Techno-economic comparison of selected solar dryers: A case study

The basic design of most commonly used solar dryers displaying varying fundamental principles of heat and mass transfer were compared with recently commercialized and patented design of Solar Conduction Dryer. Bottle gourd of 100 kg by mass, having an initial moisture content of 80% from which 77.78 kg of water was required to be removed to get the desired moisture content of about 10%, was used as drying load. The performance of various solar dryers were analyzed on the basis of three criteria, namely, the annualized cost, the present worth of annual savings, and the present worth of cumulative savings. The economic analysis shows that the present cumulative worth of annual savings for drying bottle gourd over the dryers lifetime works out to be 42,294, 23,027, 55,451, 58,740, and 37,594 USD for the case of solar tunnel dryer, solar cabinet dryer, solar conduction dryer, corrugated solar conduction dryer and corrugated and electrically backed solar conduction dryer, respectively. The economic parameters of interest, such as the payback period and the internal rate of return of dryers were also estimated. The analysis shows that the corrugated solar conduction dryer (CSCD) gives the best performance as compared to the rest of the solar dryers when compared on the basis of economics and product quality attributes.