Solar Energy at Night? 24/7 Solar Towers Could Double Energy Output

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Researchers from Qatar and Jordan successfully devised a solar energy system that can work at night, which more than doubles the energy output of current solar power stations. The researchers did so by combining two concepts—a solar updraft system and a cooling downdraft structure.

The designed model could generate enough annual energy to power 750 homes for five weeks or 1,500 60-watt light bulbs nonstop for a year. The research “An innovative twin-technology solar system design for electricity production,” is published in ‘Energy Reports’.

According to Techxplore, the origin of this type of solar system dates back to 1982 when Spanish engineers constructed a chimney-like tower with a mechanical turbine at its base. The air within the tower was warmed by absorbing solar radiation, and as the air heated it created an updraft that rose and activated wind turbines that in turn generated electricity. It wasn’t widely adopted due to massive costs and size.

The researchers, nevertheless, developed an improved updraft system and incorporated downdraft technology to achieve better results. A downdraft system centers on a tall tower, where pumps carry water to the top where warm air collects and cools it. The cooler air becomes denser than the outside air and falls through the cylinder. That cooler air drives the base turbine that in turn generates electricity.

The model is referred to as a Twin Technology Solar System (TTSS). It is almost 200 meters high with a 13.7-meter diameter, and ten downdraft towers encircle the updraft tower. This system continues generating power at night as air from daytime sunlight retains heat.

The system works best in a hot, dry climate. A simulation was based on the weather conditions of the capital of Saudi Arabia, where temperatures average above 37 degrees from spring to autumn. Its output is affected by weather (humidity, for example, slows the process). The researchers claim that the system’s reliance on a continuous supply of large quantities of water still poses an issue.