Enhancing tubular solar still productivity using composite aluminum/copper/sand sensible energy storage tubes

Water scarcity is a big challenge especially for developing countries and desert areas like Saudi Arabia. Using solar energy for freshwater production is the way forward for future development of the water industry. The present study developed a new composite sensible heat storage tubes (CSHSTs) to improve the freshwater productivity of a tubular solar still activated by a parabolic concentrator solar tracking system. 12-CSHSTs were inserted inside the trough of the tubular solar still forming heterogeneous cavities for the saline water. Each CSHST consists of three main solid components (black painted aluminum tube, copper wire and silica sand). The experimental work was conducted under the climatic conditions of Ha'il city in Saudi Arabia. Results showed enhancements by 24.05% and 20.06% in the freshwater yield and thermal daily efficiency, respectively. The developed device produced 4.9 L/m²day with 13% lower freshwater production cost of $0.0087 per liter. Inserting the 12-CSHSTs inside the trough with the heterogeneous cavities increased the contact area with the saline water. This novel configuration enhanced significantly the heat transfer mechanism. The developed device showed higher performance compared to the previous studies in the literature.