Heat and mass transfer analysis of passive solar still with nanoparticles, operating at different water depth and various slope of glass cover

The paper presents the effect of water depth and tilt angle on the productivity of solar still operating with CuO and ZnO nanoparticles. Three solar stills at tilt angle of 11 degrees, 26 degrees and 41 degrees are fabricated and tested for their performance at three water depth (4, 5 and 10 cm) and CuO and ZnO nanoparticles. The solar stills are operated in winter season and their basin area is 1 m(2). The effect of water depth, tilt angle and type of nanoparticles on convective and evaporative heat transfer coefficient is also studied. The productivity is found higher at low water depth (4 cm) and at higher tilt angle (41 degrees). The productivity of solar still with CuO nanoparticles is 2.03 L/m(2)d. While for convectional solar still and solar still with ZnO nanoparticles, it is 1.43 and 1.54 L/m(2)d respectively. The calculated internal heat transfer coefficient of solar still with CuO nanoparticles is 155.2% higher reported than convectional solar still while with ZnO nanoparticles, it is 64.8% higher than conventional solar still. It is observed that productivity of solar still with nanoparticles for 11 degrees tilt angle is even higher than that of recommended angle of solar still for winter season (41 degrees for winter climatic condition).