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.
(Score: 1) by j-beda on Tuesday September 05 2017, @03:34PM (2 children)
Of course these sorts of things don't have to do all the colling themselves to be useful. Combining them with a standard heat-pump/air-conditioner would imporve the efficiency of the AC unit and make it cheaper to run.
(Score: 1) by j-beda on Tuesday September 05 2017, @03:37PM
"cooling" rather than "colling" is what I meant to say. Not that anyone probably cares. Now I have to wait long enough to get over the "you just posted" barrier....
(Score: 2) by Zinho on Tuesday September 05 2017, @06:04PM
That's exactly the intent of the research, they want to give the A/C a better heat sink than ambient air temperature outside. A water bath cooled by these radiator panels would do the trick nicely, provided that the panels actually cool the bath faster than the A/C warms it up. That's where the 70 W/m^2 rating of the panels becomes important, it tells you how big of a radiator you need in order to handle all the waste heat the A/C produces.
PS - I don't normally change spellings when I quote someone else's post, but you mentioned it in a follow-up; I hope you're cool with the fix.
"Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin