Nissan Invents Car Paint That Can Lower Interior Temps by Nearly 10 Degrees | Hacker News Reader

Nissan Invents Car Paint That Can Lower Interior Temps by Nearly 10 Degrees

thedrive.com

43 pointsgnabgib28 comments

Related here is someone making paint that can get cooler than ambient temperature. https://youtu.be/dNs_kNilSjk?feature=shared

Living in Phoenix, anything that helps is welcome... I've thought that having even a small solar panel enabling the AC fans to circulate air while parked would help a lot.

One of my favorite hybrid vehicle hacks is that you can (using very little gas) pre-cool your vehicle thanks to electrically-driven HVAC, kWHs, and an onboard generator (engine). When my power goes out, I can also run the refrigerator and computers.

Specifically from my Toyota Camry (all 2025+ can be made AWD, too — I traded in my turbocharged Subaru). I am not an ad/bot, but will disclose that I do own TM (in addition to believing in their tech/drivetrain/hybrids above all others).

Toyota’s drivetrains are quite literally 10 years behind Tesla’s. Regarding preconditioning, Tesla’s heat pump with its octovalve can move energy between battery/motors/cabin/the outside, depending on what needs cooling/heating and what has an excess.

From the user’s standpoint, your car be scheduled or can monitor your calendar to always be preconditioned before you enter :)

This claim sounds bogus. A hybrid drivetrain is significantly more complex than a BEV drivetrain. Tesla certainly has the edge on batteries, but a battery is not a drivetrain.

Complexity itself doesn't make it better, if anything it makes it worse. They’re also worse because they’re slower, heavier, less efficient, more prone to failure, and take up more space. Don’t get me started on the toyota mirai fiasco.

My not-very-new 2018 Toyota Prius Prime also has a heat pump (for the same reason EVs do - though it's a PHEV - if it's running on battery it doesn't have any waste heat to dump inside the car for heating the humans).

Sure, but it just moves heat between the outside air and the cabin. Does not move heat between vehicle components as needed the way Tesla’s octovalve does.

An electric car can pre-cool without affecting range because you generally pre-cool off of wall power rather than battery power.

And it'd be interesting to compare how long a full gas tank on your hybrid can run a refrigerator in an emergency compared to a full battery on an EV. Your gas tank has more energy, but the battery is more efficient...

I ran two fridges and a Mac Pro (notoriously power-hungry) for 40 hours on two gallons of regular gasoline (and never had to move the vehicle the entire duration). The only caveat was I could only power on the computer when both fridges were off (or else the inverter, not original to the Toyota, will enter an `overload` state).

I use about 1kWh per 8h of fridge. So two fridges for 40 hours would be about 15% of battery, and 2 gallons is about 15% of your tank.

But average power usage of your Mac Pro would have been a lot higher since it would use power a lot more steadily than the fridge. And unplugging the fridge for a bit doesn't substantially change its power consumption.

So you did better than me by however amount your Mac Pro used.

Biggest advantage I had was I didn't have to open my garage door while it was powering the fridge.

If you have remote start you can leave the AC on when you park, and then when you're walking through the parking lot you can have the car running and the AC on for a few minutes. It does honestly help in the Arrakis-like weather of Phoenix.

"Nissan invents" is a bit of a stretch. The article didn't mention that it was "developed with" a different company, Radi-Cool, which seems to be doing this for other products.

https://apnews.com/article/heat-nissan-japan-automakers-pain...

>Susumu Miura, a Nissan Research Center manager, said there were no discernable negative effects to people’s health from the electromagnetic waves emitted by the paint

what electromagnetic waves?

I wonder how this compares to anti-flash white?

https://en.wikipedia.org/wiki/Anti-flash_white

Do you mean white?

I never thought about the weight of the paint. I asked LLMs how much a coat of paint of 120 microns would weigh. Between 5 and 8 pounds apparently.

Weight of paint depends a lot on the pigment. Some pigments are pretty dense a lot pigments are various types earth or metal oxides. Think like iron oxide (a dark red or brownish yellow) there are even heavier pigments. Organic pigments tend be lighter. Titanium dioxide is a very common pigment though since it is the main white pigment used for paint these days. If you have felt weight of titanium white vs lead white (only pretty much used for art these days) for instance you can tell the difference.

Then you have some things that are not a pigment per se but are there to help with flow and other things but are not light either like kaolin clay. Also they can be used as filler to make the paint cheaper if used in excess.

Would you believe a random Internet comment/site for that answer?

I wouldn't, so I also wouldn't believe an LLM trained on those questionable sources.

Haha absolutely first they censored unwanted content and now they feed the remains to the almighty.

Not to speak about the discredited personas on Wikipedia unable to change their decried vita entries..

I didn't expect anyone to politicize the weight of paint.

Both Gemini and ChatGPT gave quite detailed answers showing the input values, the intermediate calculations, the assumptions made. I chose to only give the final result here. But see another comment from me with details.

Did you have it show its work?

Have you ever picked up a can of paint?

Do you not allow the solvent to evaporate when you paint things? Must be a bit messy.

I’ve only used water based paints at home and thought most of the weight was water which evaporated on drying

Since folks are downvoting this comment, here's what Gemini told me, and which sounded reasonable to me. Let me know if something sounds wrong:

Paint thickness: 120 microns (0.00012 meters)

Typical car surface area: Assuming a medium-sized sedan, we can estimate this to be around 15 square meters (161.46 square feet).

Paint density: This varies based on the type of paint, but we'll use an average value of 1.2 g/cm³ (1200 kg/m³) as a starting point.

Volume = thickness * surface area = 0.00012 m * 15 m² = 0.0018 m³

Weight = density * volume = 1200 kg/m³ * 0.0018 m³ = 2.16 kg

ChatGPT was similar but chose 1.3 g/cm³ as the paint density.

At one point when airlines were concerned about rising fuel costs, several switched to a largely unpainted livery, with the polished aluminium otherwise being uncoated (or possibly with some protective clear coat), for weight savings, which were given as ~100 kilos / 200 lb if memory serves.

Those of us who remember leaded paints also recall how distinctly heavy cans of white paint, or any paint with significant amounts of white blended into it, were.

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