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ArcticMyst Security by Avery

TEC/Peltier Cylinder/Hex Idea

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A TEC is not practical in a portable. Lets just assume a few things here.

For an average 445 build you are feeding around 1.5A into the diode at around 4.5V. That calculates out to something around 5W of heat. Assuming 1.5W of that heat escapes as light leaves you with 3.5W of heat from the diode to dissipate. Now, let's assume you have a super efficient TEC, somewhere along the lines of 20%. You would need to power that TEC with more than 18 watts of power to keep the diode from heating up (Your not even cooling yet!) Now, if you have a 5V TEC you would need 3-4 amps to keep that diode from burning up.

So, you have the driver for the diode producing heat. The driver for the TEC making heat (You can't just hook the TEC up without a driver, you would freeze the diode over with condensation or just burn the TEC up.) The TEC itself making buttloads of heat and the battery making heat from the insane load you are putting on it. In short, that host is getting hot FAST. Any sort of duty cycle you would have gained will be lost because a portable laser is not much good if it's too hot to hold.

In a "lab laser" a TEC makes sense. In a portable it does not.

6 TECs in a portable is just ludicrous, and not in a good way.
 





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You shouldn't measure cooling systems in terms of efficiency, because it is misleading. A 500W AC unit can move 1500W of heat. This does NOT mean it is 300% efficient. You should instead use COP.

According to one google source, "0.4 to 0.7 is a typical range" for peltier devices. So you'd need a 5-10W TEC to keep the diode at ambient temp.

Here is a good power point if you want to learn more about TECs.
 
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can the cold side of a peltier have fins? like for more surface area, or would that work?
 
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you could put fins on the cold side but for cooling you want larger mass. the fins will dissapte a lot of coolness to the atmosphere.

just an fyi peltiers are the devices in 12v car and portable refrigerators.

michael.
 
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you could put fins on the cold side but for cooling you want larger mass. the fins will dissapte a lot of coolness to the atmosphere.

just an fyi peltiers are the devices in 12v car and portable refrigerators.

michael.

can a private citizen make a TEC or do I need some kind of industrial equipment?

private citizen example: making a vice grip from scratch is possible with a mill, and doesn't require a factory.

industrial example: making a microchip for a laptop requires a billion dollar research lab - not possible.

The plates for the TEC seem possible but the stuff sandwiched between seems complex and factory issue. Am I mistaken?
 

Things

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TEC's are made from P and N silicon junctions. Unless you could acquire these yourself and assemble them (Which could involve hundreds of junctions for even a small TEC), then no, it's not practical to make them.

TEC's that will fit in a handheld host will not be powerful enough. They are simply too unefficient and impractical at that size. You could probably only fit 2 junctions into something the size of a laser diode.

p3.gif
 
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Tec's are pretty cheap. So think making one isnt necessary. But it was invented I think with out higg tech machinery. But todays tec's are made with better materials. And the heat sinks can be found in any old computer.
 
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TEC's are made from P and N silicon junctions. Unless you could acquire these yourself and assemble them (Which could involve hundreds of junctions for even a small TEC), then no, it's not practical to make them.

TEC's that will fit in a handheld host will not be powerful enough. They are simply too unefficient and impractical at that size. You could probably only fit 2 junctions into something the size of a laser diode.

I was thinking of applying them directly to the surface of a hexagonal copper or aluminum exposed heat sink, so approximately 90mm x 50mm total, with six plates each 50mm X 15mm. Since I don't have stats (yet) on what sizes I could get custom, or how much power those sizes would take, I have no data at this time to assist me in knowing if it really is a wild goose chase.

I can only say my expectations are extremely low.
 




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