| Abstrakt: |
The composition, functions, and characteristics of microclimate systems in small greenhouses are analyzed. The features that ensure the creation of favorable conditions for growing plants are identified. It is proposed to choose temperature and humidity as the parameters of priority provision. It is taken into account that modern methods and systems of microclimate of greenhouse facilities are focused on the regulation of air mass flows and heat exchange flows. The aim of the study is to create a mechatronic system for controlling air mass flows and heating elements to ensure heat balance in a greenhouse, taking into account the thermal radiation of the greenhouse object and heat exchange processes in a closed volume. A feature of the approach is a biased algorithm for controlling heat and mass transfer processes based on a daily weather forecast. A computer model of a greenhouse facility has been substantiated and developed, which takes into account heat exchange processes in the greenhouse, heat exchange with the external environment, added heat output by heaters, convection and forced air movement in the greenhouse. The study does not take into account the effect of water vapor on thermal radiation and the mixed convection mechanism inside the greenhouse. To generalize the model, the greenhouse was modeled without plants. Based on the results of the research, a mathematical model of changes in the heat flow of the greenhouse during the day was developed in SOLIDWORKS software. A one-day simulation of changes in air parameters in a greenhouse was performed to forecast the weather in the Kherson region (May 23, 2023). The simulation was based on the design parameters of the greenhouse, an initial temperature of 20 °C in the greenhouse, and an ambient temperature ranging from 14 °C to 20 °C according to the weather forecast. The modeling results were used to determine changes in the heat flux density on the greenhouse surfaces and the total heat output of heat exchange processes. It was found that the obtained characteristics provide an estimate of the total heat transfer coefficient and heat flux of the greenhouse, which served as the basis for determining the required power of heaters and developing a control cyclogram for the greenhouse temperature stabilization system. Based on the results of the model experiment, an operating mode for the heaters was developed. The results of the study and the developed algorithm for controlling heaters are suitable for use in mechatronic microclimate control systems, taking into account daily changes in environmental parameters. [ABSTRACT FROM AUTHOR] |
