Combined Heat Dryer Machine for Food Processing

Abstract

         The objective of this research was to construct a prototype of combined heat dryer machine (solar dryer and hot water) for food processing. The design of the dryer system was divided into 3 parts: 1) a solar radiation co-heating drying cabinet, 2) a hot water tank, and 3) an operating control circuit system. Drying temperature at various locations within the dryer machine were collected every 10 minutes by using a data logger. The controlled temperatures were set at 50, 60 and 70°C, with a constant air flow rate of 0.0012 kg/s.

The results showed that the controlled temperature of 50°C, the average temperature inside the dryer was 45.10°C, while the average ambient temperature was 33.45°C. The average solar energy intensity was 523.22 W/m². At a controlled temperature of 60°C, the average temperature inside the dryer was 54.53°C, while the average ambient air temperature was 36.42°C. The average solar energy intensity was 496.35 W/m². At a controlled temperature of 70°C, the average temperature inside the dryer was 63.67°C, while the average ambient air temperature was 36.90°C. The average solar energy intensity was 841.29 W/m². The maximum thermal efficiency of the solar radiation combined with the hot water dryer was 36.08%, which was higher than that of the traditional solar dryer.