In this study, three distinct and unique modes of greenhouse drying are introduced: solar, solar-exhaust gas, and exhaust gas modes of drying. The effect of drying black nightshade seeds in the three modes was studied, using germinability as a measure of quality. In solar mode, seeds were dried from a moisture content of 89.34% (db) to 7.13% (db) with the greenhouse dryer room air temperature range of 14.82-58.46°C and relative humidity of 9.40-88.03%. In solar-exhaust gas mode drying was performed from 92.57% (db) to 6.07% (db) within a temperature range of 34.49-61.97°C and relative humidity of 7.10-39.27%. In exhaust gas mode black nightshade seeds were dried from an initial moisture content of 88.84% (db) to a final one of 9.42% (db) when the greenhouse dryer room air temperature ranged from 25.75 to 30.77°C and relative humidity inside the dryer was between 51.88 and 83.98%. The results show that exhaust gas drying mode had a difference of 12.5% when its mean germination percentage was compared to solar mode of drying. Moreover, a 16.2% difference in means of germination percentage was recorded when solar-exhaust gas mode of drying was compared to exhaust gas mode. The highest mean germination percentage was recorded at 89% for exhaust gas drying mode because black nightshade seeds were subjected to temperatures ranging from 25.75 to 30.77°C. Modified Giner’s model predicted germination changes of black nightshade seeds more accurately than modified Sharp’s model due to the higher coefficient of determination (0.6896 > 0.6853) and lower root mean squared error (6.1554 < 6.4519). The activation energy in the modified Giner’s model was found to be 7.034×1033 Joule/mole through model fitting to experimental data. In conclusion, it is recommended that the feasibility of exhaust gas energy use in drying be expanded to seeds of other African vegetable crops. Keywords: Black Nightshade Seeds Viability, In this study, three distinct and unique modes of greenhouse drying are introduced: solar, solar-exhaust gas, and
exhaust gas modes of drying. The effect of drying black nightshade seeds in the three modes was studied, using germinability as a measure of quality. In solar mode, seeds were dried from a moisture content of 89.34% (db) to 7.13% (db) with the greenhouse dryer room air temperature range of 14.82-58.46°C and relative humidity of 9.40-88.03%. In solar-exhaust gas mode drying was performed from 92.57% (db) to 6.07% (db) within a temperature range of 34.49-61.97°C and relative humidity of 7.10-39.27%. In exhaust gas mode black nightshade seeds were dried from an initial moisture content of 88.84% (db) to a final one of 9.42% (db) when the greenhouse dryer room air temperature ranged from 25.75 to 30.77°C and relative humidity inside the dryer was between 51.88 and 83.98%. The results show that exhaust gas drying mode had a difference of 12.5% when its mean germination percentage was compared to solar mode of drying. Moreover, a 16.2% difference in means of germination percentage was recorded when solar-exhaust gas mode of drying was compared to exhaust gas mode. The highest mean germination percentage was recorded at 89% for exhaust gas drying mode because black nightshade seeds were subjected to temperatures ranging from 25.75 to 30.77°C. Modified Giner’s model predicted germination changes of black nightshade seeds more accurately than modified Sharp’s model due to the higher coefficient of determination (0.6896 > 0.6853) and lower root mean squared error (6.1554 < 6.4519). The activation energy in the modified Giner’s model was found to be 7.034×1033Joule/mole through model fitting to experimental data. In conclusion, it is recommended that the feasibility of
exhaust gas energy use in drying be expanded to seeds of other African vegetable crops.
Keywords:
Black Nightshade Seeds Viability, Solar-Exhaust Gas Greenhouse Dryer, Exhaust Gas Energy