Effects of nonlinear optical parameters on the thermal performance of an indirect solar dryer under natural convection regime

Numerical analyses have been performed in order to understand the thermal behavior of an indirect solar dryer. However, not much attention has been given to the nonlinear optical properties influence on its dynamic. This paper studies the effect of nonlinear absorption and transmission parameters on the thermal performance of an indirect solar dryer. The main goal was to improve the output energy of collector and drying chamber. The nonlinear absorption and transmission coefficients are established as quadratic functions of the temperature. Theoretical investigations are conducted for the proposed nonlinear model. On the basis of these investigations, the established mathematical equations describing the solar drying system are solved numerically using a developed MATLAB program. A specific application is first made for constant absorption coefficient distribution and the predictions are in excellent agreement with the experimental results from the literature. Predictions of nonlinear optical absorption and transmission coefficients variation are then performed. A comparison of the results with constant and nonlinear absorptivity and transmissivity shows a significant 10% enhancement of the collector thermal performance by using nonlinear parameters.

Automated summary

This paper investigates the impact of nonlinear optical properties on the thermal performance of an indirect solar dryer. By establishing a nonlinear model and performing numerical analyses, it is found that the use of nonlinear parameters can significantly enhance the thermal performance of the collector.