The purpose of this research is to study the thermal efficiency of natural convection.
The working principle of natural convection solar dryer is, once the air in the solar dryer is heated
by solar energy, the air relative humidity will drop and floating up through the drying. This air
will take moisture out of the product and flow out to the ambient air. It was found from the
experiment that, in the duration of 8.00 am – 4.00 pm on a clear sky day, an all-day average
ambient air and inside the chamber temperature were 38.34°C and 63.19°C respectively. At the
solar radiation intensity of 759.53W/m2, mass flow rate of air was 0.023 kg/s and the thermal
efficiency of the solar dryer was 2.59%.