The basic idea behind a solar pond is that you have a pond -- or something more like a giant in-ground swimming pool with black lining -- that's filled with three layers of water. The bottom layer is super-salt water, in that it's been salinated while boiling until it's like 20% salt. The next layer is somewhat salty, but I don't know the exact percentage. The top layer is fresh water. If the water is clear, sunlight will heat the pond, and the bottom layer, through the magic of either thermodynamics or chemistry, will heat to 170 degrees or higher. This hot water can be used to heat homes or make steam power to use less energy or something. It could help to create the heat for hot water heaters, but you can't use this weirdly-hot pond water as tap water for tubby time, partially because leaving the water in the pond and relatively undisturbed is what makes the magic happen. And it would be gross.
Because you want a clear layer of fresh water to drive the solar pond, Jacksonville's heavy rain storms on the hottest days would likely hurt efficiency. I could imagine a solar pond working in the desert or Southern California, though I assume the cool nights would have similar negative impacts. One report I saw from Iowa said that the water layers had to be replaced too often for the system to make a real economic impact. Granted, a study pond on a university campus is different from a huge lake created in the desert, but it seems the smaller-scale projects would need to be more successful before we see huge tracts of land used for the purpose of heating water.
If solar ponds could be dual-purpose, I could see them in the 904. However, our current ponds function to prevent flooding, store polluting run-off, and scare the hell out of parents with toddlers. Imagine how much scarier it would be to know that you could be boiled alive if you fell into your backyard pond. Also, oil from roads, stray soda cans from recycling carts, and organic material like grass clippings would probably all adversely affect the salt ponds. We'd also have to say goodbye to fish, turtles, and birds because I don't think anything could live in or near a solar pond, no matter how "green" it sounds.
I'm still optimistic that some other use for all of our ponds will be developed, even if salt ponds or hydroponics won't really work. Maybe something related to tides or waves or algae harvesting. Or just using the water on our lawns for irrigation.
