Abstract
Four systems of automatic ventilation control for tobacco curing plastic house were studied in 1976 and in 1977.
Tobacco leaves were harvested and hanged at intervals of 5 days and proceeded to be air-cured for 10 days in each plastic house.
The ventilator operation was controlled by the dry-bulb temperture (35°C) at the house No. 1, by the wet-bulb temperature (31°C) at the house No. 2, by the dew point (30°C) at the house No. 3 and by the dew point (28°C) in 1976 and by the relative humidity (75%) in 1977 at the house No. 4.
Results obtained were as follows:
1. Dried leaves had normal appearance but different smoking taste in these four systems. The leaves with normal taste were only obtained by the dew point control at 30°C.
2. Precise control was performed by the dew point control and wet-bulb control. Proper ventilation was not operated in the daytime but the humidity stayed at the level lower than the aim at the house of relative humidity control.
3. The ratio of evaporative energy to total effective solar radiation at the house of dense hanging was higher than that at the house of thin hanging, and decreased in accordance with the number of curing days or the moisture contents of tobacco leaves.
4. The ratio has a practical meaning at the decision of reasonable hanging density.
