We have a Carnot gas like ammonia. We draw air into a cylinder, and it passes across the cold surfaces – giving up its heat.
As it enters the cylinder it drives a captive turbine- which supplies all power to the plant, once started.
So it leaves the plant as air at -20 C. In hot countries this injection of cold into the environment is very welcome.
It also leaves behind massive amounts of condensed moisture. Pure water with no salt in. We use some of the generated power to pump this to high storage.
Most of the power is taken to pressurise the Carnot gas. Which now reaches 253oC, and loses its heat to the sea via an Aluminium helix.
So it is a self powering system, that takes the heat from the day time air, and puts it in the sea. We also charge a battery, so at night we can invert the cycle.
Taking the heat back from the sea or lake, and putting it in the air. Now we have a rising body of air, that will drive the turbine in the other direction.