Citation:
Abstract:
This study proposes the replacement of the conventional straight absorber by the newly designed longitudinally undulated. Numerical results revealed that the new absorber could dethrone the former for several reasons: Among others, it allows a more homogeneous distribution of concentrated solar radiations on its outer surface (Monte Carlo Ray Tracking results); unlike other techniques which improve the inner heat transfer by increasing simultaneously the load of the absorber and the pressure drop within it, the proposed curved absorber is going to generate in a natural way, without any additional mechanical components, vortices within the main streaming which allowed to increase the heat transfer coefficient of about 63 % with an increase of the pressure drop penalty of about 60 %. On the other hand, it allows a drastic reduction of the size of the solar collector field. All these facts lead to decreasing the wall temperature gradient bellow 40 K. Results are obtained for the Syltherm 800 Reynolds number range 2.5×104 to 12.3×104 and a fluid inlet temperature of 450 K.