Hi, I got my hands on a bunch of these Thermoelectric Peltier devices ,thanks to Circuit Specialists.
I've never used them before but, from what I know when you apply electricity to them they pump heat.
Well, let's power it with 12 volt DC. I know the theory -(gets shocked)
Sh** ow(gets shocked again)
I know the theory behind it, but I haven't really experienced one
What? This - OWW(gets burned)
It burn-freezes
It's like you're naked in space and your side facing the Sun is boiling hot and the other side is freezing cold.
I knew this would happen
But when you really experience it, new questions pop in your head, like all my life when I ran
electricity through a conductor it always heated up.
Except now it's cooling down, and it's heating up on the other side.
It kind of works like my wife. While the rest of her body is at boiling temperature, her feet are at absolute zero.
Okay, let's power it up again and look at it with my thermal camera.
Right now, both sides are at the same temperature.
And if I power it up
This side cools down
quickly, while the other side heats up. Ooh it's burning.
(Blows to Cool it Down)
I shouldn't run it at maximum power with no heat sink.(Blows again)
Running it at 5 volts
and one side heats up,
while the other side cools down. So it's like 29 degrees here and
60 degrees here. So there's like 30 degrees different between both sides.
And if I flip the voltage here, you see the cold and hot sides
flip too. Now this side is cooling down and
that side is heating up. If I let it run for a while the cold side heats up, too
But it seems like the device is keeping the temperature difference
constant around 30 degrees at five volts. And the temperature difference between the two surfaces is power dependent.
So at maximum power the difference can be 60 to 70 degrees.
These things work based on Peltier Effect, Seebeck Effect and Thomson Effect
which is basically the extension of Seebeck and Peltier Effects.
And all these are different manifestations of the one thing that is the Thermoelectric Effect.
which happens when two conductors with different materials touch each other.
The Seebeck effect is when there is a temperature difference between the junction of
two material and rest of it a voltage is created across the junction and acts like a generator.
The voltage is typically very small in order of microvolts and increases with more temperature difference.
Measuring that tiny voltage you can measure the temperature.
That's what they do in thermocouples joining two different wires, chrome and alumel in this case,
and you can read the temperature on the meter.
In the Peltier Effect, if you run current through the same joint it can cool down and absorb heat, or
it can heat up and radiate heat depending on the direction of the current.
The problem is that I have no idea what happens in atomic quantum level that passing
electricity through two material can cool it down. I read somewhere that the electrons move the heat away.
What the hell does that mean?
If you know a good explanation, please leave it in the comments,
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So this device is fascinating! For whatever reason when you run current through it
it pushes heat from one side to the other creating a temperature difference.
Like if both surfaces start at 30 degrees Celsius running current can make one side 0 and the other 60 degrees.
But it also wastes tons of power. 50 watts max for this guy.
So it heats up quickly while the temperature difference remains around the same.
So one side could be 100 degrees and the other side 40.
But if I can somehow cool down the hot side to say 50 degrees Celsius then the cold side could be -10 degrees.
The cold side would suck the heat from the environment and pump it to the hot side.
That's why I bought a bunch of heat sinks to experiment with. So I attach the device and heatsink using a thermal compound
that fills the gap between the two and provides a very good thermal conductivity.
The metal heatsink with so many fins creates a large surface area to transfer heat to air better and cool down.
Okay, let's give it a try.
Oh look at that, the surface is getting colder. Great!
But as the heat sink is getting warmer, the cold surface is going up too.
Which means we have to blow air with a fan on the heatsink to keep it cold.
Or even better, just place the heatsink in cold water. Hehehe!
And we power it up
And there it goes! hehe
Of course as the water slowly heats up the temperature rises too.
Running cold water would help but that wastes a lot of water.
- 11 degrees. Let's add some water to the surface and power it up and see what happens.
And zip it all freezes! Heh. And if I disconnect the power...
BAM it heats right back up! These Peltier devices, or shall we call them Thermoelectric Devices, work on the same principles
I talked about, but instead of one junction of two different material,
there are many junctions placed in series like these between two surfaces made of P and N semiconductors.
Running current through them creates a temperature difference.
Also if you place a temperature difference between the two surfaces,
you create a much higher voltage because of so many junctions in series. Flipping the temperature also flips the voltage.
Let's give it a try. I have a box of tea with metal bottom, and if I pour boiling water in it,
it creates a voltage at the output of the device around...
2 volts! So I can use these to power something. Here I have a 10 ohm resistor and if I connect it to the output...
right now I'm drawing like...
160 milliamps from it. Of course the voltage drops
as the hot water cools down and the heatsink heats up. And temperature difference gets smaller.
In general, thermoelectric devices are pretty inefficient to create either cool or voltage.
Their main application is in those small cooler or fridges because they are light and small.
Now I want to put nine of these modules together to create a cooling surface/a generator, if possible.
And so I bought a big fan to blow on the heat sinks and a bunch of screws and a wood board.
Let's put them together.
F***
Ah f***
The hell? My camera of six years just blew up!
Well now I'm stuck with one camera and it doesn't have a microphone input,
so I can't really use my wireless lapel anymore. Audio quality down.
Here, my window of opportunity is made now I have to just install these heat sinks in it.
Okay, so let me show you what we've got. The fan here will blow up directly into the heatsink
I raise the heat sinks up a little bit so that the air has a chance to get over to all the fins of the heatsink.
And I put those pieces of wood in the bigger channels to block them a little bit to make sure that the air gets
to all the fins and the heat sinks are all in parallel so the air escapes from front and back vents
I noticed something interesting. It seems like because the fan is turning this way
Maximum air flow is coming out this way and out that way and there is very little air flow in these areas
so that might affect the...
temperature performance of the heat sinks. So I guess the air is not just coming straight up,
It's twisting and I guess that's where the knowledge of fluid dynamics would have helped
I've got an idea to make the air flow better using a CD cover. Let's hope it works.
So here's what I've made for the fan and I think I've seen it on some other fans before.
Basically my fan, when it blows, the air spins up like this.
But now with these fins the air instead of twisting it will hit these walls and comes straight up.
But now I've made them curved. So what happens is that when the air hits here it slips inside,
so all these fins push the air inside where there is almost no air flow and when the air hits on the outside curve of
the fins it is pushed out this way. So it spreads further out. So instead of one twisting column of air,
hopefully it's more spread out and even. Okay, let's see if it helps.
It doesn't really help that I place the fan too close to the fins, you know if there was a
greater
spacing between them the air would be much more even and would cover more of the fins. Oh, you know, I'm an electrical engineer
I'm not really qualified to do this kind of mechanical stuff
Hey, look at this! These two the airflow feels almost the same. This one feels a little bit less, but it's much more even now.
Okay, now that everything is in place, I'm gonna cover between them with silicone, not only to keep these devices in place,
but also to further isolate the hot and cold surfaces, or at least that's my thought.
I need a small pan
You don't want to have to cut a piece of sheet metal I want it nice and straight. Like this but small.
Something square and small.
Don't seem to have it
*Falling Pan*
S***
This looks good, but it's part of a napkin holder
Maybe I should buy the whole thing and cut this out of it
These metal doors are perfect if I can find one without the handle
*Falling 'Metal doors'*
S***
Fine, I'll just buy one of these and cut it
You know some people play Minecraft in their channels. I'm kind of doing the same.
I'm mining for money
Then go to the villagers to trade for tools and equipment and make my own stuff. Hey, I'm a gaming channel!
*Cutting a Metal Sheet out of it + Music*
Now I'll attach this piece of metal over my Peltier devices using thermal paste
and hopefully this piece of metal will help spread the heat evenly to all the devices
And so it's done just took a week or two and thanks to my patron's support,
I got a new and improved camera! So to thank them I'll buy them four 3d printers. Thanks for keeping my videos afloat.
Now to use it as a generator, I put all the modules in series hoping that the sum of voltages is usable
So here I'm boiling some water and with my 24 volt fan running, I put my water on top of it and
That's it?
I guess my heat sink in water was creating a larger difference. What is this good for? It's a joke!
I guess I can turn on two white LEDs in series.
Oh look one of them is red.
So a 24 volt fan a pot of boiling water and hours of work to turn two LEDs on?!
I think somewhere it said if the module is good for cooling, It's not good for power generation,
So it'd better cool! Now to make it a cooler.
Unfortunately, my power supply can do 10 amps maximum while every module can take five amps max at 12 volts
So I put every three modules in series and put the branches in parallel so that I can at least do three amps per module.
Not ideal, but hey. I'll run the unit and the fan at 24 volts so 8 volt per module.
Look at this, it's cooling quite well. Well now that it's almost settled,
it's running eight amps at 24 volts, so around 190 watts. I'm sure if I contain this it will get even cooler.
Unfortunately running more power through my modules won't make much of a difference, because my fan can remove a limited amount of heat.
So instead of this side getting colder my heatsink will get warmer.
Look at all the condensation! But it works great as a fridge if I want to make this surface super cold,
I can put my heat sink in water or ice. Maybe something to try in the future.
In any case, I learned some good stuff doing this project.
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*Outro*