Comparative study of a conventional solar still with different basin materials using exergy analysis

Influence of high porous sponges for improving the interfacial evaporation from hemispherical solar distillers

The present study aims to improve the palatable water production from the hemispherical cover solar distiller (HSD). To augment the palatable water produced from the hemispherical cover, a black sponge was utilized as a porous medium using different thicknesses, which augments the interfacial evaporation through the capillary effect of the water through the sponge. The rate of condensation of the hemispherical cover depends on the higher interaction of air from the ambient through wind velocity as the exposure area of the hemispherical cover is relatively higher as compared to the other traditional distillers. The rate of evaporation from the distillers depends on the interfacial materials used in the distillation unit, and this is achieved by using a highly porous black sponge to attain a higher evaporation rate. The thickness of the black porous sponge was optimized (1 to 4 cm), which was the operating parameter for better interfacial evaporation through the sponge, and the same has been compared to the conventional HSD without a porous sponge medium. Results showed a significant improvement in the evaporation rate using a porous medium as the palatable water produced from the HSD was improved by 72.29% using 3 cm as sponge thickness inside compared to the conventional HSD without the porous medium. The cumulative palatable water produced from the HSD using 3 cm as sponge thickness was found as 7150 mL/m2, whereas the conventional HSD without sponge, it was found as 4150 mL/m2. Moreover, using a porous sponge layer as an interfacial evaporation medium, the exergy and energy efficiencies were improved by about 512.87 and 70.53%, respectively. Similarly, with the influence of a porous sponge as an interfacial evaporation medium, the distilled water cost decreased by 41.67% more than the conventional HSD.

Water depth effect on energy, exergy losses, and exergy efficiency of solar still with wick materials: an experimental research

This study analyzes the energy and exergy destruction of a solar still with black painted wick materials (SS with BPWM) at different salt water depths (Wd) of 1, 2, and 3 cm. The coefficients of heat transfer for evaporative, convective, and radiant heat transfer have been calculated for a basin, water, and glass. The thermal efficiency and exergy losses caused by basin material, basin water, and glass material were also determined. An SS with BPWM at Wd of 1, 2, and 3 cm has produced a maximum yield of 0.4, 0.55, and 0.38 kg per hour, respectively. An SS with BPWM at Wd of 1, 2, and 3 cm has produced a daily yield of 1.95, 2.34, and 1.81 kg, respectively. From the SS with BPWM at Wd of 1, 2, and 3 cm, respectively, daily yields of 1.95, 2.34, and 1.81 kg were obtained. The highest exergy loss of the glass material, basin material, and basin water for the SS with BPWM at 1 cm Wd was 728.7, 133.4, and 123.8 W/m², respectively. The SS with BPWM's thermal and exergy efficiency are 41.1 and 3.1% at 1 cm Wd, 43.3 and 3.9% at 2 cm Wd, and 38.2 and 2.9% at 3 cm Wd, respectively. The results show that compared to the exergy loss of basin water in SS with BPWM at 1 and 3 cm Wd, the basin water exergy loss of SS with BPWM at 2 cm Wd is minimal.

The impact of the corrugated absorber shape on the performance of a hemispherical solar still for water desalination: an experimental study

Solar stills utilization has received great interest in arid isolated regions. In this study, experimental approaches have been investigated to prove the impact of the corrugated absorber shape on the hemispherical solar still performance. Four geometric corrugated shapes including present flat, triangular, semi-circular, square forms were tested for the corrugated absorber. Five hemispherical solar distillers have been fabricated and tested. The first distiller includes flat absorber (HSD-FA), the second distiller includes square corrugated absorber (HSDSA), the third distiller includes semi-circular corrugated absorber (HSD-SCA), the fourth distiller includes triangular corrugated absorber (HSDTA), and the fifth distiller is conventional (CHSD). The first and second distillers were compared with the CHSD on the first day. On the second day, the third and fourth distillers were compared with the CHSD as well. Experimental results obtained showed that, the total freshwater yield of the HSD-FA, HSDSA, HSDSCA and HSDTA were improved by 16.67, 27.08, 39.58 and 48.96%, respectively, compared over that of the CHSD. These results prove that the use of the triangular corrugated absorber shaped provides the highest thermal efficiency, and the optimum corrugated absorber shape is the triangular corrugated absorber shape.

Enhancing the performance of conventional solar still using sensible heat energy storage materials

The lack of drinkable, safe water is one problem that governments around the world are dealing with. There are many methods for desalinating saltwater, such as solar distillers, which can be used in remote places without access to traditional energy sources to produce distilled water. In this manuscript, two solar stills [conventional solar still (CSS) and CSS with high thermal conductivity material (HTCM)] were researched at the "School of Mechanical Engineering, B.S. Abdur Rahman Crescent Institute of Science and Technology, Vandalur, Chennai, India," under the same climatic condition. The HTCM (silicon carbide) works as a sensible heat energy storage material, which was placed at the basin of the CSS. The silicon carbide used in the present research is used to enhance the freshwater production during lower solar intensity period and furthermore after evening time. It has been found that the maximum fresh water production from the CSS is 1.5 kg/m² and the CSS with HTCM is 2.9 kg/m². The daily yield production from the CSS with HTCM is 93.7% higher compared to the CSS. The study also has shown that the maximum daily thermal efficiency of the CSS is 13.43% and the CSS with HTCM is 26.09%. The CSS with HTCM produced 94.3% higher thermal efficiency as compared to the CSS.

Impact of water depth on thermal efficiency, exergy efficiency, and exergy losses of finned acrylic solar still: an experimental study

This paper presents a complete exergy analysis and exergy destruction of a finned acrylic solar still (SS) at 1, 2, and 3 cm salt water depth (W_d). The coefficients of heat transfer of salt water-glass have been computed for evaporative, convective, and radiant heat transfer. Also, thermal efficiency, exergy loss of basin, saltwater, and glass was determined. The maximum hourly output of a finned acrylic SS at 1, 2, and 3 cm W_d was1.23, 0.93, and 0.81 kg, respectively. The daily yield of 5.67, 5.16, and 4.41 kg was collected from the finned acrylic SS at 1, 2, and 3 cm salt W_d, respectively. For the finned acrylic SS at 1 cm W_d, the maximal exergy loss of the basin, saltwater, and glass was 604.3, 92.8, and 141.8 W/m², respectively. The thermal and exergy efficiency of the finned acrylic SS at 1 cm W_d is 42.54 and 3.83%, respectively, while at 2 cm salt W_d, it is 37.92 and 3.22% and for 3 cm W_d is 31.2 and 2.7%. According to the findings, the exergy loss of saltwater in finned acrylic SS at 1 cm W_d is minimal when compared to the exergy loss of saltwater in finned acrylic SS at 2 and 3 cm W_d.