Hello all, I'm having a bit of a problem on a class design project. We have to design a mini-fridge for developing coutries that runs on its own power and must cost under $100 ideally (it can go over if necessary). My group decided to use a hand-crank powered thermoelectric module and fan assembly to cool down a 5ml vial inside a foam-filled food jar smaller than a lunchbox. We're having problems running it though, because our cranks produce barely enough current to run only the TE module, and there is only a slightest cooling effect. My idea is to use solar panels to operate an op-amp that can amplify the power from the hand crank to run both devices. It's been a few years since I took circuits so I don't even know if this makes physical sense. I'm just wondering whether it can be done within or without the monetary constraints. I'm also open to any other ideas for powering this thing. Other constraints include portability and a cooling capability down to below 10 celcius. It should ideally stay that way for up to 12 hours, but again, these are bendable constraints. I'd really appreciate the help. Thanks in advance.