cooling in Vacuum

[GeoNasr]

I am looking for a way for cooling a red pitaya Microcontroller in a test vacuum chamber, where its a pendulum to measure the thrust of a tested electric engine for satellite use.
Here is the weight of the used method important. We thought of a radiator, are there any other ideas?

Thanks

 

[racookpe1978]

In the vacuum of space, you can only use a radiator. Thermal conduction out from the heat source to the "frame" or "backbone" of the radiator, then thermal conduction out from the backbone to the flat "wings" of the radiator. Then radiation out to space - OR absorption FROM the sun and reflection from the earth back to the radiator wings. Yes, sometimes the radiator will be receiving heat energy as well.

But, for the test case in the vacuum chamber, you need to decide if you are going to cool the engine, or going to test the entire assembly (engine, heat transfer blocks, and radiator design and exposure. If only testing the engine, the the final heat transfer blocks can be mounted to simple (vacuum-proof) plates with internal cooling ports for any liquid of your choice - including water or alcohol or oil or even a gas like Argon or Helium. As long as the cooling liquid does not leak from the plates nor the tubes connecting the plaes to the vacuum chamber wall connections, you don't care what the final arrangement will be while testing the engine.

Later? Everything must be at the real vacuum condition of darkness, absorbtion and emissivity of the wall, wall coldness, vacuum, and light.

 

[IRstuff]

If there's no dedicated radiator, i.e., radiators are on the body, then the side that get's sun is usually opposite a side with no sun. Often these opposite sides are thermally strapped together to dump the sun load onto the dark side.

TTFN
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[EdStainless]

We used to need to cool electronics in a vacuum chamber for a 6 hour test. We mounted them to a large enough Cu block to limit the temp rise to an acceptable level. We weren't allowed any active cooling so a large heat sink was our easiest option.

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P.E. Metallurgy, Plymouth Tube

 

[chicopee]

Ed stainless is on the right path. Have a continuous copper block on both sides of the vacuum chamber(so sealing details would need to be worked out) and cool the side of the copper block outside the chamber. From conduction, the inside portion of the Cu block will cool down and somehow devise a system of attachment between the Cu block and the microcontroller.

 

[chicopee]

I have another idea and I don't know if it would work. Here it is I may have a different approach what if you impressed a low voltage source on a thermopile where one of the junctions would get cold and the other side hot. The cold side would then be inside the room.

 

[chicopee]

Oops! correction: "... Here it is: what if you impressed a low voltage source on a thermopile where one of the junctions would get cold and the other side hot. The cold junction would then be inside the vacuum chamber". The cold junction would then be fastened to the microprocessor.

 

[racookpe1978]

Well, as I said above, it depends if you need to test just a part of the spacecraft "hot spot" in the vacuum chamber, or the whole spacecraft engine and generator as a system.

 

[MortenA]

Paint the inside of the vacuum chamber black (it absorbs heat best) and (water) cool on the outside?

 

[MisterE2]

going to need more info on the chamber, standard pump and seal? diffusion pump? size? It eliminates a lot of possibilities if you have to worry about something outgassing in a chamber