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Corwyn Samba Member
Joined: December 29, 2009 Posts: 2238 Location: Olympia, Washington
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Posted: Tue Sep 21, 2021 6:48 pm Post subject: Re: New super white paint that cools. |
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Robw_z wrote: |
Emissivity and absorbance are radiative means of heat transfer. This paint resists radiative heat transfer but not convective.
So since humid air is more convective, this paint will work best where/when humidity is low.
-Rob |
MEXICO, baby! _________________ '90 White Westy ("The Longship")
FAS Gen V 2.0
The Annual Baja Rally
https://www.thesamba.com/vw/forum/viewtopic.php?t=604813&highlight=baja
"If anything's" gonna happen, it's gonna happen out there"
~ Captain Ron ~ |
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Schnippzle Samba Member
Joined: February 04, 2021 Posts: 288 Location: Swede in London, UK
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Posted: Tue Sep 21, 2021 11:55 pm Post subject: Re: New super white paint that cools. |
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djkeev wrote: |
Who remembers black lines in Florida?
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Sorry, what?! I had to re-read the sentence a few times. What colour was the road? _________________ 1988 Caravelle - FB25B - Syncro converted
2016 MB E63 AMG S - The daily driver
2019 Harley Davidson FXFBS Fat Bob - The leisure |
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ZsZ Samba Member
Joined: December 11, 2010 Posts: 1647 Location: Budapest Hungary, Europe
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Posted: Wed Sep 22, 2021 12:37 am Post subject: Re: New super white paint that cools. |
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https://en.wikipedia.org/wiki/Color _________________ Zoltan
1.9 MTdi 2wd Multivan (ex Caravelle)
Van since 2006, engine since 2008 |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32625 Location: Reading Pennsylvania
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Posted: Wed Sep 22, 2021 3:29 am Post subject: Re: New super white paint that cools. |
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So they are claiming that this new paint acts in a manner very similar to a swamp coolers operation in dry regions ...... only without the water.
And also like a swamp cooler does in a humid climate as well..... it doesn't.
Or does, but poorly.
Forgive me, I'm kinda playing devil's advocate here but sometimes new technology just isn't as it appears.
Think solid state refrigeration...... it works...... kind of.
To effectively use this non moisture based evaporative heat sink paint to cool a home would mean a total redesign in how houses are built.
If you want to suck the heat out of a house with this paint, the living space air will need to be right up against the underside of this paint.
Except for an old shack, you won't find a house built like this nor will building codes allow it today.
Most Everyone of us is living with insulation between our ceiling and our roof.
All that insulation needs to go away, but what will we do in the winter?
Repaint with the miracle heat absorbing black paint?
Just color me skeptical for a practical application cooling living space in lieu of using an Air Conditioner.
Reflecting roof heat? Yes!
Cooling living space? Not anytime soon.
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
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DuncanS Samba Member
Joined: October 17, 2013 Posts: 4583 Location: New Hampshire
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Posted: Wed Sep 22, 2021 4:45 am Post subject: Re: New super white paint that cools. |
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From ZsZ's link.
"Opaque objects that specularly reflect light of different wavelengths with different efficiencies look like mirrors tinted with colors determined by those differences."
I'm going with a polished Sterling silver roof. |
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4Gears4Tires Samba Member
Joined: October 08, 2018 Posts: 3047 Location: MD
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Posted: Wed Sep 22, 2021 5:34 am Post subject: Re: New super white paint that cools. |
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I'm going with bare metal polished to a mirror finish. _________________ '87 Syncro
Ferric Oxyhydroxide Superleggera Edition |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22668 Location: NYC/Upstate/ROW
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Posted: Wed Sep 22, 2021 7:00 am Post subject: Re: New super white paint that cools. |
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I’ve consulted to the IP group on the reflective paint. It’s not just white paint _________________ .ssS! |
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Jake de Villiers Samba Member
Joined: October 24, 2007 Posts: 5911 Location: Tsawwassen, BC
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jlrftype7 Samba Member
Joined: July 24, 2018 Posts: 3581 Location: Chicago
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Posted: Wed Sep 22, 2021 8:03 am Post subject: Re: New super white paint that cools. |
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Abscate wrote: |
I’ve consulted to the IP group on the reflective paint. It’s not just white paint |
Interesting.... _________________ '68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto |
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DuncanS Samba Member
Joined: October 17, 2013 Posts: 4583 Location: New Hampshire
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Posted: Wed Sep 22, 2021 9:15 am Post subject: Re: New super white paint that cools. |
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Argue, argue, argue. How many dollars per degree of temp saved over Tractor Supply farm white? |
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PDXWesty Samba Member
Joined: April 11, 2006 Posts: 6247 Location: Portland OR
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Posted: Wed Sep 22, 2021 9:19 am Post subject: Re: New super white paint that cools. |
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I've been trying to stay out of this discussion but I want to add some input. I'm a mechanical engineer that designs cooling systems for large commercial buildings. As in any endeavor, it's easy to get to 90% efficient for whatever type of system you're designing. To get to 95% is twice the effort. To get to 98% is four times the effort.
This paint is not meant to take the place of mechanical cooling or be placed on the roof of a van. It is meant for large applications on buildings of hundreds of thousands of square feet where a 3% reduction in cooling load means a six figure reduction in capitol cost and tens of thousands of dollars in energy cost.
Mis-applying the application and then arguing about it makes no sense. It is an advance in technology that is noteworthy in the right application. _________________ 89 Westy 2.1 Auto |
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DuncanS Samba Member
Joined: October 17, 2013 Posts: 4583 Location: New Hampshire
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Posted: Wed Sep 22, 2021 9:35 am Post subject: Re: New super white paint that cools. |
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Tnx,PDX. A sound and sane post.
I use the same analysis on getting a boat to look good. A crappy boat will look good at 200'. Going to 100' is easy with some paint applied with a broom--one hour. Going to 50' needs stripping off the broom job and going with a roller--6 hours. Going to 25' is the above, but now the varnish and so on need total restoration. 100 hours. Going to 15'--I did it trust me--a thousand hours. Below 2' many years of work. I started with a 100 footer and 28 years later she was a 2 footer.
It all depends on what you want. If bragging rights, go for it as the economics don't make sense at our scale.
Duncan |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32625 Location: Reading Pennsylvania
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Posted: Wed Sep 22, 2021 2:08 pm Post subject: Re: New super white paint that cools. |
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PDXWesty wrote: |
I've been trying to stay out of this discussion but I want to add some input. I'm a mechanical engineer that designs cooling systems for large commercial buildings. As in any endeavor, it's easy to get to 90% efficient for whatever type of system you're designing. To get to 95% is twice the effort. To get to 98% is four times the effort.
This paint is not meant to take the place of mechanical cooling or be placed on the roof of a van. It is meant for large applications on buildings of hundreds of thousands of square feet where a 3% reduction in cooling load means a six figure reduction in capitol cost and tens of thousands of dollars in energy cost.
Mis-applying the application and then arguing about it makes no sense. It is an advance in technology that is noteworthy in the right application. |
Oh, I totally agree with you and that's my point.
Reduce solar gain by reflecting the heat. Keep the attic cool.
Ah, but They are claiming it absorbs heat from the area it is applied to and sends that heat away making the entire area around it cooler than ambient temperature.
The are claiming it will act as an air conditioning.
If it can passively absorb heat and send it away, it will be an amazing product but will never work as an air conditioning without major redesign of buildings basically eliminating attic insulation or hot roof insulation technology.
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
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Westified Samba Member
Joined: May 01, 2012 Posts: 402 Location: Miami, FL
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Posted: Wed Sep 22, 2021 3:38 pm Post subject: Re: New super white paint that cools. |
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Here in Miami a white car is way cooler than a black car. The difference is 30 to 40 degrees at least. I tested our cars with my heat gun. Whites are even different. I have a white jeep and a white Fleetwood Cadillac. The Cadillac white is cooler even though to the eye the Jeep looks whiter. My brown/tan Vanagon, the Brown is really hot, burns the hand when trying to close the hatch.
For the pop top you could try what Land Rover used, a tropical roof. It is a double layer roof. Put a roof rack or bars on your pop top then put a sheet of white Star board or marine board on the roof rack. You now have a double layer roof with an air space underneath. Of course this may cause a problem going into your garage. Yes, I did own 2 Land Rovers back in the early 1970's. One had a tropical roof. Just another thought on how to beat the heat. _________________ 1984 Westy Wolfsburg, owned since 1987. FAS 2.0 NA engine conversion in 2022. |
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pdm777 Samba Member
Joined: August 06, 2012 Posts: 348 Location: Clovis, CA
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Posted: Wed Sep 22, 2021 3:48 pm Post subject: Re: New super white paint that cools. |
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For less than $25 you can paint your Westy roof white.
It lowers temps by reflecting most of the light energy.
This is why most aircraft are painted white.
White paint helps, however the sunlight beating
down on the top will pass conductive heat to the inside.
A cargo box and a small kayak
on the roof will provide shade,
and further reduction in heat conduction.
The early Land Rover expedition vehicles
had a roof shade - very cool!
_________________ 1990 Westy Full Camper |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32625 Location: Reading Pennsylvania
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kamzcab86 Samba Moderator
Joined: July 26, 2008 Posts: 7922 Location: Arizona
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Posted: Wed Sep 22, 2021 4:04 pm Post subject: Re: New super white paint that cools. |
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I imagine this product is similar in function to the "cool pavement" that's undergoing experimentation here in Phoenix: https://ktar.com/story/4686329/city-of-phoenix-sha...ent-study/ .
Is the new paint worth the cost on a steel box that doesn't have much insulation and, in many cases, doesn't have tinted windows? Remains to be seen, but I, personally, would err on the side of "no".
When my dark blue pop-top is repainted, the very top is going to be plain white, which, by itself, will make a big difference. Right now, when the sun hits it in the early morning, the "loft" begins turning into an oven.🥵 And there’s a big reason why my black Jetta was traded for a white GTI after 17 years of ownership... the white hatchback is cooler to begin with, and the A/C doesn't have to work nearly as hard to cool the interior down. _________________ ~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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wesitarz Samba Member
Joined: August 20, 2012 Posts: 1491 Location: Victoria,B.C.Canada
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Posted: Thu Sep 23, 2021 12:46 am Post subject: Re: New super white paint that cools. |
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"This paint is so white, it called the cops on all the other paints."
"This paint is so white, it called the cops Sir." |
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jlrftype7 Samba Member
Joined: July 24, 2018 Posts: 3581 Location: Chicago
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Posted: Thu Sep 23, 2021 7:35 am Post subject: Re: New super white paint that cools. |
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wesitarz wrote: |
"This paint is so white, it called the cops on all the other paints."
"This paint is so white, it called the cops Sir." |
So you watched that bit on the paint too.... Colbert had some fun with it... _________________ '68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto |
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DuncanS Samba Member
Joined: October 17, 2013 Posts: 4583 Location: New Hampshire
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Posted: Thu Sep 23, 2021 8:07 am Post subject: Re: New super white paint that cools. |
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I went with a totally clear paint so you can't even see the roof.
I'll bet I have one of the few T3s where the interior and exterior temps are the same. |
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