STUDY OF TEMPERATURE CONTROL INSIDE A PARABOLIC SOLAR DRYER USING A THERMOSTAT

Abstract

The use of solar drying equipment for agricultural products offers several advantages, including prolonging product shelf life, better control of product quality in terms of cleanliness and hygiene, and reducing energy costs, thereby increasing farmers’ income. Currently, various
types of solar dryers are available to suit different agricultural products. However, the use of solar dryers without climate temperature control systems during periods of high solar radiation can cause internal temperatures to reach up to 70°C, which may be unsuitable for drying certain products that do not require high temperatures. This research aims to study the use of thermostats to control the speed of the exhaust fan in a parabolic-shaped solar dryer measuring 1.5 x 2.0 square
meters. The control system operates on the following principle: when the internal temperature exceeds the set thermostat temperature, the fan operates at maximum speed to expel hot air. And when the internal temperature drops below the set point, the fan will slow down. The study
was conducted from January 7 to January 19, 2025, with thermostat settings at 30, 35, 40, and 45°C. The results showed that the dryer could effectively control the internal temperature at 40 and 45°C. Therefore, solar dryers equipped with thermostat-based temperature control can be suitable for drying certain products that do not require excessive temperatures while maintaining optimal drying conditions. This control method also ensures more uniform drying processes.