Thermoelectric Ocean Energy Harvesters for Maritime Sensors

Project Summary/ Abstract: Networks of maritime sensors (e.g., scanning sonar, video cameras, motion surveillance) and navigation technologies are expanding worldwide at a rapid pace to meet new demands for oceanographic and meteorological data collection, analysis, and distribution. Maritime sensor nodes are typically installed on buoys or other small marine structures and are powered locally through a combination of renewable energy conversion and marine battery energy storage. Augmenting these renewable primary power systems with locally-generated ocean or tidal energy would provide significant benefits in meeting power demand. One strong candidate for energy conversion in the marine environment is the natural temperature gradient presented between the surface water, Ts ~ 20 to 25 °C and water well below certain thermoclines, which can approach ~ 4 °C. Using an existing cold water pumping system for Rankine cycles in combination with thermal insulation and capillary pumping, cold sea water can be extracted to the surface which will enable a sufficient thermal energy supply to extract electrical energy using aquatic environment-hardened, thermoelectric devices. To achieve this goal, Nanohmics Inc. and team proposes to design and fabricate a thermoelectric (TE) energy generation system based on the companyĺs novel modular thermoelectric generator technologyŚ Thermolynx System. The modular TE and heat sink assemblies will be packaged onto heat exchanger pipe networks integrated onto the base of ocean buoys. Thermal-to-electrical power generation on a 1.5-meter-diameter buoy base of ~ 1 kW can be achieved through temperature differentials (?T) ~ 15 to 20 °C maintained between cold sea water and low-emissivity/radiative energy extracting heat sinks that back the thermoelectric device assemblies enshrouding the exchanger pipe network.