Design and Experimental Investigation of a Novel Solar Crop Dryer

The motivation of this research project was in response to issues of increasing energy demand and the surge in energy scarcity and environmental problem. Various form of fuel like oil, natural gas, wood, and coal etc. can be used for drying process but they are not cheap, and most of them are not environmentally friendly. Renewable energies are one of the promising ways to tackle this global challenge. This work is centered on the investigation solar drying process. A mix-mode solar dryer was designed for drying fruits, vegetables, and biomass. The dryer is made up of a flat plate solar collector, duct fan, two drying chamber module glazed from the top. The flat plate collector of length 200 cm, width 100 cm and height 20 cm was use to preheat the air before entering the drying chamber. The collector is made up of 3mm thick double layer of glass, V-corrugated sheet metal with 60° groove angle. A duct fan is used to provide air circulation. The drying chamber is manufactured from steel, wood, and glass. Different tests were carried out to evaluate the performance of the dryer. The dryer was used to dry apple, banana, grapes and chili pepper. For the different tests carried out the temperature, humidity and solar radiation was recorded to enable evaluation for the performance parameters such as moisture content at the end of each day, drying rate, and drying efficiency. The moisture content of apple, banana, grapes and chili pepper was reduced to their final moisture content within two days of sunshine hours. The average drying rate for apple, banana, chili pepper, and grapes were found to be 30.2 g/h, 82 g/h, 67.8 g/h and 98 g/h respectively per kg of each specimen. Keywords: Solar drying, mix-mode solar dryer, food crop and drying chamber