How to Use Solar Energy at Night

Source: Scientific American

Solar energy is great. But what can we do if there is no sulight and the energy is still needed? I've asked myself this question already many times and I even had an idea of how one could solve this. :-) Indeed, my girlfriend once bought this massage thing. It is a plastic filled with some pseudo-fluid material and a small piece of metal. When you click it, the salts start to crystalize and heat is released. It not only feels great, it can also be reused over and over again. To restore the massage thing, you simply have to boil it and the crystals disappear.



Anyway, if this would make sense, it would already be developed I think. Still, I was happy to read an article on the Scientific American website where they explain how salts can be used to store solar energy. Part of a so-called parabolic trough solar-thermal power plant, the salts will soon help the facility light up the night—literally. Because most salts only melt at high temperatures (table salt, for example, melts at around 1472 degrees Fahrenheit, or 800 degrees Celsius) and do not turn to vapor until they get considerably hotter—they can be used to store a lot of the sun's energy as heat. Simply use the sunlight to heat up the salts and put those molten salts in proximity to water via a heat exchanger. Hot steam can then be made to turn turbines without losing too much of the original absorbed solar energy.