Simulation and control of fan speed in a solar dryer for optimization of energy efficiency
Keywords:control system, energy efficiency, forced convection, optimum, solar dryer
In a forced convection solar dryer, the dryer efficiency is continuously changing during the drying process due to changes of solar radiation and temperature. So, it is important to use a control system to optimize energy efficiency based on changing drying factors. For this reason, a controller was designed, simulated and evaluated. In this research fan speed was simulated and controlled based on changing system variables accordingly to maintain the optimized efficiency. Fan speed was simulated by SIMULINK toolbar of MATLAB software. The dryer efficiency was determined by considering the mathematical relations and monitoring the air temperature in 3 positions: inlet and outlet of collector and outlet of drying chamber. All experiments were carried out in three replications. The current and optimized dryer efficiencies were calculated by using the control program. Results showed that the simulated model was capable of modeling fan speed. So, statistical analysis showed that the control system highly improved the dryer efficiency throughout its operation at probability level of 1%.