Very interesting concept here. I have thought about this myself, though mostly in relation to the heat of exhaust gases. If the thermocouple material could effectively remove enough heat energy from the engine coolant to keep the engine at standard operating temperature, why not incorporate the thermocouples directly into the engine block, possibly eliminating the need for engine coolant and a water pump entirely. That would result in not only reduction in engine load due the removal of the water pump accessory, but also greatly increased aerodynamics due eliminating the need for a radiator and front grille. Also, thermocouples that could remove that much energy could surely replace the alternator, eliminating the need for that as well. In fact, there might even be a problem with storing the extra energy generated from all of the heat. It seems this would be best implemented in a hybrid vehicle.
Just my thoughts on the issue.
