Sky Cool Cooling Panels

Nothing like this ever works as well as advertised....things that work well don't need to be advertised, they spread like wildfire person to person....Listening to the presentations given here there are many half truths and fallacies, not to mention misleading claims and lack of full disclosure...I call scam....though they may work in principal, part of the time, this tech is possibly marginally cost effective in only places like Arizona....and a white roof coating like cool seal would probably work just as well and be much cheaper....on the other hand I would love to be proven wrong, but this seems like a gimmick to separate do-gooders from their money....haha

Seems more likely they are looking for government money, like Solyndra

One in the same nowadays....

I agree with you. There is an effect there, but the question is whether it is economical. There are enough things that are not economical but are subsidized by tax dollars. And if it takes 50 years to pay for itself, it's of no use, IMHO.

The world's whitest paint could eliminate the need for air conditioning.

https://www.usatoday.com/story/news/nation/2021/09/17/whitest-paint-created-global-warming/8378579002/

Really? How does it produce negative heat and lower humidity? That would be some magical paint...

And now, a little trip to the Dark Side:

The blackest black ever made by man.

Put these two (B+W) together in the right configuration and you could drive a turbine or wind generator with the rising heat column as well as heating and cooling,depending on configuration.

Perhaps a conical spiral or a sphere with alternating colors ?

Crazy idea,I know,just thinkin'

https://www.sciencedaily.com/releases/2008/01/080122154610.htm

These just appear to be huge surface area condensers, kind of like when you upgrade your 10SEER ac system to a 16SEER, you end up with huge condenser coils. They are using the same refrigeration cycle. They are going to work no matter if the sky is clear or not, no matter that there is little IR energy to detect when you point your temperature gun at the sky....

I disagree with those who consider this to be worthless or even a scam. . .

I read the cited article. Although its math is a little beyond my current scope, the citations (over 140) and actual results obtained within those tell me that the ability to obtain diurnal (day plus night) radiative cooling exists, with significant observed temperature depressions compared to the ambient (-5 to -25 °K). The author freely concedes that this is laboratory scale work; much of it is mathematical simulation but most of those have been supported by actual experiments.

Like anything that is early in its development, much work lies ahead. Potential gains include such items as: increasing PV efficiency by cooling the panels, and decreasing energy use.

Passive radiative cooling during the night hours has been used successfully for over 40 years, and has provided all the comfort cooling needs of homes in a Central California environment; with a switch of when to expose the panels the same system has provided all the heating comfort needs for the same homes. This article cites many studies that extend the night-time use to around-the-clock real world results.

Sure, it needs further work. Some of the materials and methods may prove to be too difficult or exotic or short-lived for commercial success. In different forms this success will come. Further work will improve things. Scam it isn't.

--JMM

Have you ever wondered why the interior of your car is noticeably cooler than the outside air before sunrise? This is a simple example of radiative cooling to the night time sky. I cited the Central California homes as an example of what has been done already in more than that single location. The original article suggests that this can be extended to daytime radiative cooling with the use of a carefully selected surface material. I agree with this.

--JMM

Air conditioning is not just about lowering the temperature of the air, it's also about adjusting the humidity to make the environment comfortable, in some cases you need to raise it, but in most cases you need to lower it....Now I can't say whether this radiative system is cost effective or not, I have no cost figures, but I think we can assume that they don't control humidity to any great degree...and that a structure mounted on the roof is not going to be cheap or desirable....Like the swamp coolers there could be a niche market for these panels, I can't say...

SE,

You raise valid points. For humidity control you need a surface that is sufficiently cooler than the surrounding air. In the range of temperatures we normally have, a good approximation is that a 10 °C (18 °F) change in temperature will double or halve the relative humidity. If such a panel cools 40% of the air that passes it by 10 °C, the total air mass will have cooled by 4 °C and the relative humidity of that air mass will be close to the original (although about 20% of the total moisture content of the air will have been removed). As that air mass warms up by absorbing heat from the surroundings its absolute humidity will be the same but its relative humidity will have decreased by that 20%. This and more can be achieved using components such as are being discussed in this forum.

I worked with a operator on an oil rig around 1980 and he had installed a very effective system under his house. He built a basement style cement walled room into which he dumped several truck loads of cricket ball, think baseball, sized rocks.

The room was connected to the interior of his house and to the exterior atmosphere through a filter media. During the day when the air was hot, a fan drew the hot air through the rocks warming them and at the same time exchanging cooling air to be drawn through the house, then during the night with the fan running the warmth was drawn from the rocks to warm the house and the rocks were cooled by the ambient outside temperature.

A very effective cooling/heating system. I have lost contact long ago to see if it is still effective.

I was doubtful too, I won't even read another break thru battery story. Decades of stories, but same old batteries.

Search 10 u-meter passive cooling and mid IR passive cooling. I've been reading about this research for several years now. The results of those searches might surprise you. The proof of concept experiments and methodologies work quite well and I do believe quite a surprise for many people. The materials used are common and already being manufactured. I think there is a race on for more radiation efficiency, before hitting the market. And of course there is integration of this process with other passive systems. Like thermo electric.

Some methods are getting some ridiculous surface temp differences at high bright noon.