Thermal-Hydraulic Analysis of a Parabolic Trough Solar Collector with Serpentine Absorber having Varying Pitch

Many technologies have been developed in order to harness the maximum solar energy received from sun on earth surface. Many researchers have carried out their research work to improve the efficiency of solar parabolic trough collector by changing the design of solar collector and absorber tube. The parabolic trough reflector is a solar thermal energy collector designed to capture the sun’s direct solar radiation over a large surface area and focus, or more generally “concentrate it” onto a small focal point area increasing the intensity of solar energy received at the focal point. The aim of present research work is to improve the heat gain capacity of absorber tube by changing its shape. The present research deals with performance evaluation of parabolic through collector with conventional straight absorber tube and serpentine absorber tube under identical input conditions. For evaluation, serpentine absorber tubes with different pitch were used. The material used for both straight as well as serpentine absorber tube is aluminum. The objective of this research is to find the effect of serpentine tube pitch on pressure drop and heat transfer rate to the fluid flowing through the absorber tube. The experimental testing of parabolic through collector were conducted with water as working fluid for all three absorber tubes and readings are taken for same flow rate. In the first phase, experiments were conducted on solar parabolic trough collector with conventional straight absorber tube. In second phase, experiments were conducted with serpentine absorber tubes with varying pitch. For experimentation serpentine absorber tubes having two different pitch of 397.42 mm and 393.92 mm respectively were used. Also, CFD, Ansys fluent v 19.1 module was used in present research work to analyze the flow behavior of fluid flowing through the straight and serpentine absorber of parabolic trough collector. It is observed that solar parabolic trough collector with serpentine absorber gives better efficiency compared with solar parabolic trough collector with conventional straight absorber.