Experimental Study and Energy and Exergy Analysis of Flat-Plate Solar Still at Different Slopes Using Porous Materials and Heat Absorbent Oil

In this research, the performance of a flat-plate solar still at three slope angles of 15°, 30°, and 45° with the presence of porous material of pressed wool and heat absorbent oil in Dezful city of Iran has been investigated experimentally. The surface of the absorber plate is covered by porous material and oil circulates in the pipes connected to the absorber plate in a closed cycle. Results indicated that the energy efficiency using porous materials at slope angles of 15, 30, and 45 degrees is equal to 16.16%, 15.15% and 9.71%, respectively, and without using porous materials is equal to16.39%, 14.48% and 7.62%. In addition, the exergy efficiencies at the slope angles of 15, 30 and 45 degrees with the presence of porous materials is 1.65%, 6.65% and 4.78% respectively, and without the presence of porous materials is equal to 1.51%, 7.28% and 3.45%. The results showed that the maximum amount of distilled water produced at slope angle of 15 degree and in the state of not using porous material is equal to 3300 ml in a period of 11 hours.