What about walls and light reflection ?

[user 60570]

World's Whitest Paint Reflects 98.1% of Light. It Could Help in The Climate Fight

MICHELLE STARR
16 APRIL 2021
A new formula for white paint has given us the whitest white yet. It reflects a jaw-dropping 98.1 percent of all light that hits it, remaining significantly cooler than the ambient temperature, even when sitting in full sunlight.

If used to coat buildings, its inventors say, the paint could help in the fight against global warming by reducing our reliance on electrically powered air conditioning, a habit that's worsening the climate crisis.
"If you were to use this paint to cover a roof area of about 1,000 square feet [92.9 square meters], we estimate that you could get a cooling power of 10 kilowatts," said mechanical engineer Xiulin Ruan of Purdue University.
"That's more powerful than the central air conditioners used by most houses."
The team's work builds on paint they developed last year, which reached a then-record-breaking reflection rate of 95.5 percent. The new formula, the team said, brings it much closer to being a true counterpart to Vantablack, the black pigment that absorbs up to 99.965 percent of visible light.
The image below, in optical light on the left and infrared on the right, shows how much cooler the painted surface is than the surface around it.

 

[user 60570]

A Review of Heat-reflective Paints
John Pockett1 and Martin Belusko1
1Sustainable Energy Centre
University of South Australia
Mawson Lakes SA5095
[email protected]
ABSTRACT
In recent years, there have been a number of heat-reflective paints come on the
Australian market. These provide the same visible colour range as standard products but
perform quite differently in the infra-red region of the spectrum, reflecting more of the
invisible part of the solar spectrum. Are they effective in meeting their advertised claims
and if/when is there a benefit for their use? This paper reviews the advertising material
and data to assess their value in a field where there is little sound scientific literature on
some products and the technology of others is hidden for IP reasons.
Sunlight at ground-level incorporates incident radiation in the ultraviolet, visible and
infra-red regions with wavelengths spanning 300 to 2500 nm. Any part of the solar
spectrum where a surface absorbs incoming sunlight will cause an increase in surface
temperature above ambient temperatures. If heat cannot be re-radiated to the sky, it will
conduct through roof spaces towards the ceiling and radiate downwards through
insulation batts. This produces a heat load on buildings, resulting in loss of comfort or
an increase in electricity bills and greenhouse gas emissions for air-conditioning.
The main approaches used individually or in combination are to;
•select pigments to match visible colours using pigments that also naturally reflect
more infra-red radiation,
•utilise hollow silica/ceramic microsphere additives that reflect the longer
wavelength solar radiation and
•improve the ability to radiate any heat build-up out to the sky.
Attempts to simplify a complex situation for public consumption means advertising,
comments and claims are often made that are technically incorrect. Measurements from
some paint suppliers show not only the benefits of the paints but also claims of
‘insulation’ that are unsubstantiated and simply incorrect. Heat conduction through the
paint layer actually plays an insignificant role compared to the total solar reflectivity
and emissivity with lighter colours providing the best surface temperature reduction. It
is also shown that the use of a heat reflective paint instead of a standard paint for a
particular (visible) colour reduces the surface temperature. The benefits of heat-
reflective paints are generally smaller for lighter colours and very small for pure white.
Heat-reflective paints can attract a premium so there is a point where the added costs do
not warrant use in moderate climate zones.
It can be concluded that the most cost effective solution for coating roofs of houses
against the heat from sunlight is to paint the roof with a high build gloss Vivid White
paint. In many cases, this is not practical because of the glare. The next best option is to
start with as light as possible a colour and then to use one or another type of heat-
reflective paint with high reflectance in the infra-red to minimise the surface
temperature increase.
Keywords ⎯ heat-reflective, infra-red, paint, sunlight, surface, temperature
Solar2010, the 48th AuSES Annual Conference
1-3 December 2010, Canberra, ACT, Australia

 

[user 60570]

Abstract
Research has previously shown that ultraviolet light C (UV-C) can inactivate unexpected infection. However, this type of potential disinfection is dramatically reduced for the shadow area such as under desk or medical equipment. Because the UV-C reflectance ratio is low on the general wall surfaces. We compared Stucco against the other materials to investigate whether we could improve disinfection for the shadow area. The reflectance ratios of UV-C irradiation of each material were examined, with particular attention to the rates for the author’s Modified Stucco. To evaluate the disinfection effects of the UV-C reflective lighting, colonies of E. coli and of Staphylococcus hominis were cultured in an agar media and counted over a certain time period after applying UV-C irradiation from a sterilizing lamp onto the investigation materials. The author’s Modified Stucco, produced reflectance ratios that was 11 times that of white wallpaper. This demonstrated that the UV-C reflected on the Stucco wall having optimum components and their compositions inhibited the number of E. coli and S. hominis, resulting in significantly disinfection effects on white wallpapers. The space with Modified Stucco and then irradiated by a UV-C may give a strong disinfection effect.
Download PDF
Introduction
In recent years, many microbes have developed increased antimicrobial drug resistance1. It has also been discovered that these antibiotic-resistant infectious bacteria can be spread through contact with medical devices and environmental surfaces, becoming one of the causes for Healthcare Associated Infection (HAI)2,3. Therefore, measures to inhibit such infectious spread are urgently needed. One infection control strategy involves the inactivation of infectious bacteria using an ultraviolet (UV) germicidal lamp3,4. UV lights below 400 nm, especially around 254 nm (UV-C) show strong microbe inactivation effects by being absorbed into the bacteria DNA and inhibiting DNA from replicating5. However, the UV-C light is substantially absorbed into standard wall surfaces, reducing the UV-C light reflecting off of the wall surface33. In other words, UV-C does not reach areas that are shaded under desks or medical equipment. This reduces the overall germicidal effect of the UV-C treatment compared to the strong disinfection effect of direct UV-C irradiation onto bacteria samples.
In this study, we investigated whether Stucco, a traditional Japanese inner wall material, could be used as an effective disinfection if UV-C lighting could be projected onto the wall surfaces and reflected back into the examination room environment. For more than 1300 years, Japanese construction practices have used mortar as a base coating for outer walls and Stucco for finishing inner walls6. A typical example is the historic use of Stucco for outer walls is in Japanese castles of the 1600s7. The main ingredient in Stucco is Ca(OH)2, prepared burning calcium hydroxide mined from limestone and distilled at the super high temperature of 900 ℃ or higher. In the past, fillers, such seaweed and fibers as were added, but in the present polymers are added as thickening agents. Most Stucco formulas are a mixture of natural materials. When the Stucco is applied to the wall surface, it begins to harden by absorbing CO2 from the air through the chemical reaction Ca(OH)2 + CO2 → CaCO3 + H2O. The Stucco continues to harden for at least 10 years, eventually becoming calcium carbonate (CaCO3), a high-duty, limestone-like hard surface. For this reason, Stucco has historically been used for roof tiles and for both outer and inners walls requiring high strength8,9.
However, in the 1960s the Japanese economy grew rapidly and the use of Stucco in Japanese building practices fell due to a new dry construction method, which shortened the construction period, allowing for mass production and reduced costs. This construction trend changed Japanese inner wall materials from Stucco to white wallpaper or white paint. The use of Stucco decreased because the longer construction time and finishing time, which depended upon the techniques of Stucco artisans6. At present, the use of Stucco is mainly for special locations, such as in private homes and in hotels as wall art. The Stucco is a traditional material for inner walls in Japan as well as in foreign countries.

 

[user 60570]

Abstract
Reflective materials such as Teflon and Enhanced Specular Reflector are commonly used to maximize light collection in scintillator-based radiation detection systems. While effective, in most cases, the spatial information carried by the light is diminished or lost entirely. Retroreflectors, in contrast, better preserve the spatial information and have been shown to improve the localization performance of such systems. In this work, the relative retroreflectivity of a selection of commercial retroreflective tapes and their performance impact when coupled to a plastic scintillator are reported. We demonstrate improved localization performance with some tapes compared to Teflon and black paint.

Introduction
Recent development work on a compact neutron scatter camera (NSC) employing fast but relatively dim plastic scintillators [1], [2] has motivated investigation of surface treatments that not only maximize light collection efficiency but also preserve its spatial information content. In the extreme case, a surface that backscattered every incident photon with no angular deviation would negate the need to read out multiple sides of the scintillator, dramatically reducing the channel count of the readout electronics. Additionally, several proposed NSC designs are based on a gamma-ray imaging system using optical coded-aperture imaging [3], and may especially benefit from this type of reflector.
Commonly, Lambertian (e.g. white paint, Teflon) or specular (e.g. Enhanced Specular Reflector (ESR)) reflectors are used to maximize light collection [4], [5], [6], but in most geometries the spatial information is lost as the light is redirected to the photosensor. Retroreflective materials, or retroreflectors, can be used with scintillator-based detectors to improve the light collection efficiency while retaining spatial information; incident light originally directed away from the readout is instead backscattered 180° through its vertex (Fig. 1).
Retroreflective materials are most frequently used for markings on roads and signs since they reflect light from headlights back to the driver. Light is typically redirected by one of two methods (Fig. 2), both involving one or more specular reflections that ultimately result in photons going back the direction from which they came. However, there is an offset that depends on the feature size of the retroreflecting microstructure. The microstructures are either spherical or pyramidal and made of a relatively high index material (1.5–2) such as glass to encourage specular reflections off the interior walls.
Prior work [7], [8], [9], [10] has shown that for crystalline scintillators, retroreflective tapes may improve spatial performance; the authors of [9] improved performance by embedding the microstructures directly into the scintillator crystal, and [10] successfully employed retroreflective tape by 3M Industries. Unfortunately, there is limited quantitative information on the retroreflectivities (which depend on incidence angle) and spatial distributions of reflected light for the commercial offerings available today. Further, we could not find any information on using them with plastic scintillators. This information is required to accurately model the impact of these tapes and to understand the effect they might have on the system performance of the NSC designs under development. This article investigates the performance of retroreflective tapes compared to Teflon, black paint, and air-coupling when used as reflective surface treatments for plastic scintillators. A simple theoretical model of the effect on the light distributions observed by the photodetectors is presented and validated experimentally. The relative retroreflectivities by angle for a selection of five commercially available retroreflective tapes are also reported.
Fundamentally, the ability to find the centroid of the energy deposited by incident radiation (denoted x) in a bulk scintillator is dependent on the width w of the light distribution observed by the photosensor and the number of counts N in that distribution (see [11] for a more detailed explanation) according to:

 

[user 60570]

Attention Mr Cuda…

there will be a quiz on the above topics in the morning

 

[WeedHopper]

Laughing my fking ass off.

 

[pute]

Take me a month to pass that test. By the way....Big took the time to type all that.

 

[WeedHopper]

He will not except that answer Big

 

[boo]

sure he will, with a few minor changes...

 

[67Cuda]

So flat white,

IOP Conf. Series: Materials Science and Engineering 544 (2019) 012010 doi:10.1088/1757-899X/544/1/012010
Study on Preparation and thermal reflective properties of energy saving pigments with selective solar reflection
Yunlong Li 1, a and Yuanquan Yang2,b
1 Postgraduate, Shenyang JianZhu University, Shenyang, China
2 Doctoral student, Dalian University of Technology, Dalian, China E-mail: a [email protected], [email protected]
Abstract. Currently, the color of common reflective insulation coating is mainly white, but the white color coating is monotonous and its resistance is poor, moreover, the reflective performance tends to drop after pollution. In addition, color coating has the advantages of anti-dirty and beautiful appearance, so study on colored paint is of great significance. Based on the principle of three-tone color, the effect of thermal reflective pigments on the near-infrared reflectance of color reflective heat-insulating coatings was studied by blending three kinds of color reflective heat-insulating coatings of orange, green and purple with composite inorganic heat-reflective pigments as raw materials. The results show that the thermal insulation effect of heat-reflective pigments is significantly improved, and the near-infrared reflectance of green pigments can be increased by about 25%. The thermal reflection thermal insulation coating of the green system is 2.78 times higher than that of the same color common thermal insulating coating.
1. Introduction
Thermal reflective insulation coating is the most widely used building materials on exterior wall in the direction of energy conservation. In recent years, it has become a hotspot of research[1]. The exterior surface of the building receives solar radiation can be divided into three parts: ultraviolet region (200-400nm), visible light region (400-720nm), infrared light region (720-2500nm). The visible light region and infrared light region occupy 95% energy that the solar radiation to the Earth surface [2]. Due to the absorption of inorganic pigments and organic pigments in the visible light area, the thermal insulation properties of heat-reflective heat-insulating coatings are adversely affected by common pigments. In order to obtain a better visual effect, the multi-color thermal reflective heat-insulating coating is obviously superior to the white paint, so the study of heat-reflective pigments with both reflective insulation effect and good visual effect is the focus of current research.
There are many research results of near infrared reflective heat insulation pigments based on cooling materials of roof and exterior wall in foreign countries[3]. In 1940s, some foreign researchers began entertaining air with low thermal conductivity into multi-layer aluminum film, and then preparing heat insulation coatings after compounding with it, which opened the prelude of heat reflection heat insulation coatings. The Lawrence Berkeley National Laboratory (LBNL) and Oak Ridge National Laboratory (ORNL) began to study the solar reflectance and hemispherical emissivity of pigments in the 1990s, and the pigments were divided into several categories and the effects of the
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution
of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd 1

MEACM 2018 IOP Publishing IOP Conf. Series: Materials Science and Engineering 544 (2019) 012010 doi:10.1088/1757-899X/544/1/012010
properties, composition, roughness and purity of the materials on the solar reflectance were studied [4].

So flat white is the best choice, right ? However, why do all the commercial growers and universities use white for their walls ?


I really don't want an answer I just want to ask questions.

 

[WeedHopper]

See how this trolling **** works.

 

[ROSTERMAN]

I was under the impression that white was always far superior to any other color or material available in todays society . I always go with white.

 

[WeedHopper]

He doesn't care. He just wants to ask questions and tell you that your answer is not good enough for him.
If he doesn't stop his **** he will be moving on.

 

[ROSTERMAN]

He doesn't care. He just wants to ask questions and tell you that your answer is not good enough for him.
If he doesn't stop his **** he will be moving on.

Ya missed my point LOL

 

[WeedHopper]

No i didn't you racist *******.

 

[WeedHopper]

Guys please do me a favor and go vote on the BOTM contest. This is the last day for voting and we have some ties we need to break. Thanks

https://www.marijuanapassion.com/threads/new-2022-bud-of-the-month-for-january.80335/

 

[WeedHopper]

Cuda.
Bigsur went to a lot of trouble to give you answers to your questions and what did you do. You asked another smart-ass question. Im asking you to stop the crap and try and fit in and become a contributing member. If you can't do that then I will be forced to ban you,,, and i would rather not. It's up to you bro.
Im going to take you off slowmo so things will work better for you. Please don't try my patience my friend.

 

[user 60570]

So flat white,

So flat white is the best choice, right ? However, why do all the commercial growers and universities use white for their walls ?


I really don't want an answer I just want to ask questions.

well I’ve never been to every university and inspected every building so I’m not sure your remark is accurate without an scientific evidence to back it up

the same can be said about commercial growers , how many are there out there and how many have been surveyed to find out who is using flat white paint and who isn’t

here is another interesting scientific abstract on white paint……..no quiz here , just some extra credit assignments




Volume 1, Issue 10, 21 October 2020, 100221


Article
Full Daytime Sub-ambient Radiative Cooling in Commercial-like Paints with High Figure of Merit

Highlights

Paint using CaCO3 fillers with high concentration and broad particle size
The paint shows a high solar reflectance of 95.5% and sky window emissivity of 0.94
Field test shows >37 W/m2 cooling power and >1.7°C below ambient at noon
Commercial-like paint offers a high standard figure of merit of 0.49

Summary
Radiative cooling is a passive cooling technology that acts by reflecting sunlight and emitting radiation in the sky window. Although highly desirable, full daytime sub-ambient radiative cooling in commercial-like single-layer particle-matrix paints has not been achieved. Here, we demonstrate full daytime sub-ambient radiative cooling in CaCO3-acrylic paint by using large band gap CaCO3 fillers, a high particle concentration of 60%, and a broad size distribution. Our paint shows a high solar reflectance of 95.5% and a high normal emissivity of 0.94 in the sky window. Field tests show cooling power exceeding 37 W/m2 and a surface temperature of >1.7°C below ambient at noon. A figure of merit RC is proposed to compare the cooling performance independent of weather conditions. The standard RC of our paint is 0.49, among the best radiative cooling performances, while offering the benefits of convenient paint form, low cost, and compatibility with commercial paint fabrication processes.


two scientists observing white paint

study this chart , in it are the answers to the extra credit quiz

 

[WeedHopper]

Nice read Bigsur.

 

[Bubba]

So are your yields much larger , and how long did you grow before you perfected it
I tried it a few times and it was not worth the extra work for me. Or are you doing the CO2 to lock down all smells Hence the sealed room .

Agree. As you add more light, plant uptakes more nutes....to a point. It requires quite a bit of science. This is a high end game, with breeding specifically for this end. It requires tons of info on the chosen strains ability to uptake nutes to keep up with light available. Strain specific nute requirements, as well as maximum par for that strain, and maximum Nute uptake. Once you are at that point, and know the maximum amount of light that correlates to maximum nute uptake, CO2 can allow a little more light than the plants can to normally deal with. Most hobby grows are nowhere even close to sciences out making it a crap shoot in my opinion. But we all no about opinions....

Bubba