Improvement of uniformity in cultivation environment and crop growth rate by hybrid control of air flow devices

摘要

A complete control type plant factory has high efficiency in terms of cultivation area by constructing vertical multiple layered cultivation beds. However, it has a problem of irregular crop growth due to temperature deviation at upper and lower beds and increases in energy consumption by a prolonged cultivation period. In this work, air flow rate inside a facility was improved by a hybrid control of air flow devices like air conditioning and air circulation fan with an established wireless sensor network to minimize temperature deviations between upper and lower beds and to promote crop growth. The performance of proposed system was verified with an experimental environment or Case A wherein air conditioning device was operated without a control algorithm and Case B wherein air conditioning and circulation fans were alternatively operated based on the hybrid control algorithm. After planting leafy vegetables under each experimental condition, crops were cultivated for 21 days. As a result, Case B wherein AC (air conditioning) and ACF (air-circulation fan) were alternatively operated based on the hybrid control algorithm showed that fresh mass, number of leaves, and leaf length for the crops grown were increased by 40.6%, 41.1%, and 11.1%, respectively, compared to Case A.