Optical performance assessment of a handmade prototype of linear Fresnel concentrator

Abstract

This article aims to evaluate the optical behavior of a small handmade prototype of a linear Fresnel concentrator (LFC). The system was developed and tested as a water heater and steam generator at the Unidades Tecnológicas de Santander university, located in Bucaramanga, Colombia. Optical factors of the thermo-solar system studied were taken into account, such as concentration ratio and optical efficiency relationships. The Monte Carlo ray tracing method (MCRT) was carried out as an optical evaluation tool through the application of the free access software "SolTrace" and "TONATIUH" to later contrast the results obtained with both simulation tools. At the same time, the performance output from the simulations was compared with the optical performance of the experiments previously carried out with the device LFC, with the aim of evaluating the reliability and accuracy of the analysis developed through the MCRT methodology. The results obtained showed that the number of reflective mirrors or area of reflection has a direct impact on the optical efficiency of the prototype, where it is evidenced that there is a higher optical efficiency and a higher CR when the reflection area is larger. Similarly, direct solar radiation (DNI) has the same trend, showing that higher levels of direct solar radiation (DNI) increase optical efficiency. Finally, it was observed that the variation in the number of rays used in the simulations (10,000,000 and 5,000,000) does not influence the optical performance of the device.