Kinda an odd idea. But I work somewhere I cannot have my phone with me. So it sits in the car. Another engineer and I were talking at lunch and thought we could build a containment unit that would hold a cellphone in a car, and using the cars 12v, an arduino, and a TEC.
I have an existing low battery cutoff for my dash cam. So it will quit when the battery drops. Is this feasible to last a few hours? It hits 90 in the day outside. Phone sits in a black car, I'm thinking 130-140 in the car usually.
Will a computer heat sink pull enough heat to make the delta temp doable?
Based on a very cursory search - TECs basically can only take the object being cooled (I imagine this means it is attached to the cold side with a heatsink pad or grease) about 40-45 degrees C (104-113 degrees F) below ambient. Ambient for most available commercial TECs shouldn't be higher than 50 degrees C (122 degrees F) - but high-temperature versions are available.
So - if you try it with your standard TEC, in a well-insulated cooler or something - with a fan circulating the air on both sides - it might work. Or the TEC might fail. You might have better luck with a better TEC. You might also look into the possibility of (somehow) circulating the hot air inside the car to the outside, to bring the inside ambient closer to that of the outside (not an easy task, though).
Alternatively, you could look into mounting the TEC to the car body floor, with the heat sink outside the car (underneath) with a fan (and some kind of baffle or something to keep road debris and such from causing problems - but don't ask me how to deal with water); that way it is closer to ambient, and it will cool better (because you aren't having to fight against the heat load inside the vehicle).
Just realize the TECs also pull a ton of current - you might end up having a nice cool phone at the end of the day, but no way to start your car...
Pretty much the answer I was expecting. Was running some heat transfer quick calcs in my head and it just seems like its gonna take way too much power.
Alternatives? avoid the smarts, just go for max insulation?
