Has anyone noticed the windows on these planes become very hot when dimmed? They don’t have regular blinds but instead include a gel which can be electrically dimmed. They aren’t hot enough to burn you but uncomfortable to touch.
I got to work on these windows a decade ago! They use basically the same chemistry as in auto-dimming rearview mirrors.
Feel your mirror sometime when you're driving in traffic at night on the interstate and it's been dimmed because of the vehicle following you for some time...it will be perfectly cold.
The electrochromic material between the panes goes through an oxidation/redox reaction in the presence of a voltage. In circuit, it functions something like a low-storage battery or capacitor. It does not have enough leakage current to cause it to get hot, that's just the effect of the sun on the plane.
> The person you are replying to sounds to me like they put their hand on a window and it was hot.
The person that responded to that didn't say it was impossible: they did convey that the reason it was hot was not due to the window itself. The heat could easily be from the light being absorbed by the panel.
In my experience as someone who regularily measures temperatures of surfaces (electronics) something as low as 45°C (so just a handful degrees over body temperature) can already feel hot to the touch.
This would the area where it could just be the effects of the sun.
My experience with regular windows on airplanes is that the shutters can get quite hot as well. The energy they absorb from the sun has to go somewhere — and it gets radiated away as heat.
Do they dim to a dark color? The shades can get warm but they're white and reflect a lot of energy. If the windows are dimming to a dark color it might just be the difference in how much sun they absorb vs. reflect. I wonder if it adds up enough to become a frustration for cabin temperature.
