Experimental and numerical optimal design of a household solar fruit and vegetable dryer

摘要

In the present study, a low-cost solar fruit and vegetable dryer was designed, constructed, and tested for small-scale production, especially in households. An optimizing procedure was performed to convert a typical widely-used direct cabinet dryer into a new indirect dryer using experimental data and numerical simulations. Several well-designed experiments accompanied by CFD simulations using finite volume method were carried out. It was concluded that the proposed conversion procedure could be achieved utilizing a blackened absorber plate, an air circulating unit, and a honeycomb air manifold. The drying capacity of the dryer could be increased by more than 50% in comparison with the direct type by adding a new tray to the optimized dryer. The thermal efficiency of the proposed solar dryer was estimated 16.4%, indicating that the desirable energy performance of the dryer was superior to some available designs of solar dryers. Besides, it was observed that the proposed numerical approach was able to produce a reliable qualitative and quantitative insight into both the thermal and fluid mechanical behavior of the dryer. Finally, it was claimed that not only was the developed apparatus suitable and efficient for the household usage, but also the optimized version of the dryer could be inspiring for those who are currently using typical direct cabinet dryers to convert their dryers into indirect ones.