Pyramid solar distillers: A comprehensive review of recent techniques

The most interesting themes worldwide are those relating to sustainable water and energy supplies. They have a significant impact on any society's economic wellbeing. Desalination of brackish water has proven to be a good solution to the freshwater issue that many regions of the world face. Solar stills (SSs) are a simple distillation technique for freshwater purification. From the conventional SSs to the modified SSs, several studies have been carried out to improve the effectiveness of this technique. Pyramid solar stills are effective and efficient, ac- cording to researches that have been done to develop several types of solar stills for increased distillate pro- duction. In this review, we aim to provide an extensive review of recent advancements in pyramid solar distillation techniques, including new technologies, methods, and best practices. Consequently, this paper helps researchers choose the optimal technique to get the best-optimized productivity from a pyramid solar still. This review highlights the efforts of researchers to improve the efficiency of solar distillation systems by exploring recent techniques and innovations in pyramid solar distillers up to 2023. Various results have demonstrated the significance of modifications or improvements to pyramid SSs, such as utilizing storage materials, which can significantly increase productivity by approximately 35%. Additionally, a v-corrugated absorber with PCM can enhance the yield by about 87.4%. Furthermore, the use of wick materials can increase freshwater production by up to 122%, with jute wick outperforming cotton wick. Integrating evacuated tubes and carbon black nanofluid into a pyramid solar still can also improve freshwater production by approximately 57.1%. Combining nano and wick materials can further boost pyramid distiller productivity by up to 176% and increase thermal efficiency to 60.44%. Moreover, using pyramid distillers with revolving cylinders and electrical heaters can result in a daily output increase of 214%, producing up to 9100 ml/m2/day.