. (Of course, in The Matrix, the reason they were harvesting humans for energy was that pollution had blocked out the sun, so they couldn't use solar power. Which raises the question of how they were able to grow food to keep the humans alive in the first place. And any means of producing food artificially would consume more energy than you would get out of it. It's physically impossible. The whole central premise of the movie falls apart completely if you actually think about it for two seconds. Very disappointing, since most other movies take at least five seconds of thought before you realise they make no fucking sense.)

They were supposedly feeding the people on the 'liquified' remains of the people before.....(perpetual motion with energy growth built in), personally I feel the whole purpose of the film was for the jonas brothers to get cute chicks dressed up in S&M rubber gear, and somehow they just managed to fit a story line to that hobby.

Foxpup

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Quote from: ?? on ??

Funny you should say that, body fat is a better carrier of energy than oil fuels. Long had a suspicion about the farm bill and the number of liposuction clinics...

Food is a better carrier of energy than the body fat it produces. You can save a lot of energy by cutting out the middleman, so to speak. (Of course, in The Matrix, the reason they were harvesting humans for energy was that pollution had blocked out the sun, so they couldn't use solar power. Which raises the question of how they were able to grow food to keep the humans alive in the first place. And any means of producing food artificially would consume more energy than you would get out of it. It's physically impossible. The whole central premise of the movie falls apart completely if you actually think about it for two seconds. Very disappointing, since most other movies take at least five seconds of thought before you realise they make no fucking sense.)

MisterMe

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We need something like from the Matrix to create power to fuel our rigs. lol

firefop

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Quote from: ?? on ??

For something with erratic output like solar or wind it would make a lot of sense as you'll need a really big storage buffer to get output on demand plus you can reduce the capacity of your generator/elements to what you need at peak requirements instead of peak supply. That can be a big saving especially for wind as output rises exponentially with wind speed, a turbine that averages 2kw/h over the course of a year could potentially put out over 40 times that in gusty weather.

For situations like recovering heat from GPU's the heat output is more or less constant so there's no need for a large buffer if your trying to convert to electricity, the main thing limiting the output is the cost of the equipment due to exponentially diminishing returns the closer you get to ambient temperature, a heatsink at 20deg above ambient dissipates twice the energy of a heatsink 10deg above ambient which in turn dissipates twice the energy of one at 5deg over.

Yes, a hotter heatsink will dissipate more heat... because it's hotter...

The goal is to cool the chip... this means you move heat away from it... so you use a larger loop... for cooler block and better cooler of the cpu...

firefop

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Quote from: Foxpup on November 30, 2012, 07:13:11 AM

Quote from: Luno on November 30, 2012, 06:31:11 AM

I'm sorry Foxpup this sounds like flaming but you still don't get it: You can get useful power from waste heat from a processor without raising it's temperature:

1.; CPU/GPU 70 degrees / standard aluminium heat sink 40 degrees. air 20 degrees
2.; CPU/GPU 70 degrees / TEC hotside 70 cold side 40. makes power but have to have a larger aluminium heat sink than a processor without a TEC, as it provides thermal insulation.

Summary: If you remove 100w of heat power from a CPU to keep it at 70 degrees and there is more thermal resistance because of the power producing TEC, you just have to make the cold side either better, bigger or colder to remove the same amount of energy to maintain 70 degrees at the CPU. around 15 times as large a heat sink in this case.

I'm sorry, but I really don't get it. Huh

I'm agreeing with you. I never said it couldn't be done. I said it couldn't be done without a vastly improved cooling system, which isn't practical in most cases. Unless you think using a 15 times larger heat sink to get a measly 0.7 watts is practical (I don't).

I think the best approach to this idea is using multiple heat exchanges. Standard, water block to a large water system, then couple that to another liquid loop that's much smaller - using that to power the stirling. It's the same idea used for some solar hot water heaters, massive loop on the roof, tiny one that's used in a hot water tank as a heating element.

hardcore-fs

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Quote from: MrTeal on November 30, 2012, 02:07:21 PM

Quote from: Luno on November 29, 2012, 08:22:22 AM

Not right Foxpup, the power transmitted through the thermoelectric element can be enough to cool the gpu. 100W of heat conducted through a TEC will give you 0.7 watts of electric power: GPU 65 degrees centigrade. ambient 25 degrees. Enough to run a fan on the heat sink. Calculator here: http://www.powerchips.gi/technology/pcalc.shtml

To use 50$ on a TEC to save 0.7 watts of power is not worth your while still.

Good luck finding a fan/heatsink combo that will keep the cold side at 25C on 0.7W.

It's a myth anyway... you cannot fan cool below ambient, and IF your ambient IS below 25 then you don't really need a fan, just a correctly designed heat-sink.

DannyHamilton

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Quote from: ?? on ??

. . . you'd just have to make your coffee hotter Wink

Agreed.

DannyHamilton

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You could have picked a better time, bit hazy in here and google seems reluctant to give simple answers lately . . .

I didn't pick the time of your reply, you did. Wink

Quote from: ?? on ??

My charger says 0.55 amps max output at 5v so that's 2.75 watts so would need to run for just over 40 minuets to consume 6615 joules.

That's assuming a perfectly insulated coffee cup so the time would be shorter, maybe half an hour for a travel mug and 5 min for a glass mug, chargers are generally into the 90% efficiencies so not much lost there.

Quote from: ?? on ??

. . .you can pick one up on ebay for something like 50c that will run for about half an hour on the heat from a cup of coffee and put out enough power to put about a days worth of charge into a mobile phone . . .

I haven't double checked your math or assumptions yet, but...

Would the 5 minutes of charge that you are going to get at 2.75 watts will be enough "to put about a days worth of charge into a mobile phone"? Or the half hour? Or the 40 minutes? My phone usually takes longer than that to charge (and I rarely get a full day's use from a single charge).

Furthermore, your calculations assume that you use the full amount of energy from the mug (minus losses), 6615 joules, within the given timeframe. It seems to me that the heat won't move through the sterling engine that fast. As the heat moves through the engine, the thermal differential will drop further reducing the power output.

MrTeal

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Quote from: Luno on November 29, 2012, 08:22:22 AM

Not right Foxpup, the power transmitted through the thermoelectric element can be enough to cool the gpu. 100W of heat conducted through a TEC will give you 0.7 watts of electric power: GPU 65 degrees centigrade. ambient 25 degrees. Enough to run a fan on the heat sink. Calculator here: http://www.powerchips.gi/technology/pcalc.shtml

To use 50$ on a TEC to save 0.7 watts of power is not worth your while still.

Good luck finding a fan/heatsink combo that will keep the cold side at 25C on 0.7W.

DannyHamilton

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Quote from: ?? on ??

. . . the torque output and duration is sufficient . . .

Source?

DannyHamilton

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. . . you can pick one up on ebay for something like 50c that will run for about half an hour on the heat from a cup of coffee and put out enough power to put about a days worth of charge into a mobile phone . . .

*Dubious

Foxpup

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Quote from: Luno on November 30, 2012, 06:31:11 AM

I'm sorry Foxpup this sounds like flaming but you still don't get it: You can get useful power from waste heat from a processor without raising it's temperature:

1.; CPU/GPU 70 degrees / standard aluminium heat sink 40 degrees. air 20 degrees
2.; CPU/GPU 70 degrees / TEC hotside 70 cold side 40. makes power but have to have a larger aluminium heat sink than a processor without a TEC, as it provides thermal insulation.

Summary: If you remove 100w of heat power from a CPU to keep it at 70 degrees and there is more thermal resistance because of the power producing TEC, you just have to make the cold side either better, bigger or colder to remove the same amount of energy to maintain 70 degrees at the CPU. around 15 times as large a heat sink in this case.

I'm sorry, but I really don't get it. Huh

I'm agreeing with you. I never said it couldn't be done. I said it couldn't be done without a vastly improved cooling system, which isn't practical in most cases. Unless you think using a 15 times larger heat sink to get a measly 0.7 watts is practical (I don't).

Luno

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Quote from: Foxpup on November 29, 2012, 09:57:55 PM

Quote from: firefop on November 29, 2012, 09:32:06 PM

I've been thinking about developing a water cooling system that uses a stirling engine to cool the chip for a net gain. the only issue I see with it... is stirling engines make noise.

There's an even more obvious issue: cooling a chip and using it as a heat source for an engine (of any type) are mutually exclusive goals. If you have an effective cooling system, the chip won't get hot enough to provide enough energy to run it, as preventing the chip from getting hot is the whole point of having a cooling system in the first place. If it does get hot enough to produce a practical amount of energy, your cooling system is obviously not doing its job. It's most unlikely that any sort of heat engine will allow for more effective cooling than a simple heat sink; that's simply not what heat engines are designed to do. Like I said: possible, but almost certainly not practical.

I'm sorry Foxpup this sounds like flaming but you still don't get it: You can get useful power from waste heat from a processor without raising it's temperature:

1.; CPU/GPU 70 degrees / standard aluminium heat sink 40 degrees. air 20 degrees
2.; CPU/GPU 70 degrees / TEC hotside 70 cold side 40. makes power but have to have a larger aluminium heat sink than a processor without a TEC, as it provides thermal insulation.

Summary: If you remove 100w of heat power from a CPU to keep it at 70 degrees and there is more thermal resistance because of the power producing TEC, you just have to make the cold side either better, bigger or colder to remove the same amount of energy to maintain 70 degrees at the CPU. around 15 times as large a heat sink in this case.

Phone charging camp stove: http://www.biolitestove.com/campstove/camp-overview/features/

Tea light (ca 40W) drives a LED. As this is a standard Coke cooler TEC the temperature on the hot side is less than 70 degrees, or it would be destroyed:

hardcore-fs

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Quote from: firefop on November 29, 2012, 09:32:06 PM

Quote from: Foxpup on November 29, 2012, 08:46:35 PM

Quote from: hardcore-fs on November 29, 2012, 08:12:00 PM

Wow a workable perpetual motion machine......

No, it's just a heat engine. Heat engines produce energy by transferring heat from a heat source to a heat sink. In the absence of an external energy source, this will eventually result in the heat source and heat sink reaching thermal equillibrium (ie, the heat source gets cooler and the heat sink gets hotter until they're both the same temperature), at which point no further heat transfer can take place and no more energy can be produced. To continue producing energy, you need to either actively heat the heat source or refrigerate the heat sink, both of which require you to put in more energy than you can get out.

Heat engines can be useful for recovering energy which would otherwise be lost as waste heat, but can never produce more energy than you were wasting as heat in the first place (and in practice, they don't even come close to that).

google: stirling engine.

I've been thinking about developing a water cooling system that uses a stirling engine to cool the chip for a net gain. the only issue I see with it... is stirling engines make noise.

Some people need too develop a better sense of humour. (The only reason a photographic memory is useful)

http://dilbert.com/strips/comic/1993-10-10/

Foxpup

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Quote from: firefop on November 29, 2012, 09:32:06 PM

I've been thinking about developing a water cooling system that uses a stirling engine to cool the chip for a net gain. the only issue I see with it... is stirling engines make noise.

There's an even more obvious issue: cooling a chip and using it as a heat source for an engine (of any type) are mutually exclusive goals. If you have an effective cooling system, the chip won't get hot enough to provide enough energy to run it, as preventing the chip from getting hot is the whole point of having a cooling system in the first place. If it does get hot enough to produce a practical amount of energy, your cooling system is obviously not doing its job. It's most unlikely that any sort of heat engine will allow for more effective cooling than a simple heat sink; that's simply not what heat engines are designed to do. Like I said: possible, but almost certainly not practical.

firefop

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Quote from: Foxpup on November 29, 2012, 08:46:35 PM

Quote from: hardcore-fs on November 29, 2012, 08:12:00 PM

Wow a workable perpetual motion machine......

No, it's just a heat engine. Heat engines produce energy by transferring heat from a heat source to a heat sink. In the absence of an external energy source, this will eventually result in the heat source and heat sink reaching thermal equillibrium (ie, the heat source gets cooler and the heat sink gets hotter until they're both the same temperature), at which point no further heat transfer can take place and no more energy can be produced. To continue producing energy, you need to either actively heat the heat source or refrigerate the heat sink, both of which require you to put in more energy than you can get out.

Heat engines can be useful for recovering energy which would otherwise be lost as waste heat, but can never produce more energy than you were wasting as heat in the first place (and in practice, they don't even come close to that).

google: stirling engine.

I've been thinking about developing a water cooling system that uses a stirling engine to cool the chip for a net gain. the only issue I see with it... is stirling engines make noise.

Foxpup

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Quote from: hardcore-fs on November 29, 2012, 08:12:00 PM

Wow a workable perpetual motion machine......

No, it's just a heat engine. Heat engines produce energy by transferring heat from a heat source to a heat sink. In the absence of an external energy source, this will eventually result in the heat source and heat sink reaching thermal equillibrium (ie, the heat source gets cooler and the heat sink gets hotter until they're both the same temperature), at which point no further heat transfer can take place and no more energy can be produced. To continue producing energy, you need to either actively heat the heat source or refrigerate the heat sink, both of which require you to put in more energy than you can get out.

Heat engines can be useful for recovering energy which would otherwise be lost as waste heat, but can never produce more energy than you were wasting as heat in the first place (and in practice, they don't even come close to that).

hardcore-fs

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Wow a workable perpetual motion machine......

MoonShadow

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Those things are terriblely inefficient, couldn't make enough to justify their cost in this scenario. Better to just use the waste heat to offset building heat needs in winter.

Foxpup

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Quote from: Luno on November 29, 2012, 08:22:22 AM

Not right Foxpup, the power transmitted through the thermoelectric element can be enough to cool the gpu. 100W of heat conducted through a TEC will give you 0.7 watts of electric power: GPU 65 degrees centigrade. ambient 25 degrees. Enough to run a fan on the heat sink. Calculator here: http://www.powerchips.gi/technology/pcalc.shtml

To use 50$ on a TEC to save 0.7 watts of power is not worth your while still.

I never said it wasn't possible. I said it was less effective and more expensive than conventional cooling, and that the chip absolutely has to be cooled by something other than the heat sink. It's not impossible, just very impractical.

Topic: Thermal Electric Elements? (Read 1645 times)