Solar desalination/purification (solar stills, humidification-dehumidification, solar disinfection) in high altitude during COVID19: Insights of gastrointestinal manifestations and systems' mechanism

Experimental study of mono and hybrid nanofluids on square pyramid solar still

The lower productivity of square pyramid solar still is the prime impediment to its worldwide applicability. In the present study, efforts have been made to improve the productivity of square pyramid solar still using mono and hybrid nanofluid. The experiments were carried out with two similar square pyramid solar stills at a 1cm depth of basin fluid (saline water, mono, and hybrid nanofluid) under the climate of location (20.61°N 72.91°E). Copper (Cu) and aluminum oxide (Al2O3) nanoparticles were chosen to prepare mono and hybrid nanofluid. The 0.1% weight concentration of mono and hybrid nanofluid was prepared for experimentation. The hybrid nanofluid was prepared for the different mixing proportions of Al2O3-Cu such as 80:20, 60:40, 50:50, 40:60, and 20:80. For the case of use of mono-nanofluid, the performance of square pyramid solar still with Cu nanofluid was higher than Al2O3 nanofluid. The total productivity of 1640 mL/m2 and diurnal average efficiency of 17.00% were achieved for square pyramid solar still with Cu mono-nanofluid than saline water. A higher distillate yield was achieved for the square pyramid solar still with hybrid nanofluid than the mono-nanofluid and saline water. The diurnal average efficiency of 34.50% and maximum distillate output of 2644 mL/m2 were obtained for the square pyramid solar still with Al2O3-Cu hybrid nanofluid for the mixing ratio of 20:80. The efficiency and distillate output were higher by 27.41% and 25.19% for the square pyramid solar still with Al2O3-Cu (20:80) hybrid nanofluid than the square pyramid solar still with saline water. The distillate yield decreases with a decrease in the proportion of Cu nanoparticles.

Performance enhancement of the solar still using textiles and polyurethane rollers

The acquisition of clean drinking water in regions with limited power sources has been a challenge of paramount concern. Solar stills have emerged as a popular and sustainable option for obtaining clean water in such regions. This process involves employing solar radiation to heat up water, which is then condensed to obtain potable water. The present study introduces a solar still system that is both cost-effective and energy-efficient, while simultaneously ensuring sustainability. Fabric-coated polyurethane rollers with capillary action enhance evaporation area, leading to notable performance improvements. Water vapour condensed on the cooling chamber's inclined aluminium plate and collected in the distillate chamber within the solar still. The thermal, energetic, and economic performance and productivity of the proposed model were evaluated. The fabricated solar still boasted maximum instantaneous system efficiency and exergy efficiency of approximately 62.16% and 7.67%, respectively. This system's cost-effectiveness and performance improvements are particularly noteworthy. The daily average distillate productivity of the proposed still was estimated at 1.14 L/m2, resulting in an annual production rate of 416.54 L/year. The estimated cost of producing 1 L of distillate was 0.023 $.