School of Mechanical Engineering, Yazd University, Yazd-Iran.
Solar collector, the first part of each solar dryer system, is important for industrial and agricultural purposes. The final objective of any solar system is to maximize its output. The energy analysis is excellent complementary thermodynamic tools for this purpose. In the present study, a comprehensive thermodynamic model for energy analysis of a double pass solar air heater has been carried out. Energy balance equations have been investigated for all components of the solar air heater including insulation, lower channel air stream, absorber, upper channel air stream and glass cover. The main object of this research was to find energy efficiency of a double- pass solar air heater for all over the year of Yazd Province in Iran. Moreover, the effect of inlet length and inlet width of collector on outlet temperature of solar air heater was studied. The results of the simulation showed that the maximum monthly average energy efficiency of the solar air heater is 32.41% in January with 145solar radiations. It is attributed to the fact that the inlet length of solar air heater has a positive effect on the increment of outlet temperature of top and bottom channel and efficiency of system, also the inlet width of solar air heater has negative effect.