Car Science: dogs die in hot cars
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Hey,
Sorry, I - look, there's no point me even apologising at this stage, is there. I'm just useless at sending this on time. Let's just bin off the concept of schedules, it's freeform. Time doesn't matter and it's probably not real as a linear concept anyway. Everything is just curved space, also there might be a fifth fundamental force which will probably require rewriting the whole of science in the physics equivalent of discovering umami.* Let's fucking go.
Today's newsletter is about passive cooling, which might not be the sexiest phrase you've ever heard in your life but is about to be a really, really, really important thing. Pretty sure I've mentioned before how the next few decades, unless we crack fusion in a really big way, are going to be energy-starved. As others have previously noted and has passed peer-review, the fuck around era of fossil fuel-powered excess is very much over and we are firmly in the finding out stage where everything is going to be much, much harder.
One of the bigger issues facing us is that bits of the planet that were previously fairly temperate are now going to be roasting hot some or quite a lot of the time and the parts that were hot before are going to literally become unliveable. This will make existing very difficult. Most of our infrastructure is specifically not just crap at staying cool but actively generates heat, from vehicles (both combustion and electric) to the way it makes us congregate in places with our hot little mammal bodies.
So far the majority of high or semi-high-tech ways we've found to deal with that have all been basically variants on refridgeration. Air conditioning, in particular, works super well and is relatively basic, it can be installed most places and it just gets on with it. Problem is it's hopelessly energy intensive and the majority of installs are extremely inefficient, so a bad system is using even more than it needed to before.
Since the invention of aircon a lot more power demands have been added to grids, from data centres and computing to, yeah, electric vehicles now. And the supply of power is getting strangled, in part by specifically that heat that's demanding the cooling systems.
(I've written about this in a few places, including here but from France having to turn down reactors because rivers were too hot to cool them to heatwaves literally melting the casing from power lines in Portland, we are in big trouble with power generation and delivery and with causes that won't get any easier for a long time now)
So far, so bleak. But the good news is cars (and buildings but this is Car Science, so) don't actually need to become magnified greenhouses as soon as the sun comes out and there's a lot of research going into making coatings for them that would actively cool the internal temperature without needing any power.
Nanomaterials are fairly wild as general concepts, especially given some of them are much more viable to construct than you'd imagine from something engineered at the molecular level. So just because this uses something very high-tech doesn't mean it's not going to make it to manufacture. In fact that's kind of why I wanted to write this newsletter now because the butterfly wing stuff has moved from initial research into how insects create their passive cooling published in early 2020 to functional material prototyping stage and that's interesting to see as a progression.
So back in 2020 scientists at Columbia Engineering published this research into how butterfly wings actually work. Turns out it's extremely complicated and just that round of publication alone covered two potential applications, one in the way butterflies have a specific scale texture in their wings that cools elements of them and another about sensitivity and the way veins run through the wings.
I am not a biologist (I mean, I'm not an anything but for sure biology is way outside of things I know shit about) so I can't tell you too much about why butterflies are doing this or whatever, except that it's to regulate their temperature and is something they actively manage. But at the time that research was published there was already optimism about applications for materials that copied the butterfly structure.
The thing about butterflies' cooling is that unlike a mammal's it's not sweating or something (cars only do this when they're VERY distressed) it's purely radiative. And that's managed by the different areas of the wings having radically different material structures. We could probably get into this for ages but basically contrary to prior believe butterfly wings are very much living organs with very varied temperatures across them and being able to visualise that meant that the researchers could identify which of the scale structures had radiative cooling properties.
All good stuff: we know more about what butterflies are up to and there's some potential to apply this in other contexts. What's interesting about this type of radiative cooling is that we know colours have always affected the temperature of things, especially when exposed to light. White reflects light and heat, black absorbs and radiates it, etc. The whole reason we can see colours is because of how they absorb or reflect light differently.
So what's really wild about this butterfly thing is that the cooler or warmer parts of the wings weren't to do with what colour they were, they were to do with the scale structure. So you could make, say, a blue surface that nonetheless passively cooled itself below ambient temperature.
That's exactly what scientists at the University of Shenzhen have done this year. It's, uh complicated but basically they made a self-cooling blue that still looks blue, like on a butterfly's wings.
The multi-layer structure takes advantage of disordered materials to mean the colour can be seen from a lot of angles. Which is great because this now means the two butterfly effects (this one and the one about a butterfly beating its wings on one side of the world ending in a hurricane on the other) use disorder and chaos, which shows you that the prettiest, most delicate things in the world are in fact metal as all hell.
There's a whole load of interesting potential applications for cooling colours, from motorsport engineers getting very excited about an ultra-light nanofilm that could do the engine cover livery without cooking anything to well, cars at large. Cars, being big metal boxes, are made of pretty thermally conductive materials compared to, say, this 140-year-old house I'm in which might benefit from a nanocoating but also I'd settle for the landlord replacing the fridge first.
Which is why people like Volkswagen are more interested in this sort of thing than, well. My landlord. Who if I'm absolutely honest I don't think would appreciate me explaining this to him in lieu of rent.
Where these kinds of technologies will be needed most is in the regions most severely affected by rising temperatures. Which tend to be poor, so you can imagine the likelihood of them being delivered short of an aid programme. But adoption by eg: luxury car makers to extend their EV ranges and improve vehicle efficiency by reducing aircon usage will mean the technology gets developed to manufacturing stage, so it's not all capitalist despair snatched from the jaws of scientific optimism.
One of the reasons I'm pretty confident we could be seeing the butterfly coatings on vehicles soon is because two years ago I wrote about a semi-similar product. Ok, not really similar at all but it was also an advanced nanotech coating that played on colour absorption to create an anti-Stokes fluorescence effect.
Anti-Stokes isn't a vendetta against the cricketer, it's an effect where photons can be fluoresced (basically, sent away from) a surface with more energy than they came in with. In the case of sunlight, that means removing heat energy.
It happens in weird, cosmic circumstances and isn't easy to replicate. So engineers at Israeli startup SolCold used a multi-layered film (as with the butterfly wings blue) that incorporates a strange physical phenomenon called perfectly black bodies, which are things so absorptive they essentially replicate microscopic black holes.
By the time I interviewed SolCold in 2021 they had prototyped the film, were up to a reasonable level of production and were working on a project with VW where they'd shown they could significantly (by up to 14C/57.2F)reduce car internal temperatures with the coating, even in full desert sun.
I don't love this, as an application except that not cooking prisoners is the absolute least the Israeli prison service can do but it's been being run on transporter vans that have been shown to cool by up to 11C/51.8F with it. That suggests it's effective on bigger vehicles which would mean trains and buses could be really good candidates for reducing power consumption with the coating.
Mostly I'm bringing up SolCold's coating because that shows these things are well outside lab stage. They might not be currently on order for any automakers but the first one that takes that choice will have a big opportunity on their hands.
I kind of really hope it goes like the Twingo launch with a range of really colourful cars from the butterfly technology. Use it how it should be and make the cars with passive cooling stand out with a statement colour to say they have it.
Anyway, that's more than enough waffling from me until the next time I manage to pull together enough braincells to send this.
Hazel
x
*This actually is a thing. So there's four fundamental forces; gravity, electromagnetism, the strong force (holds atoms together) and the weak force (causes nuclear decay) and obviously because this is physics not good old reliable chemistry^ they were already up for quite a lot of debate. Every now and then someone's like whoa there can't explain what's happening here on anything from galactic to subatomic scale. Last year the chat was about a chameleon force of dark energy that forced literally galaxies apart and this year it's about the behaviour of muons, which are like chonky electrons, acting out of pocket when accelerated to nearly the speed of light in a rotation, sorta like NASCAR drivers on lap 63 of Daytona. Honestly, scientists get hype about this sort of thing on a literally annual basis and none of them have ever yet proven to be anything, not least cus trying to prove things in physics requires opening Schrödinger's box and then you've got a really pissed off cat in the laboratory.
^Unlike physics, where people argue about how things work, no one knows how chemistry works.
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