Modeling and simulation to determine the thermal efficiency of a parabolic solar trough collector system

This study presents a reduced order mathematical model to calculate the heat transfer in steady state in a parabolic trough collector, in which the radial and axial temperature profile of the system is obtained. To solve the model an iterative calculation sequence is used and implemented in Python software, in additional OpenGL is used to generate a schematic visualization of the system. Next, results are validated with data from two different heat-carrier fluids published in the literature, obtaining a maximum relative error less than 10%. The model is used to determine the thermal efficiency using water, thermal oil and nanofluids as heat-carrier fluids. Results show that the thermal efficiency of the parabolic trough collector is higher with nanofluids containing a higher volume fraction of nanoparticles: with a volume fraction of 0.04 and 0.02, the thermal efficiency is of 80% and 79%, respectively. The thermal oil has the lowest efficiency with a maximum efficiency of 76%. The nanofluids allow working at low-pressure levels in the parabolic trough collector compared to pressurized water.