This paper was aimed to evaluate the effect of fluid type on thermal performance of parabolic trough solar collector (PTSC). The simulation process was performed to predict thermal variations in receiver tube and storage tank by CFD. The experiments were conducted with 0.025 kg/s as air flow rate. Four fluid types including Nano-fluid (Al2O3, 4%), engine oil (10W40), glycerin and water and were considered for the performance analysis. Moreover, the drying process of the solar dryer was considered during the drying of apple slices with 5 mm thickness. The results showed that overall input thermal energy for dryer was about 17.36 MJ, 18.46 MJ, 17.76 MJ and 16.80 MJ for Nano-fluid, oil, glycerin and water, respectively. It also implied that using Nanofluid, oil and glycerin improved the overall efficiency of the dryer about 9.7%, 20.2% and 12.4%, related to water. The comparison of simulated and predicted results it is implied that CFD method can predict the performance of PTSC with different working fluids with good accuracy. Using different working fluids assisted with PCM did not have undesired effect on the quality of dried apples.
