Watching paint drying - how I spent my summer

The summer of 2024 was for most people just a normal summer. Or if you are NASA, the hottest summer ever since global records began in 1880. This is something that has been happening each year for the last couple of them and it’s almost like there is a trend. Some kind of global warming scenario perhaps. But I digress.

For me, however, this summer was a peculiar one. While others were basking in the sun, I found myself drawn to a far less glamorous pursuit. Namely experimenting with a revolutionary new paint with the promise to keep us all cool and save the planet from the impending heat death.

You know, normal summer stuff you do on vacation.

This peculiar paint, infrared cooling paint or self-cooling paint, with its ability to radiate heat into the cold expanse of space, intrigued me. So going beyond reading up on the subject I decided to try to make some of my own and run some experiments. I was, after all, on vacation.

It sounds like science fiction or something you just stumble upon on the internet at random but the concept behind self-cooling paint is rooted in real physics. To be more precise, the second law of thermodynamics. That dictates that heat flows from hotter objects to colder ones.

All objects emit thermal radiation, a form of electromagnetic radiation that carries heat energy. They may produce it by themselves, or they may simply store latent heat from other sources or simply reflect it.

Normally, objects on Earth radiate heat into the atmosphere, which then traps some of it, contributing to the greenhouse effect. However, self-cooling paints are designed to radiate heat directly into the cold empty expanse of space, bypassing the atmosphere altogether and passing the problem of heat dissipation to someone else far beyond this little blue marble of a planet.

This innovative approach offers a potential solution to the ever-growing problem of global warming. It presents a way for us to get rid of heat passively and use the universe as an enormous heatsink. The potential is endless.

To embark on my DIY cooling paint experiment, I delved into scientific literature, exploring the properties of various materials and their potential to radiate heat into space. I learned that certain materials exhibit high emissivity in the infrared spectrum making them ideal candidates for this application and that the wavelengths are key for this experiment to work. Armed with this knowledge, I set out to gather the necessary materials.

But first, I stumbled upon a few videos that made it all much simpler. I knew I was not the first to attempt this challenge, but the stellar work done by Youtubers like NightHawkInLight made the process so much simpler. Armed with a battle tested recipe and a well-thought-out process borrowed YouTube, and the blessing of my family, I set out to do some field experiments.

My makeshift laboratory consisted of my home office and workshop, a few paint brushes and other materials I had lying around, a thrift shop blender and a collection of household items and chemicals that are readily available at most shops.

I started with commerciality available white paint as a base line and made my own based on acrylics and pure acetone. To this, I added various substances, like sodium carbonate, calcium chloride, citric and even finely ground coffee grounds. The last one I made up of course, just to see if you are paying attention.

I followed the “NightHawkInLight’s super CaCO₃ micro-sphere pigment” process and recipe to the letter and after each batch, I carefully applied the paint to small samples of cardboard or metal.

To test their effectiveness, I used thermal probs and an infrared thermometer to measure the temperature difference between the painted surfaces and the surrounding environment. While I didn’t achieve the same level of cooling as commercially available infrared cooling paints, or the reported cooling numbers from studies from real and proper scientists, I did observe a noticeable temperature reduction in some of my experiments.

It turns out that it actually works. And for some scenarios I achieved my goal of going sub ambient, meaning that the painted area was cooler than the air around it. A net cooling effect.

The process was both exciting and humbling. It was a reminder of the power of scientific inquiry and the importance of experimentation as well as the importance of sharing knowledge. Without the prior work of others, I could not have come close to achieving this on my own. And while YouTube might have its problems it helped a lot in facilitating the transfer of knowledge in a direct and meaningful way. Thanks Ben ”NightHawkInLight” Cusick for your great work.

While my DIY approach might not have yielded groundbreaking results, it sparked my curiosity and led me to explore the fascinating world of materials science. And I’ll be returning to the subject in a later blog post.

The potential applications of infrared cooling paint are vast. From cooling buildings and vehicles to reducing energy consumption, this technology holds the promise of a more sustainable future. As research continues to advance, we can expect to see even more innovative and effective infrared cooling materials.

While my summer experiment may not have resulted in a revolutionary breakthrough, it served as a valuable learning experience. It made me leave the comfort of my office and keyboard to mix paint and to do stuff in the real world. And it highlighted the complex interplay between science and technology and the potential for individuals to contribute to meaningful innovation.

A scientist invented it, I guy on YouTube made it accessible to the masses and a middle-aged Swede tested it and wrote a blog post about it. Full circle!

As we face the challenges of climate change, it’s imperative that we continue to explore innovative solutions. Whether it’s through groundbreaking research or simple DIY experiments, every contribution, no matter how small, can make a difference.