Browsing by Author "Olagunju, Titilope Modupe"

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    Open Access
    Development of absorption solar dryer with internet-based control system
    (Department of Agricultural and Environmental Engineering, Faculty of Technology, Obafemi Awolowo University., 2023) Olagunju, Titilope Modupe
    This study investigated the effect of different adsorbent filters on the relative humidity of air and selected the most appropriate filter. This study also developed and evaluated an IoT-based control system for possible use in solar dryers. An existing solar dryer was modified by introducing the selected absorbent filter and the developed IoT control system. The performance of the modified solar dryer was evaluated and optimised by determining the effect of the drying kinetics of ginger slices on the quality of the dried products. These were with a view to enhancing the efficiency and effectiveness of the operation of solar dryers. The optimum specification of moisture adsorbent filter was obtained for four adsorbent materials (activated clay, activated charcoal, calcium sulphate, and silica gel). The data obtained for the effect of pack thickness, suction fan speed, and inlet air temperature on the air desiccation performance of the absorbents was fit in polynomial models and optimised to select the best moisture filter. IoT-based control unit was designed using the Arduino Uno microcontroller, which was interfaced with temperature, humidity, and weight sensors, which were programmed to detect and transmit sensors data to cloud server. The selected absorbent filter as well as the developed control system were then incorporated into the existing mixed-mode solar dryer, and the effect of this modification on the drying kinetics of ginger slices was investigated using response surface methodology. Responses such as total time of active drying and equilibrium moisture content were used as performance indicators of the modified dryer. The optimal conditions for the operation of the dryer, was established and the quality (proximate, phytochemicals and colour) of ginger dried at optimum condition was also determined using standard experimental procedures. The results obtained indicate that silica gel was the most effective adsorbent filter under optimal conditions of 2.03 cm layer thickness, with no requirement for the suction fan. The temperature and relative humidity sensors of the control system were effective, with average accuracies of 98.84% and 96.23%, respectively. However, the weight sensor had an average accuracy of 80.04%. This indicated that the load cell used in the study was sensitive to heat, which adversely affected its accuracy. The performance of the modified solar drying system indicates that the modification significantly aided the drying process of ginger slices, with the best drying conditions being an adsorbent layer thickness of 0.5–1.5 cm and an air velocity of 0.5–2.5 m/s. These conditions resulted in the shortest drying time and a final moisture content of 9.83 to 12.14% wb, which is recommended for safe storage of dried ginger. Nevertheless, the most desirable optimum condition for operating the modified solar dryer was found to be an air velocity of 2.5 m/s and an adsorbent thickness of 1.22 cm, which resulted in a final moisture content of 10.72%. The modification of the dryer significantly influenced the proximate and phytochemical composition of ginger slices. This study concluded that the use of an optimised adsorbent filter and an IoT-based control system can significantly improve the drying process, reduce postharvest losses, and enhance the quality of dried agricultural products.
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    Open Access
    Development of an Adsorption Solar Drying with Internet of Things- Based Control System.
    (Department of Agricultural and Environmental Engineering, Faculty of Technology, Obafemi Awolowo University., 2023) Olagunju, Titilope Modupe
    This study investigated the effect of different adsorbent filters on the relative humidity of air and selected the most appropriate filter. This study also developed and evaluated an IoT-based control system for possible use in solar dryers. An existing solar dryer was modified by introducing the selected adsorbent filter and the developed IoT control system. The performance of the modified solar dryer was evaluated and optimised by determining the effect of the drying kinetics of ginger slices on the quality of the dried products. These were with a view to enhancing the efficiency and effectiveness of the operation of solar dryers. The optimum specification of moisture adsorbent filter was obtained for four adsorbent materials (activated clay, activated charcoal, calcium sulphate, and silica gel). The data obtained for the effect of pack thickness, suction fan speed, and inlet air temperature on the air desiccation performance of the adsorbents was fit in polynomial models and optimised to select the best moisture filter. IoT-based control unit was designed using the Arduino Uno microcontroller, which was interfaced with temperature, humidity, and weight sensors, which were programmed to detect and transmit sensors data to cloud server. The selected absorbent filter as well as the developed control system were then incorporated into the existing mixed-mode solar dryer, and the effect of this modification on the drying kinetics of ginger slices was investigated using response surface methodology. Responses such as total time of active drying and equilibrium moisture content were used as performance indicators of the modified dryer. The optimal conditions for the operation of the dryer, was established and the quality (proximate, phytochemicals and colour) of ginger dried at optimum condition was also determined using standard experimental procedures. The results obtained indicate that silica gel was the most effective adsorbent filter under optimal conditions of 2.03 cm layer thickness, with no requirement for the suction fan. The temperature and relative humidity sensors of the control system were effective, with average accuracies of 98.84% and 96.23%, respectively. However, the weight sensor had an average accuracy of 80.04%. This indicated that the load cell used in the study was sensitive to heat, which adversely affected its accuracy. The performance of the modified solar drying system indicates that the modification significantly aided the drying process of ginger slices, with the best drying conditions being an adsorbent layer thickness of 0.5–1.5 cm and an air velocity of 0.5–2.5 m/s. These conditions resulted in the shortest drying time and a final moisture content of 9.83 to 12.14% wb, which is recommended for safe storage of dried ginger. Nevertheless, the most desirable optimum condition for operating the modified solar dryer was found to be an air velocity of 2.5 m/s and an adsorbent thickness of 1.22 cm, which resulted in a final moisture content of 10.72%. The modification of the dryer significantly influenced the proximate and phytochemical composition of ginger slices. This study concluded that the use of an optimised adsorbent filter and an IoT-based control system can significantly improve the drying process, reduce postharvest losses, and enhance the quality of dried agricultural products.