Solar reflective auto paint

[freebeard]

As I recalled incorrectly, it was calcium phosphate, so thanks for that.

Particle size was an issue. I've moved on to SkyCool foil:

https://www.skycoolsystems.com › technology
Technology - SkyCool Systems
We apply a Dual-Mode film to the top surface of each panel. The film reflects sunlight to prevent the panels from heating up during the day and also emits infrared heat to the cold sky, which keeps the panels and any fluid flowing in them cool 24/7/365. A fluid is pumped through each panel.

Dual-Mode Film
We’ve pioneered radiative cooling as a technology, and shown that specially designed optical films can enable this passive approach to cooling throughout the day. These optical films are highly reflective to sunlight but also emit thermal radiation exceptionally well to the cold of space through our atmosphere, enabling daytime operation during the hottest hours of the day.

Dual-Mode Film serves numerous applications

• Applied to outdoor batteries or electronic boxes
  
• Applied to outdoor shaded structures
  
• Applied on metal roofs
  
• Applied to refrigerated trucks or other vehicles

[cRiPpLe_rOoStEr]

Originally Posted by aerohead

Relative humidity is often the 'reason' why air conditioning is used. It's not just the dry-bulb temperature.

And it seems to be more effective in places where air humidity is higher, while in others a swamp-cooler may have better results. That's why I was quite surprised to see swamp-coolers for sale at a truck parts store in Manaus in 2009...

Around 'local' dewpoint temperature, air is 'saturated' with water vapor. It's impossible for perspiration on your body to 'evaporate', which, otherwise could make one comfortable.

Last time I've been in Manaus was in 2009, and I didn't feel uncomfortable with the weather. My grandfather even agreed with me that it would be cool to ride with the windows rolled down in the '06 Hilux he owned at that time. Odd enough, my grandmother usually complains that Manaus is too humid, yet Florianópolis which she often says it would be a better place to live and is where my mother already lives is also very humid...

[serialk11r]

AFAIK barium sulfate is the best white pigment for "cooling", but it's harder to get. Really though I think you just need a white vinyl wrap if you don't already have a white car. The clear coat is only a few dozen microns but preventing sunlight from heating the base coat has to help a little.

A few months ago I rented a white car at the airport on a very sunny day, and I was very surprised that the paint was nearly cool to the touch. Any white paint or wrap is going to be far better than any other color.

[freebeard]

AFAIK barium sulfate is the best white pigment for "cooling",

Any trick to getting it to disperse in Rustoleum Mixing Base?

[Logic]

Originally Posted by serialk11r

AFAIK barium sulfate is the best white pigment for "cooling", but it's harder to get. Really though I think you just need a white vinyl wrap if you don't already have a white car. The clear coat is only a few dozen microns but preventing sunlight from heating the base coat has to help a little.

A few months ago I rented a white car at the airport on a very sunny day, and I was very surprised that the paint was nearly cool to the touch. Any white paint or wrap is going to be far better than any other color.

Yes, according to my reading and IIRC:
Any white paint is better than any other colour from my reading.
Even silver!
If the pigment is super white and great at reflecting IR; it's better, but not dramatically so vs a white paint of any sort.

Wish I could find the study again.
Ah!
NB Delta T2: The difference of temperature behind the panels coated with cool and standard paints.

Calcium Carbonate: 95.5% reflective:
https://phys.org/news/2020-10-white-...-sunlight.html

Barium Sulphate: 98.1% reflective:
https://cosmosmagazine.com/science/w...int-ever-made/

An undercoat for any colour:
https://www.newscientist.com/article...n-it-is-black/

Vantablack: the opposite and freaky to look at:
https://cosmosmagazine.com/technolog...ial-ever-made/
This should work well in cold areas, but will drastically decrease your chances of being seen! Dangerous.
https://youtu.be/DOSWHyCVX-o

Vantablack sprayable: DBX2 (99%) BMW:

https://www.youtube.com/watch?v=QCI2KYhC8vk

[serialk11r]

Yes I can attest to my silver CRV being a slight disappointment in the staying cool department. It's not as bad as darker cars, but the paint definitely gets warm to the touch while white cars stay cool to the touch. The white paint was 500 dollars extra though, so I'm not too sad :P

[freebeard]

The white paint was 500 dollars extra though

Seriously? Did it have crushed mica powder in it or what.

[Xist]

My sister said that a black piece of Chevy would have cost $10,000 more than her white one.

[freebeard]

Pffft!

https://howmuchhub.com › cost-to-plasti-dip-a-car
How much does it cost to Plasti Dip a car? HowMuchHub
25 Jul 2022On average, plasti-dipping your car will cost anywhere between $550 to as high as $1,300. The total cost will depend on the size of your car, the accessories you will need to have, and how you are thinking about completing the process. In this particular article, we will try to include every information related to plasti-dipping your car.

I like Motor Oil Plastidip

cdn.shopify.com/s/files/1/0973/6008/products/Motor_Oil_2_09862beb-09ae-4625-8e67-82806773f2f5_grande.jpeg?v=1566934805

It's a protective overcoat for the original finish. Comes in flip-flop pearls.

[Logic]

Well hell!?!?
I definitely want some of this on my car here in summer!

"...The amount of sunlight absorbed by the new paint is lower than the amount of energy it radiates through our atmosphere and into deep space, so the material actually becomes cooler than its surroundings. The team plans to carry out experiments with painted tubes carrying water and hopes to create an electricity-free refrigeration effect...

...The team calculated that if 0.5 per cent to 1 per cent of Earth’s surface was covered in this paint, for instance by coating roofs with it, the total effect would reverse global heating to date..."
https://www.newscientist.com/article...ld-cool-homes/

"...the BaSO4 film stays more than 4.5 °C below ambient temperature or achieves an average cooling power of 117 W/m2..."
https://pubs.acs.org/doi/10.1021/acsami.1c02368