Patent attributes
A hybrid energy harvesting system for powering underwater vehicles having at least one thermal engine, at least one of a solar or a wave energy harvester, and a battery which stores electric energy produced by the harvesters. The energy harvesters keep the battery charged and thereby expand an underwater vehicle's operational areas to high latitudes and shallow water. Multiple thermal engines employing different phase-change materials can be used to expand the vehicle's working temperature range and thus allow it to operate over a larger area. An electric motor powered by the battery and a pump driven by the motor can be used to pump hydraulic fluid between the accumulators and external bladders of the thermal engines to cause the vehicle to descend and ascend when the thermal gradient to which the vehicle is subjected is insufficient.
