Experimental investigation of inclined solar still through localized interfacial evaporation using nano enhanced Bio wick under disparate flow rate

Abstract

Water treatment is essential for obtaining potable water, and passive solar desalination offers a renewable and sustainable approach. However, productivity remains a key challenge for commercialization. Scaling up solar desalination systems while maintaining efficiency and cost-effectiveness is a significant challenge. The current state of research in solar desalination is focused on developing scalable and sustainable solutions to address challenges faced in productivity. To address this issue, ongoing efforts focus on improving productivity under localized interfacial evaporation. The present study aims to enhance productivity, particularly at higher mass flow rates, through a series of experiments conducted in three sets. In the first set of experiments, a bare Integrated Solar Still (ISS) was utilized with various mass flow rates (0.29, 0.42, 0.75, and 1.3 kg/min). The highest hourly yield of potable water was observed during peak solar intensity, typically between 13:00 and 14:00 Hrs for all mass flow rates. However, as the mass flow rate increased, the hourly yield of potable water decreased. For instance, at 14:00 Hrs, the maximum yield was 0.235, 0.15, 0.12, and 0.06 kg/m2 for mass flow rates of 0.29, 0.42, 0.75, and 1.3 kg/min, respectively, in the ISS without wick material. The highest cumulative yield achieved was 1.6 kg/m2 during 0.29 kg/min mass flow rate, while the minimum clean water yield of 0.4 kg/m2 was obtained at 1.3 kg/min. In the second set of experiments, the goal was to improve productivity at higher mass flow rates. The use of Fe2O3-impregnated jute cloth in comparison to the bare ISS resulted in an average absorber temperature increase of 4∘C, 4.8∘C, 4.8∘C, and 4.9∘C for mass flow rates of 0.29, 0.42, 0.75, and 1.3 kg/min, respectively. Interestingly, the trend showed an increasing rate of reduction mitigation at higher mass flow rates. Simultaneously, the average water temperature increased by 4.2∘C, 4.5∘C, 6.4∘C, and 7.1∘C for the corresponding mass flow rates with Fe2O3-impregnated jute cloth. The introduction of jute cloth enhanced energy harvesting at all mass flow rates compared to the bare ISS. The maximum energy efficiency, at 48.02 %, was achieved with Fe2O3-impregnated jute cloth during the 0.29 kg/min mass flow rate, while the minimum energy efficiency, at 9.14 %, was recorded at the highest mass flow rate of 1.3 kg/min. Notably, the energy efficiency of the jute cloth-covered ISS surpassed that of the bare ISS by 12.44 %, 9.14 %, 7.15 %, and 3.14 % for mass flow rates of 0.29, 0.42, 0.75, and 1.3 kg/min, respectively. Furthermore, the addition of Fe2O3-impregnated jute cloth further improved energy efficiency, with enhancements of 8.19 %, 1.14 %, 6.36 %, and 9.57 % over the jute cloth-covered ISS for the respective mass flow rates. During the 0.75 kg/min mass flow rate, energy efficiency reached 26.12 %, closely matching the 27.3 % efficiency achieved at 0.29 kg/min in the bare ISS. The study also demonstrated a 2.29 % improvement in exergy with Fe2O3-impregnated jute cloth at a mass flow rate of 0.29 kg/min. In conclusion, the results suggest that the implementation of jute cloth over the ISS absorber basin can enhance overall efficiency and mitigate the negative impacts of increased mass flow rates via localized interfacial evaporation. The combination of a jute cloth wick and Fe2O3 nanoparticles holds promise for improving energy efficiency in solar still desalination.