Elver Loho

Since seawater has significant thermal inertia, would it be possible to create a floating platform, which uses the difference between air temperature and seawater temperature to generate electricity? The generator could be solid state (Seebeck effect), a Stirling engine, or a gas turbine. One would have to reverse the generator for nighttime operation when the seawater is hotter than the air. How would one go about calculating the maximum possible power generation given a temperature difference and the area, which it touches on both the hot and the cold side? Solid state generators seem to have an efficiency of about 5%, Stirling engines 15% - 30%, and gas turbines even higher, although they would be a bigger engineering challenge. Since these things could work around the year and use the difference in stored heat between two materials with different thermal inertia, they could be more efficient in temperate climates than solar panels. Looking at some seawater and air temperature graphs recorded at a latitude of 60 degrees, the daily temperature difference, on average, seems to be about 4-5 degrees Celsius. Given a generator efficiency of 5%, how many watts could one extract using a 10m by 10m floating generator platform?