Abstract
Water distillation systems using free solar energy are known to be easy to install, low-cost, and environmentally friendly. However, due to the low productivity of fresh water for solar stills of all types, many practical and theoretical studies have been presented to enhance the productivity of solar stills using different engineering designs and improvement techniques. The overall productivity of the model is affected by several factors, the most important of which are the design, the nature of operating conditions, and environmental conditions. The current study aims to determine the effect of changing the geometric shape of the absorber plate on the cumulative productivity of a single-slope-single-basin solar still. A single-slope solar still with a different design and a specially shaped absorption basin was studied, and the proposed model was compared with the traditional model for the same manufacturing specifications and under the same test conditions. The traditional square shape has been modified so that it begins with a three-sided polygon and ends with an arc, while maintaining the same total area of the absorption plate. In this modification, the shadow areas are reduced and the solar radiation generated on the base is blocked by the walls, in addition to benefiting from using the back wall to act as a reflective arch for solar radiation. The new design, with and without an internal reflector, is examined and compared with the traditional model under the weather conditions of the Iraqi city of Najaf. Using the new-design solar still increased daily productivity by about 47.96%, while the cost will decrease to about $0.023 per liter/0.25 m2.