Recent content by Daanh

And how about those fifty shades of grey, eh?

Hi, what happens to a cilinder of liquid helium when it heats up to room temperature? Thanks, Daan

I see it now. Yes, that could be true. The melting of the ice takes heat from it's surroundings, the remaining ice or the liquid. Latent heat is a tricky thing.

When all the liquid is at zero degrees, what will make the temperature drop more?

In what possible scenario would they both cool down? Assuming you wouldn't put them both in a deep-freezer...

Thanks for your reply Chester and Steamking. The reason behind my question is this: for a few years we have this project where students have to design and build a cooling machine, just using air and water as media and powered just by hand. This for cooling a small chamber for storing medicines...

Sorry, I mean a simple pressure cilinder, without a piston (actually, students use a Coca Cola bottle). So say Yes, but then you say that the expansion must be free and not through a turbine. I've read this in the article, and I don't get it. Expanding through a turbine surely makes the air do...

Thanks for all the replies. So an expanding pressure cilinder does work by pushing the lower-pressure gas away and therefore decreases in temperature. The most temperature drop would occur inside the cilinder, I assume? Does it make a difference if the expanding gas does more work, say in the...

Hi, thanks for your reply. Of course we know how a refrigerator works. In my situation, there is no phase change. But your link to the Joules-Thomson effect is very helpful. Although I still don't understand why it's important for an expanding gass to do work or not. Is simply expanding of air...

Hi! I'm a teacher in Mechanical Engineering, and I organize a (yearly) student's project where they design and create a cooling machine. The machine works by compressing air, cooling the compressed air, and then rapidly expanding it. This can lead to temperatures of minus 7 degrees Celsius. I...