@@thatguyalex2835 ⚠ God has said in the Quran: 🔵 { O mankind, worship your Lord, who created you and those before you, that you may become righteous - ( 2:21 ) 🔴 [He] who made for you the earth a bed [spread out] and the sky a ceiling and sent down from the sky, rain and brought forth thereby fruits as provision for you. So do not attribute to Allah equals while you know [that there is nothing similar to Him]. ( 2:22 ) 🔵 And if you are in doubt about what We have sent down upon Our Servant [Muhammad], then produce a surah the like thereof and call upon your witnesses other than Allah, if you should be truthful. ( 2:23 ) 🔴 But if you do not - and you will never be able to - then fear the Fire, whose fuel is men and stones, prepared for the disbelievers.( 2:24 ) 🔵 And give good tidings to those who believe and do righteous deeds that they will have gardens [in Paradise] beneath which rivers flow. Whenever they are provided with a provision of fruit therefrom, they will say, "This is what we were provided with before." And it is given to them in likeness. And they will have therein purified spouses, and they will abide therein eternally. ( 2:25 ) ⚠ Quran
@@thatguyalex2835⚠️ God has said in the Quran: 🔵 { O mankind, worship your Lord, who created you and those before you, that you may become righteous - ( 2:21 ) 🔴 [He] who made for you the earth a bed [spread out] and the sky a ceiling and sent down from the sky, rain and brought forth thereby fruits as provision for you. So do not attribute to Allah equals while you know [that there is nothing similar to Him]. ( 2:22 ) 🔵 And if you are in doubt about what We have sent down upon Our Servant [Muhammad], then produce a surah the like thereof and call upon your witnesses other than Allah, if you should be truthful. ( 2:23 ) 🔴 But if you do not - and you will never be able to - then fear the Fire, whose fuel is men and stones, prepared for the disbelievers.( 2:24 ) 🔵 And give good tidings to those who believe and do righteous deeds that they will have gardens [in Paradise] beneath which rivers flow. Whenever they are provided with a provision of fruit therefrom, they will say, "This is what we were provided with before." And it is given to them in likeness. And they will have therein purified spouses, and they will abide therein eternally. ( 2:25 ) ⚠️ Quran
Oh i'd LOVE to see them collaborate once! Would be a total geek-out! Or at least the conversations between them would be more than interesting/entertaining :)
Most important of all, he showed those graphs. I needed someone to explain it. It seems pretty simple now but it is nice to have someone present it. I would like to achieve really low temps with TEC. Maybe I will use CPU heatsinks with heat pipes to pump away the heat.
Recently discovered your channel and bench watched every video. Is all this research and experimentation just for "fun"? If so you're living the dream!
It’s great to see someone that goes through the calculations and explains the graphs to show the “why and how” instead of just showing it working or not. Thumbs up for the presentation of materials!
@@MindlessSuccess Deer are a bit skittish, moose are much easier to catch. It's the stomping, bleading, screaming and running that's make good stories for the sauna...
I love this channel! While I admit your TEC project is less exciting to me personally than your turbojet project (sorry), I absolutely love the way you present and approach each project you're working doing. That presentation and the explanation gets me interested in what's going on and keeps me interest irrespective of my "excitement" level. I also truly admire that you don't treat your audience as morons and more as equals, that's extremely refreshing as well. (PS: I'm the daughter of an aerospace engineer/PhD in mechanical engineering thus my excitement over your turbojet project. My dad and I used to build them when I was younger to power Go Carts and the like. We also made a pulse jet engine or two and other such nerdy pursuits. So your turbojet project though different in application from ours, is a trip down memory lane for me anyway). Keep up the fantastic work!
Thanks a lot! 👍👍 With amazing content like this, why does anyone need a subscription TV service? Instead, it's a better idea to support great channels like Tech Ingredients.
A lot of people overclocking CPU's used to stack tecs..... I guess it worked or they would not have done it, but i guess to those people electrical efficiency is not a concern its just brute power
Computer power supplies typically output at 12V, 5V, and 3.3V. So you get pretty good results with stacked peltier/TEC using those different voltages. Use what you got...
you and Jitsen Chang have failed to realize is that the man said they could be stacked for lower temperatures. So your "guessing" 'it worked or they would not have done it..' seems to indicate that you didn't catch that fact in the video. Did you watch all of it or not?
@@ChangJitsen you do need to pay attention to wattage. You seem to have failed to realize the fact that the man said you could get a greater temperature change by stacking. That temp change, or delta T, is achieved at lower efficiency but he said that it does indeed net a greater temperature differential.
If it’s that cold outside, I bet the humidity in that shop is extremely low ...I mean he said that cold tubing is perfectly dry. Here in South Central Texas, hell, you’d have to have a collection pan under that tube because it would drip constantly, and you wouldn’t need to atomize it, there would be enough of it that you could have a cold-water bath to run your return glycol tube through, probably even through a heat exchanger immersed in the accumulated condensation. Sometimes I wonder if the condenser core in my window unit would be better off buried in the cold mud swamp that exists under it almost year-round than it is just sitting there having 105 F. air blown through it. I think the concept of using a water evaporation based system to cool the the evaporation stage of a refrigerant based AC system needs to be looked at again. The idea of just dumping what at least starts out as cold distilled water onto the ground like a waste product just can’t be right ...we’re missing something somewhere...
I tried putting TECs in a stack as you showed here myself some time ago. In my test the last TEC heated up instead of cooling. I also put the 2nd and 3rd element in series across a PSU. My conclusion was that at a minimum I would have to adjust each TEC with a separate PSU to have a chance of it cooling down at all. Maybe I was feeding it too much voltage though.
The setup in the video works well, but for each type of TEC there is an optimal voltage. Use a variable voltage power supply and dial up the voltage slowly (over many minutes) untill the temperature fails to drop any further.
I was just working on a cooling system in lab using TECs and CPU Fans and I was wondering whether using a single TEC or multiple stacked together gives me better efficiency. This video really offered me plenty of insight! Great video!
Thanks for this. I know this is now an old video but i've been trying to find info on cooling a volume of air inside a box (camera inside it) with TEC's and this series (especially this video) is so useful in understanding what im trying to figure out to get this done effectively
I like TECs and I like your plan, but did you originally want a low power fridge or a super small one? Just a chest freezer, with a refrigerator's thermostat swapped in, offers a lot of space and it's very energy efficient. That's the route I went years ago - chest freezer to chest fridge conversion.
These TEC elements typically have a maximum COP when operating around 2V with a dT of 10K, however, you need a lot of them at such low voltages to get the job done! Their COP also increases a lot with increasing T(hot), ceteris paribus.
You'd be a good person to build a"Cloud Chamber" if it was of interest of you. It would be an original video if you managed to do it with large surface area of stacked peltiers. It'd make good use of your cooling loop as well.
A very amazing clarification for myself. Thank you. I will work on my patients for more info. I really could have used this video back in January. Then again, afterwards it is always gratifying to know you learned from your own R an D. To have you confirm everything, makes it that much sweeter.
Ok, so with lower voltages the TEC units can transport more thermal energy with a lower temperature difference? If these TEC units get extremely cold, like -162C, will the resistance and Amperage used increase? It seems like you might have been suggesting that if the TEC units were cooled by liquid nitrogen, that they would not become colder than the liquid nitrogen. Is that true? Are these graphs available online for different models of TEC units, or did you have to test them, or use equations to generate the graphs? Thanks for your videos, they are very insightful. I appreciate the level of detail and speech. Are you a University professor or a researcher? I have been secluded so my speech doesn't seem to be what it use to be. I hear that more social interaction helps with speech.
Freezing ice... Anyone can do that. If you're really going for cold, why not condense the gases out of the air? Randomly building a device capable of making dry ice or even liquid nitrogen would be something.
could you liquify some nh3 or cl2 with that stack? is it posible to go lower and make solid co2? diy solution of Li in NH3 would be a nice project for that stack
I was wondering about the CO2 as well. It only requires -80C or lower, could a triple or quadruple stack of TECs reach that low, even at horrifically low efficiency? You would of course need bone dry air, or else you'd just be condensing water from the air.
Funny you mentioned that. At the coldest times of the year, here in New England, -20C is routinely reached at night. We missed that window, but our little, three stage cube should easily condense moderate quantities of CO2 gas from a tank into the cavity and that is what it was originally fabricated to do. Next winter...
We might. I've thought about this and I think the most challenging part would be an easy, inexpensive way to bore the holes. I like this better than digging up the yard and there are suprisingly few videos about practical and effective methods.
@@TechIngredients I think you don't need to solve every aspect of it. Just making a DIY heatpump as a proof of concept would be enough, and let the problem of the drilling for another day.
Potentially, yes. But, given the same driving voltage, you need to apply the performance graphs I presented in the video to determine the optimal capacities for the pair.
Love it! This is off-topic, since your want to cool with "TECs" but have you heared of the "Schukey-Motor". It is a thermaldynamic machine that can also be used as a cooling device / heatpump.
They call this a thermal waterfall or thermal Cascade effect there was a great online company that had all this information and then they pulled it off the web about 8 years ago when I looked into this
Applied Science has a video on repairing an ultra low temperature cascade refrigeration unit, that uses two compressors, there is enough information to build a crude prototype.
Actually that´s not very impressive to me. I managed to get a temperature difference of >50°C (+20 to -30) with just a single TEC and a single fan Water cooler. I didn´t even insulate anything for that, nor did I fine-tune anything. For the amount of effort that went into this, this is not very good.
The assembly is rather easy and a single power supply voltage is all it needs. The lower the final temperature, the harder it gets... rapidly. The TECs become less effecient and the differential between the cold side and the surrounding environment increases the thermal load.
rotate85 That’s what my computer phase cooler runs... its a commercial unit... -35c at high power (FX-8350 at 1.7 Vcore at full stress load). Core temp peaks somewhere below 0c (my computer doesn’t show below 0c, my evaporator has a thermocouple on it for the temps. Asetech Vapochill LS
Great content. I really appreciate the thorough scientific content that you provide. I am starting to try to design a cold trap for a freeze dryer. I have a few TEC's that I thought about utilizing inside of a chest freezer to achieve the required -40C. have you tried any like this before? Do you think that it might be achievable?
Wow those are some low temps. Would love to see a video where you attempt to make a poor mans flash freezer. Having the ability to flash freeze food at a reasonable cost would be amazing. E.g. people at home could make "sashimi" grade fish, preserve vegetables etc. How could you economically make a small freezer that could rapidly take down a small food item like a filet of fish down to -35 C? Once at -35 C it could then be transferred to a conventional freezer. Sushi year round!
The next time someone starts talking about using stacked TEC to cool something I'll know it's not as simple as just stacking them and watch the LOX start flowing. I pretty sure I won't remember any details, but I just might remember this chanel, or that it was on YT. Oh lets be real I'll be happy if I remember how to search for it using google. I ate all that lead I could get my mits on when I was a kid, and I have no problem with my memory! Now what was we talking about?
I have done a 8 TEC (a square of 4 stacks made of 2 TEC) cooling a 64 cm² aluminium plate at -52 °C for a cloud chamber tanks to this video so thanks !
Thank yo very much...I tried it and gave me a good result better than before..but I used 10 vdc instead of 12 v and the two modules aboce in series connection then parallel with the bottom one...the bottom I used TEC1-12710 and the upper two TEC1-12706 and got very nice result.
Tech Ingredients Hi, I think there’s a fault in your calculations. I’ve watch your explanation several times but I cannot follow your reasoning. I think that you mixed up used power and pumped power or I just don’t get it. Since I’m the only one, chances are it’s me. The first line is clear. You use 28W to pump 18W at 33° dT Then you say: “the second is going to move 14W” Were did 14W come from? Did you mean 18W? (I think so because later your addition = 46W) “But in addition it will also have to move 28W” 28W is energy used. Why should it move that? Of that 28W used, 18W is pumped away. So I think it should pump just the 10W induced by the inefficiency of the first element and another 18W at a different temperature scale to match the first element. If you’d add a third element that element would need to pump 18W + the induced 10W of the first and the more than 10W of the second element. The second element would be less efficient since it has to work harder. The third would be even more inefficient. I think the second element would have to pump 10W + 18W = 28W. And at 4A dT would be approximately 24° So that would lead to a total temperature difference of 33°+24°=57°. At very low temperatures the elements become even less efficient so the difference would be less if you start at around freezing.
@Conservator yeah I was confused about that part of the calculation also and rewatched it several times more. Then I started searching the comments to see if I was the only one.
He misspoke when he said 14 instead of 18. Otherwise, the calculation is correct. When you put in 28W, 18W of power moves from the cold side to the hot side, but the device has also absorbed the 28W you put into it. In order to keep the whole thing from heating up, you have to pump out the 18W which you've moved to the back side AND the 28W you put in. The 28W is just the price you pay to make the power move from one place to another.
Michael Biggs Hi, Thank you, you are right. My error was that I thought 18W would go in and only 28W would go out. But than (as per conservation of energy) only 10W of electric energy should have gone in. The element uses 28W so (indeed) 46W must go out. So these elements are better in producing heat than they are in cooling.
I'm confused about back wall in you last version of refrigerator. First goes back wall. then 12 thick aluminium blocks which are screwed to back wall. and these 12 blocks are built into polystyrene foam. then go 12 TEC and then 12 water blocks. Is this correct sequence? Or i something didnt understand?
Always wanted to know what happens if one cascades TEC's. Then ended up reading up on CO2 in ultra low temp refrigeration, minor issue with the triple point and the ice blocks pipes. Fascinating.
Thats true, I did also home testing and is not working with stacking them together. the next stage gets hotter, and the next also, that all peltier modules are to weak to cool each other.
How effective are one of these TEC stacks at applying cooling to an active heat source? Like would it be effective at combating the heat generated by a desktop CPU? The pro-sumer market for desktop cpu cooling is pretty huge and if it's possible to make something more effective, even at the cost of significantly more watts, people would throw money at it. Maybe throw out a utility patent if one doesn't already exist. Even if you don't think it'd work, someone less smart than you would probably pay good money to buy that patent off you. More money for cool projects and interesting engine projects :)
TEC's are very bad at handing actual heat power. They can reach very low temps like in this example, but that's only really because very little heat (in watts) is actually being added to thee system. If you add one of these stacks to a CPU, even at idle, a modern CPU will actually get hotter than if you used a stock air cooler. The TEC's simply cannot remove that amount of thermal power. About 15 years ago, CPU's were much slower and didn't produce nearly as much heat (again, in watts, not absolute temperature), and so this could be used and some people in the overclocking or enthusiast scene experimented with peltiers, but... They were rarely any good, and they consume a shit-ton of power themselves. Back then, a TEC stack could consume more than the rest of the entire PC. What IS possible however is to use TEC heat exchangers to cool down a water loop, basically building a water chiller, and using that chilled water (with antifreeze of course) to cool the CPU. That does work, but you are essentially using the water cooling radiator to cool the TEC, and the TEC cools a separate loop, that in turn cools the CPU... If that makes sense. The reason this works, is because the radiator can remove a lot of heat from the TEC, and it allows the water to drop below ambient. You still need a really chunky TEC heat exchanger though, probably 4 or 6 TEC elements in parallell (not in series!!), which is a lot of power. Easily 200 watts ++, just to drive the TEC's.
Mythricia it’s a lot more units than that, Der8aur made one with 8-12, something like that, and I think he’s going to have a hard time, it was overheating at idle because he had mediocre air coolers on the TECs, haha! He was running them at 360w on the TEC, but that’s so not going to cool modern Intel CPUs above duel core... it’s also kind of expensive needing 20 waterblocks (hot side plus cold side), the massive radiator for the TECs, the extra PSU, and so on. I much prefer my sub-zero phase cooler, lower power and handles real heat load while keeping core temps under load below freezing, very hard to find those coolers, but you can make most of it out of a refrigerator or air conditioner... so not super pricey if you could get the evaporator heads without brazing one yourself (mine is just a commercial unit, I got lucky and actually found one).
Stacking them and using them in series--in terms of one in front of the other relative to the coolant flow--aren't the same thing. I think you are confusing "in series" and "stacking." I want to see what the efficiency effects are when you actually use a series of them in line with the coolant flow.
so, i am very interested in when you say, "like a micro chip", ive seen attempts at this on modern processing units, usually placing it cold side onto the chip with a thermal pad, or grease. But it always seems to result in the chis continuously heating and never really finding its happy spot, or heat soak as i were. i assume this is because a micro processor has alot of variable temps? as well as the ineffective heat sink? would it be better to say run one on something like a radiator instead of direct contact to a chip. Or is the statement not ment for something like a CPU,or GPU, rather a different chip altogether? as for efficiency to a cpu i dont see how this could really be a major benefit regardless water cooling, and near sub ambient is getting better and better, could you possibly produce a video on the subject? i also was super interested in the idea of using some form a descant based cooling system, similar to your air condition system to build some kind of super cooling water loop that would kinda rock the tech world. Although ultimately i think said project may be impractical. Any way love the content, thank you for making such inspiring content!
Could you show us how to make a personal quantum computer for use at home? This came out this May, by the way: Drozdov, A. P., et al. "Superconductivity at 250 K in lanthanum hydride under high pressures." Nature 569.7757 (2019): 528.
I have seen some 5 and 6 stage TEC units made for cooling missile guidance sensors and FTIR detectors. To get VERY cold what you need to do is stack them like a pyramid. A big high element count one on the bottom, heat spreader in between, a 3/4th element count one on top, and repeat as desired. You can get to about -140 to -180 deg C. The floor is because of the heat generated by the devices ❤
That process becomes extremely inefficient because the loss at each stage multiplies. A differential of 140 degrees is possible, but remember that the "hot" side isn't at zero degrees centigrade.
I stacked two TECs connected in series, but the upper (hotter) one got almost immediately electrically damaged (infinite resistance). Actually, the hotter module has to remove more heat from the cooler module. If it doesn't succeed then its temperature difference increases, which leads to lower heat removed, and so on. It seems the advice to stack TECs with same current was wrong. Could you, please, provide more reasoning?
Sure. You need to consider the performance curves for each module. Then, starting with the top (coldest), identify the amount of heat you want to pump and at what temperature. Calculate the power necessary to move that much heat and look at the power curve as it relates to the temperature differential they will produce. Next, add to that pumped heat the power consumed in that module and again look at the power curves and how hard you need to drive the next module to move that total amount of heat and achieve the remaining temperature differential to get to the overall differential you need. This process requires you to look back and forth across these curves to reach an optimal system. It's kinda fun.
So in terms of CPU cooling, is it roughly watts = watts? IE 65w TDP CPU needs 65w worth tec cooling? My question then is how much more cooling you need above that. However if you have to watercool your TEC on your computer this quickly becomes a scenario only for extreme overclockers. The dream is of course to have CPU be cold under load, any idea how the numbers work for that, and what the TEC setup would look like?
CPU cooling is like any other heat load and the performance graphs for TECs include COP to describe this. Temperature differential determines COP which for a TEC can range from near zero up to 2-3 for very low dTs. A COP around one would be typical for a TEC enhanced CPU cooler.
One sees the connection between evaporation removal of high frequencies resonances in gases and the hotcold Junction equivalent in this demonstration video, that led to laser cooling of Black-body Singularity-> Bose-Einsteinian Condensation achievement. Multi-stage Energy (spin
I love this idea and I think it might work. A sound wave in gases (liquids) must heat and cool certain zones (low and high pressure distributed along the length). If this is done in a cascade (next line from the top), then low and high temperatures can be achieved. That is, it is possible to make an air conditioner or heater without moving parts. You just need to move the temperature gradient from certain zones and transfer them to the next. This is difficult, since there are no devices that can be bought on aliexpress and tried this principle quickly, to make a video.
I like this guys spirit, but daaaamn is he tedious! I don't think it's possible for a person to be so yawn-inducing. He elevates pedancy and tedium to the level of high art. Irrelevant details and tacit, commonly assumed concepts are presented with surgical precision. Indeed, concepts known since grade school are delivered as if this video they're in is just practice for when they are brought before the Novel Prize committee. How often, and how many angles must he approach in describing the temperature differential between two TEC's operating on top of one another? Do we really have to be told that the refrigerator couldn't have been made of glass because it had to have excellent insulating abilities? Couldn't we just have assumed that glass isn't good at insulating? *Sigh* That being said, I do like the guy's spirit, and his obvious devotion to the material. But he must learn that being pedantic adds nothing to enhance the viewers' learning curve, and only incites yawns. Perhaps a visit to Ben's page (Applied Science) or Styro Pyro's page (yes, I did go there) would be of value so that the producer of this vid can learn something in the way of eliciting excitement. Arousing excitement can only be done by introducing new concepts, not by the tedious repitition of the unimportant details of existing concepts. Plus, his fridge is too big. What's so awesome about TECs is their compactness; therefore the fridge should be compact (think shoebox sized). And your'e making a video about cooling systems. Did you really have to film this thing during the dead of winter? I mean, really. Refrigeration systems in January. We can do better!
Haven't watched the whole video yet, but if efficiency isn't a constraint, you can still reach a higher temperature differential per cascade reducing the voltage per TEC layer and most imporatantly, by using more TECs per level as you cascade. Essentially, each layer has more capacity to support the layer before it. You would need increasingly large thermally conductive plates to separate one layer from the next so that you can fit a matrix of TECs. An example, though I haven't done the math would be: layer 1 would have 1 TEC, layer 2 would have 4, layer 3 would have 20, layer 5 would have 100. Again I haven't done the math, but this seems plausible. Now, you'll need some huge copper plates and lots of intricate insulation blocks, and still you'll have a slight voltage drop per TEC per layer. Each additional layer must be able to pump the total heat created by all TECs before it and still maintain a high temperature differential. Increase the number of TECs and slightly reduce the voltage so that the temperature differential is maintained. I want to try this experiment myself! Making my own liquid nitrogen/oxygen sounds like an interesting endeavor even if it is highly inefficient. Also, you'll need one hefty power supply!
Take a look at our more recent video on dry ice and electronic cooling. Liquid nitrogen is out of the question no matter how much power you're willing to use. Nevertheless, you are right about the design of a cascaded system.
hello mister can you help me, If I want to make a fish cooler box with a capacity of 16 liters containing 3 kg of fish, how many Peltier modules do I need and what voltage and current do I use so that the power is not too large? Thank You
That isn't enough information. What is the thickness and type of insulation insulation of the box? If you start with ice and just want to keep it frozen and cool down the fish, you'll need much less capacity than if you want to cool the fish AND cool room temperature water with it.
The delta T you demonstrate is 53.5. I just did this with a single TEC1-12708. I don't think stacking these things does anything because the bottom unit can only ever move a max Q
It does make a difference and that is why there are commercial units fabricated as permanently mounted, stacked assemblies. You can achieve a relatively large delta T with a single module, but the heat flow becomes miniscule. Multi stage units can exceed a 100-degree delta T.
This is an honorable quest. The ability to extend the usable lifespan of food by electromechanical means is an earmark of the Modern Age. Everyone takes it for granted until the power goes out for a week. Because it's easier to pass thermal energy to a dense cool sink than a warmer sparse sink, pairing any cooling technology with a geothermal heat exchange mechanism will usually improve the cooling technology's efficiency. I use one ground loop to cool several PCs, an inverter, and a chest freezer. As soon as I find a window air conditioner or refrigerator that's "broken", I'll turn it into a geothermal heat pump for my workshop, withdraw some thermal energy from that heat bank I created.
5:39: have you confirmed your series example experimentally? Rather than putting the elements front to back, consider a freezer inside a freezer where you've already moved the energy out of the first freezer before you start the second freezer. That would be a true series operation. A similar example would be using a mercury pump to make a vacuum. Each iteration of the pump is working off the vacuum that the previous iteration created. Each stage is more difficult but you don't have to go back and recreate all the other vacuums. They are retained for you with the check valve. It's like a Russian egg of freezers.
The problem is that no system is perfectly insulating and so you will eventually reach an equlibrium tempreture between heat pumped and heat leaking back in.
TECs and LEDs. Two of the most overdriven and abused technologies available today lol People need to ease up on them... They both do much better on every level when you don't try to brute force your way to the goal with them 🤷♂️
@Tech Ingredients if u stack peltier module u have to multiply the number of module at each layer... 1 2 4 8 16 because peltier module generate lot of heat and have poor ability to take that heat generated away, so a solution is to multiply them at each stage... ur setup is able to reach a -3 to -55c thats kinda great, but give a try to a a 1 2 configuration and then a 1 2 4 config i bet the 1 2 config wil get same temp differential or even higger cuz u have now 2 peltier taking heat away from the hot side of the first one, so its hot side wil be at lower temp.. and also because dissipation surface will be multiplied at each layer..; instead of having x1 surface to dissipate heat from 3 peltier u will have x2 surface... and its not worth using peltier module to dissipate heat from computer.. they can go low in temperature but canot move lot of heat and a processor is lot of of heat get a search on youtube from people who already try cooling cpu with peltier... the compute start then shoot in minute at 90 c and even go to over heat protection shutdown...
That stacking technique is how series peltier work. But as I described in these cooling videos, the inefficiency multiplies as well. In addition, the semiconductors that make up the modules become progressively more inefficient as the temperature drops and these properties combine to limit the low temperature capabilities. Cryogens like dry ice and liquid nitrogen become more practical at very low temperatures.
-3 degree outside and you managed a -56 degree for a stacked Peltier. That's more than 50 degrees drop in temperature. I wonder, if the modules weren't stacked together, would it still be able to get that same -56 degrees Celsius?
Placing the cooling fans outside is not commercially viable and for practical purposes it would be better to just blow the cold air from outside into the box or thread the cooling liquid tubes into the frozen topsoil. Currently the heat transfers to the cooling liquid and then back to air which is not efficient, because of the huge molecular density difference between gases and solids/liquids.
Molecular density is not relevant, what matters is heat content and mass flow. However, you are right that outdoor fans are not practical, but can be when the remote cooler is located in a cool room like a basement or a better alternative would be to route the cooling liquid to a buried gound loop.
So, great vid tho would have liked to know, Tec vss Tec2 and a actual peltier ?, i know the tec2 is an stacked version of tec 1 , and not like a pyramid stack. but a peltier device being somthing else ? also , what is the resistance delta of that little pot, how much watts or jules can it actually cool ? its volume or surface area ? allot of ppls out there want to use these for cpu cooling, i use them to cool my waterloops, not the cpu itself...like a chiller.
Stacking a TEC in any way, whether a pyramid or as we did in our other video on dry ice vs electronic cooling will decrease it's already low effeciency. It is the only way to achieve extremely high tempreture differentials, but the heat removal in watts will be limited.
Yes, but because the TEC is a heat conductor when the voltage is off this can reduce the efficiency. Higher frequency works better and if the PWM is used for fine control on top of a steady voltage then this works even better.
This is very helpful. I am planning a cloud chamber project, and I want to build one with a larger, top-down viewing area approximately 8 inches square. Ideally, I'd like to consistently get the cold plate below -30 C in a + 22-24C room, and have it operational for at least 30 minutes at a time.
My hunch on how to make the tecs more effective. pulse them. This will normalize the difference in temperature between pulses, maintaining higher efficiency. ;)
PWM actually is worse. The effeciency decreases as the current rises and that is the instantaneous current, so you don't want peaking currents for the same average.
