More playing with the Mr. Tea....
I put the heating element back in the shell and then removed the top, to access the internal "exit" tube. I pulled that and looped it so that the heated water would just squirt back into the cold water resevoir, instead of having to go to an external cup, make a mess, loose heat, etc.
I filled the machine with could water. It holds a little less than a quart.
I flipped the machine on, with the exit hose pinned down and a kitchen thermometer held in place in the water resevoir.
I set a timer and checked the temperature as it went up.
Here's the temperatures in ℉. after various times.
3 mins: 140℉
4 mins: 160℉
6 mins: 185℉
7 mins: 196℉
8 mins: BOILING! Ack! Why did I turn away from my experiment right then! It started squirting all over my kitchen! :
The thermo-cut-off never cut in. I think it is only designed to turn off power at something like 400 degrees.
Again, I am only experimenting right now for fun, and to see how all this might work.
I think it shows that a heater element like this one has plenty of power to heat water or anti-freeze to significant temperatures!
A system actually installed for heat in an electric car would need a separate on/off switch, safety cut-off, and likely a pressure relief of some sort.
I did NOT do this experiment with anti-freeze because it costs more, is messy, and I don't want to use my only kitchen (FOOD) thermometer in anti-freeze!
As to compatibility of anti-freeze with the Mr. Tea, what's the concern? It's an aluminum tube. Aren't there lots of aluminum parts on cars nowadays? Do those cars require special coolant?