Stories
Slash Boxes
Comments

SoylentNews is people

posted by martyb on Tuesday September 05 2017, @12:16PM   Printer-friendly
from the will-it-cool-my-beer? dept.

New water-cooling solar panels could lower the cost of air conditioning by 20%

Most of us have heard of solar water heaters. Now there's a solar water cooler, and the technology may sharply lower the cost of industrial-scale air conditioning and refrigeration.

The new water coolers are panels that sit atop a roof, and they're made of three components. The first is a plastic layer topped with a silver coating that reflects nearly all incoming sunlight, keeping the panel from heating up in the summer sun. The plastic layer sits atop the second component, a snaking copper tube. Water is piped through the tube, where it sheds heat to the plastic. That heat is then radiated out by the plastic at a wavelength in the middle region of the infrared (IR) spectrum, which is not absorbed by the atmosphere and instead travels all the way to outer space. Finally, the whole panel is encased in a thermally insulating plastic housing that ensures nearly all the heat radiated away comes from the circulating water and not the surrounding air.

Researchers at Stanford University in Palo Alto, California, recently placed three water cooling panels—each 0.37 square meters—atop a building on campus and circulated water through them at a rate of 0.2 liters every minute. They report today in Nature Energy that their setup cooled the water as much as 5°C below the ambient temperature over 3 days of testing [DOI: 10.1038/nenergy.2017.143] [DX]. They then modeled how their panels would behave if integrated into a typical air conditioning unit for a two-story building in Las Vegas, Nevada. The results: Their setup would lower the building's air conditioning electrical demand by 21% over the summer.


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 4, Insightful) by Bill Evans on Tuesday September 05 2017, @12:25PM (15 children)

    by Bill Evans (1094) on Tuesday September 05 2017, @12:25PM (#563730) Homepage

    According to this writeup, they're not really solar panels, are they? They're just panels that sit on the roof, and don't depend on the sun for anything, and certainly not for generating electricity.

    Starting Score:    1  point
    Moderation   +2  
       Insightful=2, Total=2
    Extra 'Insightful' Modifier   0  
    Karma-Bonus Modifier   +1  

    Total Score:   4  
  • (Score: 2) by requerdanos on Tuesday September 05 2017, @01:54PM (13 children)

    by requerdanos (5997) Subscriber Badge on Tuesday September 05 2017, @01:54PM (#563753) Journal

    they're not really solar panels, are they?

    According the the explanation above, they work in spite of the sun, not because of it. My first thought was, "How is that solar? They work in the dark." Yet TFS actually says...

    Now there's a solar water cooler

    So the inescapable conclusion is: Either I completely misunderstand, or TFA completely misunderstands.

    • (Score: 3, Insightful) by Sulla on Tuesday September 05 2017, @03:02PM (6 children)

      by Sulla (5173) on Tuesday September 05 2017, @03:02PM (#563768) Journal

      Marketing. I think it is safe to say a majority of people think solar is cool, so if you tack solar onto it people will think it is a good idea.

      --
      Ceterum censeo Sinae esse delendam
      • (Score: 3, Touché) by Thexalon on Tuesday September 05 2017, @03:27PM (1 child)

        by Thexalon (636) on Tuesday September 05 2017, @03:27PM (#563779)

        That reminds me, I need to up the price of my 100% organic solar-powered air carbon removers. That's a much better name for them than "trees".

        --
        The only thing that stops a bad guy with a compiler is a good guy with a compiler.
        • (Score: 3, Touché) by requerdanos on Tuesday September 05 2017, @05:04PM

          by requerdanos (5997) Subscriber Badge on Tuesday September 05 2017, @05:04PM (#563821) Journal

          my 100% organic solar-powered air carbon removers.

          Of course, trees actually *are* powered by the sun.

      • (Score: 2) by fishybell on Tuesday September 05 2017, @03:40PM (3 children)

        by fishybell (3156) on Tuesday September 05 2017, @03:40PM (#563786)

        My parent's house in has a solar water heater [wikipedia.org]. My mom is convinced it works by using electricity to heat the water. I even pointed out that there are only water pipes coming in from the roof, and she still won't believe it.

        Calling these solar panels causes the same kind of confusion the solar water heater has: the word solar ends up equating to electricity.

        • (Score: -1, Offtopic) by Anonymous Coward on Tuesday September 05 2017, @03:58PM (1 child)

          by Anonymous Coward on Tuesday September 05 2017, @03:58PM (#563793)

          Your mom sounds like a typical Trump supporter

          • (Score: 1, Offtopic) by Sulla on Tuesday September 05 2017, @04:07PM

            by Sulla (5173) on Tuesday September 05 2017, @04:07PM (#563796) Journal

            The stupid on one side will think that this is some sort of electricity generating home cooling super device, and the ones on the other side will be mad that the unsustainable usage of air conditioning is being subsidized. Both suck.

            --
            Ceterum censeo Sinae esse delendam
        • (Score: 2) by maxwell demon on Tuesday September 05 2017, @07:45PM

          by maxwell demon (1608) on Tuesday September 05 2017, @07:45PM (#563889) Journal

          My mom is convinced it works by using electricity to heat the water.

          Well, in some sense it does: Light is an electromagnetic wave, and it heats up the water by acting on the electric charges in the solar heater's matter, causing its molecules to vibrate and transfer that vibration to the water. Were there no electrically charged particles in the matter making up the solar water heater, the light couldn't heat the water.

          --
          The Tao of math: The numbers you can count are not the real numbers.
    • (Score: 2, Informative) by Zinho on Tuesday September 05 2017, @03:12PM (5 children)

      by Zinho (759) on Tuesday September 05 2017, @03:12PM (#563772)

      You are correct, and the headline is confused. The only connection these units have with solar panels is that they can both be mounted on a rooftop.

      --
      "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
      • (Score: 2) by GreatAuntAnesthesia on Tuesday September 05 2017, @03:55PM (4 children)

        by GreatAuntAnesthesia (3275) on Tuesday September 05 2017, @03:55PM (#563792) Journal

        Could you mount one on top of the other?

        • (Score: 2) by bob_super on Tuesday September 05 2017, @04:25PM

          by bob_super (1357) on Tuesday September 05 2017, @04:25PM (#563805)

          Maybe, but what makes the confusion worse is you don't have to mount them on the roof at all...

          By the way: Hey, I put ultra-reflective coatings on your Vegas roof and your AC bill dropped! Why did they bother with the water thing?

        • (Score: 2) by Zinho on Tuesday September 05 2017, @06:43PM (2 children)

          by Zinho (759) on Tuesday September 05 2017, @06:43PM (#563863)

          No, the cooling panels radiate heat into space, and need a clear view of the sky to operate. You can't mount a solar panel above it; otherwise the equilibrium temperature of the water in the cooling loop will be close to the temperature of the solar panels (which get pretty hot). The right way to mount these would be to put solar panels on the south-facing slope of the roof and radiator panels on the north-facing side. [1]

          [1] Bonus points for having asymmetric slopes; south-facing solar should be angled off of horizontal at the same number of degrees as the local latitude, north-facing slope should be at 90 degrees from the south to maximize view of the sky and minimize solar exposure. People who design earthship-style [cloudfront.net] homes would be able to incorporate this fairly easily into their roofs. [2]

          [2] This assumes that the people who build earthships are into air conditioning, which they aren't. The earthship design calls for passive geothermal cooling for the air in the home. The shallow pitch on their north-facing roof slope is also already radiating heat from the home into space, so putting insulated boxes above it negates that benefit. Again, maybe in higher latitudes having the extra insulation would be good for winter time. Not sure where the system would fit into the summer operation of a proper earthship, but it's worth thinking about. Also, pretty much every house would benefit from having better roof design based on latitude, hence my use of the phrase "earthship-style homes" rather than simply "earthship homes". And now I'll shut up, because I've been rambling too long already.

          --
          "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
          • (Score: 4, Touché) by maxwell demon on Tuesday September 05 2017, @07:47PM (1 child)

            by maxwell demon (1608) on Tuesday September 05 2017, @07:47PM (#563891) Journal

            [1] Bonus points for having asymmetric slopes;

            Some people live at a latitude of 45 degrees.

            --
            The Tao of math: The numbers you can count are not the real numbers.
            • (Score: 2) by Zinho on Tuesday September 05 2017, @09:29PM

              by Zinho (759) on Tuesday September 05 2017, @09:29PM (#563932)

              [1] Bonus points for having asymmetric slopes;

              Some people live at a latitude of 45 degrees.

              Nice, that earned a "touché" mod from me. Well played.

              I'd have no objection to people living at 45 degrees north or south of the equator having symmetrical front/back 45 degree roof slopes.

              [aside]/Zinho looks up which locations lie on the 45th parallels[/slope]

              Looks like New Zealand, Argentina, and Chile are the winners in the south. In the north it's France, Italy, several former Yugoslavian states, Ukraine, Russia, Kazakhstan, Uzbekistan, China, Mongolia, Japan, and the US States between Oregon and the northern border of Vermont. It would be an interesting exercise to build an Earthship up there and see the reaction it would draw on the permie message boards if I bought pre-fab trusses for its construction. :P

              --
              "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
  • (Score: 2) by chromas on Tuesday September 05 2017, @07:57PM

    by chromas (34) Subscriber Badge on Tuesday September 05 2017, @07:57PM (#563894) Journal

    Solar Freakin' Coolways!!!12