Articles
ENVIRONMENTAL CONTROL AND OPERATION MONITORING IN A PLANT FACTORY USING ARTIFICIAL LIGHT
Automation of the environmental control and operation monitoring was attempted, and the following results were obtained.
The environmental conditions were controlled by an ON/OFF operation using a programmable controller.
Under lighting conditions of 16 hrs/day and intensity of 330–650 μE/m2/s, the temperature was kept in the range of 25 + 0.5 °C in light period / 20 + 0.2 °C in dark period, humidity of 70 + 5 %. CO2 concentration of 900 + 50 ppm, and wind velocity of 0.5 + 0.1 m/s were regulated.
The electric conductivity (EC) and pH of the hydroponic solution were adjusted to 1.3 + 0.1 mS and 5.5 + 0.5, respectively.
Under the above conditions, the growth of lettuce was accelerated, and the fresh weight increased to about 75 g in 29 days after the germination.
At this time, power consumption for lighting and total power consumption were respectively about 1.1 kwh/plant and 2.5 kwh/plant.
Thus, light power and total power consumption became about 50% and 20% less than that of the conventional facility using high pressure sodium lamps by the close lighting method with fluorescent lamps.
Furthermore, by the automated the data processing system and remote monitoring system, labour for data processing was saved remarkably.