The Design and development of an IoT-integrated solar water-heated drying system for macadamia nuts

Abstract

This paper presents the design, development, and testing of an IoT-integrated solar-powered macadamia nut drying system for small to medium-scale farmers. Utilizing a solar water heating system as the primary heat source, it switches to grid electricity as needed. IoT technology allows real-time monitoring and control of temperature, humidity, hot water flow and the moisture content of the macadamia nuts, optimizing drying while conserving energy. The dryer was evaluated over three days in the rainy season in Vietnam’s Highlands, comparing performance with and without IoT control. The results indicated that without a set temperature threshold, chamber temperatures reached 42.1°C and 45.1°C on days one and two, respectively. However, with a temperature threshold set at 38°C on the third day, chamber temperatures stabilized between 37.5°C and 39°C from 10:08 to 19:27, leading to a 16.7% reduction in energy use compared to the first day. Testing with 5.04 kg of macadamia showed energy savings of 32.6% compared to traditional electric dryers, even in cloudy conditions, while maintaining high drying quality and reducing costs. This innovation boosts efficiency and supports sustainable agriculture.