Enhancing cooling efficiency of pottery clay with rice husk for IoT- enabled off-grid water cooling system

Soil, widely available and known for leveraging the principles of evaporative cooling, has been historically used in pottery-based cooling systems. Enhancing the efficiency of cooling, soil requires improved porosity and water absorption capacity, which can be achieved by incorporating burnout additives like rice husk. Rice husk, an agricultural by-product, is abundant and environmentally problematic when discarded or burned, making its utilization in soil a sustainable solution. This research underscores the potential of rice husk-enhanced pottery soil combined with IoT technology as a transformative solution for eco-friendly and intelligent water-cooling applications. The study investigates to enhance the evaporative cooling efficiency in pottery soil through the integration of rice husk as additives. Soil samples are sourced from three distinct geographical locations in Bhubaneswar, Odisha, and characterized based on their geotechnical and physical properties, including porosity, and water absorption capacity, that directly influence the evaporative cooling. The research aims to determine the optimal soil-rice husk composition for maximizing cooling efficiency. Experimental earthen containers are fabricated with varying rice husk and sand proportions, fired at 1300 °C, and subjected to controlled water-cooling tests. For the research, an IoT-based temperature monitoring system, employing DS18B20 sensors and ESP32 microcontrollers, record temperature variations to assess performance. The results indicate that soil from a site is identified with its higher porosity and water absorption capacity, exhibited superior evaporative cooling efficiency. Containers made with 30 % rice husk of the total content demonstrate improved cooling performance due to enhanced porosity and water absorption capacity. The optimized soil composition is further implemented in an IoT-enabled dynamic flow earthen water-cooling system to evaluate continuous cooling performance. Integrated IoT sensors monitor and regulate key parameters such as water temperature, water level of the earthen chambers, and water flow rate, ensuring optimal cooling performance in real-time. The system cool water from 32.5 °C to 20 °C in 4 min and 18 s with a 3 % evaporation rate. In this research, IoT has been implemented for monitoring and regulation; however, it can be excluded in practical applications, with solar power integration ensuring operation without dependence on grid electricity. This system is highly useful in resource-limited areas, as it offers an eco-friendly, passive alternative for water cooling without relying on advanced infrastructures.