TL;DR - “real” gases heat up or cool down when they are throttled through a valve from high pressure to low pressure. This is because of interactions between the molecules and it’s an interesting property. Counter intuitively, maybe, they flip from cooling to heating at some temperature. A one plot summary in two plots: interactive plot
Motivation I read a blog post from a researcher hypothesizing about the mechanism behind the Joule-Thomson effect.
TL;DR: In a recent camping trip we noticed just how cold our propane tank was getting after cooking for a while - we started out pretty chilly anyway (about 50 F). The physics of this is cool and I wanted to play with modeling it.
I have one of these little two burner propane stoves that we use when camping, it looks something like this:
While we were cooking breakfast and boiling water for coffee, we noticed that the propane tank was getting super cold - there was not only a thick layer of frost forming on the outside, but a small chunk of solid ice on the bottom of the tank where it met the picnic table…
In the Fall of 2017, while finishing my PhD I taught ChE thermodynamics to a class of graduate and advanced undergraduate students at the University of Rhode Island. I recently discovered some of my old course materials and decided to post them publically. It was a project based class, so after the first few lectures, most of the class meetings were spent working on problems and projects.
Either way, I hope they are useful to someone!