Mathematical modeling and computational fluid dynamics simulation of cabinet type solar dryer: Optimal temperature control

Abstract

AbstractThe mathematical model for determination of auxiliary energy required to maintain set air temperature in the drying chamber is proposed for cabinet type solar dryer. The model is developed considering the heat exchanges across the dryer control volume with solar radiation intensity and set temperature as input. The sole purpose is to minimize the auxiliaries. The computational fluid dynamics (CFD) technique is used to simulate the air flow inside the drying chamber for different operating conditions. The simulations results for the temperature are very close to the results from mathematical model. The dryer configuration discussed in illustrative example found to have minimum auxiliary consumption at 45°C with total auxiliary expense of 97.3 kWh per day. When applied to full calendar year, the optimum temperature is found to be function of ambient temperature and solar radiation intensity. The results obtained from mathematical model are found to be in well agreement with simulation results. The simulation results provide a region with 1.2 m to 1.6 m on X‐ordinate, 0.8 m to 1.0 m on Y‐ordinate and 0.7 m to 1.2 m and 3.7 m to 4.3 m on Z‐ordinate where average temperature can be sensed. It helps in modulating the auxiliary input/s in integration with solar heat.