Awesome, that is very helpful.

> Then the _material_ is a store of energy. Once it's exhausted, the condensation will stop.

The paper points out that the sample was surface that maintains a particular temperature (20 degrees C in this case). The water condenses, the material heats up, the thing its sitting on removes that excess heat to maintain the temperature. No violation of CoE or TD.

Without that temperature controller, the material would presumably continue to store the heat, which would make it hotter than the ambient temperature. By how much is, as you point out, something to be characterized.

Thermodynamics says that the heat will equalize, so that excess heat will conduct to the air around it (it's not in a vacuum so it doesn't have to radiate it). That will lower the temperature of the material which will then condense more water and heat up again. My original thought was you could enhance that conduction by putting a heatsink on one side of the material.

The paper states that inside the pores they have managed to create a space that changes the parameters around the vapor carrying capacity of the air which results in the water condensing even though it would not have condensed outside those pores. Then they go on to describe how the effects of hydrophillic and hydrophobic materials, used in conjunction, create spaces near the molecular limit of water molecules and how the forces acting on that water might result in it condensing. When the vapor does condense, the heat goes somewhere, and they assume its going into the material (reasonable assumption in my opinion) and that their temperature controlled platform is then removing it. I found the description of how that water expresses to the surface a bit more "hand wavy" but that they observed liquid water on the surface, and that it is somehow coming from the material they created, seems reasonably well supported.

I think for the purposes of this discussion we're done. I really do appreciate that you are skeptical and feel that some of the more well tested laws of physics are being violated :-). Since we can only go on what they wrote up, I did make the presumption that they too know the laws of physics and have a good faith belief that they are not being violated either. It is one of the things I look for in papers that talk about things like this. Also the journal where they published their paper, Science Advances, is a refereed journal so I would presume that the reviewers were also satisfied they weren't violating any well known laws of physics. Doesn't mean that you should believe what they say, just that it's not obviously wrong.