08 Aug Masdar Institute project uses sand to store solar energy
Researchers at Abu Dhabi’s Masdar Institute of Science and Technology are testing a pilot device that can store solar energy in sand to increase the efficiency of power plants and provide energy at night.
The technology uses gravity to drain sand from a higher basin into a lower one, heating the sand grains with solar power during the change.
In the lower basin, the solar energy can be stored and taken out at low cost to generate extra energy if needed, during peak hours at night for example.
Nicholas Calvet, an assistant professor at the Masdar Institute’s department of mechanical engineering said: “Two pilot models of the system have been tested in an effort to prove its efficiency and applicability on a large scale in big projects.”
The researchers will now test a more sophisticated model in preparation for its commercial marketing.
These tests will include researching the thermal stability of sand and its specific heat-absorption capacity. The results showed the ability to store thermal energy up to 800-1000 degrees Celsius.
Sand is abundant in regions with a lot of sunshine and it’s inexpensive to obtain, unlike traditional storage media used in thermal storage systems such as synthetic oils and molten salts.
“The hourglass idea inspired the system, as it uses two reservoirs connected to one another vertically across a narrow passage that allows the movement of ‘cold’ grains of sand from the upper reservoir to the lower ‘hot’ one,” explained Calvet.
The sand is heated by running cold and through a solar heat gatherer, where it is heated before being stored in a hot reservoir. The hot sand can be used to run electricity-producing turbines.