[Updated on Apr. 18] Integration of CiNii Articles into CiNii Research

太陽熱利用による穀物の人工乾燥(I): ビニ-ルハウスを集熱器としたもみの通風乾燥


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1)This Study was conducted in order to attain much reduction of the petroleum required for grain drying, the consumption of which is now the largest in all grain producing processes. A new drying method, whereby solar energy is directly used as much as possible, was employed.2)This grain drying method making use of solar energy is as follows: Flat bed type forced-air dryers are placed in a 90㎡ green house which is used as a solar collector, and heated air is sucked through grain layers to be exhausted out of the green house. Experiments were conducted in 1980 and 1981 in order to study whether such a solar dryer system has a drying rate and a drying capacity large enough to be incorporated into the existing mechanized harvesting and processing operation system in our country.3)In 1980, drying experiment using one flat bed type placed in the house mentioned above was performed to learn what degree of drying rate attained by utilizing solar heated air in the house only. As a result, it was found that final drying of raw paddy is accomplished within a short period of time, that is, within a day or so when drying is performed on fine days.4)In 1981, drying experiment was performed, using 3 flat bed type forced-air dryers placed in the house mentioned above, to study how much time is needed to dry a certain amount of raw paddy. As a result, it was found that final drying of 4 tons of such paddy can be accomplished in one or two weeks inclusive of rainy days, though both harvesting and drying operations are greatly affected by the weather. It is estimated that by full use of this equipment, final drying of 14 tons of such paddy harvested from 3 ha of paddy field can be accomplished satisfactorily in 45 days in the proper harvesting period from mid-September to the latter part of October.5)Mean moisture reduction rate representing the drying rate was 0.71%/h as the average of measurements in 1980. In 1981, it was 1.0-1.5%/h on fine days and 0.5%/h on fine days and 0.5%/h on cloudy days, and 0.44%/h as the average of measurements obtained in total forced-air drying time inclusive of rainy days.On the other hand, the collector efficiency of the house as defined by the formula (1-7) was 14.1%as the average in 1980 and 24.4% as the overall average value in the experiment in 1981.6) With regard to the relationships between cumulative solar radiation, quantity of heat delivered by solar system and amount of evaporated grain moisture in the experiment in 1981, it was found that these were nearly in a proportional relation as shown in Fig.1-12



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