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DIY IR Thermal Suit

Posted: Wed Jun 17, 2015 2:44 am
by D5CAV

Re: DIY IR Thermal Suit

Posted: Wed Jun 17, 2015 8:39 am
by JustinR
So...BIT here... Why not outfit fatigues (with hookups for boots, gloves, and headwear) with an inner layer of cheap thermal blanket, followed by a system of small water tubing, which would draw the heated water to a thermoelectric plate and convert the waste heat to electricity to run the water pump (and possibly charge batteries or power devices depending on efficiency achieved), thus reducing heat signature and cooling the user without a big bulky gillie suit type cloak that keeps heat in?

Thermoelectric efficiency is based on temp difference between the two sides of the plate, but if you're in a desert environment during the day you have to blend with surrounding temperatures more than hide excess heat. Batteries could provide individual cooling, reducing fatigue. At night, the system would work as normal to reduce thermal signature. In a cold environment, you're going to be completely covered already, and batteries could be used with alternative fluids that won't freeze to provide whole body heating.

Thoughts?

Re: DIY IR Thermal Suit

Posted: Wed Jun 17, 2015 11:23 pm
by Aesop
A not-insignificant number of the guys we worked with on the CA border had day jobs and advanced degrees working for companies like Hughes, Litton, and FLIR.
And had the time, inclination, and spare funds to look at the problem of detecting people crossing over, both from a hobbyist point of view, and with an eye on at-work applications for same.
You can defeat thermal with a wet suit.
Or by smearing your naked body with mayonnaise.

Neither is practical for most normal applications under field conditions. :P

For those, nothing more complicated than a large throw rug is necessary.

And I defer to the hardcore physics guys, but the problem with a dedicated suit is that TANSTAAFL; you can move the heat, but you can't remove the heat. No matter what you devise, something's going to be hot, and show up. You can change the profile from a human body shape, but you'll just make the new signature the pump/machinery/a large rectangular cold spot/whatever.

Also, both rocks and trees are significantly warmer than the background environment under thermal observation. So whatever you devise, if it moves, hot or cold, it'll be detected, be identified as not-a-rock-or-tree, and then if appropriate, ventilated with appropriate amounts of lead/steel/expanding nitrate-based gasses. At which point the heat signature will assume room temperature, but you won't care because you'll be dead.

People with vast budgets have tried and are trying to crack this. Even if they come up with something, the entity observing will merely change to a different part of the spectrum, or combine multiple spectrums simultaneously (there are already dual simultaneous NV/thermal sights commercially available), rendering any such tech a huge waste of effort and investment.

As the USAF learned when illiterates shot an F-117 down with relatively limited resources.

The two best ways to defeat observation is to either go where there isn't any, or blind/kill the observers. Pretty much perpetually.
The rest is mainly toys for geeks, and rent money for the Dr. Emmett Browns of the world. NTTAWWT.

Re: DIY IR Thermal Suit

Posted: Thu Jun 18, 2015 6:40 am
by JustinR
Aesop wrote:And I defer to the hardcore physics guys, but the problem with a dedicated suit is that TANSTAAFL; you can move the heat, but you can't remove the heat. No matter what you devise, something's going to be hot, and show up. You can change the profile from a human body shape, but you'll just make the new signature the pump/machinery/a large rectangular cold spot/whatever.
Remove, no, but you can change the heat energy into electrical energy, hence the thermoelectric plates, with the side being heated on the inside, the other side on the outside of the suit exposed to the ambient with a heat sink and fan to keep it close to ambient, but hidden from direct line of sight with a shroud. The real question is whether such a system would be able to collect enough of the body heat to allow an individual to blend in with the underbrush when not moving, and have the thermal efficiency to convert the heat to electricity without causing the outside of the plate and heat sink to become, as you said, a small but intense hot spot. I'd have to do more research and perhaps buy a small thermoelectric plate to outfit to a glove with water tubing to test the viability. Because it's fun. :)

Re: DIY IR Thermal Suit

Posted: Thu Jun 18, 2015 12:20 pm
by Precision
JustinR wrote:
Remove, no, but you can change the heat energy into electrical energy, hence the thermoelectric plates, with the side being heated on the inside, the other side on the outside of the suit exposed to the ambient with a heat sink and fan to keep it close to ambient, but hidden from direct line of sight with a shroud. The real question is whether such a system would be able to collect enough of the body heat to allow an individual to blend in with the underbrush when not moving, and have the thermal efficiency to convert the heat to electricity without causing the outside of the plate and heat sink to become, as you said, a small but intense hot spot. I'd have to do more research and perhaps buy a small thermoelectric plate to outfit to a glove with water tubing to test the viability. Because it's fun. :)
I would like to subscribe to this newsletter. I am interested from a technical as well as practical stand point.

Re: DIY IR Thermal Suit

Posted: Thu Jun 18, 2015 12:53 pm
by Greg
JustinR wrote:
Aesop wrote:And I defer to the hardcore physics guys, but the problem with a dedicated suit is that TANSTAAFL; you can move the heat, but you can't remove the heat. No matter what you devise, something's going to be hot, and show up. You can change the profile from a human body shape, but you'll just make the new signature the pump/machinery/a large rectangular cold spot/whatever.
Remove, no, but you can change the heat energy into electrical energy, hence the thermoelectric plates, with the side being heated on the inside, the other side on the outside of the suit exposed to the ambient with a heat sink and fan to keep it close to ambient, but hidden from direct line of sight with a shroud. The real question is whether such a system would be able to collect enough of the body heat to allow an individual to blend in with the underbrush when not moving, and have the thermal efficiency to convert the heat to electricity without causing the outside of the plate and heat sink to become, as you said, a small but intense hot spot. I'd have to do more research and perhaps buy a small thermoelectric plate to outfit to a glove with water tubing to test the viability. Because it's fun. :)
Suspect thermodynamics is not your friend here.