Omid Karimi Sadaghiyani - Department of Mechanical Engineering, Urmia University of technology, Urmia, Iran
S.Mansureh Khaljani - Department of Mechanical Engineering, Sahand University of technology, Tabriz, Iran
M.Mohammad Sadeghi Azad - Department of Mechanical Engineering, Urmia University of technology, Urmia, Iran
Iraj Mirzaee - Department of Mechanical Engineering, Urmia University, Urmia, Iran

In this paper, the effect of evacuated glass cover on convective heat loss and exergetic efficiency is studied. First, the evacuated receiver tube of LS-2 parabolic trough collector is simulated and analyzed with computational fluid dynamics (CFD) to compare with Dudley’sexperimental data at Sandia National Research Laboratory (SNRL). The results have good agreements with tested results. Secondly, this mentioned collector and its absorber tube are simulated without evacuated glass cover for various wind speeds and collector orientations. The temperatures of the receiver tube and ambient are assumed 350 and 300 K respectively. Finally, exergetic analysis of each case-studies are calculated and effect of wind blast and collector orientation on the exergy destruction and exergy loss are investigated. It is found that when wind blows on the convex side of the parabolic mirror, the impressibility of outlet temperature from wind speed is least than other orientations. Also, if the wind blows on the convex side of the parabolic mirror, the impressibility of outlet temperature from the variation of orientation is most than other orientations. Also, With increasing of orientation angle from -90 to 90, the exergy loss and destruction of collector increase. Therefore exergy efficiency of collector will be decreases. With increasing of wind blast from 5 to 15, the exergy loss and the destruction of collector increase. Therefore exergy efficiency of collector will be decreases. Also, using evacuated tube leads to increasing of exergy from 10% to 60%.

Evacuated absorber tube, Parabolic trough collector, Exergetic efficiency, Exergy destruction, Exergy loss