And ideally, you have fins and a fan on both sides of the peltier element because relying on convection alone is ... complicated and will likely lead to the "fr

And ideally, you have fins and a fan on both sides of the peltier element because relying on convection alone is ... complicated and will likely lead to the "freezing on one side" issue. Side note, that's also why modern fridges and freezers all have fans on the inner side at least, it massively helps with preventing ice buildup.