Here is a photo of a typical local rain catchment system including tank: Tanks average about 10,000 gallons. Here we have rain all year, but the windward side gets more rain than the leeward side. I get enough rain that with a 50 gallon barrel and 7 feet of gutter is enough for showering and dishes. Note that my water usage does NOT include drinking water. Almost nobody drinks catchment water because of the risk of leptospirosis here, which comes from bird droppings that fall on the roof.
I was getting excited about this idea until I got to this sentence: "Evaporative coolers tend to perform poorly or not at all in climates with high ambient humidity, since the water is not able to evaporate well under these conditions." I'm in the wet tropics, unfortunately. I have seen one local cupboard in a house that was built before refrigeration. The top shelf had holes in it, but I have not figured out how it was supposed to work. I think it's an icebox, and something I could research. Mainly I'd like to upgrade my solar and then buy an energy-efficient fridge. I will go check out the resources you have here on solar systems
There are propane refrigerators https://www.amazon.com/dp/B01N9A4MHQ/?tag=survivalmonke-20 and these that run on 110 VAC/LPG/12VDC... https://www.amazon.com/dp/B071XQ2NDY/?tag=survivalmonke-20