Scalable Solar Energy Monitoring with Message Queuing Telemetry Transport (MQTT) and Node-RED

Abstract

This study presents the design and implementation of a scalable, secure, and robust Internet of Things (IoT) based solar photovoltaic monitoring system utilising the Message Queuing Telemetry Transport (MQTT) protocol integrated with Node-RED. The methodology employed a systematic approach comprising architectural design, simulation validation, security implementation, and performance evaluation. The system architecture incorporated MQTT brokers for efficient publish-subscribe messaging and Node-RED for data processing and visualisation, with security implemented through Advanced Encryption Standard (AES-256) encryption. System performance was evaluated through MATLAB simulation using real solar Photovoltaic data. Results demonstrated exceptional voltage monitoring (18.5V-22.5V, standard deviation 0.87V), current measurements (0.2A-4.8A, temporal resolution ~500ms), power output calculations (3.7W-108.5W, error margin <1.2%), and solar irradiance monitoring (100-985 W/m²) with a strong correlation coefficient of 0.93 between irradiance and power output. The system maintained a 99.87% uptime with bandwidth consumption of only 4.2 KB/s during peak transmission and minimal packet loss (0.07%). The findings confirmed that MQTT/Node-RED integration provides significant advantages for IoT-based solar monitoring, including reduced bandwidth requirements, minimal data loss, and responsive alerting capabilities (average notification time of 2.3 seconds), addressing critical gaps in existing monitoring solutions.