Productivity enhancement of stepped solar still by loading with magnets and suspended micro charcoal powder

Solar desalination technology is an eco-friendly and sustainable pathway to generate pure water. In the current investigation, the stepped solar still were loaded with 10 magnet rings and charcoal powder of 75 microns to make the still efficient. Three different types of solar stills namely, conventional stepped solar still (CSSS), magnetic stepped solar still (MSSS), and magnet charcoal stepped solar still (MCSSS) were tested simultaneously at 1 cm, 2 cm, and 3 cm depths of water. The deployment of magnets in MSSS and magnets and charcoal in MCSSS were found to significantly enhance the radiative, convective, and evaporative rates of heat transfer. The highest total heat transfer rate was found in MCSSS which was more than the rates in MSSS and CSSS by 30.94% and 91.70%, respectively. The cumulative yield outputs in MCSSS were 104.54% and 23.28%, respectively, higher than CSSS and MSSS. The exergetic efficiency in MCSSS was higher by 31.84% and 145.82%, respectively, in comparison to the MSSS and CSSS. In addition, an economic evaluation was carried out and the annual distillation cost and overall cost of one liter of water per 0.25 m² were found to be 48.6 and 0.029 USD, respectively. The results emphatically indicate that the proposed solar still is a simple and economical technique to improve the distillate output in an eco-friendly manner.

太阳能海水淡化技术是获取纯水的环保且可持续的技术路径。本研究中，研究者向阶梯式太阳能蒸馏器（stepped solar still）中加装10个磁环与75微米粒径的木炭粉末，以提升蒸馏器的运行效能。本实验同时测试了三种不同类型的阶梯式太阳能蒸馏器：传统阶梯式太阳能蒸馏器（conventional stepped solar still, CSSS）、带磁阶梯式太阳能蒸馏器（magnetic stepped solar still, MSSS）以及磁炭复合阶梯式太阳能蒸馏器（magnet charcoal stepped solar still, MCSSS），测试时的水深分别设置为1 cm、2 cm与3 cm。研究发现，在MSSS中加装磁体、在MCSSS中同时加装磁体与木炭粉末，可显著提升辐射换热、对流换热与蒸发换热的传热速率。MCSSS的总传热速率最高，分别较MSSS与CSSS提升了30.94%与91.70%。MCSSS的累计产水量分别较CSSS与MSSS高出104.54%与23.28%。MCSSS的㶲效率分别较MSSS与CSSS高出31.84%与145.82%。此外，本研究还开展了经济性评估，结果显示，在0.25平方米的装置面积下，每升蒸馏水的年度蒸馏成本与总成本分别为48.6与0.029美元。研究结果充分表明，所提出的阶梯式太阳能蒸馏器是一种可通过环保方式提升产水量的简便且经济的技术方案。