How To Make Infrared Cooling Paint (Electricity Free Air Conditioning)

Check out my sponsor Brilliant and use this link for 20% off a premium subscription: brilliant.org/... In this video I make ultrawhite radiative paints for passive, electricity free cooling.
Here is a partial list of the resources and relevant websites I found while researching this project:
Article about CaCO3 and BaSO4 Radiative Cooling in Commercial-like Paints: www.sciencedir...
This is a patent related to the above article: patents.google...
Formation and Application of High Reflectivity Controllable Barium Sulfate Microspheres: www.mdpi.com/2...
Designing Porous Polymers for Daytime Radiative Cooling: www.proceeding...
This is the only company I found that has installed sky cooling panels in limited test cases: www.skycoolsys...
This article describes testing of a radiative cooling film using glass microbeads as the infrared emitter: www.sciencedir...
Website associated with the above article: www.radi-cool....
Big thanks to everyone that supports this channel on Patreon! A special thanks to my top patrons: Teague Lasser, Eugene Pakhomov, and those who have chosen to remain anonymous. Thank you!
/ nighthawkprojects

[@Nighthawkinlight]

This video has been dubbed using an artificial voice via aloud.area120.google.com to increase accessibility. You can change the audio track language in the Settings menu. Este video ha sido doblado al español con voz artificial con aloud.area120.google.com para aumentar la accesibilidad. Puede cambiar el idioma de la pista de audio en el menú Configuración. Este vídeo foi dublado para o português usando uma voz artificial via aloud.area120.google.com para melhorar sua acessibilidade. Você pode alterar o idioma do áudio no menu Configurações.

[@metamud8686]

I can change subtitles, but there is no mention of changing the 'audio track' language in settings. There are 'Annotations', 'Playback speed', 'Subtitles' and 'Quality' (which relates to video quality, not audio). Where in the 'Settings' menu are we supposed to find this alternate audio track? 🤔

[@Nighthawkinlight]

@@metamud8686 It may take a day or two longer before it's available. I just submitted the new audio tracks yesterday

[@t_y8274]

@@Nighthawkinlight I think it's just not available in the app yet

[@Nighthawkinlight]

@@t_y8274 No, I'm having issues from my end. It's a very early test feature and I'm going back and forth with the developers while they try to solve the issue in KZbin itself. I'll get it fixed in a few days one way or another

[@t_y8274]

@@Nighthawkinlight very cool new feature though, hope to see it used soon!

[@samevans4834]

Let's all take a moment to appreciate how this man took research and development that could easily have been monetized in the form of a paper, or even a patent if he expanded on the cooling panel idea, but chose to gamble on ad revenue to make it publicly available for anyone curious to watch, and documented all his steps and testing so that knowledgeable people could replicate it easily. Great work!

[@MichaelOnines]

The patent space is already full of applications and grants for this technique. There's a demonstration install at a Smart & Final building in Stockton where roof panels are being fed the waste heat from the coolers. I imagine a lot of the study is seeing what kind of sensitivity there is to dirt accumulation on the panels.

[@winterbreeze5709]

researchers don't get paid to publish papers

[@Ranstone]

@@winterbreeze5709 But their names live on for eternity, even of someone only reads their name once every thousand years.

[@winterbreeze5709]

@@Ranstone "monetize" literally means "turn into money." doesn't have any connotations of glory or recognition

[@guard13007]

And let's also acknowledge how fucked up patents are. Someone could come along, take this exact process, and patent it, and suddenly it's illegal for him to use this technique. :D Oak Ridge National Laboratory did that with a large scale 3D printing technology recently.

[@aleksandarvasilevski7410]

I would propose small experiment with painting aluminum cylinders and measuring temperature with precise pt100 sensors in the centers of the cylinders. Cameras have noise and are imprecise in measuring ambient temperatures on materials with different emissivity. Measuring accumulated heat in cylinders over several hours exposed on sun can make results more applicable in real world.

[@pattheplanter]

I agree 👍but silver would be better than aluminium.

[@D-Vinko]

@@pattheplanter How in the fresh hell would he get Silver Cylinders,

[@TheSkytherMod]

@@D-Vinko silvers pretty cheap, get a sheet or two and roll it into a cylinder

[@pattheplanter]

@@D-Vinko A shop?

[@erins.5420]

I also propose using multiple materials. Residential and commercial buildings are not typically made with a metal shell to be painted. How about wood, concrete, drywall, brick, stone….the list isn’t too long but long enough to want testing on more substrates than metal be it aluminum/silver/steel.

[@mikeselectricstuff]

When experimenting with unusual surfaces, you can't trust the temperature shown by a thermal camera as you don't know the emissivity figure of the surface. You need to use physical temperature probes. Maybe coat onto foil with pt100 probes under the foil

[@Nighthawkinlight]

I'll be using thermocouples for more extensive testing now that I have a proof of concept

[@circuitguy9750]

@@Nighthawkinlight Your result was at least partially because you were 'reflecting' the sky more than the paint itself radiating due to its temperature. Your paint was more reflective (you confirmed that with the flashlight), so it was probably reflecting the sky better. Not saying you don't have the sub-ambient effect and it's amazing work, but it's invalid with the thermal camera as a measurement device. I.e. confirming this top comment - I have a decent bit of experience using a thermal camera on HV electronics - we measure off of stickers with a known calibration and it's common to see 10-20 C differences between the sticker and random metallic bits at the same (within 1-2 *C) temperature. Edit: Interestingly, if this paint really was beating the black body curve, and if your IR camera happened to be sensitive to that wavelength, the IR camera would show your paint as hotter than ambient because it was emitting more at that wavelength than it received for passive cooling.

[@Nighthawkinlight]

@@circuitguy9750 For strong reflected tempertures as you get with a metal surface you need something that gives specular reflection, rather than diffuse which is what my paint gives. That effect is also obvious because it happens immediately, where my paint starts at the same temp as the surrounding material when first put into the sun and can be seen cooling gradually. The calibration is not perfectly accurate between the two varieties of paint but it's not extremely far off. I'll compare thermocouple results with the thermal imaging next video. I think you've misunderstood how this paint works slightly by mentioning it should show up brighter on thermal. The paint doesn't emit any more IR light than anything else at a given temperture, it's that it emits a particular wavelength. The intensity of the emitted IR still goes down as the paint cools and so it will read darker on thermal cam like any cold object. Common thermal cameras only measure light in levels of intensity, not by wavelength.

[@circuitguy9750]

@@Nighthawkinlight Thanks for the reply, again - amazing work and I appreciate you sharing. I really may be missing something and would appreciate a clarification (perhaps in a future video if it's worthwhile). (Edit - and I would agree the gradual cooling is almost certainly proof its working) Your atmospheric IR window is 10 um or so. The calibration for your camera probably assumed a black body radiator (or close enough). I would expect your paint to emit more IR at 10 um than a black body radiator at the same temperature and I would expect it to stay that way to remain in equilibrium with a lower temperature than its surroundings. I.e. it's the increased radiation at 10 um compared to a black body that is providing the cooling effect. I had to Google this (didn't know), but it looks like most IR cameras only measure the 3-6 um wavelength; so you wouldn't see that effect.

[@terrafirma9328]

Does it matter what surfaces are painted. If you paint metal, does this change the differences? Imagine painting a

[@1xm_mx1]

As an architect, I've used calcium hydroxide (lime wash) to paint walls for solar reflectance and passive cooling. It takes about 3 coats of limewash to get the consistency and thickness and 3 days to accomplish this, since one coat takes a day to dry off, and then it gets wetted again to apply another coat. We add a binding agent for cohesion and a bit of indigo powder to the lime wash to get the bright white color since limewash itself is off-white in color by itself. The bonus of using limewash is that it absorbs CO2 from the air as it ages to form Calcium Carbonate.

[@honeytubs]

Very interesting! It seems much easier to make lime wash than the barium he was messing around with in the video. The video mentioned calcium carbonate but no tests. It would be nice to see the test results for calcium carbonate vs white paint from the store.

[@gsmontag]

My understanding is that limewash works great in warmer climates, especially if not very humid. Whereas in temperate locations where for long stretches of the year humidity is near 100%, some molds and other things can grow on it. Not a dealbreaker by any means, but does reduce the useful lifetime.

[@marlifords4026]

That's very useful info. I didn't know architects carried this sort of knowledge.

[@SSingh-nr8qz]

Very cool. Question, how to you prevent the wood from rotting? I live in a very rainy area that gets hot in the summer and brutally snowing in the winter. Usually I have to treat wood to keep it from rotting.

[@1xm_mx1]

@@SSingh-nr8qz we use tropical hardwoods for the timber frames of the doors and windows, and they naturally don't rot.

[@aclearlight]

As a science educator (chem prof) I can't say enough about how wonderful this was as a study in creative, methodical investigation leading to a noteworthy payoff in a relatively do-able time frame. Students sometimes get scared by the notion of "scientific research" and fear not being up to it, yet shown here, in a clear and empowering manner, is a wonderful example of how curiosity, patience, and informed diligence were able to arrive at a remarkable and practical goal - no super powers required! I'm retired now, but I can well imagine showing this video to students in a general chemistry class as a fun way of inspiring and empowering them towards a career in research.

[@Nighthawkinlight]

Thank you, that's high praise

[@powerelectronics7544]

@@Nighthawkinlight I want to ask you if you could perhaps Do Measurements In direct Moonlight And Shade At Night And post a video about it Because if the Sun Supposedly Reflects Light off of the Full moon I would really love to see your results I am not a very middle class guy Live in a 3rd world country and thing's are not as available as in 1st world countries So even if i had the money i couldn't just get everything in your video to test it myself You have it on hand It would really be appreciated And i believe it would be a good Test

[@powerelectronics7544]

@@Nighthawkinlight i have a Feeling just because of some of my own experimental tests I've done regarding Full moon and Night Shade Using infrared cameras and Lazer thermometers That your Results Wil perhaps Give the complete Opposite Results And that is the reason why I Am so curious about this Pigment of paint you have made in your video

[@powerelectronics7544]

@J. Curtis Yes Young people should do more research I agree with your statement I've thought myself over a decade period In electronics I didn't go to a collage/university Leaning Electronics I read a lot of theories and many books from publishers all across the earth Just to teach myself the Fundamental working principle Of all modern Electronics I studied Mechanical Engineering at A Collage And i did that line of work for about 3 and a half years and i wasn't really happy in that field The economy in our country is pretty dull the say the least So for me to have to pay another collage intuition was not how i went about it The internet is a Vast Vast source of information you could basically say Everyone that has access to Internet Has Free Education In a sence I studied and bought my first Proper Soldering station and started with Easy circuits And i did repairs for friends and family And i bought myself an Oscilloscope Not a very expensive one just one that works for my needs And i started going into more and more advanced research papers published by major scholars across the earth And that is how today i have a degree in Power Electronics I just took the standard Bar test for power electronics and passed with flying colours

[@powerelectronics7544]

@@Nighthawkinlight the Full moon and Night Shade Infrared camera and Laser thermometer Experiments i have done Have shown me that The Moon Reflects an opposite light than that of the Sun The Sun is Hot And the Moon is Cold Measuring temperatures in Direct Full moon are Colder that temperatures in Night Shade And i believe because of this Fact If you do, that which I have asked in my First comment Your results will be the Complete Opposite It will Generate Heat instead of Being Cold in direct moon light Opposed to it being in Night Shade But you don't have to believe what i have said I do hope you do this in your Series about this Pigment of paint Because we do Have Day and we have Night Your results would formally be inconclusive If you had not done it in both Sun light and Day Shade And Full moon and Night Shade If that makes Logical sense to you

[@chemicalsymphony]

The "brown tint" at 8:28 looks like a hell of a lot like Rayleigh scattering from fine particles (aka the reason why sunsets are red). I suspect your reaction worked without any side reaction as you are describing, but the particles end up being extremely fine. This explains why you can't get rid of it; the colour is from the particles, and they might be so fine that's it's forming some sort of colloid either by itself or with the EDTA, which makes it really difficult to separate.

[@PedroDaGr8]

In this case it would more likely be Mie Scattering, rather than Rayleigh Scattering (though it certainly could be both), as the particles would likely be larger than the wavelength of light they are scattering. Everything else is correct, that "milky" coloration is very indicative of scattering.

[@Muonium1]

I had the exact same thought. The light coloration looks exactly like what one would expect from the classic few drops of milk in fishtank of water with a flashlight beam through it Tyndall scattering demo.

[@noalear]

Yup! I was thinking the same thing. I immediately thought of purple Au nanoparticles.

[@Kargoneth]

Liquid smoke.

[@stevenclark2188]

That's what I was about to say: it looks like a structural color, or the colloidal weirdness of milk.

[@GuillotinedChemistry]

As a high school chemistry teacher, I find a lot lot to love here. Great examples of precipitation reactions and thoughtful experiments and imaginative predictions and analysis. I lost count of all the chemical and technical challenges Ben had to overcome to get his final results. As always, Ben's humility and curiosity serve as a wonderful role-model to any citizen-scientists be they adolescents or adults. This is the way science gets done... by failing again and again and using the failures to come up with the next interesting question! Side thought about barium compound solubility... Although barium is pretty toxic and soluble barium compounds can be dangerous, the insoluble barium sulfate is actually given internally to add contrast to help doctors clearly see and diagnosis x-ray and CT scans. Again a really neat practical application of those solubility rules students sometimes under appreciate. Always great to see what you are up to, Ben!

[@Nighthawkinlight]

Thank you! I almost mentioned that people are prescribed giant doses of barium sulfate but that part of the video was already getting wordy.

[@SeeTheWholeTruth]

At present, contrast dye nationwide is out of stock for months. There are doctors having to choose who to give what little supply they get to priority patients, and there is no resolution in sight. So, while all of this is nice, reality is the collapse of all of the issues of resource and goods bringing more and more failures currently. Lidocaine is nearly impossible to find as well. Ambulances are sitting months for parts, with no real certainty of when they will be delivered, and calls are getting told, cant do it, find another way in.

[@fuzzywzhe]

As an engineer I see a problem here, if something can passively cool an object in a closed system, you're violating the law of entropy. If a paint would be able to reduce the temperature of the object it was applied to, a Stirling Engine could be mounted to it to produce a perpetual motion machine. I consider this video complete scientific hokum which is becoming more prevalent on this site due to censorship. Such a paint, if it existed, would violate our understanding of physics. Anybody that go through high school physics should recognize this nearly immediately if they thought about it. But you may never see my comment, since the purpose of Google is to disseminate false information today.

[@dlorien7306]

@@fuzzywzhe many people seeing your comment, just not saying anything because they recognize you're wrong

[@Nighthawkinlight]

@@fuzzywzhe This is not a closed system. The paint is interacting directly with the coldness of space through a transparent band of the atmosphere. Heat is flowing from hot to cold.

[@alexanderyounis5704]

This is my very first comment on a KZbin video ever. I am a developer from Europe living in The Bahamas and currently implementing my residential eco-project that was almost a decade in the planning. I am commenting to support your channel and express my appreciation for your professional efforts and expertise by sharing your research in an accessible way that has potentially incredible implications for our environment and the well-being of all. I know these are big words, but living in a country where it is 90% hot and sunny year round, the amount of energy, building materials, pollution used and generated just for cooling is significant and unsustainable. Thank you for your efforts and we will try to reproduce your methods and test them on our project. Looking forward to see if you were able to increase the performance further sub ambient temperature. Good health and cheers from the islands!

[@tuckertruckerpatriot312]

Imagine what all could be researched and discovered if NightHawkInLight had unlimited funding from a developer from Europe living in The Bahamas! I would sponsor him if I could but... alas, I am a truck driver that listens while barreling down the highways. All I can give is my encouraging words. Best Wishes. Lots of GOOD Stuff to learn here.

[@bobudd3555]

@@tuckertruckerpatriot312 hahhahah

[@cherriberri8373]

I just wanted to say I think it would be absolutely amazing to see some kind of Infared cooling pain on homes so soon!

[@joncook6167]

Have you used a lime wash?

[@royromano9792]

Have you had any luck?

[@sigvardr7682]

Incredible stuff. As a homesteader, being able to paint the roofs of livestock pens and shelters with this could save the vulnerable ones during heat waves in a way that is more sustainable and realistic than a climate controlled environment.

[@ThePinkBinks]

Grow ivy over the roofs of your pens. The ivy absorbs the sun’s radiation and keeps them cool in the summer and warmer in the winter. Also look into geothermal heating and cooling using heat pumps.

[@davidegaruti2582]

you could also put a chimney on top and have warm air come back in trough a hole underneath the ground , but honestly i am just speculating right now

[@scottdowney4318]

@@ThePinkBinks That is the only realistic 'sustainable' way. And I hate that word sustainable, it has a ton of political baggage along with their build back better, better than what exactly, it works fine, but they just according to their ideologies cant stand the way it is.

[@LuLe232]

Try to get your hands on the white paint used for road markings, it shouldn't be to hard to get, and try it on a section of roof.

[@Nickfletchertheskibum]

Only problem with ivy or any vine plant on a structure is the possibility of rot or structural failure from the added weight. Vines will Ruin brick work. Ask my current employer tried to warm them over the vines on the brick on hr building. They said oh it looks lovely plus its been here for decades. I told them those vines are going to rip the bricks right off. That was an expensive repair lol

[@AppliedScience]

Really interesting investigation. I had never heard of that plastic foam reflector idea. Maybe the temperature differential could power one of those handheld Stirling engines.

[@teekotrain6845]

@@donnerpartysupplies5187 the powers that be wouldn't allow it. We could be driving cars that run on water if they hadn't killed Stanley Meyers RIP

[@Jimunu]

@@teekotrain6845 The only thing youre cultivating is cynicism and defeatism combined with unconstructive conspiracism.

[@MostlyPennyCat]

Another cooling idea, this is an old one, is a dual layer (usually fabric as this is a shade while camping thing) Two layers, outer one is white, reflective. Air gap in between, but open at the sides. Inner fabric, I suppose could be black to radiate heat better but probably irrelevant. Sun hits the outer Outer heats the air gap Hot turbulent air comes out the sides, even better if there's a breeze to carry the great away. Inner air gap also acts as an insulator against the air inside the tent/under the shelter.

[@MostlyPennyCat]

Maybe the Black Top should become the White Top.

[@MostlyPennyCat]

Maybe airbrushing would get the full-of-air-gaps effect from the Barium paint?

[@TheMightyZwom]

I was immediately thingking about making panels with this paint. So yeah - I'm looking forward to a series!

[@wobblysauce]

Window blinds/shutters... for summer

[@dragonballzgt1989]

a cover for my chicken coop to cool the poor girls off

[@andrewkaiser1606]

Yes! Also can you show the calcium carbonate route? Its a lot more common...

[@unbekanntunbekant4587]

Dont try hiding from Police with this because your WiFi Shows defently where you are

[@Sythemn]

I personally am quite annoyed that none of the reasonable methods for doing this have been commercialized yet. It’s been years for some of them that were supposedly at the “We can manufacture this tomorrow” level. Thanks for the effort into figuring this out.

[@Netheralian]

Because there are more efficient systems that provide considerably higher cooling capacity. Passive paints are good for reducing summer heat loads, but aren't good enough for primary cooling.

[@Sythemn]

@@Netheralian For AC or refrigeration level cooling where humidity control is also a concern you are correct that these are not sufficient. Even the best case scenario I'm aware of topped out at -10 C (-18F) from ambient which is not sufficient on 85F+ days. However, for lowering the heat load of roofs and for potentially dramatically increasing comfort in open air structures, many of these would be a wonderful option. Especially in hot dry locations. The film by Radicool (UC Boulder invention) is already being used successfully on large projects in Asia for AC reduction. It just isn't available to the public.

[@trp2413]

@@Sythemn - if my roof is 110 instead of 115, wouldn’t that lower the cooling load on heat pump?

[@lemonlupinreuben5362]

@@Netheralian that's because you're thinking of paint as a substitute, rather than as an assistant or supplement.

[@runed0s86]

Selling more powerful cooling systems is more profitable than painting a building once

[@MakeTeachRepeat]

If you keep the solution hot for some time, heating it, it “digests” the solution and smaller crystals give way to larger, more orderly crystals. Also makes filtration much easier.

[@PedroDaGr8]

This is correct! A great use of Ostwald ripening.

[@gramursowanfaborden5820]

this phenomenon is visible in geology, with slower cooling granites having larger crystal sizes.

[@MakeTeachRepeat]

@@gramursowanfaborden5820 this is similar but in a heated solution there is an equilibrium with dissolution and crystallisation constantly happening, so smaller crystals have a larger surface area to dissolve from, so they tend to dissolve more than crystallise, while bigger crystals keep more mass during the process. It’s a statistical bias towards larger particles rather than the slower cooling effect which allows particle to find the growing faces of the crystals and making bigger ones.

[@gregdaweson4657]

Is that not common knowledge?

[@bjmcculloch]

Have you actually done this for barium sulfate? While what you’re saying is true in general, I’m fairly confident that the solubility product of BaSO4 is far too low for Ostwald ripening to occur to any significant level.

[@shadowkyrin]

I managed to get barium sulfate spheres (at the size of < 5μm) from China to where I am in SE Asia and mixed it with a transparent acrylic paint base. Did a few rudimentary comparisons with the available white paints, and achieved an average delta of 3°C. It's still a huge impact for an area of the world that relies heavily on AC. Currently trying to figure out if it will hold up to the thrashing of monsoon rains. 😅 But I love it if there was a series in this.

[@frankwilldo2434]

Even more important in places where ac is impractical or just unaffordable to most of the population.

[@chironjit]

As someone from SEA who is struggling to find white roof tiles, I can imagine how helpful this would be.. it's insane that for countries having hot and sunny weather all year long that roof tiles are all dark

[@shadowkyrin]

@@chironjit there is a company in Thailand that does alu-zinc roof tiles with a layer of insulation pre installed. I think it comes in white too. I had to order mine from Australia tho because they wouldn't do flat standing seams. Only the usual wavy kind.

[@JohnDoe-jq1br]

@@shadowkyrin Do you know the name of the company? I intend to build a home in Thailand.

[@MrBalrogos]

I have question what about white paint and on top of that glass beads are sprinkled, that type of paint is used in europe to make reflective stripes on road.

[@AgentWest]

As soon as you mentioned micro-spheres my first thought was sand blasting glass beads. They are tiny, transparent, and fairly spherical. In addition, they are very similar (if not the same as) what's used on reflective road markings and high quality projector screens. In the case of roads, the paint is first sprayed pretty heavily, then these beads are metered onto it while it's still wet, sinking in and adhering to the surface. It appears that barium sulfate is used more as a filter rather than a pigment, so using off-the-shelf substrate mixed into regular white paint (instead of making acetone/acrylic mix) may be more convenient. As for heating/cooling panels, what about regular sign board (the kind that all election signs are made of) with one side coated with this reflective paint and the other matte black. Depending on the need, the panel is flipped over to present either side to the sun, cooling or heating water/air passing through.

[@ytSuns26]

That is an excellent idea especially since flipping the board would be straight forward and simple . Flexible tubing and a wave type of motion. Extreme right extreme left.

[@AgentWest]

@@ytSuns26 Good point. Since it's only 180* of rotation, a basic tube will be able to do that, so no need for a special sealed pivot or anything. If nothing else, loosely wrap the tube around panel's support shaft once or twice, that will give it plenty of slack.

[@billyandrew]

I love this guy! He simplifies complicated procedures, making it easy to follow his step by step guides, covering all manner of topics. He's one cool chemistry/physics teacher, academia's loss and our gain and long may his channel run! 👏👏👏👍

[@martinjohnson2359]

Please do more of this series on this paint. This can be a big game changer in so many ways.

[@UwuUwu-td7do]

He could start a company, by making and selling those cold panels

[@fontexstudios]

probably very useful in hot and developing countries, like in Africa and South America

[@arinasan247]

I love how he went through all the trouble of making some of these substances himself when he (later) discovered that he could have just bought them. Wonderful video!

[@phoenixfireclusterbomb]

Lol, the difference between a poor man and a rich man.

[@bierymolina4379]

That would be good for phones/cases that get into sun and heat

[@pretzelboi64]

It's still a good learning experience. Doing the chemistry yourself makes you a better chemist.

[@UpenShenoy]

The world needs more people like you, such passion and crystal clear communication. Thank you. Looking forward forward to seeing your series.

[@camrouxbg]

One of my favourite things about this video (and most of your previous videos) is how you talk about and show the process of trial and error, making mistakes, and learning from them. Giving this perspective really helps to show students (and everyone else) that persistence can pay off. You started with a question, did some literature review, and started trying your own methods based on your review. When it didn't work, you went back and took a look at the literature for something you might have missed. Thank you so much for so effectively demonstrating this process. Even though you cannot possibly show every trial and every pain-staking error, you really demonstrate the scientific method quite effectively. Please keep doing what you're doing :)

[@dave7038]

A related subject you might be interested in exploring is the use of this type of radiative cooler to condense moisture from the air at night. As the panel drops below the dew point in the evening it collects water that can be allowed to run off for jobs like watering seedlings (maybe useful for establishing plants in remote areas, like green belts in arid locations). For cooling tasks it might be possible to absorb the water into the panel to provide evaporative cooling the next day. You might also try combining this cooling paint with ultra black paint on a water wicking material to make a passive solar still. Water would wick up to the warm black surface, evaporative, and condense onto the coler white paint, then run off for collection. Production is limited to solar power input, but low thermal mass means it can start producing very quickly after exposure to sun, rather than needing to wait for a larger mass of water to warm up.

[@MontyCantsin]

Skywalker moisture harvesting becomes reality

[@chuckgoecke]

This works best where there is some humidity in the air, so coastal desert areas work pretty good, but large super dry deserts like the Sahara it probably wouldn't.

[@asdf35750]

Be careful when using IR to measure temperature. The emissivity of your barium paint is different to the emissivity of your ultrawhite paint, particularly in the IR spectrum where you are doing the measurement. This means that what looks like a cooler surface may in fact be a surface that is the same temperature, but not emitting as much IR because its emissivity is lower.

[@philippbaschab7408]

That's what I was wondering about. Do infrared thermometers measure different frequencys or should'n the barium paint appear hotter because it radiates more heat?

[@atomictraveller]

i live in tucson, have no AC and chainsaw for a living. this time of year it's 92 to 94 indoors, all day all night. each year i'm more cooked, shitting my guts out at the end of each week. i'd be more than happy to test the efficacy of any paints on my campaign hat or roof.

[@KleinfeldTechnical]

I opened up the comments to address the same issue. There are field / experimental methods to determine the emissivity and to compare that of two surfaces. One that would be usable for this instance can be easily set up. One easy test: Take the painted panel, such as the one with the X or "Cold" into a uniform temperature area where radiation is not a factor. Using contact heating with something like a hot water bottle, heat the surface to at least several degrees above ambient. Take an image immediately on removing the hot water bottle. At that point, the temperature of the surface should be uniform. If the IR image is not uniform, there is an emissivity difference. Having the sample in the bottom of a box would improve the test a little, by providing a uniform background temperature and radiation environment.

[@senatorjosephmccarthy2720]

@@atomictraveller , How did the people live and work in the area of the southern states for the thousands of years they did so? Did they acclimate? Learn to work within their limits?

[@atomictraveller]

@@senatorjosephmccarthy2720 yeah joe, but today people own property and you have to edge bunkers and shit.

[@broklond]

Here in Hungary (and probably all of Europe) Ca(OH)2 mixed with water is used as a standard white paint, which over time turns into CaCO3 by catching CO2 out of the air. Didn't know it had cooling properties, but makes sense why our single family homes don't heat up as fast 😮

[@Sekir80]

Really? How can I check a random paint vendor what they use?

[@MAMG78]

Here in Spain, it´s the same!

[@chrisfromsouthaus2735]

Calcium carbonate is really interesting. I grew up in a small country town in South Australia, where the major bedrock was limestone. The town had many old mining cottages, built from the limestone, and those with painted outside walls where always noticeably warmer, on hot days, than houses with bare stone walls. Some of the old folks would put this down to the houses without paint "breathing" better, but this would make a lot more sense. Considering many of these country towns, sitting on limestone, experience extreme summer heat, I could see the limestone becoming a very important local resource.

[@shinjisan2015]

When calcium carbonate was listed I was hoping to see it used.

[@mgumodena]

True, in fact in Southern Spain most towns are completely bleached with ultra white lime paint almost every year. This keeps them much cooler.

[@ytskt]

@@mgumodena Exactly, so is some some parts of Greece and India. I am wondering why he chose to use BaSO4 and not CaCO3 as calcium carbonate is much more commonly available as already used as paint.

[@vociferonheraldofthewinter2284]

I just started experimenting with calcium carbonate coatings. The stuff has great properties all the way around and is a fantastic building material.

[@danielf3623]

@@shinjisan2015 Probably because Calcium Carbonate-based paint is just old-fashioned Whitewash

[@leifhietala8074]

I've been reading about passive radiative cooling in the atmospheric window for years now, but this is the first time I've seen someone even approach the results using off-the-shelf, commercially available materials. And it is VERY exciting. Pretty much everywhere in the world that has any kind of cooling season needs this.

[@AmaroqStarwind]

Maybe combine this with the radiators used for air conditioning and/or peltier modules?

[@leifhietala8074]

@@AmaroqStarwind AC yes, peltier modules no. BUT more on that in a moment. I'm all for heat rejection that tunes the rejection specifically into the atmospheric window. Getting the heat out of the world is good, all things considered. I'm concerned about all the people who are so heavily pro-nuclear power, too - they want to dig heat out of the ground in the form of fissionable materials, and then release that into the atmosphere. I know it isn't CO2 which does a good job of capturing solar heat, but still. Peltier devices are pretty cool unless you're using them for cooling - then they're terrible. Generally their coefficients of performance don't rise above about 0.7 or so - for every 100 watts of energy you pump in, you only remove about 70 watts of heat from whatever you want to cool. Note that this is for the best TEDs, and for cooling an object below ambient temperature. If you want to cool something that is already above ambient temperature then even a merely fair COP can beat 1:1. But it's easy to beat 1:1 COP with regular compressor-based refrigeration. _Easy_ and fully baked. If you want to deploy a TED as heater when it's cold outside, you will get over 1:1 COP but again, you get a bigger bang for the buck with refrigerant-based technologies. A TED makes sense, however, if your needs are very low-amplitude and require high reliability - a TED can be designed to work effectively with no moving parts, just big ol' heat sinks and sufficient draft height to ensure air movement over the sinks. Bob's your uncle.

[@AmaroqStarwind]

@@leifhietala8074 Kyle Hill has a lot to say about nuclear power. I’d suggest giving him a look.

[@incognitotorpedo42]

@@leifhietala8074 Are you sure the math works out for the idea that nuclear power is adding heat to the atmosphere when you compare it to a fossil fueled plant? Imagine two power plants, one coal fired, the other nuclear, both producing one GW. Both create more than one GW of heat energy, because the Carnot inefficiency requires that. In each case, the excess heat is released to the environment, and each create one GW of electric power that is mostly converted to thermal energy at point of use. Thus the heat output of each plant is roughly the same. However, the coal plant produces vast quantities of CO2 that stays in the atmosphere for a thousand years, all the while collecting heat from the sun, with a collector area the size of the Earth. I think the greenhouse effect of the CO2 will dwarf by orders of magnitude the heat energy generated at the plant.

[@skipfred]

I mean, this is not going to cool your house. I assume the video title is a bit tongue in cheek, because it certainly will not work as air conditioning for a normal house. Still cool though, pun intended.

[@Alexander_Sannikov]

8:40 the "brown tint" is likely not actually a contamination, it's tyndall scattering, it's (almost) the same effect that makes sky blue and the sunset red. it looks red because it outscatters predominantly blue light in all direction and the remaining red light passes unchanged, that's why from the side objects with tyndall scattering look blueish and when observed through they look reddish.

[@bjmcculloch]

The fact that it never settles out - even in the centrifuge - supports the notion that it’s particles that are too small to settle (due to Brownian motion keeping them suspended). However, EDTA does form precipitates at low pH, so I wouldn’t rule out the possibility that these solids may be principally EDTA.

[@serenacula3256]

this is incredible... I had absolutely no idea this was even physically possible. The amount of uses for this are mind-boggling. Power-free sub-ambient cooling, just incredible.

[@wizrom3046]

It is NOT possible. Sub-ambient temperatures cannot be achieved by a reflective coating. This is an obvious fact to any student of physics. There are serious errors in his method.

[@dangeary2134]

@@wizrom3046 the goal here is to release more heat than is absorbed. This is why supersonic aircraft like the Concorde are painted with white epoxy. The single Concorde that was painted blue had a speed restriction just because of the color. This also has possibilities in other environments that are controlled. My first thought to application were cooling things in other semi-controlled environments, such as cooling and refrigeration. The concept is sound, and needs more research.

[@wizrom3046]

@@dangeary2134 ... hi Dan, sorry I will retract my earlier statement, after reading some research papers it IS possible to get slightly below ambient temperatures via radiating heat energy to the sky. I'm not sure how much use it would be in refrigeration because it can only get about 1 to 2 degrees below ambient in daytime if everything is perfect. And needs to be pointed at the sky. Since this works by the surface being super-reflective I have concerns about its viability since surfaces soon get dirty and contaminated and even in a few weeks their reflectivity can degrade by 20 or 30 percent, making this no better than standard white paint. Then of course in real life it has to be cleaned constantly introducing a new cost, and of course the painted surface has to be able to withstand constant cleaning which might mean changes to the paint that make it more expensive or less efficient than the laboratory paint. This is interesting technology for sure, but has a long way to go.

[@dangeary2134]

@@wizrom3046 I get where you are coming from. It would definitely not be a stand-alone tech for refrigeration, by no means. That being said, consider the other things that help with cooling. Evaporation is a big one. Peltier Effect devices are quite good as well. Imagine coating aluminum with this stuff, and placing it in a shaded area. Whether it is in a structure or under something is irrelevant. The energy is leaving the paint, and that is what is desired. Application is more than for an entire structure. I just think outside of the box.

[@BobbyDukeArts]

Very cool. I mean, slightly below ambient temperature :D Seriously, I love your videos

[@Nighthawkinlight]

Thanks!

[@jeanlesueur6936]

In my country, a distributor of sport equipment (Decathlon) made camping shelters with a special cloth they call "fresh". As I bought one of those, I found it incredibly efficient, by far as I could think possible. First, I thought it was a simple reflective surface, but after searching on it appears to be far more complex : some kind of laminate of several compound interacting with heat. As far as I can understand, it's certainly working using the principle you exposed.

[@jean-micheldupont1150]

Yes, I have some friends who bought these, I couldn't believe how cool they were compared to mine on the same camping spot.

[@johnmcdaid692]

My thoughts exactly, the Fresh Tarp is amazing

[@dzhong111]

This is pretty incredible stuff. Two thoughts: 1. The stated aim was to test the barium sulphate against commercial OTS paints. However, the test article was actually barium sulphate impregnated in the snow-pattern acrylic. It would be interesting to compare the snow-pattern acrylic with and without barium sulphate. 2. During the discussion at the end about the form of the practical application, I thought that for houses, the paint could be applied to a blanket that would be draped over the roof and secured somehow (the latter should be easy - there are products for temporarily waterproofing houses with damaged rooves). I don't see any obvious downsides, but interested to hear if anyone can think of any.

[@andrewstambaugh8030]

I think it would be better to have sheets. Flip and lock them 1 way for winter, flip and lock the other way for summer. And you'd have the cool house on the block that doesn't just put up Christmas lights but changes color for winter.

[@TheNewton]

For 2. Also see swamp coolers.

[@andrewstambaugh8030]

@@TheNewton Having researched and practically experienced, swamp coolers are not good. And when you consider all the issues, I'd pay for ac every time over dealing with them: 1. My biggest issue with swamp coolers: They struggle to do very much. 6deg in very ideal conditions, but that isn't sustainable and actual is more in the range of 1-2 or 3-4degF. Is that nothing? No. You can feel the difference (and the mugginess it creates...) But if it's 95deg, that still leaves your house/shop above 90! In the heat of day, his paint was doing much more than that (did he say 20deg?), and even a moderate sized ac unit soundly beats a massive swamp cooler. 2. Health risk: like the humidifiers they basically are, they are prone to making the air stank and swampy smelling. But the smell is only the _unpleasant_ part. An uncleaned swamp cooler will start to mold and that can do nasty things like give even people with healthy lungs asthma that may not go away after exposure stops. And it can make an entire building infested with mold bloom and uninhabitable. 3. Free? That's usually the biggest claim to fame. Cool your house for free. Only if your time, effort, and cleaning chemicals are free. And it doesn't accidentally get spilled and do water damage... Speaking from exp as part of a non-profit renting a building, a single spill accident immediately got us a "you can't use those anymore or you'll have to cover extra insurance," unhappy faces, and almost a several thousand dollar repair bill. You also add the restriction of needing close water access to your venue choices (running hoses throughout a building is a bad idea for water damage risk). Plus the huge hassle of effort to clean, taxing our volunteer free labor. Between money and hassle, we quite practically could not afford to keep using the swamp coolers we already owned. Plus the cost of 1 accident would have dwarfed the cost of several years of using AC for more comfortable temps. Even in the hot desert where I currently live, it generally costs about $5 in peak heat of July & Aug to AC my house down to very comfortable temps (I like it cool). And I rarely ever have to clean my ac. And it's not likely to be a health issue if I ignore cleaning it for years at a time, so I'm not forced to drop everything and deal with it to avoid poisoning everyone. And if anyone has wooden musical instruments, you probably already know that jumping from the extreme of very dry to very humid and visa versa is a great way to see an instrument break on stage. You could solve that for the mere cost of renting & setting up the swamp coolers a full day earlier and contracting the musician to come a full day earlier to leave their instrument there to acclimate for 24hrs...

[@shinrakishitani1079]

The only issue I can see with that is that depending on how it's applied the paint may peel off, ideally you'd either have solid panels or seal the paint between a supportive and a transparent layer, I'm not sure which flexible transparent materials allow the specific wavelength of IR to pass through, reflecting would be fine but absorbing would defeat the main feature of the paint.

[@nahometesfay1112]

@@andrewstambaugh8030 I'm currently in a swamp-cooled house that is 20F lower than outside. When I return home and turn on the cooler the temperature normally drops 10F. There is no smell and the air doesn't feel particularly humid. It sounds like you use it in a commercial context and I don't know how swamp coolers scale up, so that might be why it works so much better for me. It could also be a lack of circulation in your building. Swamp coolers in normal operation should replace all the air in the cooled part of the building in a matter of minutes so every room needs a slightly open window (like an inch). If all the windows and doors in the building are closed then the swamp cooler would perform about as well as you described. The swamp cooler also could have been too small for the area being cooled.

[@Zaptastic]

Love this topic, saw probably the same article this year and did some research and realized there was some "secret sauce" involved. I encourage you to explore this fully as your work will likely benefit everyone on the planet. Sounds a bit over the top, but energy savings like this are huge for humanity. You are doing work that benefits all of us and I really appreciate and support you.

[@Tabletsculptingtips]

I think your videos are the gold standard for the invention/making/science education genre. I particularly appreciate how you often find insightful and elegant “least effort” solutions to quite tricky problems: such as when you made a giant cone from a large roll of plastic lawn edging material - brilliant! - But there are countless other examples too. Could I suggest a future video topic (partly because I would love to see the end result) the title could be something like “Strongest homemade material” or “Homemade alternative to epoxy putty”. Your starting point would be an amazingly tough ( extremely hard but also non brittle) material made from a mix of damp paper pulp, premixed drywall compound, flour and PVA glue. If you search for “smooth papier-mâché clay”, you will find a video from a channel called “ultimate paper mache” which will give the recipe and instructions. I recently made this recipe expecting to get an amateurish substance suitable for small craft projects, but the strength and effectiveness of it has left me genuinely shocked. In the past I’ve used polyester resins, epoxy resins, cement mixtures, and various high end professional gypsum plasters, including what I believe is the hardest commercially available gypsum plaster in the world; yet this cheap homemade clay is, in many respects, superior to them all. You could easily make functional, weight bearing objects like furniture from it. It is also quite similar to your initial recipe for starlight. It is not perfect however: it shrinks slightly and is not waterproof. I think the waterproofing issue could be trivial to solve using waterproof pva or a waterproofing agent added to mix. The shrinkage problem might be trickier to solve. With your knowledge of chemistry I suspect you could take this basic recipe and transform it into something utterly remarkable. There are various recipes for similar materials, but they all involve pva glue as a binder, and then some sort of powder to add bulk: flour, cornstarch, plaster of Paris, marble dust, paper pulp (for tensile strength) etc. I think it could be a fascinating family of materials to experiment with and try to optimise, and I suspect a video called “ Strongest homemade material” would do quite well. Anyway, it’s just an idea I thought I’d share in case it interested you. All the very best.

[@Nighthawkinlight]

Thanks for the idea!

[@piethein4355]

Nah it's good, but tech ingredients is still better ^^

[@imraff]

@@piethein4355 nowhere near as accessible as this channel though. Nighthawk is the gateway drug, TI is the hard stuff.

[@AlexandreLollini]

Be aware that thermal cameras have very difficult time with reflective surfaces and do not see thru glass for example. you should try to measure temperatures ON THE BACK of the painted surfaces, try and simulate a metal roof or the metal of a car shell. This is an excellent subject of research !

[@EweChewBrrr01]

Glad to hear that you're better. You're such a good educator that you even make watching paint dry an enjoyable and interesting experience.

[@nunyabusiness863]

😂😂What are the odds of being able to use that joke again?

[@EweChewBrrr01]

@@nunyabusiness863 That's Nunya Business :P

[@alexanderkozlov2539]

Mate, you are the perfect illustration of "quality over quantity" with your videos been quite infrequent, but extremely thorough and exciting to watch!

[@glenngriffon8032]

Pretty interesting. I'm living in the desert, off-grid, so a no electricity solution to keeping cool sounds awesome. Sorry to hear about your health issues. Hope you're better.

[@HissoriRenda]

I'm just blown away at the work you put into your projects. Such high quality explanations and your execution is always approachable

[@freman]

Even if without reaching sub ambient, a 20 degree drop on the temperature of a skin of a building in the sun is going to keep the inside of the building so much nicer

[@happyzahn8031]

I like the 'transparent' notion as my house is already painted. One wall faces the brutal afternoon sun, hot enough to burn skin touching the paint. Infrared reflective coating over the paint seems like a real win in my situation as that wall is very warm on the AC-inside of the house. On another note, I have always wanted some kind outdoors heat exchanger for that wall with the other side of the house to do something, like perhaps generate electricity since the temp difference is probably 20+ degrees for 3 hours.

[@TheKingofRandom]

This is incredible, and we need to get our hands on some ASAP!! 😮

[@kori228]

you guys still active?

[@thehotdogman9317]

@@Baitrix1 The original TKOR squad that is.

[@ApocEdits]

@@Baitrix1 yeah they ripped it from a deadmans hands and gave it to some random

[@bailey125]

@@ApocEdits Yep, they really are doing Grant a disservice. They need to rebrand.

[@bringer-of-change]

I definitely want some too. I wonder if this can be used to make an infrared shroud for thwarting FLIR 🤔

[@9squares]

Ingenious. I find it amazing that in the year 2022, this technology hasn't been previously exploited on a commercial scale.

[@Dimon811]

I think we run into a efficiency reason. It's been a lot easier to just push a bunch of power (electricity) at a cooling solution for years, and get a higher efficiency that way. Only recently are we starting to run into power issues where you can't throw more electricity at something and get a better result due to either the lack of power available (or possible currently) or a massive uptick in cost. We've only just recently started looking into low power ways to improve by little bits because we're getting close to the limits of our current tech.

[@9squares]

@@Dimon811 Yes, I think that is very true, you define the Industrial Age. However, I would argue power constraints have been with us all along. Had we been willing to acknowledge that infinite growth on a finite planet doesn't equate, the consequences might not have been so abrupt. The era of abundance is over. Especially with regard to carbon based fuel sources. For that precise reason, this technology is very exciting to me.

[@LappingMaster]

This content is pure gold. I want more of this, for example, a long time test for painting a car or something similar.

[@oliverford9325]

House walls

[@cujet]

Our Schmidt Cassegrain telescopes take about 2 hours to cool below ambient and become stable enough to use for quality images. This paint is performing the same task. I'm not surprised a clear plastic coating helped.

[@JustInTime0525]

Thank you for bringing such a cool way of passive cooling into the public's eyes, hope your health issue gets better! Also it would be amazing to see you collaberate and exchange ideas with Tech Ingredients, both brilliant individuals innovating with front-tier science in a homeshop setting, just to think what you guys could accomplish

[@nedisawegoyogya]

THANK YOU SO MUCH!!. I've been designing this paint 2 years ago based on the papers you've mentioned but stopped because I have no budget to do the experimentation part. Now that you've done it, I can cut some of the more expensive experimentation part.

[@TiSapph]

I've been reading about this technology for a while, it seems to be called "reverse greenhouse effect" by some. An interesting one I found was a polypropylene aerogel made by dissolving the PP in mineral oil and cooling it. By controlling the void size they managed to make the material highly reflective in the visible, but very transmissive in the infrared. In addition the material is obviously a great insulator. If you then put an optimised IR emitter (emitting only in the atmospheric window, being reflective otherwise) layer on the back of it, you get high reflectance for most of the spectrum and good IR emission. Problem I see with approaches that use polymers is that they will eventually break down under UV. In general the top layer of a panel must be IR transmissive at least up to 10um, ideally optically transmissive or reflective, and environmentally stable (not soluble in water, strong, UV resistent, ...). There aren't many materials like that, especially ones that are easy to manufacture in large panels. Maybe a thin sintered layer of MgO or BaSO4 would work, but no idea really.

[@GeorgeAlbercook]

Have you seen the work with PDMS (Polydimethylsiloxane). Almost the perfect emission spectrum from 1mm.

[@hherpdderp]

Put suncream on it 🌞

[@coopergates9680]

MgO reflects in the infrared window, too? It has the same issue as CaCO3, it wouldn't take a very strong acid to react with it. MgO might also absorb atmospheric moisture to convert to the hydroxide

[@TiSapph]

@@coopergates9680 I was under the impression that MgO is transparent up to 10um, but yeah it seems not to be. It's also not particularly stable, you are right. BaSO4 wouldn't be all that great either as top layer because it has an absorbance band right around 8-9um. Great as a tuned IR emitter, but as top layer (at ambient temp) it would block the radiation coming from the back of the panel and also heat it by IR emission.

[@coopergates9680]

@@TiSapph My assumption is that even more transparent materials like MgF2 and CaF2 don't emit much IR in the atmospheric window, but should I look up more emission spectra? Another possible mechanism when the sun is out is fluorescence, since most materials aren't transparent to UV, but some, like cotton, would re-radiate much of that energy as visible light, which of course is in an atmospheric window.

[@ericlotze7724]

23:30 Open Source Radiative Cooling Panels?!? *Absolute* 👏 *Legend* 👏 Definitely deserve every bit of publicity and patreon money!

[@petesmith13]

6:48 the barium sulphate microspheres were probably to improve barium sulfate X-ray (CT most likely) contrast fluid if they want to do a CT scan on your digestive system they get you to drink a couple litres of barium sulphate (it tastes horrible no matter the flavours they add) so that there is something in your digestive system to provide contrast to the x-rays iodine is also used but often that's injected so provides contrast for blood vessels rather than digestive tract

[@jhoughjr1]

Barium is nothing. The GoLytely is against the Geneva convention

[@evannibbe9375]

I think directly painting a warehouse actually works just fine, even in winter, particularly if the work people do inside is intense enough to reliably make people sweat (such as Amazon fulfillment centers), or if computers are running a server inside. With direct painting, as opposed to panels, you gain more benefits from the built-in insulation of the building.

[@sometimessnarky1642]

Wouldn't panels add more insulation?

[@alphanaut14]

I suspect you can experiment with different void sizes by replacing the water in acetone with other materials of different surface tensions. Alcohol vs glycol might affect the reflectivity.

[@klausbrinck2137]

Acetone and ethanol would evaporate with the same rate/speed, while what he does, is using water, cause it stays there for longer, after the acetone is long gone, and then, the water too will disappear.. It might lead to some interesting or new results (maybe ethanol disolves better in acetone, and leaves even smaller cavities behind, than what water would), but at first sight, it seems contradictory.

[@trrao4408]

He makes everything looks so simple and with a wonderful explanation. Love his videos and wishing him a speedy recovery and wonderful health ahead

[@thisllub]

I worked on pigmented emulsions years ago. The particle size and composition of the emulsion (paint in this case) drastically alters the covering power of the pigment. It would be fun playing with this one.

[@aetius31]

Great video, the porous acrylic was genius! I have done some experiments about radiant paint a few years ago, from my experience the best way to get significant cooling is to make two thick layers (100µm or more each): one base layer of barium sulfate paint and a top one with titanium dioxide. The top layer act as reflector while also providing thermal insulation jus like polyethylene film. You can improve a little bit the cooling (fraction of degree) by choosing a good reflective metal just like aluminum as the coated material (you can go hardcore by using silver coating, but it will defeat the purpose of cheap and simple method). The porous acrylic was really nice find, I bet you will get killer results by using it on the top titanium dioxide coating.

[@killrade4434]

When you started talking about the amount of cooling I thought about a distillation AC that could use a solar heater and liquid desiccant simular to the one tech ingredients made. It could use very little electricity from the grid. If use as a low wattage thermal could also power low voltage water pumps for the AC making it very efficient.

[@momallanimal2449]

I saw a few monthes ago with super great interest TechIngredients videos on this subject! I'm since a year or more fan & subscriber of you channel and I'm so happy to see you also treated this subject (with an much appreciated tribute to TechIngredients) with your own creative research, tests, formulas, ... : Great to see you also try to spread and complement this particular knowledge, extremely important in my mind for some of the challenges we already have and will for sure have to face in very near future!!! Big thanks from France!

[@placeholdername3907]

Waited 5 months, totally worth it!

[@tracybowling1156]

It is always so good to see you. I do hope that you make this a series. People like you are changing the world for the better!

[@jimhodg]

I have a narrow boat that gets extremely hot internally, I’ll definitely be keeping a eye on this! Although a full white roof wouldn’t work cooling panels made using it would certainly be interesting

[@charleslambert3368]

have you considered sticking a sheet of material (alu would work) a couple of inches above the roof, tropical land rover style?

[@MontyCantsin]

Wouldn't solar power be enough to run a small water pump in a line that transfers heat between the inside of the boat and the water outside?

[@royromano9792]

The possibilities are endless. I'm thinking solar collectors but just So that everyone is clear. If you make and implement this for any reason, you will have something 10-15 years ahead of what any consumer could get their hands on. It's mind-blowing future tech that he gave to everyone free of charge. He's like a sorcerer.

[@polandturtle]

Which highlights the ridiculous disconnect between science and industry. I remember reading about this years ago from the research community, it turns out it’s this easy to make and it’s not in every Walmart, despite the money and even lives it can save.

[@airfriedquadsbw]

Having been in the coatings and adhesives industry for 20 years, and it being part of my family for a lifetime. I LOVE THIS! ❤️ precipitated pigments are easier to get than this. Just request a sample. YOU NEED FUMED SILICA to keep your solids in suspension and some calcium carb to fill the space between the pigments. Hydrated alumina will help with heat.

[@Nighthawkinlight]

Thanks very much for the info! Is the fumed silica in the category of a dispersant?

[@pohjoinenkala9301]

@@Nighthawkinlight Fumed silica Is used to make epoxy behave like peanut butter and stay put and not drop out of the seam. Thixotropic? smth

[@airfriedquadsbw]

@NightHawkInLight it is used as a dispersant, and a free flow agent in powders. It is amorphous silica. Like popcorn but silica. Huge surface area. Cubic cm has the surface area of a football field. Aerogel is made of it. And space pens utilize it. It makes spray paint spray under sheer, and stay in place when applied. It builds a gel like structure in paint that holds solids it suspension. Very hydrophilic. Can be treated to be very hydrophobic. Hydrophobic version is alot of fun. Will Make a bubble of air around your hand(or anything) when under water. Apply soap then water to remove.

[@fredericapanon207]

@@airfriedquadsbw is fumed silica the same as silica fume? I first learned of that by-product of silicon refining as an additive to concrete to make it flow in shotcrete applications.

[@airfriedquadsbw]

@Frederica Panon they are the same, except the byproduct version is not 100% pure. Some black specs are found in the so called silica fumed. i did import the silica fumed, and thought the name was just a language translation thing. The specs are not a problem in products like concrete or dark plastics. But is a problem for white coatings(pigmented coatings start white) And is not food grade. Fumed Silica can be Code X, or food/med grade. Un to 2% Fumed silica is safe in food products like powdered soups and powdered creamers. It helps free flow powders as well as liquids. Powdered soups would be solid chunks without it. MAGIC SAND, sand that doesn't get wet is made with hydrophobic Fumed silica. In the can of paint it builds a gel type structure that helps suspend the raw materials in the liquid.

[@loganrussell48]

I think it would be really cool to have it be transparent as well, for use on glass and other window materials. Having a transparent layer on windows of a house or building could help reject *some* of the heat while still letting the window function as a window.

[@CharlesBosse]

It would be interesting to test the first paint (the one that "didn't work well" because of transparency) on a window with a normal glass control.

[@buckaroobonzai2909]

They already make a cheap solution for windows. It's basically a shade sticker that blocks out a lot of the heat and UV light. It doesn't obstruct the view and I think it works really well. The room feels cooler as soon as it is put up. You can buy this product at most home improvement stores.

[@mfgxl]

I would like to use what you are talking about on my cement roofing tiles here in hot Arizona that is almost always sunny.

[@pictsidhe6471]

Thermal control coatings are already available for windows.

[@Fearmylogic]

What if you took your barium powder, and had mixed it with paint that is already white? Would you have lost some of the reflectivity of the white paint? would they have added together to make an even white-er paint? Would you still get a decent IR reflectivity. OR, what if you coated the dry white paint, with your nearly clear barium paint? Would you have gotten the best of both worlds? There are so many questions, and experiments that could be done. I really hope you explore as many as possible, such as coating already dry paint with the most clear barium paint that you made. How much would it chance the color, if the color isn't white? Would a coating on either white paint, or non-white paint still let it be cooler than an uncoated section? Even if it's not cooler than ambient, If it's not absorbing as much heat, that would create cheaper cooling solutions for houses, or a shed, for example.

[@geodeaholicm4889]

brilliant ideas

[@jeffersonsharp2292]

At first I didn't want to watch this, as having watched your first video, as well as tech ingredients videos on the subject, I was unsure there would be enough new information to justify nearly a half hour of my time. Now, after having watched it, and sitting here with my mind completely and utterly blown, I wish I had time to immediately rewatch it.

[@xoblyxanier]

Very interesting project, as always! I'm not sure, if we can trust the temperature readings from the IR meter though. Couldn't it be, the effect you are observing is just a difference in reflectivity? This could also explain the difference between direct sunlight and ambient light. Maybe you could try measuring the temperature using photochromic paint or some other method

[@Nighthawkinlight]

Much of the temperture difference is caused by a difference in reflectivity, in that the more reflective paint absorbs less heat and stays cooler in the sun. It's easy to tell with the IR cam when you're dealing with reflection that throws off the readings and I'm certain that was not happening during my important measurements. For one because the paint does not change temperature instantly when moved in and out of direct light.

[@umbrel]

I suppose that the relevant metric would be the other side of the wood after long expose under the sun. Either way you will know if it really cools down or not when you build your panels. Another possible use of your paint + plastic layer would be as the back reflector for solar heater, the kind with a coil of flexible piping. It should return radiant heat to the coil instead of absorbing it in the support structure. I'm not sure if the efficiency gain would be meaningful though.

[@xoblyxanier]

@@Nighthawkinlight Thanks for clarifying! Especially the fact the temperature doesn't change immediately under different illumination is solid proof of an accurate reading. Never having handled IR cameras myself I can't judge how well they measure different materials and surfaces. But I'm quite sure there are some assumptions when converting measured IR wavelength to the temperature of the emitting (or reflecting) surface which might not necessarily hold through for pigments with a atypical spectrum.

[@Kevin_Eder]

@@umbrel I'm not really familiar on the details but if the goal is to reflect as much back for the tubes to absorb, would a mirrored surface be better? I've seen survival shelters that use mylar blanket as a reflective back and a thin plastic sheet as the front to trap heat, so maybe a similar idea.

[@lucbuydens1783]

@@Nighthawkinlight Hi. IR thermometers/cameras work with specific wavelength bands and you have to know the emissivity of the object in that wavelength band to get precise measurements. Here you are doing all you can to change that emissivity spectrum. I would be very skeptical about the FIR temperature readings without a specific calibration.

[@LabCoatz_Science]

You're a true inspiration man! Every project I've seen from you is a masterpiece; I can't wait to see what's next!

[@Lukegear]

I was amazed when I heard about the invention of this type of radiant cooling paint and now I'm so thrilled to know that you managed to make capable DIY version! This is quite awesome! Thanks a ton for the great content!

[@haroldkline4898]

I make paint for a living. I am a lab tech. We use TIO2 to achieve a white that is good on its own, but can also be used to make other vivid colors. The lighter the shade, the more TIO2 is required. Cool video!

[@stanmacdonald1073]

I'm building a small, remote observatory. It is necessary to keep the optics at ambient temperatures to avoid distortion from warmed air currents in the optical tube. The effect is dramatic. It would be desirable to keep the closed observatory as close to the night observing temperature as possible. I don't have power at the site so cooling is challenging. If this is substantially cooler than white light in sunlight then in all for it! P.S. I agree with the comments about IR camera not being good at measuring surface temperatures.

[@ransombot]

Be interesting to see the difference between painting it on a conductor of heat like copper (maybe copper tape/foil) or maybe expanded graphite roll/sheets and painting it on an insulators like expanded polystyrene or firebrick. I'm betting the substrate is important with panel's.

[@x9x9x9x9x9]

Such a cool idea. Hopefully someday this becomes common place. Just not sure how good microplastics are in paint.

[@jimmyk2182]

Easily one of the most underrated KZbinr/inventor out there. Proof of work pays off in the end. Keep it up

[@surki2080]

This is so interesting, would love a series, and if its possible for you to build a prototype of the cooling pannel it would be amazing to see, great work as always!

[@kooskroos]

Would like to see the performance of the calcium carbonate!

[@melindawolfUS]

I live in a desert that regularly gets to be 115 f 😭. So every degree counts! I love these ideas, you've taught me so much that I can use out here in the heat to reduce my cooling costs. Please make your paint available? I would certainly be a customer to paint my roof (in winter I would cover the roof in rotting hay and tarps to hold it down, so the paint will be covered up when I want to stay warm).

[@TheRainHarvester]

I'm not sure if barium runoff would be bad for food/watering plants. Maybe calcium carbonate based paint would be safer?

[@kraftzion]

We definitely need a series. Can you improve the white paint by adding barium sulfate? You mentioned calcium carbonate, what are it's relative properties?

[@jophmac]

Calcium carbonate is the main component of limestone, chalk, and has been used as a rough surface coating called white wash.

[@kraftzion]

@@jophmac and how does it compare to barium sulfate as far as emitting in the narrow band ir that transmits to space?(RELATIVE properties)

[@ellisgl]

Calcium carbonate is the ingredient used in "White 2.0", IIRC. I wonder if silver may help in some part of this equation.

[@justinw1765]

@@ellisgl I wonder if it is a specific particle size?

[@RandomNooby]

Thank you, my ship is painted light grey one side, and matte black the other, I rotate it for solar panels and IR reflection and absorption, depending on the ambient temperature to save on heating and cooling bills. .With this idea I can upgrade. Thanks for sharing...

[@alexanderweck181]

Great Work ! For your further work see also the Pyrgeometer for measurement of the cooling effect especially by night. Some year ago we made some passiv cooling devices for small off grid electronics in desert areas. It consists from a liquid reservoir with free gasphase in contact with the electronic heat sink and a vacuum tube insulated solar collector connected with the reservoir by a tube filled with the vapour from the liquid and a downcomer at the low point of the collector going down to the liquid reservoir and submerged below the liquid surface. The solar collector (better "radiator to space") was installed on a high point in that way, that it only sees the sky an no surrounding buildings, rocks or other surfaces with ambient temperature. At day the solar collector and the gase phase in it gets really hot by the sun, but thats all: the liquid (and in cases when pure water is used as working liquid) even ice in the low reservoir stays cool and is able to cool the electronics by heat capacity and gets slowly warmer respective the ice melts. More interesting by night: because of the very low sky temperature above the desert (air mass is dry and there are no clouds) the vapour from the liquid chamber condenses in the solar collector that works as an radiator to space and cool liquid refluxes to the liquid chamber by the downcomer because of gravity. If you get problems with ice plugging that can easily be solved by using alcohols like methanol or ethanol as working liquids or such alcohols as additives to the water. In the beginning you heat up the system to boiling temperature at normal pressure to remove all non condenseable gases (especially ambient air) or use a vacuum pump, before you seal the system (system works under low pressure condition and with pure vapour phase only). If you want an ice buffer, you use a chamber with pure water under normal pressure and a submerged tube coil filled with working fluid under low pressure (refrigerants like propane or alcohols work) as an heat exchanger on low point. I am shure, that the system could be improved with your paint, compared to the black surface of the vacuum insulated solar collectors (insulation tube should be made from infrared transparent glas ceramics).

[@onestoptechnologies7305]

I have looked at these systems before. They are very "cool!" Pun intended. One I was looking at used coconut shell activated charcoal and methanol. Unfortunately, they don't seem to be practical for residential cooling needs, refrigeration/air conditioning.

[@mhdm]

Idea: experiment with infrared cooling/barium sulfate coatings on solar panels! Anyone who measured/experimented with solar panels can tell you that their efficiency significantly drops when they heat up just in sun (I measured ~20% current drop at start/ambient temp vs after ~5 mins in sun). Such a coating might seem counterproductive cause it reflects light and well, solar panels need light. But the wavelength of light really matters here. First, (commonly used) solar panels can't use >1100nm IR light - it's not energetic enough to make electrons move in Si. The sun puts out significant 1100-2400nm IR light which just adds heat. We'd want a coating that reflects this 1100nm+ NIR light. Thus a way to turn the experiment "failure" at 5:01 on its head as a good starting point for such a selectively reflective coating: you got high visible light transparency / low reflectance and I'd guess significantly higher NIR reflectance (particle size being the important factor). Finally, the infrared cooling effect will be beneficial year round to keep solar panels more efficient.

[@MastaSquidge]

Passive cooling can be achieved with aluminum heatsinks on the back side however it's more likely to be far more cost effective to just add more panels.

[@jaykoerner]

That interferes with the solar emission gathering potential of the solar panel, unfortunately barium sulfate is not transparent so the entire front is irrelevant since you can't coat that(even selectively reflectivty would effect the energy gathering since solar panels do collect even that energy) solar panels collect, the sides and frame while it would be helpful would be fairly negligible in comparison to the amount of heat they can get rid of, the back would just reflect the back from the roof on of the solar panel again likely, unfortunately all in all it's a nice idea but physics says no,

[@mbmurphy777]

Cool stuff. I guess it makes sense that the more barium you can get in there the more radiative cooling you’ll get. I’s love to put some of that stuff on the roof of my car. I have a Tesla model three and the only thing I don’t like about it is the glass roof gets seriously hot in the summer despite tinting etc. I’d love to put some kind of temporary coating on it during the summer months.

[@Nighthawkinlight]

Maybe it could be developed into a rubberized coating that peels off clean in winter. Lots to experiment with.

[@juanolotgn]

@@Nighthawkinlight Maybe you could paint over it with another paint in winter - ideally something that would come off with just soap or alcohol. Unsure if this is possible

[@vegasguy73]

Cool stuff indeed!

[@timng9104]

@@Nighthawkinlight i realize a small water content makes PDMS or some PVDF films cloudy, but not that white, but should be able to engineer it. Free standing reflective films will be really cool.

[@tomfromoz8527]

@@Nighthawkinlight Rubberized... like latex paint. Sounds like a plan! LOL > Tom's wife Pam

[@paulmurphy3838]

I dont know about his sponsor but this guy is absolutely brilliant, in the top Mensius class, talks in dulcet tones, extremely erudite and sounds humble to boot.

[@BeyondSlowMotion]

Always top tier with the insight & knowledge! Amazing work as always man. 🔥🔥🔥

[@CaptnApathy]

once you get cooling panels working, it would be nice to see if the cooling is enough to keep a stirling engine turning a small generator, or to see how it would effect a stirling engine already running on heat from a solar heating panel.

[@MontyCantsin]

If you can get a Stirling engine running, then you can use that to run a loop of refrigerant through another panel, increasing the temperature drop achievable by "passive" means. The heat difference between the Earth and space is a giant potential source of energy whose only running cost is dropping the temperature of Earth. Pretty sweet. Banking heat from the day to run an engine at night could further help with the efficiency.

[@wesbaumguardner8829]

Not only are you a genius, you put a ton of time and effort into your projects. Well done!

[@robertwilson8789]

I think a practical use for this process would be to use it for vertical blinds for large glassed in areas because they could be used to reflect either inside or outside depending on the season .

[@DistracticusPrime]

Love this idea! Someone further up is hoping for temperature-sensitive paint, but this achieves the same effect with just a flick of the wrist twice each year.

[@robertwilson8789]

@@DistracticusPrime I think it would be productive for a younger man than me to do a little experimenting with this as all that is needed is a good slat . To my mind you want an absorbent surface and a reflective surface separated by an insulated materiel just to offset the differences between the two surfaces and mount the blinds between the two layers of glass with a venting system at the top of the sash that vent heat out in summer and inside in winter .

[@DistracticusPrime]

I seem to recall most glass is IR absorbent, but probably it depends on the specific products. If the outer glass panes are mostly IR transparent, your system wouldn't even need the venting system and could be sealed.

[@robertwilson8789]

@@DistracticusPrime That's a good point however I am extremely sceptical of trying it with a sealed system .I think the inside glass will need to be opened for cleaning and repairs . I have had bad luck with double paned glass that has lost its purge and gotten stained inside . Unless it is hermetically sealed it will stain inside eventually .On the cost side though it could be brought inline with a double paned system as it only requires a wider glazing sash . about 4 inches would do it .

[@connectropy]

​@@robertwilson8789Saw a video somewhere of a house (not in US but Northern Hemisphere) that had 4-ply floor to ceiling windows. They insulated but allowed solar gain as needed. Very specialized.

[@HyRkt]

It would be amazing to see a series on this. Low electricity AC is a must for the future.

[@simonlinser8286]

this is great! i was doing a bit of research into this topic and ended up using just white titanium dioxide paint and it actually absorbs heat! i did see something about the barium paint but it sounded complicated. thank you for this video, if enough people keep experimenting with this stuff we can actually make a difference. the more heat we can reflect back out to space the better.

[@irvalfirestar6265]

I'm interested in how this paint will perform in tropical 'summer' temperatures of 30-40C, especially to places as tight and suffocating as in the New Delhi slums. I've watched some videos of NGOs painting flat Indian home roofs white to combat deadly daytime heat, and having a cheap sheet of clear plastic in addition to the paint might help in reducing heat conduction from the wind and protect the paint from weather. It's not as good as your snow barium paint, but at least plastic sheets are super cheap.

[@ArminLks]

Very educational video! I am working in a lab formulating coatings for roofs. One other way to achieve high TSR is to use GlassBubbles. You can achieve a TSR up to 94%. I will do a few tests of a combination of Barium and GlassBublles very soon.

[@justingriffin2546]

GlassBubbles thats amazing are you in the usa-does your company have a wesite?

[@flaviog.7628]

I guess you could say that this paint... is really cool 😎

[@gilliancanvin8551]

I absolutely loved this. My youtube algorithm for quite a while has been terrible, but after selective pruning I was able to find content like this again. I can't thank you enough for your work! Cooling panels make a lot of sense.

[@probitypraxis]

This is great work and I am really looking forward to the next in the series. I've been working on design concepts for cooling panels using this general concept and while developng the paint is a critical first step there is more to making an actually useful panel than just painting something white. In real world conditions the white surface will get dirty and weathered if directly exposed to the elements, reducing the ability of the coating to do its job. To make something practical, that is more than just a short term demonstration of the principal of panel cooling, you'll need a design that deals with these factors. It's a design challenge I find really intriguing and I am looking forward to see what you come up with.

[@justinw1765]

You would probably want to put some kind of super hydrophobic coating on (perhaps as a substitute for thin polyfilm?), so that would less app to get dirty as fast and would quickly/easily wash with some rain or the like.

[@makoyoverfelt3320]

My man. I found this channel just the other day and it's already, by far, my absolute favorite channel. Unrivaled in essentially every category.

[@Svorty]

This was so interesting, I would absolutely love to see this as series.

[@oliverford9325]

100%

[@RaviolistRavioli]

Absolutely incredible work and documentation of your process. I can't even begin to think of the amount of work this took.

[@Splarkszter]

i forgot how your channel is called and never found it again. I got the new video notification and damm good content you make dude.

[@Nighthawkinlight]

Thank you!

[@SSingh-nr8qz]

This is what actual science looks like. It is not perfect or absolute. It's a refinement process riddled with missteps but ultimately learning from one's own mistakes and using the insights of others to gain more knowledge. Consider how in this video, he went back over the papers he was using and found a better way of doing things. Most tech today is based on that very process. I usually skip to the end of videos like these to see the end process in action, but this channel is one of the few I actually watch from start to finish to watch his scientific process in action.

[@Briaaanz]

Incredible video. Wish i had been able to watch ones like it growing up. You're doing a great job educating and encouraging people to pursue chemistry

[@cdburner5911]

I would love to see, once you get the method optimized, the amount of heat that can be radiated per square meter, for example, if it were to be supplied with warm water. Also, with the idea of cooling panels and thermal batteries, it would be interesting to combine the idea with a low temperature phase change material, such as glauber's salt, and see how cold can be stored at night, and how long it takes for any absorbed heat to penetrate to the inside.

[@dakkonblackblade6537]

Thank you so much brother for all your time, research, effort, and pure love you put into these videos. They're very few people left out in this world he generally want to teach and show people new techniques and new ideas on things that aren't normally discussed and you really go above the bar when presenting your videos, demonstrations, narrations down to the details of explaining how to do it yourself.

[@InssiAjaton]

Once in my now pretty distant past, one of my education topics was something I might call "Light and Illumination". It ended up with road illumination and similar topics, but at the beginning it talked about measuring (basically comparing) light with different means. One method used a chalk wedge. One flank was illuminated by the unknown light source and the other one with an adjustable (dimmable) reference source. You adjusted the dimmer dial, until the wedge tip disappeared. At that point the brightness of the unknown could be read from the dial of the reference light. Well, then they described better white materials than the piece of chalk, and it was barium sulfate that got the crown. In the lab, there was an integrating sphere that was internally coated with that barium sulfate paint. I think our lab exercise consisted of grading some light bulbs with the sphere.