Thermoelectric Cooling

[BrianG]

Yesp, not worth what you get IMO. There are ultimately three ways to deal with heat:

1: More efficient components.

2: Less current.

3: Heatsink with thermal mass and surface area.

Everything else is just adding complexity.

I have two Quark 125's that use the top plate (connecting the three diffs) as a heatsink and it works wonderfully without the need for any additional active cooling. The chassis is another good heatsink and gets lots of airflow. I just wish more ESCs were built similar to the Quarks in how the FETs are mounted...

[pinkpanda3310]

Originally Posted by BrianG

Yesp, not worth what you get IMO. There are ultimately three ways to deal with heat:

1: More efficient components.

2: Less current.

3: Heatsink with thermal mass and surface area.

Everything else is just adding complexity.

I have two Quark 125's that use the top plate (connecting the three diffs) as a heatsink and it works wonderfully without the need for any additional active cooling. The chassis is another good heatsink and gets lots of airflow. I just wish more ESCs were built similar to the Quarks in how the FETs are mounted...

So if the extra power consumption wasn't a big issue then the quark would be one of the better esc's to try this on, right? Mount the plate between the esc and chassis. Like you said, it just transfers the heat and the chassis has thermal mass with lots of surface area and lots of air flow.

I can't see it benefiting other esc's like the mmm, rx8, hw150...etc without having to modify the casing.

But if you do work something out, we'll need to see pics

[BrianG]

Originally Posted by jayjay283

The way I was understanding this technology was that it just turned electric heat/ energy into cold. My fridge and stuff as I understand it have freon or the greener version now which does it. (im no hvac but I was debating going to school for it as my marketing degree has proven worthless). I have fingers I can look around I dont want to be a dense annoyance and I don't expect you all to educate me for free lol but maybe a hint or 2 where to look or just keep going on the OPs topic and ignore me and ill learn from there.

Yes, your fridge/AC uses a coolant which needs to be compressed and pumped to cool. The Peltier junction does the same thing, but electronically instead of mechanically (or would it be chemically?). Don't feel bad about the degree, my AAS has also proven worthless. Neat for this hobby, and to fix odd stuff around the house, but useless otherwise.

Originally Posted by pinkpanda3310

So if the extra power consumption wasn't a big issue then the quark would be one of the better esc's to try this on, right? Mount the plate between the esc and chassis. Like you said, it just transfers the heat and the chassis has thermal mass with lots of surface area and lots of air flow.

I can't see it benefiting other esc's like the mmm, rx8, hw150...etc without having to modify the casing.

But if you do work something out, we'll need to see pics

Yeah, but any type of active cooling is going to draw a decent amount of power. In a home appliance, the difference in weight or the difference in "runtime" in a 1:1 vehicle is irrelevant (unless you are concerned about fuel economy). But in the R/C world, both of those are major considerations. A Peltier junction big enough to pump ESC (or motor) heat would take at least 20-30watts. That can put a big dent in runtime. The point I was making wasn't necessarily about the Quark specifically, but more about how its design was ideal for mounting in such a way to use the chassis (or mounting plate) as a natural heatsink without the need for fans or active cooling devices.

[J57ltr]

Brians right it takes a lot of current and they will never handle the loads placed on them in a RC. I have used them for a lot of things playing around with them and they are very fragile, basically you have 2 ceramic plates with a bunch of what look like surface mount caps sadnwiched between (these are the PN junctions). Wiki is not the area you want to look for real information on this (or anything else for that matter). They are very brittle and can break easily Shear loads are real bad on them and I have ruined a few just from dropping them on a table.

Go here then start reading the rest of the info at the bottom of the page. There are a few.

http://www.ferrotec.com/technology/t.../thermalRef01/

a module that will draw 6A @ 12V will pump about 170 BTU's. With 6 of these modules I was able to pull a 2# block of aluminum down to 5.5F in 20 minutes using a water cooled system And drew over 36 amps continously. I have a little one that will bring a small heatsink to the point where it's white from condensation in a few minutes using a 3S A123 pack, but it draws 4 amps ALL THE TIME. I have it graphed in my eagle tree, I'll post it up when I get home. I also have a module that will draw 30 amps all by itself.

And you can also generate power with them as well, pretty cool


http://www.rc-monster.com/forum/showthread.php?t=23193

There is a pic in this thread with the water cooled one I made.

[Modding_out]

Dude! that's awesome! for 7.99 do you guys think I can stick that thing between my AMD Sempron CPU and it's huge heat sink? Or should I just go with a professionally made unit? I would love to give my cpu frost bite.....

[BrianG]

Originally Posted by J57ltr

Brians right it takes a lot of current and they will never handle the loads placed on them in a RC. I have used them for a lot of things playing around with them and they are very fragile, basically you have 2 ceramic plates with a bunch of what look like surface mount caps sadnwiched between (these are the PN junctions). Wiki is not the area you want to look for real information on this (or anything else for that matter). They are very brittle and can break easily Shear loads are real bad on them and I have ruined a few just from dropping them on a table.

Go here then start reading the rest of the info at the bottom of the page. There are a few.

http://www.ferrotec.com/technology/t.../thermalRef01/

a module that will draw 6A @ 12V will pump about 170 BTU's. With 6 of these modules I was able to pull a 2# block of aluminum down to 5.5F in 20 minutes using a water cooled system And drew over 36 amps continously. I have a little one that will bring a small heatsink to the point where it's white from condensation in a few minutes using a 3S A123 pack, but it draws 4 amps ALL THE TIME. I have it graphed in my eagle tree, I'll post it up when I get home. I also have a module that will draw 30 amps all by itself.

And you can also generate power with them as well, pretty cool


http://www.rc-monster.com/forum/showthread.php?t=23193

There is a pic in this thread with the water cooled one I made.

I thought I remembered them being fragile too, but wasn't sure so I didn't post it. I too did some experimenting a while back, and they are pretty interesting. It's been a long time (and I don't feel like searching right now), but I have a question for you. I understand the application of current causes heat to be pumped from one side to the other. Now, let's say we are applying 12v @ 5A through a device. How much of that 60w is being dissipated as heat on the hot side? In other words, what is the efficiency. So, not only do you have to get rid of the heat being pumped, you also have to get rid of the heat produced from any efficiency losses.

Originally Posted by Modding_out

Dude! that's awesome! for 7.99 do you guys think I can stick that thing between my AMD Sempron CPU and it's huge heat sink? Or should I just go with a professionally made unit? I would love to give my cpu frost bite.....

You might need to either get a fairly large one, and/or stack them. They have a limited delta temperature rating, so the amount of cooling you get will be determined by the ambient air temperature, the amount of heatsinking you have, current flow through the device, and the device rating. I'm sure I don't have to tell you that if the device cools below room temperature, you will get condensation. So, your CPU will get frostbite, but also get waterlogged. Not good.

[J57ltr]

Brian,

On the efficiency 2 numbers pop into my head 30% and 65%, I'll look it up I have the notes, I think here at work.

You really need a large heatsink on the "hot" side (if you reverse polarity the change sides), they are capable of 70F temperature differentials so the colder you can keep the hot side the colder it gets on the cold side.

Think of this if the air temp is 100F and you can keep the hot side at 135F then you can only get the cold side to 65F. I used large fans or water cooling for my large projects. One thing you have to deal with on electronic applications is condensation. I shorted out a few devices (was able to fix them but that is another story), just because of that. They are really cool I have a dual probe digital temp (K-type) that I tracked temps with. It’s really neat to see the condensation form and then all of a sudden it starts turning to ice all across the plate.

Jeff

[aqwut]

Originally Posted by BrianG

Yesp, not worth what you get IMO. There are ultimately three ways to deal with heat:

1: More efficient components.

2: Less current.

3: Heatsink with thermal mass and surface area.

Everything else is just adding complexity.

I have two Quark 125's that use the top plate (connecting the three diffs) as a heatsink and it works wonderfully without the need for any additional active cooling. The chassis is another good heatsink and gets lots of airflow. I just wish more ESCs were built similar to the Quarks in how the FETs are mounted...

You're absolutely correct.. I've tried cooling with the TEC from ebay... it was just a waste... although it's good for cooling the motor after running, but during running... it's just a waste... Although it could be good for a closed system water cooling for the bigger scale stuff.. if you could have the hot side exposed on the outside..

[J57ltr]

Not even for the big scale stuff the more transfers you have the more losses you have a well designed heatsink system will outperform even a watercooled system if you have real long run times (an hour), thermoelectrics add complexity and you are going to loose 30% right off the bat. Run off of a power supply they are great, but batteries even Li-po you are going to run out of power in a hurry. When I charged my 4S1P pack last night I put about 1.4Ah back into it and only ran it for about 25 minutes give or take 5. I was going to graph it but I didn't bother I may later today with the temps and everything so you can see how they can perform.

JEff