Experimental Study of the Performance of Cylindrical Solar Still with a Hemispherical Dome

Developing solar still glass cover is an important key to increasing both productivity and thermal efficiency. In present work, a new glass cover shape adopted of a vertical cylinder with spherical dome on the top. This design run under the climatic conditions of Najaf city in Iraq. A comparison done with traditional single slope still of the same basin area. Three cases of cylinder height taken 5 cm, 15 cm, and 20 cm. Two sets of experiments done, one in winter, and the other in summer. In each experimental day all climatic variables recorded by using a weather station, while another recording done for stills parts temperatures and hourly productivity. A yield amount of 5.8 l/m(2).day for 5 cm height, 6.7 l/m(2).day for 15 cm height, 7.25 l/m(2).day for 20 cm height, and 4 l/m(2).day for single slope solar still. Thermal efficiency measured was 18.8% for 5 cm height, 22% for 15 cm height, 23.3% for 20 cm height, and 15% for single slope solar still. Summer measurements may suggest that hemispherical solar still is more efficient than cylindrical solar still with hemispherical dome (CSSHD), but winter measurements show the opposite. [GRAPHICS]