A Thermal Node Model for Predicting Heat Transfer in Mixed Type Solar Drying System

Abstract

The present paper deals with an equivalent two-dimensional prediction of a mixed solar drying system performances using a thermal network procedure and the numerical simulation. The aim has been to build the equivalent electric circuit of the mixed solar drying facility and investigate the space and time variabilities of temperature transfer in a solar drying system.The balance equations modelling the physical elements are approximated iteratively using the finite difference method. The results obtained indicate that the proposed two-dimensional predictions based on sinusoidal approximation of solar radiation and air temperature inputs adequately describe both collector and dryer temperature profiles. The influences of various parameters such as the space resolution, the mass flow rate, the average temperature and solar radiation inputs have been investigated and discussed. The numerical simulations show that the temperature of each element of the drying system is not uniform and varies considerably with the space and time nodes, and therefore increases gradually from the first-node of the macroscopic drying flow to the end-node.