Research On The Intelligent Greenhouse Monitoring And Control Based On Agricultural IoT And CFD Simulation

Agricultural Internet of Things provides a new idea for the monitoring and control of agri-cultural production environment.It can realize the intelligent,networked and precise manage-ment of agriculture.It is one of the key technologies to realize agricultural modernization.The intelligent greenhouse system based on agricultural Internet of things,can realize the monitor-ing of the greenhouse environment through the network,and can implement accurate green-house control according to crop environmental requirements.Then,it can achieve the scientific and efficient management of greenhouse.Greenhouse simulation based on the CFD solves the problem of modeling and analysis of complex greenhouse environment,which can provide the theoretical basis for the optimization of sensors distribution and optimization of control strategy in the intelligent greenhouse system.By analyzing the special needs of greenhouse monitoring and reference to the Internet of Things standard architecture,this paper propose an intelligent greenhouse architecture based on agricultural Internet of Things,and design the intelligent greenhouse monitoring and con-trol system based on this architecture.The sensing control layer is based on the Zig Bee and RS485 sensor network and computer control module,and is optimized for reliability,scalabil-ity,flexibility and low power consumption.The network transport layer supports a variety of data transmission and synchronization mechanisms,and is optimized for security,reliability and efficiency.The network transport layer establishes the hub of the system layers.The application layer includes the data center,WEB server and intelligent strategy learning control subsystem.The application layer provides a cloud storage solution based on Hadoop and My SQL for the massive greenhouse history data,and provides a high availability and maintenance-free cloud server and an optimal control strategy based on the CFD simulation model.The terminal access layer using WEB front-end technology and React Native system provides a user interface.The intelligent greenhouse monitoring and control system were deployed and tested in the experimental greenhouse.The results show that the system meets the expected design require-ments and the actual production requirements.The wireless sensor network is stable and reli-able,the data sampling is accurate and stable,the delay of synchronization is low,the control orders is issued quickly and accurately,the control status acquisition is accurate and stable.The data center is working fine,and there is no slow queries or exceptions.The cloud WEB services is running stably,the API responds quickly,the returned data is complete and accurate.Aimed at the requirement of summer mechanical ventilation optimization for the typical multi-span plastic greenhouse in southern China,a full-scale 3-D transient and steady CFD model was established.By using the intelligent greenhouse monitoring system,the variation and distribution of temperature in the greenhouse under the various mechanical ventilation con-ditions were measured.The veracity and validity of the model for transient and steady simulation are verified by the comparison between the experiment and simulation results.Under the high ambient temperature,the CFD model was carried out to investigate the impact of design param-eters,such as the number of working fans,the length of greenhouse,the inlet temperature and the ambient environment temperature,on the cooling effect of the mechanical ventilation.And then,the cooling effect under different control strategies of mechanical ventilation were simu-lated to reduce the energy consumption.According to the simulation results,the distribution of monitoring points and the summer mechanical ventilation control strategies were optimized.After the analysis of the CFD simulation results,the system can monitor the whole green-house environment of 1280 m~2 with at least 5 monitoring points using the optimized distribution of monitoring points.It effectively reduce the number of monitoring points and the monitoring cost.And the optimized control strategy of the system can reduce the energy consumption by about 60%,while the average temperature of plant canopy only increases by 0.21℃,which effectively improves the cooling efficiency of mechanical ventilation and reduces the energy consumption.The intelligent greenhouse monitoring and control system based on the architecture of this paper has flexible node arrangement,wide monitoring range,low power consumption,high relia-bility,strong stability and flexible expansion,can meet the intelligent and scientific management requirements of the greenhouse.Combined with CFD simulation analysis,the optimized moni-toring point distribution can effectively reduce the monitoring cost,and the optimized mechani-cal ventilation control strategy can effectively realize the energy saving and emission reduction.The system can also realize the centralized interconnection of the greenhouses in the different areas to build the agricultural big data and Io T platform.The system is of great significance to the agricultural scientific research and engineering control,and it is helpful to improve the level of agricultural modernization and promote the development of agricultural internet of things.