Testing outcomes of IoT based continuous crop weight and PAR sensors at industrial greenhouse
¹Riga Technical University, Institute of Industrial Electronics and Electrical Engineering, Azenes 12, LV-1048 Riga, Latvia
²SIA ‘Latgales darzenu logistika’ greenhouse, Kloneshniki, Mezvidi parish, Ludza region, Latvia
Industrial greenhouses have automated control systems for climate, lighting, irrigation, ventilation, and heating regulation using different types of feedback sensors. Nowadays it is a trend to increase the data precision and measurement data amount, thus various additional IoT sensors are installed, and the regulation becomes more precise, due to available data, which enables new analytical features to create new control rules or strategies. The general aim is to raise the level of process automation, quality, energy efficiency, and other important parameters. Still, further, we go into data resolution and amount, and the problem of data reliability and interpretation starts to become a challenging problem. In this article, authors focus on earlier developed PAR sensor modules and continuous tomato crop weight sensor modules (TWS) testing and received data analysis from an industrial greenhouse. Both sensors were tested in detail at the tomato greenhouse of ‘Latgales Darzenu Logistika’ in Mezvidi parish, with a total growing area of 5,062.4 m2 from 1.05.2022 to 30.06.2022., and gathered data is analysed for this period. Received sensor data can be used as the main feedback signal to create a lighting control strategy, same time increasing energy efficiency and reducing also costs. As artificial lighting energy consumption costs make 20–40% of total greenhouse costs, it is worth having a more precise lighting control system algorithm, integrating the crop growth increase and accumulated light energy during the day from the sun, and then adding only the missing amount (also period) of light provided by artificial lighting. Experimental studies of both sensor data, show that plants reaction can be monitored, as by decreasing the lighting period and temperature setpoint by 6% each, the plants daily weight gain decreases by 14%, and it can be measured already in first day after the new settings were set in place.