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Solar power AC units, soon or never?

  1. Jun 30, 2009 #1
    It seems to me that solar power and air conditioning are made for each other. As of now there are several different companies making smaller adsorption/absorption AC units, but they are overpriced compared to their electric driven counterparts giving limited return on investment. Here's what I've found:

    LiBr units: expensive and mostly large units. (few residential applications.)
    Silica Gel or other Adsorption: expensive and the desiccant takes up a lot of space. Also mostly larger units.
    Ammonia: not in commercial use due to safety concerns.

    There may be others, but these are all I could find that are thermal driven. Since a PV driven solar AC is just electrically driven I don't count it as a viable option until PV power is cheaper than grid power.

    What is your take on solar powered AC? Is it doomed to failure until we have new technology that makes it affordable or are we just waiting for someone to build a cheap standardized unit? Is there anything I haven't mentioned?
  2. jcsd
  3. Jul 1, 2009 #2


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    That's pretty much my take on it. I do have tentative plans to install a small solar panel, but only because it will power something that would be a pain to wire in to the main power.
  4. Jul 1, 2009 #3


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    Don't forget to consider Air and the many ways it is used, it retains the solar even when the sun is not visible.:smile:
  5. Jul 1, 2009 #4
    May be true. I was hoping that the relative inexpensiveness of solar thermal power could make this affordable in the short run.

    True, but when you see a wind powered AC unit you let me know. The reason why this is focused on solar is because there are many thermal driven chillers on the market, and because you need AC the most during the middle of the day. Also wind power is much more expensive to get than solar thermal power.
  6. Jul 1, 2009 #5


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    http://www.rotartica.com/pub/index.html?http://www.rotartica.com/pub/ingl/02_absorcion.htm" seems to have one. Though googling it just shows people talking about it for the last year. No mention of price. And you know how that goes. If you have to ask, you can't afford it. :frown:

    Anyone know where I can buy some lithium bromide? Might be fun to build one. :smile:
    Last edited by a moderator: Apr 24, 2017
  7. Jul 1, 2009 #6


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    I was referring to compressed air, not wind, although if the principles are the same, compression reduces the size of the system.:smile:

  8. Jul 1, 2009 #7
    I've looked at the Rotartica units before online, but the company is still only in testing and not mass production so price is still up in the air. Compressed air for a cooling cycle is possible, but the volume of air needed is the problem, that's why people use an absorption cycle or rankine cycle for cooling. Stirling coolers have promise, but if they ever go into production they will be prohibitively expensive.

    On a side note, I did attempt to build a small silica gel chiller, but the problems with maintaining a vacuum caused it to become a garage ornament. Might build a LiBr chiller eventually since I like the idea of a liquid desiccant much better, just don't have the tools right now.
  9. Jul 9, 2009 #8
    I read about a design that uses a desiccant 'waterfall' to absorb humidity from indoor air and regenerates the desiccant using solar heat. http://www.solarteam.org/page.php?id=641" [Broken] Still a ways from practical, but pretty neat idea.
    Last edited by a moderator: May 4, 2017
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