Apologies if this is already known, or obvious to some of the more physics-educated of you, but I wanted to put forth a "discovery" I made recently. Quotes because I'm sure it's not a novel concept in the real world - in fact googling the title of this post yields many results. I was happy to discover the behavior in ONI however, and I find it tremendously useful.
I wanted to share, because while the concept of using heat exchangers is well-known in the community (for example when cooking p