Modelling of the Relation Between Temperature and Velocity of Air at the Outlet of a Flat Plate Solar Collector

Solar air heating collector is a simple device used for air heating by solar energy that can be applied for various kinds of tasks. In this study, a flat-plate solar air heating collector with a shutter window absorber and blower speed control system was designed and fabricated. The blower speed control system consists of three LM35 sensors, AVR microcontroller, two solar panels and a blower. Outlet air temperature was measured by control system providing variable speed to put it in specified temperature range. The collector was evaluated in outdoor open area for a week. Regarding the importance of different parameters affecting the collector efficiency, the temperature and velocity of air at the outlet were selected for modeling system performance. From conventional linear and nonlinear regression models, eight models which were more general and more likely to explain the relationship between two above-mentioned parameters were selected for statistical analysis. Based on the results, the fourth-degree polynomial regression model was proposed for interpretation of the empirical relation between temperature and velocity of air at the outlet of the collector. The model with coefficient of determination equal to 0.99 showed the best fit among the investigated models.