Remote Monitoring and Control of Refrigerators Through MQTT Protocol with AES Encryption

Monitoring energy consumption and increasing energy efficiency is one of the most popular topics of today. There are many studies on issues such as instantaneous energy consumption and the detection of devices that consume more energy than necessary. This study focuses on refrigerators that we have at least one in every home and workplace. This number increases even more when other public areas such as hospitals and markets are considered. Refrigerators are one of the devices that have to be constantly connected to power supply and whose energy consumption changes periodically according to the preset temperature value. In this paper we present a system which will provide refrigerator manufacturers with the opportunity to remotely monitor the temperature, humidity, current, voltage and power consumption of refrigerators connected to WiFi in various locations. By using the PZEM-004T module, variables such as temperature and power values as well as energy consumed and power factor can be monitored. Thus, according to the data obtained by refrigerator manufacturers from different points and regions, significant improvements can be made in terms of energy efficiency. In addition, refrigerator users will be able to monitor the operation through a mobile application using BLE (Bluetooth Low Energy) connection, owing to the ESP32 (Hybrid WiFi and BLE) module. Both sides will be able to detect fault conditions such as energy fluctuations, power cuts, temperature rises, and open door in a refrigerator containing critical materials. Furthermore the designed system allows also remote intervention and corrections of certain problematic situations. On the other hand, the sensitive issue of user privacy is also taken into consideration. User privacy is maximized by adding Advanced Encryption Standard (AES) encryption to the Message Queue Telemetry Transport (MQTT) communication, which is frequently used in Internet of Things (IoT) systems but does not have in-built security.