Experimental and CFD survey of indirect solar dryer modified with low-cost iron mesh

•Numerical and experimental analysis of adding mesh modification to the absorber plate.•Iron mesh modification of absorber plate increased collector efficiency up to 10%.•Effect of mesh modification on the performance of double-pass indirect solar dryer.•Determination and comparison of quality characteristics as TPC, TFC and ABTS. In the present work, double-pass indirect solar dryer (DPISD) and double-pass indirect solar dryer with mesh absorber modification (DPISDMA) have been designed, analyzed, manufactured and tested. The main aim of this study is improving the thermal efficiency of double-pass solar air collector by integrating iron meshes. Pepino fruit (Solanum muricatum L.) samples in two thicknesses have been used in the experimental study. Also, CFD analysis of both solar air collectors and drying chamber and quality metrics such as phenolic, total flavonoid contents and antioxidant activity have been conducted. Numerical simulation and experimental results showed that using mesh modification has positive influence on the performance of the collector. The highest value of the average efficiency of the dryer was obtained in DPISDMA for the thin sample thickness as 23.08%. According to quality analyses, the experiments which done in DPISDMA gave the best results with highest values of TPC, TFC and antioxidant activity values (p