Study on the effect of conical and parabolic solar concentrator designs on hybrid solar dryers for apricots under variable conditions: A numerical simulation approach

ABSTRACT

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.

KEYWORDS:

• Heat mass transfer
• solar drying
• hybrid solar dryer
• modeling
• apricot
• nancy

Highlights

*Three conical and parabolic solar concentrators were studied for drying of apricot;

*Heat and mass transfer of hybrid and non-hybrid solar dryers were modeled and simulated;

*The model was validated using data obtained from Elazig (Turkey);

*The performances of the solar dryers using the conical solar concentrator in Nancy (France) were presented.