Investigation of heat transfer enhancement in a tube with twisted tape by using concentrating solar power

Abstract

Concentrated solar power is one of the renewable energy sources in the world that can be utilized from solar energy by combining and concentrating it. In this numerical study, computer software was used to investigate the parabolic trough collector consists of a mirror and tube made of copper covered with a vacuum glass. The twisted tape made of aluminum is placed inside the tube to generate swirl flow and turbulence around the axial centerline of the absorber tube with the working fluid. Water was used as a working fluid with turbulent flow, the Reynolds number varied for the range of 2000 to 9000. To describe the present study, continuity, momentum, and energy equations are used. The angle of inclination of the twisted tape has been taken into account in six different values: 25 °, 33 °, 45 °, 50 °, 55 °, and 60 °. A study occurred in the city of Istanbul in Turkey with 41° latitude and 28.97° longitude for a periodic time from 9:00 am to 3:00 pm, for four different selected months, September, October, November, and December. Results illustrated increasing in outlet temperature of 7.83%, 14.89%, 19.57%, 21%, 4.76%, and 12.23% for twisted tape with 25°, 33°, 45°, 50°, 55°, and 60° respectively, compared with the plain tube. Nusselt number increases by 18.51% , 39.88% , 41.01% , 43.95% , 12.38% , and 22.4% for twisted tape with 25° ,33° ,45°, 50°, 55° , and 60° respectively, compared with the plain tube.