Heat Transfer Enhancement of the Absorber Tube in a Parabolic Trough Solar Collector through the Insertion of Novel Cylindrical Turbulators

This study includes an experimental and numerical analysis of the performances of a parabolic trough collector (PTC) with and without cylindrical turbulators. The PTC is designed with dimensions of 2.00 m in length and 1.00 m in width. The related reflector is made of lined sheets of aluminum, and the tubes are made of stainless steel used for the absorption of heat. They have an outer diameter of 0.051 m and a wall thickness of 0.002 m. Water, used as a heat transfer fluid (HTF), flows through the absorber tube at a mass flow rate of 0.7 kg/s. The dimensions of cylindrical turbulators are 0.04 m in length and 0.047 m in diameter. Simulations are performed using the ANSYS Fluent 2020 R2 software. The PTC performance is evaluated by comparing the experimental and numerical outcomes, namely, the outlet temperature, useful heat, and thermal efficiency for a modified tube (MT) (tube with novel cylindrical turbulators) and a plain tube (PT) (tube without novel cylindrical turbulators). According to the results, the experimental outlet temperatures recorded 63.2 degrees C and 50.5 degrees C for the MT and PT, respectively. The heat gain reaches 1137.5 Win the MT and 685.8 Win the PT. Compared to the PT collector, the PTC exhibited a (1.64 times) higher efficiency.