4 ms·

Space is around -270°C cold. The heat would dissipate so quickly, much better than even liquid nitrogen cooling.

by roflmaostc 3y ago

deleted 3y ago
[deleted]
gideonparanoid 3y ago
Without convection or conduction?
roflmaostc 3y ago
ok to correct myself. Due to lack of much air, heat would only dissipate by Black body radiation. One would need to calculate if that could cool down the chips efficiently.
- Ekaros 3y ago
  It won't. There is reason why we use fans. There is two ways to handle high heat loads, convection or evaporation. And you would run out of evaporative material in space pretty quickly.
- bee_rider 3y ago
  I think this is a very popular mistake to make. It is sort of a well known bit of trivia, but only because everybody has to correct themselves on it at least once, haha.
- asdfman123 3y ago
  If it's dissapating through black body radiation the temperature of space isn't really that relevant to cooling. You can radiate heat from the surface of the earth into space via the sky, but you don't lose much energy that way.
  - roflmaostc 3y ago
    > You can radiate heat from the surface of the earth into space via the sky, but you don't lose much energy that way. That's not quite true. Black body radiation is the only reason why earth does not heat up much more. It's the only factor with a negative radiative forcing. Solar radiation is the only main incoming source of energy, and black body radiation the only outcome with almost the same magnitude (which is huuuuge btw)
    - asdfman123 3y ago
      What I mean that building a system to radiate radiate energy into space from the surface of the earth isn't very cost effective, and it's undoubtedly far less expensive than building a system you would launch into space. The actual surface of the earth has the advantage of being able to use the whole surface of the earth. On earth you can use things like fans and evaporative cooling. It's far superior to making huge space radiators, but nothing is free.
lathiat 3y ago
You would think so, but that's not as simple as you would think. On Earth that cooling generally happens by conduction and convection to the air. In space there is mostly no atmosphere, you have to radiate that heat which isn't quite as easy as it sounds: https://www.space.com/21059-space-station-cooling-system-explained-infographic.html https://www.space.com/21059-space-station-cooling-system-exp...
badcppdev 3y ago
If you think about why a vacuum flask or thermos is used to keep drinks hot (or cold) for an amount of time you'll realise that space / a vacuum is a very good insulator. An object in space loses heat according to the Stefan-Boltzmann law of radiation. That use the fourth power of the temperature differential so you get boost from the background of space being -270C. BUT the Stefan-Boltzmann constant is 5.67 × 10−8 J/s · m2 · K4 and that is the problem. You can do the numbers yourself but various internet sources suggest that spacecraft radiators can only cool between 100 and 350 W of internally generated heat per square meter. That is a big radiator for not much cooling.
_Algernon_ 3y ago
Air cooling occurs by convection which is completely absent in space. Similarly, advection and convection seem unlikely to contribute much. That leaves mainly radiation which is a lot slower: https://en.wikipedia.org/wiki/Heat_transfer#Heat https://en.wikipedia.org/wiki/Heat_transfer#Heat

Space is around -270°C cold. The heat would dissipate so quickly, much better than even liquid nitrogen cooling.

deleted 3y ago

[deleted]

gideonparanoid 3y ago

Without convection or conduction?

roflmaostc 3y ago

ok to correct myself. Due to lack of much air, heat would only dissipate by Black body radiation. One would need to calculate if that could cool down the chips efficiently.

Ekaros 3y ago
It won't. There is reason why we use fans. There is two ways to handle high heat loads, convection or evaporation. And you would run out of evaporative material in space pretty quickly.
bee_rider 3y ago
I think this is a very popular mistake to make. It is sort of a well known bit of trivia, but only because everybody has to correct themselves on it at least once, haha.
asdfman123 3y ago
If it's dissapating through black body radiation the temperature of space isn't really that relevant to cooling. You can radiate heat from the surface of the earth into space via the sky, but you don't lose much energy that way.
- roflmaostc 3y ago
  > You can radiate heat from the surface of the earth into space via the sky, but you don't lose much energy that way. That's not quite true. Black body radiation is the only reason why earth does not heat up much more. It's the only factor with a negative radiative forcing. Solar radiation is the only main incoming source of energy, and black body radiation the only outcome with almost the same magnitude (which is huuuuge btw)
  - asdfman123 3y ago
    What I mean that building a system to radiate radiate energy into space from the surface of the earth isn't very cost effective, and it's undoubtedly far less expensive than building a system you would launch into space. The actual surface of the earth has the advantage of being able to use the whole surface of the earth. On earth you can use things like fans and evaporative cooling. It's far superior to making huge space radiators, but nothing is free.

lathiat 3y ago

You would think so, but that's not as simple as you would think. On Earth that cooling generally happens by conduction and convection to the air. In space there is mostly no atmosphere, you have to radiate that heat which isn't quite as easy as it sounds: https://www.space.com/21059-space-station-cooling-system-explained-infographic.html https://www.space.com/21059-space-station-cooling-system-exp...

badcppdev 3y ago

If you think about why a vacuum flask or thermos is used to keep drinks hot (or cold) for an amount of time you'll realise that space / a vacuum is a very good insulator. An object in space loses heat according to the Stefan-Boltzmann law of radiation. That use the fourth power of the temperature differential so you get boost from the background of space being -270C. BUT the Stefan-Boltzmann constant is 5.67 × 10−8 J/s · m2 · K4 and that is the problem. You can do the numbers yourself but various internet sources suggest that spacecraft radiators can only cool between 100 and 350 W of internally generated heat per square meter. That is a big radiator for not much cooling.

_Algernon_ 3y ago

Air cooling occurs by convection which is completely absent in space. Similarly, advection and convection seem unlikely to contribute much. That leaves mainly radiation which is a lot slower: https://en.wikipedia.org/wiki/Heat_transfer#Heat https://en.wikipedia.org/wiki/Heat_transfer#Heat