Solar thermal drying performance analysis of banana and peach in the region of Gafsa (Tunisia)

The solar drying of foods is considered among the most important green and sustainable food preservation techniques. The development of efficient solar dryer designs and the investigation of food drying characteristics will improve considerably the food preservation. This work proposes to project a solar chimney-dryer and to pack out an experimental thermal study in order to take the appropriate thin layer drying mathematical models for both banana and apricot. The design, essentially composed of an absorber, a glass and a chimney, is described in detail and its functioning, based on air heating, is clearly explained. The evolution of glass temperature, absorber temperature and chimney temperatures are investigated experimentally. All experiments are carried out under the meteorological conditions (solar irradiance and ambient temperature) of the region of Gafsa-Tunisia (34.4311 degrees N, 8.7757 degrees E) during the days June 05, 2018 and June 07, 2018. The solar thin layer drying of two products (banana and peach) is investigated experimentally for two drying air flow rates. Nine empirical mathematical models that predict the evolution of moisture ratio during the thin layer drying process are presented and compared to experimental results. A nonlinear regression analysis study is carried out to select appropriate models for banana and peach drying.