(searched for: doi:10.1155/2020/9205283)
Published: 22 January 2022
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects pp 1-23; https://doi.org/10.1080/15567036.2022.2028038
Usually, the solar air heater (SAH) is placed in a fixed position based on the tilt angle. This situation adversely affects the thermal performance of the collector, considering the natural motion of the sun. In this experimental study, two SAHs of equal dimensions were designed. A PLC solar tracking system was integrated into one of the SAHs to track the sun in two directions (East-West, North-South). The thermal efficiency values of the SAHs were calculated according to three different mass flow values of the air in the SAH by using the “I” and “II” laws of thermodynamics. It was observed that movable SAH has two times more average heat transfer value, 47.8% more energy efficiency, 2.4 times more exergy efficiency, 20% more coefficient of performance (COP) value, and 23.8% more average collector outlet temperature than fixed SAH. In addition, it was measured that the average irradiance on the absorber plate in the movable SAH is 38% higher than the fixed SAH. After, CFD analysis modeling was carried out for SAH outlet temperature values. The SAH outlet temperature values modeled by CFD analysis were compared with the experimental results. SAH outlet temperature value model was modeled by CFD with less than 1% error value for turbulent flow. As a result of the calculations made with experimental data, it was shown that the PLC tracking feature was an important method to use solar energy more effectively on SAH.
International Journal of Green Energy, Volume 18, pp 1613-1631; https://doi.org/10.1080/15435075.2021.1914632
The main objective of this paper is to present a numerical model and simulation of coupled heat and mass transfer of solar dryer with various solar concentrator shapes considering the thermo-physical properties of apricot and climatic conditions of Nancy France. The resolution of the model will permit the prediction of the temperature and humidity of the solar air heater at the collector and drying chamber and also determine the moisture profile during the drying process. The thermal performance of each concentrator design was compared for best performance. A solar dryer with a non-coaxial conical concentrator presented for drying of apricot under the variable external conditions was used for the validation of the model. The numerical results showed a good agreement with experimental data determined for Elazig town Turkey. Numerically the global results were satisfying for moisture content and air temperature for the solar dryers. Parabolic concentrator had comparatively poor drying kinetics when compared with conical concentrators while co-axial design outperforming the non-coaxial design for drying kinetics. When applied in Nancy France environment to dry 30 kg of apricot with an initial moisture content of 3.5 kg/kg (db), lower energy consumption of 8.143 MJ per kg of water removed was determined for non-hybrid drying with non-coaxial conical concentrator while intermittent deployment for 2 MW electrical power consumed more energy with the higher energy of 18.668 MJ per kg of water extracted. For simulation on the environmental condition of Nancy France under the winter, summer, autumn and spring periods drying kinetic were better for drying with 1 MW continuous drying, while drying with 2 MW discontinuous drying performed better in the autumn period. Generally, non – hybrid drying performed poorly compared to others but is more energy utilization efficient compared to others.