Mathematical Modelling and Experimental Study of an Enhanced Double-Slope Glass Solar Still

Abstract

Solar desalination is considered an important technology for solving the water shortage problem. In this research, a mathematical modeling and experimental study of an enhanced double-slope glass solar still were developed and evaluated based on a comparison with the conventional one. The two solar still were designed and fabricated at the Faculty of Engineering, University of Tabuk, and compared in the same operating climate conditions. The solar radiation model was developed, tested, and used with the solar still mathematical modeling to predict water productivity and daily efficiency. Copper T shape pieces were used in the solar still basin to increase the free water surface area inside the still at a water depth of 3 cm. The results indicated that the average measured and calculated values of accumulated productivity for conventional solar still were 3.01 and 3.32 L/m2.day respectively with a deviation of 9.3%. The corresponding average values for the enhanced solar still were 7.03 and 8.16 L/m2.day respectively. In addition, it can be noticed that the maximum measured daily thermal efficiency was about 56.4% and 25.31% for enhanced and conventional solar still respectively. Also, the cost evaluation was performed, and the results concluded that the enhanced double-slope glass solar still with cost per liter was about 0.0024 $/L/m2. The modeling and experimental results were compared based on the statistical evaluation methods and it is clear that the proposed mathematical model gives a good prediction of solar radiation and performance for the enhanced doubleslope glass solar still.