Electricity from Heat: The Seebeck Effect in Action
ฝัง
- เผยแพร่เมื่อ 19 พ.ค. 2024
- Generating electricity from heat without any moving parts sounds like science fiction - yet it's possible! Traditionally, the heat to electricity conversion is done with things like steam turbines and other mechanical systems. But by applying the Seebeck effect, we can directly convert a temperature difference to electricity. In this video, we go over what the Seebeck effect is, how it can be used, and then demonstrate using it to power a small circuit.
Sections:
0:00 - Introduction
0:11 - Electrici-tea generation
1:03 - Seebeck effect explained
2:03 - Thermoelectric generators
2:48 - The importance of heatsinks
3:20 - Demo: Circuit overview
3:54 - Demo: Assembly
5:54 - Demo: Trying it out
7:12 - Discussion on real-world uses
7:59 - Conclusion
Parts:
LED - LTL2R3KRD-EM
TEC - Hebei TEC1-12706
Context:
I made this video to explain the Seebeck effect to students in the 6-8th grades (US grading system). As a result, some terms have been simplified based on the expected prior knowledge of the students. For example, "heat" in physics refers specifically to energy in transfer, but in the presentation, it is used in the more colloquial sense.
This video was shown at the 2020 Virtual Cool Science Festival. Learn more at www.coolscience.org/cool-scie....
Special thanks to Keysight Technologies for loaning the oscilloscope used in this video! The views I express and materials included in the video are my own and not those of Keysight.
Other Credits:
Lighter_sparks_and_flame.jpg: Hustvedt derivative work: Octave.H, CC BY-SA 3.0, via Wikimedia Commons
Cricket Lighter isolated: Anton Zelenov , CC BY-SA 3.0, via Wikimedia Commons
Thanks! I WAS NOT ABLE TO UNDERSTAND
BUT YOU MADE ME UNDERSTAND IN A VERY SIMPLE WAY 😀
Very neat tutorial. Now this Seebeck effect got my brain fired up. Just need to think of heat and cold... to make more electricity. Thank you!
Thank you, I had an assignment regarding thermoelectric generators and your video helped me a lot. I also cited your video in the references.
Thanks for sharing, nice set up and presentation ❤
Very nice explanation, simple, linear, clear: well done! Would you add some figures, like what is the efficiency of this system, how many millivolt per centigrade difference?
thank you for this video, now i can finally wrap my head around how TEG works!
Now, that was nice! Thanks for the clear explanation!
Great video. Beautifully explained.
wonderful video. i appreciate you going all out for this.
Thank you. I now understand the meaning of life. Very well done 👍
Important .... clear explanation.thank you❤️👍
Great explanation and demo.
Thanks for giving very useful info.
Very informative video! Thank you!
Great and neat and helpful!! thank you very much
very nice demonstration and fun video...thanks
didn't realize they could power the whole spacecraft, how cool
I just want a massive one on my furnace, fireplace, stove, or etc....I wonder what the potential max output could be with current tech...
Perfect explanation.
thanks for sharing, im investigating as well!
Wonderful video, well done. Subscribed.
Nice exp and explained. Wow. Thanks
great video mate well done
great demo subbed
Nice video. I was thinking of solar pv with t. If the amount of volts can be increased by the thermal hot water running in hotwater pipe then a slim TEG lengthways running parallel to pipe could increase the voltage in the day and even create voltage in the night.
this is super cool, thanks
Nice Video Thanks Bro - From Sri Lanka
Lovely video!
thank you, today i understand why my project don't work back 10 years ago 😂
Great vid. I have a 1/4 scale steam locomotive and I’d like to power an LED headlamp from waste heat in the smoke box and its very tall chimney. I could mount a heatsink facing the direction of travel ie in cool air compared to the smoke box temp. The smoke box wrapper and it’s chimney get very hot. To picture the loco: it is very similar in design and construction to an Orenstein and Koppel 40hp model, but scaled down to run on 184.1mm gauge track.
Any thoughts?
Caleb.. THIS IS LITERALLY what I was looking for.
The Planet Venus will provide unlimited energy to our Vehicles and underground bases.
👁️👃👁️🙏
This man has balls for cutting wires so easily like that
your video was amazing
Video yang sangat mengedukasi dan nyata. Bukan palsu
They are most used as TEGs in stove fans and as TECs in (very small room) dehumidifiers and all sorts of inefficient car bottle coolers
Great video... 2 things :
1) I'm missing how current flows threw the TEG
2) It's unfortunate that the Seebek Effect is unminded by using a Pelltier device (TEC in reverse)
The net effect of heating one side is the accumulation of electrons on one end of the device and the formation of two weak electric fields that both want to accelerate electrons in the same direction when connected correctly in series (see polarity at 2:03). When a circuit is completed between the two terminals of the TEG through some external device, excess electrons can flow from the negative terminal to the positive terminal where they cancel out with the "holes" or absences of electrons that have accumulated on the positive terminal. As long as the far side of the positive terminal is still heated, this cancelling disrupts the equilibrium meaning more "holes" will drift towards the positive terminal due to the heat releasing more electrons to flow through the conductor connecting the two semiconductors and into the hot end of the n-type semiconductor. Of course, the n-type semi conductor is also repelling electrons from the hot end, so these electrons are also forced back to the negative terminal and the cycle starts again. Some key things to keep in mind is that this all happens essentially simultaneously as the electrical field propagates through the system, and that the temperature difference needs to be present to maintain the power generation since the movement of electrons from one to the other happens by the heat exciting the electrons until they move into the conduction band, and then they move away taking the energy with them (and effectively cooling the hot side a little bit, hence why the Seebeck and Peltier effects go hand in hand). If the two sides end up the same temperature, even though they may be excited, the net charge on both ends are the same so there is no net electric field, and hence no net electron drift.
And yeah, Seebek is definitely not as much of a household name since the typical device is named a Peltier module or in other contexts simply a TEG/TEC.
loved the video and the explanations...thank you
Can you make a closed circuit using a magnet gun and diodes as a current electric booster using a battery to ignite the current in circles with a coil around a cylindrical metal to create a perpetual current motion that uses a led to replace the battery in the same coil that consumes less energy we applied to ignite the current or that won't work?
great vid bud
Also... This could be a good idea to use against anything that looses heat during its primary function e.g. motors, lamps (put them on lamp shades) etc
ICE exhaust pipes
What a good idea!
well done
Very good
What is 10 how many volts each one produces or how many watts so I can put a bigger electric motor on stove fan for instance how many would I need for a 12 volt motor
what if you connect a battery to charge the heat plate or what not, and have one that one charge another batter using the excess energy from the first battery? then wouldn't that be unlimited heat, plus indefinite battery power?
Awesome
very interesting! how would a graph showing the temperature on x-axis and voltage on y-axis look? would it be linear?
The relationship between the temperature *difference* and the open circuit voltage is indeed linear over it's normal operating range, where the coefficient of proportionality is known as the Seebeck coefficient.
thanks for the information. do you know how many poles inside one peltier? thanks again
I'm not sure what you mean by how many poles, but if you mean the number of peltier couples in series in the device that's usually specified by the first part of the part number. So for example, a TEC1-12703 has 1 layer (TEC1) of 127 couples (127) with a nominal max current rating of 3 amps (03).
Many tropical countries have hot air flowing in winter n summers. Thinking how to use this hot air to generate electricity.
Thanks
I have some questions which are related to 2 Peltier cells in contact. (QUICKLY PLS)
1.What happens when we keep both heat sides of 2 Peltier cells in contact?
2. Will there be any reaction when we keep the heat sides of both Peltier cells in contact and the model surrounded by water? The heat sides will act as a core of the Earth and the cool sides surrounded by water as crust of the Earth.
3. Can we change the heat energy into force, so that the 2 forces exerted by both Peltier cells are equal(balanced force) and they can cancel out each other which leads to no reaction?
4. How much volt can this Peltier cell produce and which volt battery is needed to store the produce? Which volt Peltier cell are u using?
5. In order to store the electricity produced, should we use any resistors or other electric components in-between the circuit?
1. The "hot" and "cold" sides are just terms that establish the polarity of the device. If you put the heat source on the hot side, and a cold source or heatsink on the cold size, then the voltage generated would be positive (red lead at a higher potential than the black lead). If you reverse it, then the they would switch. So putting two "hot" sides together doesn't really do anything here.
2. No, nothing would happen in this case. The two sides of the Peltier must be at different temperatures to be able to generate electricity. Rembember, the Seebeck effect requires a temperature *difference* to generate electricity. If the whole thing was immersed in water that is all the same temperature, then no electricity would be generated.
3. I'm not really sure what you are saying here, but to convert heat into a physical force, you could use something like a bimetallic strip. These are sometimes used as thermal switches to turn stuff off when it gets hot. However, the force generated in this case is pretty minimal.
4. For any electricity generation, there is an I-V curve that specified the current that can be supplied over the operating range of voltages. Volts alone is generally meaningless as it's a function of the load current as well. For example, in the hot water case with the full array the scope shows 3 volts when providing 2.55mA of current, so that's about 1.9mW of power per TEG. But again, this isn't the maximum power point, just one that I picked since it's adequate for this demonstration. The maximum volts rating for Peltiers isn't really what you should be looking at, since that assumes the device is being used for cooling purposes, and it's the maximum that it can safely tolerate. You would have to do your own I-V curves for each device under the temperature difference that you expect to operate it under to be able to determine the maximum power point for each device. The peltiers used here are TEC1-12706 from Hebei. For storage in a battery, you would likely need to design a charge controller, and you could use whatever battery you want pretty much.
5. Here I'm using a capacitor for a small amount of energy storage. If you were truly using this in an energy harvesting capability, you would want to design a maximum power point tracking circuit that can adjust the load impedance seen by the Peltier to get the maximum power transfer. Resistors burn (waste) electricity, they don't store it. The resistor in this circuit is used to help limit the current through the LED so it doesn't burn out.
@@funtechu Thx a lot!!!
Can we use TEC Peltier cell to generate electricity and cool surroundings simultaneously?
5:35 it looks like you should clean that heatsink off a tad, and lay something on top of the TEG to apply pressure.
Could you explain how a thermocouple creates electricity, say to power a solenoid in a heater? So when a thermocouple is heated, some electrons move to the fixed or cold side of both metals, and the one that has more electrons creates pressure or voltage. But do the electrons flow from one metal to the different metal to create a circuit? Thanks
First to answer the part about the use of thermocouples in things like gas stoves, furnaces, and so on. In these cases, a thermocouple is placed in or near the pilot light so that a solenoid can turn off the gas if the pilot light goes out to prevent a gas leak and large amounts of gas buildup which could cause an explosive hazard. These thermocouples use two pieces of metal that are different and where the voltage drop across the connection between the two of them is known to be closely (and ideally linearly) related to the temperature. The voltage is small (typically only a few millivolts), and they are either paired with a solenoid that can stay open when powered with such a tiny voltage, or in more fancy systems there may be a small circuit that uses the tiny voltage to power a relay that then allows a much larger voltage through to hold the solenoid open. Here is an excellent demonstration of a thermocouple in action with a direct-drive solenoid rated for 30mV th-cam.com/video/7m5ZDvOoVwU/w-d-xo.html
For the more broad explanation of why this works, the explanation in this video at 1:03 is oversimplified because it was prepared for Middle School students, but the fundamentals are there. When a semiconductor is heated at one end, the extra thermal energy results in the dominant charge carrier migrating away from that end because there is enough energy for it to jump into the conduction band, and then the charge carriers repel each other, resulting in a concentration of the charge carrier at the other end. For an N-type semiconductor these are electrons, so the heated end become more positive because electrons are being repelled towards the colder end. For a P-type semiconductor these are holes migrating which in effect just means that electrons get accelerated in the opposite direction. This same effect happens when two different types of metals are connected as well since the conduction bands of metals is slightly different for each material.
This build up creates a potential difference, but it doesn't become a circuit until you connect it into a loop so there is some path for the potentially to go. (it's in the name - circuit means a circular loop or route). So if you connect the two hot ends together and the two cold ends together, there is now a path for the excess of electrons on the N-type cold end to get to the excess holes on the P-type cold end, and similarly for the extra electrons on the P-type hot end (signaled by a reduction in the number of holes) to get to the electron-starved side of the N-type hot end. Keep in mind that as electrons absorb energy from heat and jump into a conduction band and move away, they carry that energy away cooling it in-proportion. This is how the peltier effect works which is the inverse of the seebeck effect, and basically shows how you can pump heat by applying a current to a similar thermoelectric setup. Note that while it might be easy to think of these things as happening in some set of causal order (heat up N side, electrons pushed to cold N side, electrons return to cold P side drawing more holes to that end, releasing more electrons from the hot P side which then return to the N side replenishing it), the reality is that all the effects happen essentially simultaneously like how in a gearbox all the gears turn simultaneously, and they are inextricably linked so that effects on one of the gears directly impact the others. Also keep in mind that electron traversal is really slow, so what is actually moving are the EM fields induced by the imbalance of electrons and those propagate at the speed of light. If you want to understand the physics behind it further, and the mathematical equations for modelling the effect, I recommend checking out Fundamentals of Thermoelectricity by Kamran Behnia.
Anyway, bit of a long response, but hopefully this helps
One other think I forgot to mention, many of the self-powered thermocouples that you will see in furnaces and the like are actually a whole bunch of thermocouples connected together in series (called a thermopile). This increases the voltage (placing items in series adds the voltage) to bring the overall voltage up to a level that is high enough that it can directly power a solenoid.
Here is a video showing the visual difference: th-cam.com/video/--nI0u_k9kc/w-d-xo.html
Here is a video I found of someone cutting open a thermopile so you can see inside: th-cam.com/video/DrRSydm0QjY/w-d-xo.html
Just thinking how to use suns magnified rays to make this work. If other ends of conductors are submerged in thermo-resistant substance, I can't see why that wouldn't work
Question - it’s winter here now, and from my understanding, the ground at 6 feet deep should be a constant 10 degrees C or so while the surface temperature is below freezing. In theory, with one side at the surface and one 6 or more feet deep, wouldn’t this generate electricity with this type of setup?
So there are several aspects of this question that are fairly limiting. The ground below a certain depth isn't "magically" at some constant temperature, rather depending on how insulating the soil it, it may stay above freezing during the winter (look up information on "frost line"). However, by putting some device that is conducting the heat away from the ground out to the surface, it would likely pretty quickly equalize, so the energy generated would be negligible. Since soil isn't particularly conductive, this means that it wouldn't be able to replenish the lost heat fast enough. It's best to think of the ground not as some infinite source of heat, but rather as a large thermal mass. That mass will either heat up due to the sun, or in rare areas with geothermal activity, due to geothermal heat (but in that case there is already a much more efficient source of energy available). Similarly, since the thermal difference between the ground temperature and the air temperature is small (say only in the 10-20 degree celcius range), then the energy generaged by a TEG would be small as well. Especially because getting that thermal difference to the TEG over a distance of several feet would mean losing most of that temperature difference along the way due to the thermal resistance of whatever material is used to conduct the heat.
So the simple answer is, yes it could theoretically be used to generate a small amount of power, however due to limitations it probably wouldn't be worth it. Throwing up a single small solar panel, or wind turbine would probably be far less expensive to generate an equivalent amount of energy.
@@funtechu ah, cool, thanks for the reply!
excellent video love u
question, what is the background sound of your video?
It's "Professor Umlaut" by Kevin MacLeod: th-cam.com/video/Oel6rxdIQag/w-d-xo.html
How about using multiple sources like fresnel lens/parabolic mirrors to heat up one side that has a super conductive surface to transfer the heat evenly over the vast layers of peltier services... and utilizing cryogenic devices that create liquid nitrogen/oxygen to super cool everything on another layer of conductive piping (so you can heat and cool the homes in the general area, reduce energy usage to heat the waters, reduce a/c usage, create better preserving of food we have (which they are deliberately destroying), plus the other avenues you can use it for.
Why are those pads kept between the sick and hot water .
Please Reply !
Are you referring to the thin grey pads that are between the TEG and the surface that it is in contact with? Those are thermally conductive pads and help ensure that heat energy can flow between the two surfaces, they function similar to thermal paste, but are a little easier to clean up (and have slightly poorer performance).
May I ask why do you use multiple TEG's? How much voltage does 1 TEG have? Thank you!
As mentioned in the video, the reason to use multiple in series is to increase the voltage across the load. This is because the voltage is dependent on the temperature difference between the two sides, so to get it high enough that an LED could turn on, they needed to be combined in series (where voltages add). This video is a simplified example that was produced for elementary and middle school students, and doesn't represent how you would actually use a TEG for energy harvesting. Instead you would use an energy harvesting circuit that can dynamically match the output impedance presented to the TEG array for maximum power transfer (remember, power = volts * amps). You can see the voltages produced by the temperature difference of my hand to room temperature at 6:04. The oscilloscope is showing units of 500mV per grid line, so under those operating conditions, and assuming the led is just barely turning on (1.6V forward voltage) that is a current of (2-1.6)/470 = 851µA, with a voltage of 500mV per TEG.
You can learn more about maximum power transfer here: en.wikipedia.org/wiki/Maximum_power_transfer_theorem
Just keep in mind that for the purposes of this demonstration I was not trying to maximize power transfer, I was merely trying to find an operating point that would work for the purposes of this demonstration. It is unlikely that I picked the most efficient operating point.
@@funtechu Ohh this is wonderful. Thanks for the information!
Also, may I know what is the formula for the output voltage of the TEG? Thanks!
@@meldalumpines2138 There it's no direct formula since it varies by the TEG. Some TEGs will have a graph in the datasheet that shows the approximate performance, but you generally need to characterize a given device on your own.
@@funtechu Okaaay. Now I understand. Thank you so much!
Nice
5:05 Holy OVERKILL!!!
👍
Great
i've seen that some people do this with 2 heat sinks, 1 with cold water and 1 with hot water, whats the cold water for?
The cold water in contact with the cold side heatsink helps keep that side close to the temperature of the water (because the thermal resistance of the heatsink-to-water interface is low). So it's similar to what we do here, but in this case we are just using ambient air temperature for the cold side instead of water.
What else can we use instead of the heatsink?
The goal of the heatsink is to provide a low thermal resistance interface between the TEG and the air. If this thermal resistance is high, then the overall thermal difference between the two sides will not be as great, and the energy produced will be much lower.
Basically, you can use whatever thermally conductive materials you want, to connect the TEG to whatever you are using for a thermal sink. Heatsinks are one of the best options for air and water because of their high surface area.
6:07 I've been known to ::pops collar:: turn on a light here and there with *just* my hand also. ^_^
can moving cars' friction generate enough heat to generate a substantial amount of electricity, say enough to power streetlights?
Doubtful. Cars crossing pavement has relatively little friction and wouldn't create enough of a temperature difference, plus TEGs are pretty fragile and sensitive to vibrations. There has been some discussion of using piezoelectric generation on highways, but that also has pretty big practical limitations.
@@funtechu thanks a lot for your reply sir, i will try to think of something else to solve this problem
So I can use the window AC until inside
whats the absolute highest quality and maybe industrial thermoelectric you can get? I've actually been looking and I don't see much. it's puzzling....
Most TEC and TEG designs are standardized because deviating much in material, structure, and design will change the performance, and most are already optimized for their respective purposes. Since most follow a consistent part number scheme, you can see the options here: customthermoelectric.com/tech-info/te-encyclopedia/part-structure-option-codes.html.
Typically choice boils down to thermal distance, area constraints, and whether the TEC is sealed or not to prevent moisture from getting in.
For example, using the description here: customthermoelectric.com/tech-info/te-encyclopedia/what-tec-do-i-have.html we can break down what the TEC1-12706 used in this video actually means: "TE" is the same, "C" means it is a standard cooling designed device (vs a smaller form factor), 1 means it is only a single stage (there are not multiple TEC stages stacked on top of each other for a higher thermal difference), "127" is the number of TEC pairs in series in this device, and "06" means "06" amps which is the maximum amperage you can drive it at when using it for cooling, in this case 6 amps.
any data on amps or volts
So just some background on this project, I put it together for a demonstration for middle school students for a local science festival. As such I didn't spend a lot of time characterizing the devices other than for figuring out how many I would need to combine to be able to drive an LED. I did some basic characterization with a 300 ohm load and a 1k ohm load, but that was just on a piece of scratch paper, and is long gone.
However you can get a pretty good estimate from looking at the video. The scope is plotting V (in 500mV/division) and you can use the provided circuit to compute roughly what the current is. Multiplying those together, you get the power which is generally more useful.
Using some simple back-of-the envelope calculations, we can get some estimates. For the case where I place my hand on it, the scope reads about 2V on the output in steady-state. The LED used is LTL2R3KRD-EM and I used a series 470 ohm resistor. If we estimate that the LED was close to just barely turning on, then the forward voltage would be probably close to 1.6V. This gives a current of (2-1.6)/480 = 851 μA for the whole array, and a total of 851μA*2V = 1.7 mW of power. This comes out to a power of about 425.5 μW per TEG with the temperature difference between my hand and the ambient temperature.
For the hot water case, the voltage goes up to 3V, and the LED was on brightly so we'll use the full 1.8V forward voltage rating. This gives a current of (3-1.8)/470 = 2.55mA for the whole array and a total of 2.55mA*3V = 7.66mW of power. This comes out to a power of about 1.9 mW per TEG.
Hope that helps. If you are interested in using a TEG for any application, I recommend fully characterizing it under the conditions you will be using since various TEG and TECs operate more efficiently in different temperature ranges. For example, that's the reason I'm actually using a TEC in this video instead of a TEG, because they are generally more efficient when operating near room temperature. Products that are branded as TEGs are typically designed for high temperature operation.
Also keep in mind that the impedance presented to the TEG will wildly change how much of the power is transferred to the load. This is why in a commercial application you would probably use some maximum power-point tracking energy harvesting circuit to get the most out of each TEG. In this case the intention was making things simplified and easier to understand given the expected audience.
ok apart from space I have a geyser near me what do think?💡🧐
it's really boiling hot what if I make a double pipe one inside the other and covered with aerogel one pipe channels the hot water and the bigger one channels the sea water and is covered from the top with earogel
what if the pipe is made entirely from peltier I think it has some potential if utilized correctly
It would probably be more feasible to just take the water sources to a single location and then do the exchange there. That being said, if you have geothermal activity near you, you probably would get much more power generation for the cost by building a normal geothermal electric system using a more traditional system (dry steam, flash steam, binary steam). You can learn more here: www.nrel.gov/research/re-geo-elec-production.html
@@funtechu 😊 thanks for taking time to reply
can we use a hot cup of tea to produce enough electricity to charge a phone? with the second circuit
The short answer is no because the energy needed to even power a phone is on a whole other scale from the energy being generated here.. A hot cup of tea on that side would likely only be able to produce a few milliwatts of power. I ran some back of the napkin math in another comment and got about 7.66mW of power peak for the hot water case (which is actually better than the hot cup of tea would be because there is only a thin metal bottom). And even so, it would cool down to room temperature in 5-10 minutes so you are talking only a total of around 2-3 Joules per cup of tea in the best case scenario. This is much lower than even the standby usage of most smartphones. For example, an iPhone 12 has a battery that stores around 40,000 Joules. In standby the phone uses around 50mW, so the hot cup of tea wouldn't even keep up with the energy drained with the screen off and the phone in standby mode.
The Seebeck Effect is definitely interesting, but the energy generated in most situations is rarely enough to make it worth it, especially for any terrestrial use. The reason they work so well for space travel is because radioactive material is a good constant source of heat, space is a good constant source of "cold" (a place to radiate that heat so the difference remains), and they are essentially zero maintenance.
@@funtechu thank you so much for your reply
why wouldn't a traditional PN junction depletion region (like, in a diode) appear somewhere @2:16 in your explanation?
Also, if heating only makes the positive and negative more positive and more negative, this should also work without heating. (as in, indeed that P or N by itself is electrically netural, but once in contact, holes and electrons will start migrate, just like what your animation is showing @2:06) that would lead to absurd conclusion like "if a diode's both end connected to a wire, we will get some electricity flowing forever".
A depletion region does form (you can see the cancelling around 2:06 in the animation), however it isn't relevant to an explanation at this level (this video was produced for elementary/middle school students). Heating an end increases the concentration of the primary charge carriers in the material (electrons in N-type, "holes" in P-type), on the end that is heated. This is due to the increased energy providing a mechanism for primary charge carriers to jump into the conduction band. This concentration results in the temporary charge differences shown, but it will eventually reach equilibrium and no current will flow if the two ends are not connected.
But, as you note, if you connect the two ends (through a load, or even simple short circuit), this electricity will flow "forever". This is true, only *as long as the temperature differential remains*. Once the two ends of each semiconductor reach the same temperature throughout, no more current will flow because the charge density is the same throughout the semiconductor. Indeed, the material will reach thermal equilibrium faster than by normal conduction alone because some of the thermal energy is being carried away by the primary charge carrier activity and dissipated in the load.
Hopefully this helps clear some things up. If you want a deeper discussion on thermoelectricity, and in particular why certain materials are chosen over others, I'd recommend reading "Fundamentals of Thermoelectricity" by Behnia.
Go post it on Steemit too.
when you heat up one side of the module what happens to the other side??
The other side will gradually heat up as well unless you are actively sinking the heat away from that side.
Can we store this heat energy in a battery?
Yes, the energy generated could be stored in anything you normally store electricity in. Keep in mind though that it's a pretty small amount of energy generated, so practical use is limited.
Sir i think it generates very less current so it may be a drawback....
Can you do anything (please reply)
1) increase the temperature difference (keep the cool side cool with a better heatsink, heat up the hot side), 2) better match the load impedance using an energy harvesting chip (not covered in this video due to the intended audience), 3) use more in series/parallel depending on if you need more voltage or current respectively, or 4) use something else for energy generation because while this is an interesting effect, its practical uses are limited
@@funtechu THANK YOU VERY MUCH FOR YOUR QUICK RESPONSE
can it light up a 20w bulb
From the calculations in another one of my comments, the energy generated by my hand vs ambient is 1.7mW for the 4 TEGs, or 7.66mW for the hot water example. Note that these are not optimal operating points as discussed previously, and were merely chosen for this example. So to power a 20 watt bulb would require 47,059 TEGs using body heat, or 10,444 TEGs using hot water.
So the short answer is, no, it's not practical to power a 20 W light bulb using these TEGs.
@@funtechu thanks
Why need the heat sink thermal heat
Generator
this would work well with solar on top of buildings, using the difference between the air conditioned building and hot solar panels.
The problem is that Air Conditioning takes energy as well, so you would end up using more energy than you would generate.
We need efficient storage options, which is the Achilles hill.
You should use these in houses. Inside temp is different that outdoor temp.
Except, it typically takes energy to maintain that temperature difference, and the amount of energy generated would be less than the energy expended to maintain that difference.
@@funtechu when it's 105 degrees outside I usually keep my house at 70 degrees with a Air Conditioner.
@@funtechu ...I can always have a temperature difference. It just depends on insulation in my house and how shaded my house is.
What happens if you connect 1 million of these in series?
I wanted someone to explain something to me: It doesn't make sense for the holes to move away from the heated region (in the case of the p-type), since they are the absence of electrons, they should actually be exactly in the heated region, since the heating causes electrons to go to the cooler region.
I agree that it is unintuitive at first glance, and it requires a little background in semiconductors to really grasp it, but I'll do my best to try to explain it in a more simple manner. Semiconductors are materials that are doped with an impurity so that they either have an excess of electrons (n-type) or holes (p-type). What this means in practice is that the impurities are either electron donors, or acceptors, and as long as there is enough activation energy present, electrons can either be donated to the conduction band, or captured from the conduction band.
The key to understanding the thermoelectric behavior of semiconductors is to realize that this activation energy must be present to allow the release or capture of electrons, and that the material is always in a constant state of flux, with electrons being release or recaptured continually depending on shifting temperatures (which help electrons jump over the energy barriers) and on proximity (where if they are close enough that the electrons wave function overlaps, they can quantum tunnel through the energy barrier).
What this means in practice is that when you have an n-type semiconductor, the impurities don't all release their electrons into the conduction band all at once. Instead, there is a constant flux of electrons jumping into the conduction band, and jumping back. The higher the temperature, the more free electrons there are floating around in the conduction band, and the lower the temperature the fewer free electrons are floating around. If there are more electrons released into the conduction band (higher temperature), that will create an electric field that causes electrons to drift away from the heated end until they reach a point of equilibrium. At the point of equilibrium, this electric field pushes more electrons towards the cooler end, so the net effect is that the heated end is more positive, and the cooler end is more negative.
Now the tricky part: p-type semiconductors. It requires activation energy for the impurities to "capture" electrons. When an electron is captured out of the conduction band, that region of the material becomes more positive in its conduction band, and we represent that as a "hole". The higher the temperature, the more electrons can be captured, and thus the more holes form. This change in the concentration of holes (increase in hole concentration, reduction in electron concentration at the heated end) causes electron drift in the opposite direction, and causes holes to propagate away from the heated end as more electrons are captured. At equilibrium, more holes are present on the cool end, and more electrons are present on the heated end, so the net effect is that the heated end is more negative, and the cooler end is more positive.
Hopefully this helps. If you are interested in learning more, I'd recommend Fundamentals of Thermoelectricity by Kamran Behnia. It includes helpful energy band diagrams when going over the concepts so you can see how different materials function over a variety of operating conditions.
With this circuit can you turn electricity in to heat
Yes, it works in reverse as well, as a heat pump. So if you apply a voltage, you can transfer heat from one side to the other. Look up the "Peltier effect" for more details.
@@funtechu so technical can it be a solar panal?
@@uhoh5473 It could be used to generate electricity from the sun by letting the sun heat one side and then passively cooling the other side. But it would be way less efficient than a normal photovoltaic panel of course.
Why the capacitor?
it could be a nice technology for implementing digital temperature sensor on a pot or a pan 🍳🤓
Good observation! This is actually the exact same principal that is used in a thermocouple which it used to take temperature measurements. If you have a kitchen candy thermometer or meat thermometer, they typically have a thermocouple in the tip of the pointy end, though there they typically use two different metals for the Seebeck junction instead of semiconductors so it can handle a wider temperature range without being damaged.
@@funtechu i actually meant that it would be also able to power up the digital led display with the power of temperature - however after writing that again i've realised that led display would prolly die quickly because of the temperature 🔥
Wooooooo oh my good nes
Why not produce electricity by using waves if electricity is converted to waves DN da same can be reversed
How about volcanoes, seems legit me u could use this in Iceland.
I don't have any idea why they don't use it!
Why dont they make solar panels using those thermal electric generators? You can hear air or water in a closed box with glass over it painted black. Theres your heat, and under you could have heat sink.
I missed this comment, but the short answer is that that process would be way less efficient than just a regular photovoltaic panel. PV is honestly remarkably efficient and inexpensive for what you get!
At 6:23 the video reminded me the movie Matrix.
"Change a human being .... into this"
_holds up a D battery_
let say you want to use it to power 80w like it work
Wish you shoved volts and amps and maybe used a candle
Thank you I live in a third world country.
And I am developing a new product we can use for heat to electricity conversion.
Or you can use the heat from the sun...
Just put it in pure sunlight and it works as well
Lets use this technology to mine ₿itcoin people . lets get the heat from the miners generate electricity to power the miner and rinse and repeat.
That’s the solution I’m here for I’m designing a mining machine for it.
Big brain move
U could make electricity just by using these and a magnifying glass lol
True, though for solar concentrators there are many designs that would yield much more energy per square meter