Researchers in Abu Dhabi are testing a pilot device that can store solar energy in the sand to improve the efficiency of power plants and provide energy at night. The technology, developed at the Masdar Institute of Science and Technology, uses gravity to drain sand from a higher basin into a lower one, heating up the sand grains with solar power during the transition. In the lower basin, the energy can be stored and withdrawn at low cost to provide extra energy if needed. These tests will involve researching the thermal stability of sand and its specific heat-absorption capacity. The results showed a capability of storing thermal energy up to 800-1000 degrees Celsius. Unlike traditional storage media used in thermal energy storage systems, such as synthetic oils and molten salts, sand is abundant in regions with plenty of sunshine and inexpensive to obtain. The sand is heated by running cold sand through a solar heat collector, where it is heated before being stored in a hot reservoir. This hot sand can be used to run electricity-generating turbines. The cycle is completed by returning the cooler sand to the upper cold sand reservoir. Researchers say that more research and funding is needed to commercialize the technology.
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