Enhancing tubular solar still performance using novel PCM-tubes

The present study developed a novel PCM-tubes geometry to be used inside a tubular solar still with parabolic solar concentrator. Paraffin wax is filled inside 12-aluminum tubes working as a PCM material. Copper rods are installed inside the paraffin wax to enhance thermal properties. Parabolic concentrator solar tracking system is used to intensify solar radiations on the tubular solar still. Experimental work was executed under the climatic conditions of Ha'il city (27.64 °N, 41.75°E) 965 m above sea level in Saudi Arabia. The 12‑aluminum tubes were black painted and placed inside the trough. Results show a great enhancement of the freshwater productivity and device performance with relatively low production cost. Using PCM-tubes enhances the productivity and efficiency of the developed device by 40.51% and 38.25% respectively. The yield, efficiency and cost per liter are 5.55 L/m²day, 44.1% and 0.00782 USD for device with PCM-tubes compared to 3.95 L/m²day, 31.9% and 0.0163 USD for device without PCM-tubes. The developed device was able to reduce the freshwater production cost by 21.8% achieving a very competitive cost compared to the available solar desalination techniques. Further development of the tubular solar still is required in the future research effort.