Active cooling Cryo paint on decks?

[JBP-PA]

Looking at those linked articles, it appears that these paints are designed for radiative cooling as well as normal reflecting (blocking) of sunlight. The radiative cooling aspect is what mostly sets them apart from any normal reflective paint (bright white), with increased reflection a minor difference.

So measuring the temperature of their surface isn't the correct way to judge them. This would only, at most, show any difference due to reflection. At worst, it will show increased temperatures due to radiative cooling.

The correct measurement seems to be measuring the inside temperature of something coated with the paint. Maybe paint a fiberglass or metal container with a temp sensor inside?

Mark

I know, I know, I know. Jeeze.
If you just finished a couple test panels, tell me you wouldn't throw it on something hot and see what happens.

 

[JBP-PA]

This is also a bad test because it is afternoon and the starboard side is shady. Interesting none the less. The cooling paint (from the INSIDE, ALL RIGHT!) Is only a couple degrees cooler than normal white paint. My car's windshield shade on the starboard on partial shade is much hotter, like 10 degrees, which I'm surprised at.

 

[thinwater]

This is also a bad test because it is afternoon and the starboard side is shady. Interesting none the less. The cooling paint (from the INSIDE, ALL RIGHT!) Is only a couple degrees cooler than normal white paint. My car's windshield shade on the starboard on partial shade is much hotter, like 10 degrees, which I'm surprised at.

In fact, the difference between white and light colors is much greater than common sense tells us. Our eyes are very n-linear. Off-white is often FAR off-white from a cooling perspective, and beige is a pretty dark color. A primary color can be darn close to black. Surprising.

It's hard to tell, because the windshield cover is partially (fake) aluminized, but at a glance, it might be 82% of the way to black. They'd be better off with bright white.

 

[colemj]

Does that fan in the hatch have saw blades to keep things interesting?

It doesn't precess hanging from a strap?

 

[JBP-PA]

Does that fan in the hatch have saw blades to keep things interesting?

It doesn't precess hanging from a strap?

The fan is new. A fathers day gift. The blades are seriously dangerous. I've hung it from the hatch as shown, as a ceiling fan, and from the dodger. It blows a lot of air, but I'm not sure if it retains a place on my wee little boat.

 

[capta]

Even if it does work, I'm not sure it is worth the trade for bright white reflecting decks and cabin tops. I've been aboard boats with bright white gel coated decks and cabin tops and I found them to be very uncomfortable on my eyes, even with shades on.
The technology certainly exists, if you consider things like the tiles on the space shuttle, but the practicality may not be here yet.

 

[rgranger]

I found them to be very uncomfortable on my eyes, even with shades on.

 

[colemj]

The majority of boats I have been on have bright white decks, including the boat we are on now. I've never found it an issue.

The only decks I've found an issue are the ones that are anything else but white. They get so hot you can get burned. Teak and the faux teak EVA decks are terrible for this, but even off-white and tan decks are bad.

Mark

 

[JBP-PA]

Even if it does work, I'm not sure it is worth the trade for bright white reflecting decks and cabin tops. I've been aboard boats with bright white gel coated decks and cabin tops and I found them to be very uncomfortable on my eyes, even with shades on.
The technology certainly exists, if you consider things like the tiles on the space shuttle, but the practicality may not be here yet.

FYI, I'm not painting the decks, I'm covering hot spots like dark windows that get really hot. It is indeed bright though, much brighter than the decks and painful to look at (without sunglasses).

 

[thinwater]

If covering hatches is the thing ...

• Painting can work if it's never occupied, like a sail locker. This is probably more for UV and non-slip than heat. I've painted locker hatches, since dark, slippery, UV-vulnerable plexi seemed like the wrong choice (GRP or alloy would be smarter).
• Covers work for hatches that open. Typically they are insulated, or lightly insulated, so color is not a major factor. Also warmer in the winter and reduce condensation.
• Awnings. An air gap makes a lot of difference, because heat must be transmitted by convection twice.