6581RE: [hreg] Solar powered A/C
- Jul 9 7:30 PMKevin, 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 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
> 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!
> From: evelyn sardina [mailto:evelynsardina@...]
> Sent: Monday, July 09, 2007 5:53 PM
> To: firstname.lastname@example.org
> 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
> Dominique. As I understood it, all (new?) houses there must harvest
> and use photovoltaics on their roofs. Sorry, I have no details.
> - 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
>> 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
>> 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
>> to hear our a/c sucking up energy all summer long (but not enough to turn
>> off & sweat).
>> Welcome to the group.
>> 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
>> 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
>> 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
>> 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
>> 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
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