Gravity flow hot and cold seperation apparatus

Starting with a pond on high ground water flows into a long pipe in the sun. A timed valve fills an insulated hot tank. At night the hose gets very cold a valve opens at 4am and starts filling the cold tank.   Note in Puebla's mountains the temperature difference from day to night is high. After the hot or cold has been used up the water can be used for irrigation. Had thought of using cold water to condense atmospheric moisture but I think it would produce close to nothing.

Interesting ideas. I wonder if the night chilled pipe would condense more if in a more humid greenhouse or any humid space. Then reuse for irrigation maybe? I’ve wondered about filling in the unwanted windows in my school bus with stainless steel or plastic chiller plates that drain into little gutters and into condensation bottles at night. I think I could collect a gallon per day from only a few windows.
I’ve never thought of using pond water to heat a greenhouse. Or cooling.  Reverse siphoning at night on passive solar thermal domestic hot water systems (PSTDHW) can be a problem so they put check valves in place to prevent it. But if it was a designed in Permaculture function?. It seems like a environment such as a Earthship house would have potential to condense humidity.
What about an air pipe? I’ve wondered about a long cloche or crop row cover that goes down and up a hill into a space that needs heat or cooling. It could suck air  out of the house at night drawing in cold air to chill the house for the next hot day.
 Using the natural temperature swings in your region is a good example of permaculture thinking. Where I live in the Puget Sound there’s not as much temperature swings (delta T).