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6581RE: [hreg] Solar powered A/C

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  • Paul Archer
    Jul 9 7:30 PM
      Kevin, you seem pretty well versed on the subject, so perhaps you can answer
      this question for me: (why) is the heat from the A/C itself not used in the
      process? It seems to me that you could take cold (well, cool) water and run
      it through a heat exchanger with the condenser coils (or whatever passes for
      condenser coils in an absorbtion unit), and then on to the solar collectors,
      for a gain in efficiency. Or is there something I'm missing with that?

      Paul


      9:24pm, Kevin Conlin wrote:

      > Hi Folks, I believe the solar powered system in the Caribbean was a solar
      > thermal absorbtion chiller. There have been several attempts to do this,
      > usually using a commercial absorbtion chiller that uses solar hot water from
      > evacuated tube collectors as either a pre-heat with natural gas final
      > heater, or using the chiller at lower efficiencies with lower temp solar
      > water. The absorbtion chillers are a very proven and extremely reliable
      > process generally designed to use waste heat or stream in the low 200'sF.
      > They are known to run for 50 years or more as they have very few moving
      > parts and very low energy consumption, most of which runs pumps. They are
      > mostly found in large factories or plants, I remember seeing a large one at
      > a Procter & Gamble paper plant that used waste heat from a cogeneration
      > turbine. The plant maintenance crew loved it because it ran so quiet and
      > smooth, and never required attention. Unfortunately, this process is not
      > scaled small enough for residential use, I think the smallest units are 20
      > tons, but with lower evacuated tube collectors coming out of China, it may
      > be practical for commercial scale systems.
      >
      >
      >
      > There was one system at NASA over 20 years ago, but like most demo projects,
      > it was very expensive, over engineered and under built. There was also a
      > home builder here on Houston that offered solar AC in the late 70's,
      > Morgan-Barnhart was their name, and they used tracking solar thermal trough
      > concentrators mounted on the roof. (Nice aesthetics!) They also failed,
      > due to various mechanical and other problems, as well as the relatively poor
      > and often cloudy solar resource here in Houston during the summer. Tracking
      > collectors are better suited to cloudless regimes like west Texas, NM, AZ
      > etc..
      >
      >
      >
      > I believe there are some residential systems being offered in Japan, but I
      > have no first hand knowledge of them. Solar A/C has long been one of the
      > holy grail's in the industry, it seems like a practical compromise using
      > proven technologies would be a solar driven geothermal system.
      >
      >
      >
      > That's all I can recall from memory, it would be great if someone would
      > commercialize the technology and do it right, after all, they've been
      > working on it for 30 years!
      >
      >
      >
      > Kevin
      >
      >
      >
      > _____
      >
      > From: evelyn sardina [mailto:evelynsardina@...]
      > Sent: Monday, July 09, 2007 5:53 PM
      > To: hreg@yahoogroups.com
      > Subject: Re: [hreg] Solar powered A/C
      >
      >
      >
      > A freind just got back form Costa Rica. He brought back a picture of a long
      > black hose that sits on top of a roof in a work house in the farm where he
      > stayed. It provided all the hot water needs for the shed. It was rolled up
      > in many layers and was just sitting on top of the roof. I think it was tied
      > to the roof. I asked him to email to the group but he unsuscribed. It
      > seems to me we make things that have simple solutions simply too
      > complicated. I am not suggesting a hose on top of our houses but a tankless
      > water heater or solar water heater?
      >
      > Ariel Thomann <ajthomann@...> wrote:
      >
      > I had lunch last week with a friend whose family still lives in the island
      > of
      > Dominique. As I understood it, all (new?) houses there must harvest
      > rainwater
      > and use photovoltaics on their roofs. Sorry, I have no details.
      >
      > Ariel
      > - We are all Human beings here together. We have to help one another, since
      > otherwise there is NO ONE who will help.
      > - All countries need a NO REGRETS strategic energy policy. Think ahead 7
      > generations.
      > ------------------------------------
      >
      >> Hey Steven:
      >>
      >> I recall about 10 (maybe more?) years ago hearing about a hotel in the
      >> Caribbean using solar a/c, but I didn't hear anything more about it. It
      >> seems like we would hear more about it if it were successful. However, my
      >> cynical side makes me wonder if information is being suppressed. I would
      > also
      >> be very interested in more information. I wonder what effect scale has on
      >> such a system. i.e. Would it be suitable for residential use. It bothers
      > me
      >> to hear our a/c sucking up energy all summer long (but not enough to turn
      > it
      >> off & sweat).
      >>
      >> Welcome to the group.
      >>
      >> Henry
      >>
      >> Steven M <marzolian@yahoo. <mailto:marzolian%40yahoo.com> com> wrote:
      >> Greetings, all.
      >>
      >> I was raised in Venezuela, where it's no hotter than Houston but it lasts
      > all
      >> year round :-). Both there and in Texas, I have often
      >> thought of all the energy being used just to keep things cool indoors.
      >> Wouldn't it be better if there was an A/C system that sat on the roof and
      >> worked better the hotter it got?
      >>
      >> Years later, on the first day of my first class in thermodynamics, the
      >> professor asked us to write down briefly what we knew about the
      >> subject, and what we hoped to learn. Alas, the class didn't give me any
      > easy
      >> answers to that question, but I'm still interested,
      >> especially with our electric rate hikes here in Houston the past
      >> couple of years.
      >>
      >> Then, a few weeks ago I saw an article about a solar-powered
      >> airconditioner. It was not just solar cells connected to a
      >> conventional (Freon-type) unit, and it's not a "swamp cooler", but there
      >> wasn't enough information to understand how it works.
      >>
      >> I once read somewhere that the Houston metro area has the largest
      >> concentration of A/C devices in the world. Don't know if it's true, but it
      >> makes sense. We're so big, our electric rates are so high, and it's so
      > hot,
      >> that if those systems make sense anywhere, it would be here. Or would it?
      >>
      >> Yesterday I went went looking online. There are lots of proposals out
      > there,
      >> but I didn't find any local contractors, nor any aystems that seem to be
      >> available as immediate replacements for conventional A/C.
      >>
      >> Does anyone have any thoughts or information about the status of solar
      >> powered air conditioners? Is there any likelihood that they'll be more
      >> practical any time soon?
      >>
      >> Steven Marzuola
      >>
      >>
      >>
      >>
      >
      >
      >
      >
      >
      > _____
      >
      > 8:00? 8:25? 8:40? Find a flick in no time
      > with theYahoo! Search movie showtime shortcut.
      >
      >
      >
      >



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