Researchers from the Arab world have developed a new type of power plant which can generate electricity from solar power and cool air for 24 hours throughout both day and night, while desalinating seawater at the same time. The invention stands to revolutionize the field of solar power plants.
By now it is clear that the demand for energy and clean water will only rise in the coming decades. Global climate change is expected to acerbate the challenge of supplying freshwater to the world, and that situation may become even more dire due to the abundant use of fossil fuels (mainly oil), which emits greenhouse gases like CO2 (carbon dioxide).
Clean energy sources – especially sustainable and renewable ones – are desperately needed if we are to mitigate climate change and its hazardous impact on the environment. Clean energy sources generally include solar, wind, geothermal and hydropower. While Solar is highly regarded as a clean energy source, solar panel production may be expensive and even injurious to the environment. Solar chimney is one way to circumvent those limitations, with low production costs.
Solar chimney power plants are nothing new: the first one was demonstrated and tested in Spain in the 1980s. Each solar chimney is composed of three components: a collector at the base, a mechanical turbine and the tower itself. The collector harvests the sun energy and heats the air in the chimney. The hot air rises up the chimney with great force, making the turbine blades rotate, thus converting the sun energy into mechanical one – which is then converted into electricity.
Solar chimneys are not only useful for generating electricity. Excess heat emitted from the system can be utilized for water desalination. Indeed, researchers have proposed integrating solar chimneys with water desalination plants, thereby killing the proverbial two birds with one stone.
Why haven’t solar chimneys been adopted for general use, then? There are many challenges in the way of scaling-up these power plants. For one, they suffer from low thermal efficiency. They also require a large land mass to sit on, and a high chimney for optimal energy output. Researchers and engineers have focused in recent years on cost reduction and optimizing efficiency, with new and innovative designs.
Researchers from Al Hussein Technical University in Jordan, University of Sharjah in the United Arab Emirates, Qatar University and University of Wisconsin Stevens Point, have recently teamed up to suggest a novel design of a hybrid solar chimney power plant, which combines a cooling tower with a solar chimney.
The new structure includes a pool of seawater, which is distilled as a side-effect of the chimney’s function, and a cooling tower. The cooling tower functions as an opposite of the solar chimney: water sprinklers spray a mist of water at the top of the tower, which evaporates into cool air. The cool air becomes denser than the surrounding air, and is thus driven downwards where it causes a turbine to rotate.
Usually, solar chimneys and cooling towers are two separate structures. However, in the new design the two are combined: the tower functions as a solar chimney during the day, and as a cooling tower at night. The system can also function differently under varying weather conditions, to optimize its electricity production.
The researchers ran a simulation of the conjoined solar chimney and cooling tower, revealing that the structure could produce electricity and distilled water throughout both day and night, for 24 hours straight. The combined solar chimney and cooling tower could there be used widely to produce clean energy and drinking water, reducing carbon dioxide emissions and reliance on fossil fuels at the same time.
The cost of erecting the combined structure should be similar to the cost of constructing either solar chimney or cooling tower on their own, but the resulting structure would produce electricity throughout the day and night. The new system is therefore much more efficient and cost effective when compared to a traditional solar chimney, which can only produce electricity for an average of 8 hours a day. Furthermore, artificial intelligence engines can control the mode of operation of the power plant, to optimize energy output.
Taken together, the combined solar chimney and cooling tower is an invention that could revolutionize the traditional solar chimney concept, and mass-scale power plants of this kind. This development could help in the fight against climate change, while providing fresh drinking water to people in the furthest corners of the Earth.
The researchers behind the research are Emad Abdelsalam, Feras Kafiah, Ahmad Azzam and Ibrahim Alzoubi from Al Hussein Technical University in Jordan; Muhammad Tawalbeh from the University of Sharjah in the United Arab Emirates, Fares Almomni from Qatar University in Qatar and Malek Alkasrawi from the University of Wisconsin Stevens Point in Wisconsin.
Original content by Nawartna