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New Thermocell Could Turn 'Waste Heat' Into Electricity
dryriver sends this quote from Phys.org:
"Harvesting waste heat from power stations and even vehicle exhaust pipes could soon provide a valuable supply of electricity. A small team of Monash University researchers ... has developed an ionic liquid-based thermocell (abstract). Thermocell technology is based on harnessing the thermal energy from the difference in temperature between two surfaces and converting that energy into electricity. The new thermocell could be used to generate electricity from low grade steam in coal fired power stations at temperatures around 130C. This would be implemented by having the steam pass over the outer surface of the hot electrode to keep it hot while the other electrode is air or water cooled."
What went around comes around !!
How do you keep the other side of the item cool? The waste heat goes somewhere?
Have you compiled your kernel today??
How do they plan on keeping the air or water cool? Sounds like a net energy loss.
Greatest source of hot air in the country. Expected to solve the energy crisis.
We already suffer a glut of energy, but I suppose this might serve as a nice little accessory for your backyard distillery...
“He’s not deformed, he’s just drunk!”
The idea to use the Seebek effect and generate power from temperature differentials is centuries old, the only problem is it's very low efficiency in the 10 % range. A gas turbine can achieve 50% efficiency, while a nuclear reactor steam turbine is about 33% efficient, heat to electrical. So an efficient method to directly extract electricity at high efficiency would revolutionize power generation.
Did Congress repeal the Laws of Thermodynamics?
I would love to see how this would work on a nuclear power plant. Since they seem to put out alot of steam this should provide a sizeable increase in power output. And the best, cleanest source of energy we have, would get even better.
This sort of thing is nothing new. They might have a new way of doing it. Funny how the efficiency is not mentioned.
Harvesting waste heat from power stations and even vehicle exhaust pipes could soon provide a valuable supply of electricity.
Value is relative. $1 says the value of the electricity produced doesn't come close to what is needed to produce the widget. I'm guessing here, of course, because TFA doesn't say how much electricity it can produce.
PhD student Theodore Abraham said that by using heat already produced in industrial processes that would otherwise be untapped, the thermocell is an attractive method of relieving some of the present reliance on fossil fuels.
See above, cf. the well-known phrase "pissing in the sea".
"We have found that it can work at elevated temperatures typical of important heat sources, as opposed to water-based systems, which cannot operate at temperatures above 100 degrees Celsius," Professor MacFarlane said.
This was either written by one of that new breed of marketeers that infest educational institutes or the good professor has never heard of superheated steam. Please, God, let it be the first one.
"The major benefit of a thermocell is that it harnesses energy that is already readily out there; you're just harnessing energy that is otherwise lost to surroundings," Mr Abraham said.
Mr Abraham was supervised by Dr Jenny Pringle of Deakin University who said the development was a significant achievement for a PhD student.
Maybe where he works. The last place I worked that had steam plant used the waste heat to... heat the buildings and provide hot water. Still, it is an impressive achievement for a student. It's just a shame that the article was so over-inflated.
tl;dr It's a novel variation on the classic thermoelectric generator, but neither the article nor the abstract say how well it works.
The electricity issue is not a generation issue. We have enough technology to produce more electricity that we need. The problems we have are transmission , storage, and reliability. While we can produce much more energy than we need the challenge is to store it for when we need it, transmit it to where we need it and to be sure that it will not fail. For example, solar farms in the Sahara desert could power all of Europe. The issue is transmitting that power to Northern Europe and storing enough power to last the night. While Some HVDC line are being installed it is not enough to get that power to Germany and north.
Thermoelectric power has been around for a long time. There is, literally, nothing new about this. The efficiency is still not high enough to make it worthwhile for any sense of scale. They are better off using waste heat the way they currently do, to heat up the incoming cold fluids that get turned to steam through heat exchangers.
On cars, you do not get enough power out of the current materials to make it worthwhile.
The press release: ""The device offers the possibility of a cheap and flexible design suitable for harvesting waste heat in the 100- to 200-degrees Celsius range."
The abstract: "Power densities reached >0.5 W*m-2 in unoptimized devices, operating with a 130 C hot side."
For half a watt per square meter had better be incredibly cheap and flexible considering wind and solarare about 4 and 10 times more dense, respectively, on a real-world basis. Nevermind that gains in optimization must be offset by losses in building a system which can pass cooling water over a large surface area and delivering the cooling water to it.
How different is this from existing Peltiers? Peltiers were all the rage back in the Celeron 300A days, but the amperage output is minimal at best.
moox. for a new generation.
We've had the ability to turn waste heat into electricity for decades. From complex like the stirling engine. To simple like the thermocouple.
We're not going to do it. Why? MONEY!
World is run by cheap greedy fucks. And these solutions all cost money to implement. You know what doesn't cost money (right now)? Dumping the waste heat to the air.
i guess you hold a bunch of patents for this technology already?
welcome to hindsight
Are the units on that graph right? 15,000 gigawatts sounds high for renewable energy generated in just the northeast...
i guess you hold a bunch of patents for this technology already?
welcome to hindsight
Hindsite?!?
Of course! Patent beans to energy after they've been used for food!
A feeling of having made the same mistake before: Deja Foobar
How about placing ionic liquid-based thermocells on a home roof? Then wire the output to the "Electricity Grid?"
I just wish I could write a Grant for this. It sounds like a "cool" project.
This Technology: 0.5W per square meter
Solar Irradiance on Earth: 1361W per square meter
I imagine the idea is that you have a profitable process that generates waste heat. If this becomes cheap enough, it'd be a way to make a few more nickles on what you already have.
Oh please. With such lop sided support for the notion we might already have enough carbon in the air,why not apply this to low-grade heat differentials in
* oceans
* buildings in sunny places like the parched SW US states
* my freakin' roof [and that is in upstate NY]
but first, please headline the INSTALLED $/Watt. we can take it from there...or not.
or did some coal company pay for this finding?
SLASHDOT: news for people who can't concentrate on work or have no life at all and got tired of yelling back at the TV.
If only it could be used to cool off a CPU and generate a bit of excess energy to power misc. devices.
Without going too deep into a lesson on thermodynamics, there is not going to be much chance that this works in a modern power station.
Let me put it this way. Current power stations are already engineered to be as efficient as possible. This generally means they are keeping the phase translations of the working liquid using the minimum temperature differentials possible to avoid entropy loss over the ideal Carnot cycle. Any thermally driven power producing device put in series with the heat exchangers is not likely to capture any more power than will be lost by the increased temperature differential required by the device. If this wasn't true, why don't we just attach a boat load of sterling heat engines (http://en.wikipedia.org/wiki/Stirling_engine) to do the same thing? Reason: It wreaks the efficiency of the power plant by making the temperature differentials higher.. Chances are this new idea has the same problem.
Now, on your car, or other internal combustion engines, there *might* be some application, but I don't think there will be enough power output to make up for the weight increase. There is a HUGE amount of waste heat from your car engine but the question is how efficiently can we capture that and make useful energy out of it? Answer: Not very... Worth looking at because of the amount of heat being just dumped and the high differential temperatures but not likely to be much gain overall.
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
So glad scientists are finding ways we can make more effective use of coal. Because, for my money, we can never burn enough coal. Mmm, coal - nothing better!
Hell, I've been using a thermocell when hunting and camping.
http://www.thermacell.com/mosquito-repellent
Extracting usable work energy from waste heat has always been possible. The problem isn't making the heat do work. The problem is doing so cost-effectively. For most applications, these heat capture devices have such low power densities that it's counterproductive to add them (e.g. adding a stirling engine to your ICE car's exhaust system would burn more fuel due to the extra weight than the fuel savings you'd get from putting the heat energy to work). At that point, it's not worth implementing compared to just dumping the heat straight into a heat sink.
The abstract says they're getting power densities of 0.5 Watts/m^2 in an unoptimized device. That's pretty deep in "not worth it" territory. This device would have to have an area of 1,5000 square meters exposed to the car's exhaust gases just to generate 1 extra hp. I suspect the additional back-pressure alone from all that piping (never mind the weight) would cost the engine a lot more than 1 hp of generation capacity.
Right. What we have here is another crap materials science article. Somebody did something vaguely interesting at lab scale, and then issued a bullshit press release.
Trying to get the last remnants of recoverable energy out of a heat engine is an old game, going back to the reciprocating engine era. Basic steam engines had one cylinder running off boiler pressure. Double-expansion steam engines had a second cylinder running off the output of the first. The second cylinder is bigger and runs at lower pressure. Triple expansion steam engines had a third, even bigger cylinder. Some quadruple expansion engines were built, but this is a diminishing-returns thing, and triple expansion is about as far as it's worth going economically. Marine engines were often triple-expansion.
Large steam turbines do the same thing, with a succession of rotors of increasing size. Three to twelve stages have been used. Again, this is a diminishing returns thing. At some point the steam condenses to water, which you don't want to happen inside the turbine. Existing turbines get close to that limit. Some turbine plants have a partial vacuum going into the condenser to keep the steam as a gas below 100C. 90C exit temperatures are not uncommon. Almost all of the usable energy has been extracted with an exit temperature like that.
If this new thermoelectric thing is a better way to convert heat to electricity than a steam turbine, it should replace steam turbines, not just be used on the cold end of the system. An efficient solid-state way of converting heat to electrical energy would be valuable. All the existing thermoelectric devices have low efficiency compared to heat engines. Back around 2011, there were several startups getting Federal grants for R&D into "heat harvesting". Commercial products were supposed to appear in 2012. Didn't happen.
Operating at 130 deg on the hot side it produces 0.5 W/m^2. If we wreap a 3 feet by 3 feet section of it around the exhaust pipe, it would give us 0.5 Watts. I am not sure, even the old thermocouples might generate this kind of power.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Like all other science threads on any site where neckbeard dicks congregate:
"This will never work because I watch Mythbusters and I know more about science than any inventor."
Thank you.
I would love it if this comes to fruition; but I am sick of the breathless articles showing us the future without actually showing us anything. CANCER CURED! headlines that later are shown to only be in one mouse which later exploded. ITER would be a great example. The other day I read a headline about a Fusion Breakthrough; basically they had laid a brick or two at the ITER project (literally this was the headline and real story). I am still interested in the above story but I wish they would moderate the story a bit. Minimally I want to see the thing hooked up to a car exhaust generating a useful amount of power (say running an air conditioner).
A few months back I read a great article about a battery breakthrough. Then they had this postage stamp sized thing powering a LED. I can power a LED with a slice of lemon. Power up an iPhone and you've got my attention. Power a car and you've got the world's attention.
Commercial fossil power stations already drive their stack gas temperature about as low as practical via various heat capture methods, reheat systems, etc. The limiting factor generally is not recovering more energy from stack gasses but the desire to never drive the stack gas temperature below the dew point in that exhaust gas, doing so causes all sorts of negative chemical consequences for the stack itself, pollution control equipment, etc., increasing maintenance cost and reducing equipment life due to aggressive corrosion of stack components and structure. Plants I operated were strictly kept from dropping below dewpoint on the exhaust for this reason, not to mention temperature input constraints for effective operation of some pollution control equipment, you CAN recover more energy from stack gasses, but doing so hits a cost negative and reliability wall. Always remember that waste heat/energy for a utility station equates to large $$$, if there's a practical way to extract more energy from a given amount of fuel, they are likely there as quickly as they can implement it. But the carnot cycle and other less heat cycle related limitation put up a pretty tough barrier to going further, Perhaps this is useful for more "pure" exhaust gas or waste heat streams, but I don't see it happening for commercial fossil power stations
I remember a 70s (probably popular science) article about using low grade waste heat to increase efficiency. In principle it works. bit the efficiency (Carnot limit) is very low, and the power density is low. In most places where waste heat is usable it is already in use (large power plants for example). It is often better to just use the heat for non power-generation applications (like heating buildings).
In a sense the 1800s idea of the "triple expansion" steam engine was to use the waste heat from the first stage.
A few years ago I read about someone intending to capture residual energy from steam that had already driven one turbine and cooled to around 130 Celsius, by using it to heat another liquid that boiled at a much lower temperature so that it could drive a second turbine (and then the condensed water could feed back into the original loop). Is this not going anywhere?
From the article: "The top performing redox electrolyte (..) yielded output powers of 522 mW per square meter."
Seems that to get the 1 GW power of a nuclear reactor, one would need the active surface of a square of 43 kilometer side coated with that Cobalt stuff.