Physics Can you guess the maximum efficiency with which useful mechanical work can be extracted from the pond?

In solar ponds contructed in Israel, the Sun's energy is concentrated near the bottom of a salty pond. With the proper layering of salt in the water, convection is prevented and temperatures of 100 C may be reached. Can you guess the maximum efficiency with which useful mechanical work can be extracted from the pond?





This question has something to do with thermodynamics|||The maximum efficiency in thermodynamics (work extracted from heat flow between two reservoirs at different temperatures) is 1-Tc/Th , where Tc and Th are the temperatures of the cold and hot reservoir respectively.





Hence in your example the max efficiency, assuming the air temperature is 20 C, is





1 - 293/393 = 0.254 , i.e. 25.4%