Thermal analysis and performance evaluation of a solar tunnel greenhouse dryer for drying peppermint plants

The obtained data revealed that drying peppermint as leaves reduce the drying time and achieve the highest percent of volatile oil compared with drying whole plants. Drying peppermint at flow rate of 2.10 m3/min, load the greenhouse by about 4 kg/m2 and operate the greenhouse by continuously fan operating system tends to increase the drying rate by 22.78% and 24.8% for whole plants and leaves comparing with periodical system.