I rush wrote this so forgive any errors.
We all know space can be really cold and that also means if you got some place cold and another place warm then you can also use that to run anything from steam turbines to steam engines in a sort or reveres process to the way we usually think about steam power. Yes space is a long way up and yes you cant use water but you can use liquid ammonia.
This idea is probably not practical but if it interests you I will have some ideas on pneumatic towers i.e. towers held up by inflatable bags, as a possible idea to build very low cost very high towers for the idea of using them for mass drivers for space
Here is how this works. Ammonia as a gas dose not weigh much so it goes up the much larger diameter but thinner walled diameter pipe with less force, than what the liquid ammonia comes down in the smaller diameter thicker walled tube.4 or 5 miles of pipe filled with liquid ammonia comes to a lot of pressure at its bottom. You can use the liquid ammonia just as you would water behind a dam and maybe again as you would in a steam engine when it goes into the warmer water and boils back to a gas that goes back up again. If the top of the mountain is a bit more than minus 30 C then no pressure is needed to re liquefy the ammonia but of course the warmer it is at the top the more pressure you need to re liquefy the ammonia but because its an all closed system its really easy to control.
Now my experiment is a bit similar but if it works you wont have to climb a mountain and can actually get much lower temperatures than the surrounding air while sitting on the near surface of the earth. I even got my piece of germanium metal to actually try this and will post the results here.
Here is how it will work if it does. I have read about what is called the infrared window and its used to explain how our earths surface cools by emissions. Those long wavelength heat radiations that are similar to what we feel near a camp fire. Even an ice cube gives off these emissions they just absorb more than they emit and of course the ice cubes emotions are at a slightly lower energy too.
What's unusual here is that a shinny metal like germanium is transparent to these emissions while reflecting light and yet those same emissions wont pass through a piece of glass.
With germanium its possible for it to be cold to the touch and while at the same time you could feel the heat from a fire from its other side and that's not something a lot of us have ever had the experience of trying.
The infrared window I have read is about 10% transparent to this infrared and as we all know about this green house effect and that carbon dioxide decreases this transparency. That's still quite a lot when you remember that space is typically almost 300 C bellow room temperature. Space is approximately nearly -270 C and or about 4 C above the absolute coldest temperature. Room temperature is about 20 C.
Remember ever being told that if you had a very sooty tall chimney that you could look up its insides and see stars even during the day. Well this experiment below was somewhat influenced by that and I am hopping it can be made not only to work at night but even during the day. Never actually tried looking up from inside an old chimney but I am hopping its at least partly true.
Here is an illustration of the planed experiment and I plan to try getting this to work even in daylight. Note that the germanium if its reflective enough could turn out to work even under direct sunlight but I do expect its efficiency would be considerably reduced. Using a shade just large enough to shield the sun should certainly help.
It is important to remember that everything emits this heat radiation so I will have to place the germanium window where its above most objects like trees etc. Radiation moves in straight lines just like light so if its in line of sight from the perspective of the window then its heat radiation can get in as well. For maximum effect we want just the sky and or space. I am guessing that clear skies should probably work best.
Its just an old thermos bottle with graphite powder at its bottom but its the germanium window that even while it will be warmed by the surrounding air will not re emit much of its heat radiation back onto the black graphite at its bottom while allowing the graphite to cool to the much lower temperatures of the higher atmosphere and or of space itself. Things that absorb head radiation poorly also emit it poorly as well. With an our atmospheric "infrared window" only an average of 10% transparency I am just guessing I might get a 10% lower temperature based on an almost 300 degree difference and maybe at most get about 0 C on a warm day. A hot summer day temperature is about 30 C and that's about 10% of 300 but only guessing here how this would actually work. If the the atmospheric "infrared window" were instead 100% transparent it would probably be just like it would be on the moon with no atmosphere, then you could probably even liquefy air even in daylight and if the thermos was good enough at insulating.
Yes I got my small germanium window on ebay and am just waiting for the chance to set it up for a try. Be careful with it if you plan to also try this as its quite brittle.
Anyone want to guess at the temps it might get for day and night.