Heat Sinks in Space? How?

[IDNeon]

OK so in general a computer heat sink relies upon the ability to heat the ambient surroundings and remove it generally by a medium such as air.

But how can this be done with say ... a super computer in space?

If I'm correct, space being a non-medium, would be a poor conductor leaving all thermal transfer to radiation (example infrared/thermal radiation).

Is such radiation enough to offset the heat accumulated in a spaceship by a computer system (far more advanced than what was on the space shuttle)?

As heat sinks and fans remove heat from the computer it just heats up the space ship. ...how then should or could that heat be dumped from the ship?

Contrary to popular belief things do not freeze in the shadows...the -200 in the night and 200 in the day term is actually meaningless.

If you were to throw yourself out of the airlock, you wouldn't explode, you wouldn't freeze in the shade (tho you might cook in the sun light).

You'd suffocate and you would oveheat because humans dump most their temperature by air convective cooling.

I'm sure a ship is the same way...on a space station the heat sinks are probably sufficient because most heat is body temp and ancient computers which didn't run very hot?

Just a fun topic for discussion hope to hear clarifications and etc.

 

[patonb]

Your analogy of the space station is very wrong.

The station would get extremely hot due to the solar radiation, and as such they use both water and Liquid ammonia, which is -30C roughly, to absorb heat, then transfer it out to space.
Check out this:
International Space Station's Cooling System: How It Works (Infographic)

Space is cold, and not quite a true vacuum. So you can still radiate heat due to potential difference between a rad and space.
The rads will obviously be designed a lot different than say a cars.
Again, see how the ISS does it:
External Active Thermal Control System - Wikipedia, the free encyclopedia

 

[Joe C]

For electronics like computers, they use heat pipes

Constrained Vapor Bubble heat pipes were operated on Earth and then launched into space and operated in the microgravity environment of the space station. "Heat pipes operate at a considerably higher temperature and pressure in microgravity than they do on Earth," explains Constrained Vapor Bubble Principal Investigator Joel Plawsky,

NASA - Keeping Cool With Heat Pipes on the Space Station

 

[IDNeon]

For electronics like computers, they use heat pipes

NASA - Keeping Cool With Heat Pipes on the Space Station

Both were great replies but let me reword my question more accurately.

Because heat transfer is much reduced by lack of convective cooling etc, how will future space craft discharge even greater amounts of heat?

I guess i envision a point when super computers of many exaflops generating massive almost nuclear reactor levels of heat, will overwhelm ordinary cooling processes in the constraints of space.

I suppose you could just run more ammonia pipes around the dark side of the ship....but what are the limitations?

Etc?

When will electronic heat generation overwhelm normal cooling methods.

 

[iParanormalx]

liquid helium

 

[patonb]

I'm assuming the amount of heat generated will dramatically be reduced when we get to that point. Even today our power consumption and generated heat has dramatically decrease.
I'm sure we will find even better advances that will decrease heat produced.. Cold fusion, dilithium crystals?? and methods to produce super cool heatsink type devices.


Also to note, space applications use Gallium Arsenide instead of Silicon for the process/transistors. These are much better for high temp resistance, though about $1mil/Kg.
Gallium arsenide - Wikipedia, the free encyclopedia
My old Prof was at one time the leading producer of GaAs crystals.

 

[Joe C]

The article I linked too stated they were using Pentane in the heat pipes, which is a flammable gas that's also found in gasoline and propane. I found it odd that NASA would use a flammable gas

 

[patonb]

The article I linked too stated they were using Pentane in the heat pipes, which is a flammable gas that's also found in gasoline and propane. I found it odd that NASA would use a flammable gas

Not really.. You need 3 things for combustion. Fuel, Ignition, and OXYGEN. NH3 (Ammonia) is highly toxic even in small amounts and corrosive to metals. Pentane under 350C is inert to most materials, plus a leak can be safely smelt, if stink is added" before it becomes dangerous.

Remember, even Hydrogen is benign under 5% and over 95%, as there's not enough Oxygen to burn.

You ideally run a 2 fluid loop, keeping the "Dangerous" fluid isolated from your crew cabin.

 

[Joe C]

One would think the pc's on space station would be in the same atmosphere as the astronauts.
Can't say I know the upper and lower limits of flammability are for pentane, it does boil around 96f

 

[patonb]

Depends as there are probably many other none human interface pcs in things.

However, the actual quantizes of Pentane are probably it's safety limits. Between 1.5% and 7.8% are explosive.

However, the pentane reference in the nasa link isn't a heatsink design test, but "how do heat pipes work in 0G" experiment.
Pentane is just a median that was used to see how fluid/vapor operate in 0G situations. Plus it was only 3/4" to 1.5" in height.
Probably chosen as it does boil at just above room temp.