1mo ago

Penn Engineers Discover a New Class of Materials That Passively Harvest Water from Air

blog.seas.upenn.edu Penn Engineers Discover a New Class of Materials That Passively Harvest Water from Air - Penn Engineering Blog

A serendipitous observation in a Chemical Engineering lab at Penn Engineering has led to a surprising discovery: a new class of nanostructured materials that can … Read More ›

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Engineers Discover New Class of Materials That Passively Harvest Water from Air

blog.seas.upenn.edu /penn-engineers-discover-a-new-class-of-materials-that-passively-harvest-water-from-air/

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pull water from the air, collect it in pores and release it onto surfaces without the need for any external energy
If this is legit, it's going to be revolutionary.
- If a "passive dehumidifier" is possible using this and a funnel/hose, that could be extremely exciting for basement and cellar owners everywhere
  
  depends how space efficient it is. maybe you would you need to fill your entire basement with the stuff for it to work.
  
  A surface-area maximizing structure like a radiator grille could probably be used if it's anywhere near reasonable, but yeah, that could be a concern
- That seems like it would violate the law of entropy by turning a high entropy state (water vapor mixed into the air) into a lower entropy state (water in liquid form), but I'm probably just missing something.
  
  I don't at all understand why the second law of thermodynamics is being invoked. Nonetheless, capillary condensation is already a well-studied phenomenon. As the scientific article itself notes, the innovation here over traditional capillary condensation would be the ability to easily remove the water once it's condensed.
  Re: Entropy:
  Entropy is a statistical phenomenon that tends to increase over time averaged across the entire body, i.e. the Universe. Not literally every part of the Universe needs to increase its entropy as long as on average it is increasing. You're evidence of that: your body is a machine that takes entropy and pushes it somewhere else.
  Water vapor is a high-energy state compared to liquid water. What you're saying therefore is the opposite of how the second law works: water vapor's energy tends to spread out over time until it eventually cools back to a liquid. Liquid water is a higher entropy state than water vapor.
  
  The entropy of a little water mixed with air is higher. As with anything that mixes a little.
  
  Condensation is exothermic, though, so the material will heat up slightly
- Yeah that was my thought too. I hope it makes it to actual use cases and not just lab proof of concept.

38 comments