1. The first question is precisely because many people like you have asked why the second law of thermodynamics was concluded
2 The second question, yes, it. is quite possible, you can lower the sea water by 1 degree, not all of it will be used to carry out work, but part of it will be used to carry out work, it is quite possible, and now we we have the technology and the capacity, why is no one doing it?
Due to “energy density”, if 1 cubic meter of seawater is reduced by 1 degree, can the energy released be compared to the same volume of fuel?