Abstract
•Experimental investigation of single-slope greenhouse dryer with solar absorber north wall.•Effects of employing graphene nanoplatelets in black paint on thermal and drying performance.•Drying time was reduced between 75 and 90 min with north wall modifications.•Exergy efficiency was improved from 2.70% to 5.38% with the use of nano-enhanced north wall.
Greenhouse drying systems are sustainable and clean applications for preserving agricultural crops. In this work, a single-slope greenhouse drying system has been modified with solar absorber and thermally insulated north wall. Also, the designed and manufactured north wall has been coated with graphene nanoplatelet-embedded black paint. Greenhouse dryers with north wall and nano-embedded north wall modifications have been experimentally compared with a conventional greenhouse dryer. Main goal of this research is to upgrade the performance of a greenhouse drying system without using any auxiliary heating device and complex structural components. According to the experimental outcomes, drying time was reduced as 75 and 90 min by utilizing north wall and nano-enhanced north wall, respectively. Furthermore, exergy efficiencies of greenhouse dryers with north wall and nano-enhanced north wall were attained as 4.67% and 5.38%, respectively while this value for conventional greenhouse dryer obtained between 2.61 and 2.70%. Moreover, utilizing graphene nanoplatelets in black paint improved the specific moisture extraction rate as 40% in comparison to conventional greenhouse dryer.