Investigation of the drying parameters at the drying system with natural convection supported with solar energy

Investigation of the Drying Parameters at the Drying System with Natural Convection Supported with Solar Energy In this study, two different drying systems supported with solar energy with natural convection are designed and manufactured to realise the drying process of apple and pepper in Elazığ. Effect on drying behavior of solar radiation, wind velocity, relative humidity, temperature and product dimensions is examined at these drying systems and at drying process realised with laying method at the external environment conditions. At the end of experimental studies first moisture contents of dried products at the drying systems and the external environment conditions, and variations in the moisture content at the certain time periods are determined and then, humidity rate are calculated. The corelation of the values of resolvable humidity rate obtained by analysis and experimental study is examined by analysis and experimental study is examined by regression analysis. Consequently, the equations of resolvable humidity rate theoretically developed are obtained using the curve fitting method as time depedent. As a results, it is seen that relative humidity decreases, reduction in the moisture content of dried products increases and drying time decreases when the temperature of drying air increases. In the period realised of drying process, it is determined that the temperature values obtained in the drying systems increase depending up on values of increasing solar radiation. It is seen that reduction in the moisture content decreases and drying time increases as thicknesses and weights of dried products increase. The results show that absorber surfaced dryer is better than drying process external environment conditions and dryer having tubular collector. In absorber surfaced dryer, moisture contents of apples are reduced averagely from %86 to %7.9 while moisture contents of peppers are reduced averagely from %94.5 to %8.21. Temperatures in the dryer are obtained between 43.2°C and 55.9°C in the drying of apple while they are obtained between 41.6°C and 56.5°C in the drying of peppers. Key Words: Natural Convection, Regression Analysis, Relative Humidity, Dryer