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• Two parabolic solar collectors with rectangular absorbers as built-in solar stills were constructed. • The distribution of the concentrated solar flux on the surfaces of a rectangular and tubular absorbers has been addressed. • Solar desalination experiments were performed under atmospheric and reduced pressures. • Desalinations under concentrated solar flux, atmospheric and reduced pressures were performed. • Desalination under reduced pressure showed significant performance improvement. This study presents, experimental and theoretical investigation on solar desalination using parabolic trough solar collector. Two parabolic troughs with tow rim angles of 101.4° (PTC1) and 75.75° (PTC2) were equipped with two rectangular absorbers as built-in solar stills. The local concentration ratio (LCR) on the surface of the rectangular absorber has been calculated and compared with that on the surface of a tuber absorber having similar surface area. It has been demonstrated that the shape of the distribution of LCR on the surface of a rectangular absorber was different than that on the surface of a tubular absorber. However, both absorbers were found to gain almost equal concentrated solar flux as indicated by the areas under the distributions. The generated vapor in the rectangular absorber was transferred to a 30° single slope solar still with basin area of 1 m2 which was used as a condenser. Results on solar desalination showed enhanced performance in obtaining salt free water. The productivities of PTC1 in March and April were of about 7.5%, and 9.8% greater than that of PTC2, respectively. Results show that the productivity of PTC1 under reduced pressure was of about 58% greater than that of the same PTC under atmospheric pressure. In addition, the productivity of PTC1 under reduced pressure could reach about 2.97 L/h during the peak period with a daily efficiency of about 87%. [ABSTRACT FROM AUTHOR]

In this work, the annual performance of single basin single slope, double slope and pyramidal shaped solar stills has been investigated experimentally and theoretically. Experiments were conducted in Ma'an area in Jordan throughout the year from January 2015 to December 2015 on clear days using solar stills with different orientations and different tilt angles of 15°, 30° and 45°. Mathematical models of solar radiation and solar desalination were developed to simulate the availability of solar radiation in Ma'an region, Jordan (Latitude: 30.7 N, Longitude: 35.7 E), and the performance of the solar stills. The average basin area was found to be of 0.64 m 2 and 0.82 m 2 in January and July, respectively. Model simulations were validated against experimental measurements and a reasonably good agreement was obtained. Annual optimal tilt angles of 30.3°, 45°, and 65° were suggested for south oriented single slope, double slope and pyramidal shaped solar stills, respectively. Under optimal settings, the single slope solar still was found to be the best system with improvement in productivity of about 28%. On a seasonal basis, a south oriented double slope solar still with tilt angle of 35° was found to perform, slightly, better than the other stills in summer. [ABSTRACT FROM AUTHOR]