Proposing novel approach for indirect solar dryer integrated with active-fan and passive-chimney: An experimental and analytical investigation

Solar energy utilizing for drying products was considered the important friendly method to the environment in order to minimize the fossil fuels dependence. With removing the content of moisture, fruits life can be improved and these can be conserved and utilized for long time. Solar technique of drying not evaporates only but provides safe storage and products controlled. The aims of this experimental work were to determine how the proposed design of an indirect solar dryer (Chimney [natural convection] and Fan [forced convection]) influence on the drying performance and the rate of evaporation for drying grapes in Egypt. Compared to open sun solar dryer (OSSD), the dried grape product from the indirect sun drying process (in both cases) is protected from pollution and dust. In addition, the grape samples are dried faster by the recommended indirect SDs than by the OSSD. The results showed that the moisture content (MC) of the grape sample in the chimney-SD dropped from 79.80 % to 14.04 % and for the Fan-SD to 15.83 % during three days of the experiments. In contrast, the average MC for the tray in the OSSD was 70.76 % for the same time. Furthermore, the mean collector thermal efficiency for the Fan and Chimney-SDs was 27.02 % and 29.18 %, respectively. The production costs were estimated at 4.65 $/kg and 4.5$/kg of dried grapes for the Fan and Chimney-SDs, respectively. Finally, The CO2 mitigation were 286.25 kg/year and 337.18 kg/year for the Fan and Chimney-SDs, respectively.