Simulation of solar drying of chilli in solar tunnel drier

This article presents modelling of a solar tunnel drier by taking into account heat transfer in the collector and coupled heat and mass transfer within the drying unit. One set of equationswas developed to predict cover temperature, absorber temperature and air temperature in the collector and another set of partial differential equations was developed to predict the air and chilli temperatures and moisture content for drying of green chilli in the solar tunnel drier. The first set of equations was solved iteratively and the second set of equations was solved numerically on the basis of an exponential solution over the finite difference grid element using the outlet air conditions of the collector as inlet conditions of the drying unit. The simulated air temperatures in the collector and the drier agreed well with the observed air temperatures. Good agreement was also found between experimental and simulated moisture contents for drying green chilli.