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Dacosta
12-08-2010, 08:13 PM
Looks like another requirement to be an astronaut is to be an ammonia tech.

http://www.npr.org/templates/story/story.php?storyId=128932238


After reading this article I was wondering how one would build an ammonia refrigeration system in space.

How would you deal with the fact of no gravity, all the liquid would not sit at the bottom of the High pressure receiver, and the pumps would not have sufficient NPSH.

Or how would you condense without wet bulb or even an atmosphere to reject heat to.

Grizzly
12-08-2010, 08:58 PM
WHY WOULD YOU WANT TO?
Surely in a negative atmosphere the problem would Lack of heat?
Grizzly

Peter_1
13-08-2010, 07:54 AM
Grizzly, the station is surrounded by almost a vacuum, with 'nothing'
So all the heat generated inside the station remains in the station. If you install a heat exchanger outside the station, there's even no air to change your heat with. Seems not that easy.
Even a 'simple' airliner uses its 'expensive compressed energy' of the turbines to generate cold they need inside the cabin and it's mostly -50°C outside.

brian_chapin
13-08-2010, 02:58 PM
The heat from all the electronics is rejected out as infrared radiation by large radiators.

http://science.nasa.gov/science-news/science-at-nasa/2001/ast21mar_1/

I'm assuming the "cooling pump" they've been having trouble with is actually a compressor of some kind because 700# is a HELL OF A PUMP.

zolimer
21-10-2010, 08:24 AM
Looks like another requirement to be an astronaut is to be an ammonia tech.

http://www.npr.org/templates/story/story.php?storyId=128932238


After reading this article I was wondering how one would build an ammonia refrigeration system in space.

How would you deal with the fact of no gravity, all the liquid would not sit at the bottom of the High pressure receiver, and the pumps would not have sufficient NPSH.

Or how would you condense without wet bulb or even an atmosphere to reject heat to.
I am no scientist, with that said I believe that you can overcome the gravity issue by using centrifugal force. It would be like taking a balloon that is half filled with air and half filled with water and swinging it around by the knot! The water would hug the outer extremes. as an added bonus if you spin the vessel fast enough you may not even need a pump.

And the condensation problem is easy
we can replicate that kind of atmosphere easily i would think!