Abstract:
Coal as a bulk cargo has the potential to undergo spontaneous heating (self-heating) due
to oxidation processes influenced by temperature and humidity inside the cargo hold. On
board MV. Bulk Batavia, cargo condition monitoring is still conducted manually and
periodically, resulting in temperature and humidity fluctuations that are not observed in
real time. Previous studies have generally focused on IoT-based monitoring systems in
warehouses or land-based storage facilities, while the implementation of real-time and
continuous monitoring systems for coal cargo on ships remains limited. Based on this
condition, this study aims to design an Internet of Things (IoT)-based monitoring system
to measure coal cargo temperature and humidity in real time and continuously in order to
detect early symptoms of self-heating and maintain cargo quality during the voyage.
This research employed a Research and Development (R&D) approach using a prototype
model through stages of needs analysis, design, development, implementation, and
evaluation. The system was developed using an ESP32 microcontroller, a PT100
temperature sensor integrated with the MAX31865 module, an SHT31 humidity sensor,
an I2C LCD, a buzzer as an alarm indicator, a 5V cooling fan, and the Blynk application
for remote monitoring. Testing results showed average temperature and humidity changes
of 7.44 °C and −4.4%, respectively, in charcoal briquette simulations, and 6.24 °C and
−3.2% in heat gun simulations. The threshold test confirmed that the system automatically
activated the alarm when the temperature exceeded 55 °C with a 100% success rate and
no false alarms or error. A four-hour stability and endurance system test demonstrated low
standard deviation values of 0.33 °C for temperature and 0.89% for humidity, indicating
minimal fluctuations and stable sensor readings without significant deviation, as well as
stable Blynk connectivity without data loss. Validation results indicated a feasibility score
of 98.67% from nautical and IoT experts and 95.8% from 20 nautical cadets, both
categorized as “Highly Appropriate.”
This research demonstrates that the designed IoT-based monitoring system satisfies
functional, technical, and operational criteria as an early warning system for detecting
initial signs of self-heating and preventing the degradation of coal cargo quality through
real-time and continuous monitoring of temperature and humidity in the cargo hold.
Future work is recommended to include the integration of gas sensors, the implementation
of backup power systems, and the addition of visual indicators at critical temperature
thresholds to enhance monitoring effectiveness in ship operational environments.
Keywords: Coal; Humidity; Internet of Things; Self-heating; and Temperature.