Thermal evaluation of a multipurpose solar dryer

Abstract

Solar drying of food is one of the oldest methods of preservation and is used both naturally and with specialized equipment. This study aimed to evaluate the
thermal performance of a multipurpose solar dryer with a capacity of 12 m³, located at the Solar Energy Research Center (CIES), built in the 1980s and
currently operating under conditions different from its original design. Temperature measurements were taken in the drying chamber using an infrared
camera to obtain thermal profiles and calculate the heat transfer coefficient, comparing it with the values reported during the design stage. Measurements
were conducted with the ventilation system turned off and in operation. The results showed maximum temperatures of 79,8 °C without ventilation and
73,7 °C with ventilation, highlighting the regulating effect of the ventilation system on the thermal behavior of the dryer. An approximate increase of 6 °C in
the temperature of the material being dried was observed when the ventilation was active. The obtained heat transfer coefficient indicated that the current
thermal efficiency of the equipment is 98.8% compared to the design efficiency, suggesting that the dryer maintains thermal performance close to its original condition and does not require structural modifications from a technical-economic perspective.