alt Hacker NewsThe equation has a ^4 to the temperature. If you raise the temperature of your radiator by ~50 degrees you double its emission capacity. This is well within the range of specialised phase change compressors, aka fancy air conditioning pumps.
Next up in the equation is surface emissivity which we’ve got a lot of experience in the automotive sector.
And finally surface area, once again, getting quite good here with nanotechnology.
Yes he’s distracting, no it’s not as impossible as many people think.
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> aka fancy air conditioning pumps
Yeah, pumps, tubes, and fluids are some of the worst things to add to a satellite. It's probably cheaper to use more radiators.
Maybe it's possible to make something economical with Peltier elements. But it's still not even a budget problem yet, it's not plainly not viable.
> getting quite good here with nanotechnology
Small features and fractal surfaces are useless here.
Raise the temperature of your radiator by 50 degrees and you double its emission capacity. Or put your radiator in the atmosphere and multiply its heat exchange capacity by a factor of a thousand.
It's not physically impossible. Of course not. It's been done thousands of times already. But it doesn't make any economic sense. It's like putting a McDonald's at the top of Everest. Is it possible? Of course. Is it worth the enormous difficulty and expense to put one there? Not even a little.
Even if you create a material with surface emissivity of 1.0:
- let's say 8x 800W GPUs and neglect the CPU, that's 6400W
- let's further assume the PSU is 100% efficient
- let's also assume that you allow the server hardware to run at 77 degrees C, or 350K, which is already pretty hot for modern datacenter chips.
Your radiator would need to dissipate those 6400W, requiring it to be almost 8 square meters in size. That's a lot of launch mass. Adding 50 degrees will reduce your required area to only about 4.4 square meters with the consequence that chip temps will rise by 50 degrees also, putting them at 127 degrees C.
No CPU I'm aware of can run at those temps for very long and most modern chips will start to self throttle above about 100
This makes zero sense.
> Next up in the equation is surface emissivity which we’ve got a lot of experience in the automotive sector.
My car doesn't spend too much time driving in vacuum, does yours?
> And finally surface area, once again, getting quite good here with nanotechnology.
So your hot thing is radiating directly onto the next hot thing over, the one that also needs to cool down?