I am thinking about solar water heating. The way that the system gathers heat is by moving any heated water into into the cylinder where it rises to the top and cold water is taken from the bottom of the cylinder and moved through the heating panel. Because the hot water will always rise there will always be a temperature difference between the water at the top and the bottom. But because of the motion of the water molecules the heat differential will disperse. So, for example, If the temperature is 50°C halfway up the cylinder, what will be the highest and lowest water temperatures in the cylinder? Thanks.