An Experimental Investigation Of Thermal Desiccant System Integrated With Solar Dryer For Low Energy Dehumidification Process /

Abstract

Drying agricultural products requires a huge amount of energy and the daily increasing price of fuels and the depleting conditions of fossil fuels turned our attention toward renewable energy resources. Solar energy is a gift from God to our country in which almost 300 out of 365 days we receive a tremendous amount of solar radiation. Because of the sinking economy and fluctuation of oil prices worldwide despite putting extra pressure on our import bills it’s the best solution to shift to solar energy to cope with this issue. Pakistan being an agricultural country produces a considerable amount of fruits and vegetables each season. But the problem lies with their transportation, spoilage wastage in different ways like insects, etc. So with keeping all these above-mentioned problems an indirectly forced convection desiccant integrated solar dryer was fabricated and tomatoes which are of huge importance in our day-to-day life were dried. The fabricated system was tested outside the thermal shed located at USPCASE NUST H-12 Islamabad. The system consisted of a solar flat plate collector, drying chamber, solar panel blowers, desiccant bed, solar charge controller, and battery. To increase reflection parabolic reflectors were also used and placed above the drying chamber supported with the help of screws. Experiments were performed during sunshine hours and with the integration of desiccants drying was also conducted during off sunshine hours. With the help of solar panel blowers and battery was charged and during off sunshine hours’ experiments were carried out by powering the blowers with the help of the battery. The products were weighed before and after every mode of solar drying during two days period with the help of electric balance. The moisture removal was also calculated at the end of each mode of drying. Similarly, dryer efficiency was calculated with the help of data. The temperatures were measured with the help of 12 channel data logger. The moisture removed after two days of experiments was 56% and overall dryer efficiency was 44%.