Machines of Industrial Drying Systems


solar air collector

A solar dryer is an enclosed unit, to keep the food safe from damage, birds, insects and unexpected rainfall. The food is dried using solar thermal energy in a cleaner and healthier way. Basically, there are four types of solar dryers;

    1- Direct solar dryers – in these dries the material to be dried are placed in a transparent enclosure of glass or plastic. The sun heat he material to be dried and enclosure causes a heat build up due to the “green house effect” the drier chamber is usually painted black to absorb the maximum amount of heat.



    solar collector for drying





    Picture: A Solar air collector for using method:2

    2-Indirect Solar Dryers – in these dryers, sun does not act directly on the material to be dried, thus making them useful in the preparation of those crops whose vitamin content can be destroyed by sunlight; the products are dried by hot air heated by the sun.

    3-Mixed Mode Driers – in these dryers the combined action of solar radiation incident on the material to be dried and the air preheated in solar collector provide the heat required for the drying operation.

    4-Hybrid solar dryers – in these dryers, although sun is used to dry products, other technologies are used to cause air movement in the dryers. Example fan powered by solar

solar air collector for dryers