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It is imperative to mitigate the convective heat loss from the receiver to improve the overall efficiency of the parabolic dish concentrator. In this study, the reductions of convective heat loss from the cylindrical‐hemispherical receiver are numerically analyzed and the model was validated by the experimental data from literature. In the first case, the impact of the glass cover on convective heat loss is examined under conditions of both natural and forced convections at various receiver orientations (γ = 0°, 30°, 60°, and 90°). Numerical results clearly demonstrate that the use of a glass cover significantly reduces the intrusion of surrounding air into the receiver cavity which leads to an enhancement of the stagnation zone inside the cavity and, as a consequence, a noticeable reduction in convective heat loss is observed. To perform analysis of the receiver with glass cover under forced convective condition, the wind velocities over the receiver are considered in the range of 1–6 m/s. The maximum reduction of convective heat loss using the glass cover is achieved to be 58.44% with wind velocity of 5 m/s at γ = 60°. In the second case, the influence of air curtain at the receiver aperture under natural convective heat loss conditions is analyzed. The analysis incorporates three variables: receiver orientation (γ = 0°–60°), nozzle width (Lnoz ${L}_{\mathrm{noz}}$ = 0.002–0.004 m), and nozzle outlet velocity (Vnoz ${V}_{\mathrm{noz}}$ = 0.5–3.5 m/s). The results show that the air curtain minimizes the outflow of receiver inside air and results in an improvement in the stagnation zone inside the cavity. The maximum effectiveness of the air curtain is found to be 43.2% at nozzle width of Lnoz ${L}_{\mathrm{noz}}$ = 0.004 m and nozzle velocity of Vnoz ${V}_{\mathrm{noz}}$ = 1.5 m/s at receiver orientation of 60°. It is also noteworthy that the optimal nozzle velocity decreases with the increase of nozzle widths. [ABSTRACT FROM AUTHOR]

This research investigates the impact of the glass cover's optical properties on fresh water production in solar still desalination systems. By examining the transmissivity, absorptivity, and reflectivity of the glass cover under different operating conditions, the study aims to optimize the yield and efficiency of the desalination process. A validated mathematical model is developed, integrating energy and mass transfer with the glass cover's optical properties. For Matroh City, the research determines the optimal tilt angle of the glass cover (21.7°) and reveals absorptivity values ranging from 0.086 to 0.112, reflectivity values ranging from 0.076 to 0.89, and increasing transmissivity values from 0 to 0.84. Furthermore, a variable monthly optimal tilt angle outperforms a fixed annual tilt angle, resulting in a 2.5 % increase in annual distillate production. The results indicates that with an increase in glass thickness from 5 mm to 20 mm, the daily yield and efficiency decrease from 6.6 kg/m2 and 31.5 % to 5.2 kg/m2 and 24.9 %.This research provides valuable insights into the influence of glass cover optical properties on solar still desalination performance, contributing to renewable energy-based desalination processes. The implications extend to the development of sustainable water sources, greenhouse gas reduction, and addressing water scarcity challenges.

This research investigates the impact of the glass cover's optical properties on fresh water production in solar still desalination systems. By examining the transmissivity, absorptivity, and reflectivity of the glass cover under different operating conditions, the study aims to optimize the yield and efficiency of the desalination process. A validated mathematical model is developed, integrating energy and mass transfer with the glass cover's optical properties. For Matroh City, the research determines the optimal tilt angle of the glass cover (21.7°) and reveals absorptivity values ranging from 0.086 to 0.112, reflectivity values ranging from 0.076 to 0.89, and increasing transmissivity values from 0 to 0.84. Furthermore, a variable monthly optimal tilt angle outperforms a fixed annual tilt angle, resulting in a 2.5 % increase in annual distillate production. The results indicates that with an increase in glass thickness from 5 mm to 20 mm, the daily yield and efficiency decrease from 6.6 kg/m2 and 31.5 % to 5.2 kg/m2 and 24.9 %.This research provides valuable insights into the influence of glass cover optical properties on solar still desalination performance, contributing to renewable energy-based desalination processes. The implications extend to the development of sustainable water sources, greenhouse gas reduction, and addressing water scarcity challenges. [ABSTRACT FROM AUTHOR]