Effect of Copper Fins on Fresh Water Productivity of Pyramid Solar Still

This research work presents an experimental performance assessment of a pyramid solar still (PSS). The square type of PSS is developed and tested under the environmental conditions of Kanchikacherla (16.6834°N, 80.3904°E), Andhra Pradesh, India. It is used to produce the fresh water and hot water simultaneously from the brackish feed water for domestic applications. Conceptually, it is expected that the rate of evaporation is higher when the surface area for heat absorption and rejection is more. Therefore, the pyramid solar still has been tested for smooth absorber plate (CASE-1) and the absorber plate with copper fins positioned horizontally at 140 mm (CASE-2) and 90 mm (CASE-3) apart. Experiments have been carried out between 7:00 AM and 7:00 PM, only on sunny days, for reducing the impact of variation in solar radiation intensity. It has been observed that the amount of distillate yield strongly depends upon the solar radiation intensity and ambient temperature. The introduction of copper tubes, which act as fins, on the black absorber plate leads to increase in daily fresh water production, up to a maximum value of 1.95 L/m2 for CASE-3. The distilled water output for CASE-3 and CASE-2 is about 60% and 33% higher than that of CASE-1, respectively. Additionally, the water quality (WQ) parameters such as total dissolved salts, pH, and electrical conductivity (dSm−1) of the produced fresh water are measured as 28 mg/L, 7.02, and 0.08 dSm−1, respectively, which meet the WQ-standards as suggested by the World Health Organization.