The purpose of this study was to designed and fabricated a 10 kg capacity forced convection solar dryer integrated with thermal energy storage materials, TSMA and TSMB, using locally sourced and low-cost materials for drying agricultural products. The dryer consists mainly of a well-insulated solar collector, drying chamber and photovoltaic components. The maximum collector and drying chamber temperatures obtained from three experiments at no-load conditions with two different thermal and without thermal energy storage materials were 86.2, 91.3 and 80.3 C; and 67.8, 70.8 and 54 C respectively, at the corresponding maximum solar radiations of 716.5, 810 and 724.7 W/m. The recorded minimum drying chamber relative humidity of the solar dryer with TSMA, TSMB and without was 27, 24 and 23% respectively, and the corresponding ambient humidity was 70.8, 56.8 and 56.2%. A full load drying process using cocoa beans with TSMA took two full days, 10 hrs (58 hrs) to reduce initial moisture content of cocoa beans from 0.6 to 0.034 g water/g w.b. The maximum drying temperature and thermal efficiency obtained were 54 oC and 48.8% respectively. The dryer was thus viable for drying products within short time with little temperature control mechanism. RÉSUMÉ. Le but de cette étude était de concevoir et de fabriquer un séchoir solaire à convection forcée d’une capacité de 10 kg qui intègre aux matériaux de stockage thermique, TSMA et TSMB, en utilisant des matériaux locaux et à faible coût pour le séchage des produits agricoles. Le séchoir comprend principalement un capteur solaire bien isolé, une chambre de séchage et des composants photovoltaïques. Les températures maximales des capteurs et de la chambre de séchage sont obtenues de trois tests en conditions sans charge avec deux matériaux de stockage thermique différents et sans stockage thermique étaient de 86,2, 91,3 et 80,3 °C; et qui sont respectivement à 67,8, 70,8 et 54 °C aux radiations solaires maximales correspondantes de 716,5, 810 et 724,7 W / m. L'humidité relative minimale enregistrée de la chambre de séchage du séchoir solaire avec TSMA, TSMB et celle sans eux était respectivement de 27, 24 et 23%, et l'humidité ambiante correspondante était de 70,8, 56,8 et 56,2%. Un processus de séchage à pleine charge des grains de cacao avec du TSMA a pris deux jours complets, 10 heures (58 heures) pour réduire la teneur en humidité initiale des grains de cacao 24 ACSM. Volume 42 – n° 1/2018 de 0,6 à 0,034 g d’eau par gramme de poids corporel. La température maximale de séchage et l'efficacité thermique obtenues étaient respectivement de 54 °C et 48,8%. Le séchoir était viable pour sécher les produits en peu de temps avec peu de mécanisme de contrôle de la température.

methods

Development of solar air heaters & thermal energy storage system for drying applications in food processing industries

Design and fabrication of a forced convection solar dryer integrated with heat storage materials

To increase the efficiency of solar air collectors (SACs), the combined effects of baffles and delta winglet vortex generator (DWLVG) on the performance of SAC have been investigated. An experimental setup has been made, and numerical simulation is carried out in Ansys Fluent. The numerical investigation is validated by the experimental study and focused on the number of baffles as well as the number and the height of DWLVG. The results show that the SAC with no baffles and DWLVG has the lowest efficiency with the maximum value of 13%, while for SAC with six baffles and three pairs of DWLVG, the efficiency reaches up to 20%. The exergy analysis of three cases, SAC without baffles and DWLVG, SAC with six baffles without DWLVG, and SAC with six baffles and three pairs of DWLVG, shows that the maximum exergy efficiency of the SAC is 30.44% and occurs when the height ratio and the number of DWLVG pairs are 0.5 and 3. The results show that for SAC with six baffles and three pairs of DWLVG, the energy and exergy efficiency improve 7.4% and 12% on an average basis compared to the typical flat plate SAC, respectively. This improvement in thermal and exergy efficiency is due to the implementation of DWLVG which produces more turbulence and eliminates the vortices generated at the corners of SAC.

background

Experimental analysis and exergetic assessment of the solar air collector with delta winglet vortex generators and baffles

Performance study of a solar chimney air heater

/pdf/design-construction-and-performance-assessment-of-a-hybrid-52f14f7hua.pdf

Development of solar air heaters & thermal energy storage system for drying applications in food processing industries

Citations

Design and fabrication of a forced convection solar dryer integrated with heat storage materials

Experimental analysis and exergetic assessment of the solar air collector with delta winglet vortex generators and baffles

Performance study of a solar chimney air heater

Design, construction and performance assessment of a hybrid solar dryer using forced convection principle

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