Re: [Vo]:Radiative Cooling with new Ultra White paint

[H LV]

This part doesn't make sense to me.

"But here is the exciting thing..."
https://youtu.be/Ay6ckBojc_0?t=219

Harry

On Wed, May 5, 2021 at 10:49 AM Jürg Wyttenbach  wrote:

> All bodies do radiate away heat. During day light time solar radiation
> more than compensates the heat loss.
>
> But a highly reflective layer almost (96-97%)stops this compensation.
>
> IR radiation is just a function of surface temperature and the air
> interface.
>
> Just a small riddle: What happens if you use this paste as sun-cream and
> go for a daylight tropical desert walk?
>
> J.W.
> On 05.05.2021 16:31, H LV wrote:
>
> This video talks about a new ultra white paint which the inventors claim
> could dramatically reduce air conditioning costs.
>
> https://www.youtube.com/watch?v=Ay6ckBojc_0
> see also press release:
>
> https://www.purdue.edu/newsroom/releases/2021/Q2/the-whitest-paint-is-here-and-its-the-coolest.-literally..html
>
> However, the explanation doesn't make sense to me. If the new paint is so
> good at reflecting sunlight in the visible as well as the infrared and
> ultraviolet regions how can it facilitate indoor cooling? They are claiming
> that it can transmit infrared radiation but isn't a good reflector of
> radiation also a bad transmitter of radiation?
>
> Harry
>
>
> --
> Jürg Wyttenbach
> Bifangstr. 22
> 8910 Affoltern am Albis
>
> +41 44 760 14 18
> +41 79 246 36 06
>
>

Re: [Vo]:Radiative Cooling with new Ultra White paint

[Jürg Wyttenbach]

All bodies do radiate away heat. During day light time solar radiation 
more than compensates the heat loss.


But a highly reflective layer almost (96-97%)stops this compensation.

IR radiation is just a function of surface temperature and the air 
interface.


Just a small riddle: What happens if you use this paste as sun-cream and 
go for a daylight tropical desert walk?


J.W.

On 05.05.2021 16:31, H LV wrote:
This video talks about a new ultra white paint which the inventors 
claim could dramatically reduce air conditioning costs.


https://www.youtube.com/watch?v=Ay6ckBojc_0 


see also press release:
https://www.purdue.edu/newsroom/releases/2021/Q2/the-whitest-paint-is-here-and-its-the-coolest.-literally..html 



However, the explanation doesn't make sense to me. If the new paint is 
so good at reflecting sunlight in the visible as well as the infrared 
and ultraviolet regions how can it facilitate indoor cooling? They are 
claiming that it can transmit infrared radiation but isn't a good 
reflector of radiation also a bad transmitter of radiation?


Harry



--
Jürg Wyttenbach
Bifangstr. 22
8910 Affoltern am Albis

+41 44 760 14 18
+41 79 246 36 06

[Vo]:Radiative Cooling with new Ultra White paint

[H LV]

This video talks about a new ultra white paint which the inventors claim
could dramatically reduce air conditioning costs.

https://www.youtube.com/watch?v=Ay6ckBojc_0
see also press release:
https://www.purdue.edu/newsroom/releases/2021/Q2/the-whitest-paint-is-here-and-its-the-coolest.-literally..html

However, the explanation doesn't make sense to me. If the new paint is so
good at reflecting sunlight in the visible as well as the infrared and
ultraviolet regions how can it facilitate indoor cooling? They are claiming
that it can transmit infrared radiation but isn't a good reflector of
radiation also a bad transmitter of radiation?

Harry