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6589RE: [hreg] Solar powered A/C

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  • Gary Beck
    Jul 10, 2007

      I was associated with some waste heat driven chiller development efforts earlier in my career.  If you are building a campus, a hospital, a hotel, or a large active adult multiunit complex for 500+ people call me*, or call a really big company** first and then call me.


      But if you are building a house, you will do much better if you concentrate your efforts/$ on designing an then building a super insulated, air tight, clean interior, low emission building that can also occasionally enjoy natural breezes, and therefore requires 1/4 the cooling load. Trust me on this.


      Gary Beck, P.E.

      Eco-Holdings LLC

      4010 Blue Bonnet Blvd., Suite 114

      Houston, Texas 77025


      Tel: 713-377-4209

      Fax: 832-201-5338

      Cell: 713-530-1950


      FYI- Taking heat to cold without the use of electric driven compression of a refrigerant involves capturing large amounts of heat (solar, geothermal, waste steam, exhaust stacks, etc.), and then using it as energy in lieu of a compressor’s mechanical energy to drive a refrigeration loop.  After that energy does it does its work, the majority of it is then rejected into the atmosphere though cooling towers or some other means. The amount of heat energy converted into cold is on the order of about 5%. Commercially available units were limited to about 40 tons of cooling. A 20 ton unit was made for a while by Nishiyodo but that was very limited. Smaller units are in the works, but the ROI on a good design should rule these out unless you have too much $$, in which case you should also contact me.*


      * Link to me – www.eco-holdings.com (also see office above)


      ** Links to big companies with good experience and interesting heat-to-cold technologies-



      http://www.adsorptionchiller.bigstep.com/  some adsorption chiller ‘bullets’ are

      • Water used as refrigerant, no freons, no Li-Br, no ammonia means : No hazardous leaks, no corrosion, no chemical testing, no replacement.
      • No compressor means: No alignment, no high voltage, no high pressure, no overhaul, no oil change, no surging, no vibration or noise.
      • Stable chilled water out-put driven by a wide range (194 to 122oF) of hot water.
      • Capacity out-put remains stable as in-put fluctuates. No back up burner required.
      • Simple and short start up / stop time
      • 38 F of chilled water is in the standard specification.
      • Constant operation - 24 hours / 7 days a week.


      From: hreg@yahoogroups.com [mailto: hreg@yahoogroups.com ] On Behalf Of Kevin Conlin
      Sent: Monday, July 09, 2007 9:50 PM
      To: hreg@yahoogroups.com
      Subject: RE: [hreg] Solar powered A/C


      Hi Paul,  I’m afraid that’s over my head.  I’m familiar with the technology, but can’t explain it chemically, perhaps one of the smarter engineers can explain it.  The absorbtion chillers do not have conventional compressors, the heat is used to drive a chemical process using lithium bromide where I think it is vaporized, then used to absorb heat as the reaction reverses. It is a chemical phase change process, not a vapor/compression process.


      With regard to using water to cool the Freon in a conventional AC unit, I think those do exist, they are called de-superheaters and they make domestic hot water by pre-cooling the Freon before it enters the coils.  The problem is there is more hot water than the household can use, so it’s effect is limited. A Houston AC generates more hot water than even a swimming pool can absorb, even using spray bars for night time cooling, a NASA engineer tried it some years ago, and as he put it, he had the largest crab-boil in Houston !


      Sorry I don’t have time to Google any of this, I’m just getting back from vacation to several hundred e-mails and going from memory.




      From: Paul Archer [mailto: tigger@ io.com ]
      Sent: Monday, July 09, 2007 9:31 PM
      To: hreg@yahoogroups. com
      Subject: RE: [hreg] Solar powered A/C


      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?


      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
      > 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
      > a Procter & Gamble paper plant that used waste heat from a
      > 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
      w:st="on"> China , it may
      > be practical for commercial scale systems.
      > There was one system at NASA over 20 years ago, but like most demo
      > 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
      > concentrators mounted on the roof. (Nice aesthetics!) They also failed,
      > due to various mechanical and other problems, as well as the relatively
      > and often cloudy solar resource here in
      w:st="on">Houston during the summer. Tracking
      > collectors are better suited to cloudless regimes like west
      w:st="on"> Texas , NM, AZ
      > etc..
      > I believe there are some residential systems being offered in
      w:st="on"> 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@ yahoo.com]
      > 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
      w:st="on">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
      > 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
      > water heater or solar water heater?
      > Ariel Thomann <ajthomann@pol. net>
      > 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,
      > 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,
      >> cynical side makes me wonder if information is being suppressed. I
      > also
      >> be very interested in more information. I wonder what effect scale has
      >> such a system. i.e. Would it be suitable for residential use. It
      > me
      >> to hear our a/c sucking up energy all summer long (but not enough to
      > 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
      w:st="on">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
      >> 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
      > easy
      >> answers to that question, but I'm still interested,
      >> especially with our electric rate hikes here in
      w:st="on"> 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
      w:st="on">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
      >> 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
      >> 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.

      ------------ --------- --------- --------- ----
      "Looking down the barrel of a loaded gun...
      Just to see where the bullets come from!"
      --Screaming Blue Messiahs--
      ------------ --------- --------- --------- ----

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