Design Of Environmental Monitoring System For Railway Reefer Container

With the improvement of living standards,cross-regional shopping is becoming more popular,hence how to preserve the freshness and quality of refrigerated food has become one of the hot issues of concern.Railroad refrigerated container transportation is a significant part of national cold chain transportation,which is characteristic of wide coverage and long distance and is significant for the real-time monitoring of refrigerated containers.In the internal environment monitoring of China’s railroad refrigerated containers,the traditional detection method is to place temperature sensors at the entrance and exit of the refrigerated containers.However,as the box is too long,the temperature between the air supply and return of the cooling device has a certain difference,sometimes able to reach 4 ～ 5 ℃.Hence the room temperature measurement method of the single-point chiller does not accurately and practically respond to the temperature and humidity inside the container,resulting in the deterioration of refrigerated goods.In order to realize real-time monitoring of the internal environment temperature and humidity of refrigerated containers,a remote monitoring system of the internal environment of railroad refrigerated containers based on the ZigBeenetwork and LoRa network is developed.The railroad refrigerated container internal environment remote monitoring system studied in this paper integrates embedded technology,ZigBeewireless communication technology,LoRa wireless communication technology,Bei Dou positioning technology,4G wireless communication technology,and other key technologies.ZigBeeself-organizing network has six built-in collection points to collect temperature and humidity information inside the reefer container,which can reflect the temperature and humidity inside the reefer container in a three-dimensional and accurate way.The collected temperature and humidity data are transmitted to the core microprocessor in the driver’s room through the LoRa module for point-to-point wireless communication.The core microprocessor also has an external Bei Dou module to obtain location information and real-time response to the running status of the train.The temperature and humidity data inside the reefer container are uploaded to the cloud through the 4G module,thus realizing remote monitoring of the environment inside the reefer container.The remote monitoring system adopts modular design,including temperature and humidity data acquisition module,power management module,Bei Dou/GPS positioning module,4G module,ZigBeeand LoRa.The remote monitoring system for the internal environment of railroad reefer containers studied in this paper is conducive to the intelligent management of cold chain transportation.And IIC,SPI,and serial ports are reserved in the data acquisition module for monitoring system expansion and improvement of functions.