These windows have a circulatory system of microfluid that keep the glass cool. These windows would keep the inside of the room much cooler and cut energy costs.
More info: https://www.seas.harvard.edu/news/2013/08/self-cooling-windows-let-in-sunlight-without-heat
My first reaction was: "This smells like hype." Then I read the link, and there was little or no elaboration of the radiative and thermodynamic principles that could be involved, i.e., it read like fluff. I don't buy it.
ReplyDeleteThe red flag re hype is the "light without heat" meme. First, even if the windows work, all they do is carry heat away, i.e., are fancy air conditioners, and in no way is there "light without heat"; the water can intercept heat on the way in and on the way out, and carry it away ... to where? The water will have to be cooled to be recycled. Again, looks like a glorified air conditioner ... and the advantage would be lower cost of operation, perhaps, depending on how the water is eventually cooled and recycled.
Here's the thing: light that enters a room as visible light is reflected/refracted/absorbed/re-emitted by the objects it impinges on, and eventually degraded into infrared spectrum waves. Glass normally passes visible light better than infrared, so the net effect in a glass-enclosed space is that on balance, heat is introduced into the room and relatively trapped.
The water in the glass can capture and carry off the infrared/heat frequencies while (like glass) passing the visible frequencies, so far so good. But there is no magic here: the water must be cooled, and that will take work on a hot day -- perhaps not as much as conventional air conditioner.
Conservation of energy: if energy as light is coming in, it must go somewhere.
Ummmm...David, thanks for explaining this...however I'll follow this subject closely and see where it goes.
ReplyDeleteWhat I want is glass that passes infrared in only one direction based on a voltage that can be flipped so that it is net cooling in summer and net heating in winter ... ;)
ReplyDeleteCome on David.... I want teleportation :))
ReplyDeleteBetter yet: the window can be a zero-pass filter for infrared in one direction (possible, using arsenic as a thin layer) and then be swiveled around so that one can choose which way it blocks. This is not a pipe dream; teleportation is.
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