Thermo-economic performance enhancement of the hemispherical solar still integrated with various numbers of evacuated tubes

Abstract

Experimental investigations of the hemispherical solar still (HSS) augmentation with various numbers of evacuated tubes (EVT) were performed and evaluated. The modified hemispherical solar still (HSS-EVT) performance was illustrated with two categories of EVT distributions and compared with the traditional HSS (THSS) design. In the first category, the EVT was distributed on the water basin perimeter in all directions (Dis-ɸ), and in the second category, the EVT was distributed in the south direction (Dis-So). The impact of various water heights (Hw) from 1 to 4 cm was also studied. Results revealed that the integration of EVT had a significant influence on distillate performance. The highest daily production rate at 1 cm water height of HSS-EVT was 5860 mL with an increment of 551, 316, 156, and 91% compared to THSS at NEVT = (16, 8, 4, and 2 tubes), respectively. The productivity increment by 7.2%, when compared EVT distribution (Dis-ɸ) with (Dis-So) effect. The reduction of water level to 1 cm increases the yield by about 5.96, 11.61, and 18.74% with HW (2, 3, and 4 cm), respectively. The proposed system's peak energy and exergy efficiency value was 42.29 and 5.57%, with an increment of 47.30 and 124%, respectively, related to the traditional one. The maximum daily production related to the exposed surface area was 6.69 L/m2 at NEVT = 8 tubes. The estimated cost varied between 0.00237, and 0.0101 USD/L.