Keeping drinks cool as you drive

They are heat exchange devices. So one side will get cold, but the other side will be hot. Hot + plastic cupholder? Not sure it is a great idea just to keep your flavoured syrup cold. One ice cube will do the same trick.

 

With the proper device, you should be able to. All "cooling" units are really heat exchanges. You can't make something cold, you can only remove its heat but it has to go somewhere. Next time your house's air conditioning is on, go feel the air coming off of the outside unit! It is blistering hot, and the cooler you want it the hotter the exhaust air is. Same reason why the fools that try to cool down their rooms by opening the fridge doors are always disappointed. The fridge makes a huge amount of heat to cool down the little 30cu ft inside. Open the doors and now your exhaust is in the same chamber and since nothing is 100% efficient, it will just get even hotter.

Pretty neat little devices though, and the ability to swap the hot/cold is pretty unique and awesome. This + a fan/exhaust might work. But they do sell purpose made cup holder chillers. Or even full gloveboxes if you really want to do it.