A comprehensive review on different kinds of solar dryers and their performance

Solar radiation use for drying is one of the oldest applications of solar energy. The high availability of solar energy and the rapid reduction of fossil fuels have attracted much attention to developing large-scale
solar systems. An efficient dryer is able to increase the quality and quantity of the product and reduce the drying time. In fact, reducing energy consumption is an effective way to reduce costs. In general, solar
dryers are low capacity equipment which made based on empirical and quasi-experimental data and theoretical designs. Generally, the drying sector is one of the major energy consumers in the world.
Considering the growth of the energy crisis, reducing energy consumption in this sector by using solar  energy can guarantee the containment of this global crisis. One of the biggest benefits of solar energy is
its endlessness and its full availability, but its disadvantages can be the absence of this energy during night and difference in its amount in different hours of the day. Design of hybrid solar dryers and using of
energy saving batteries containing phase change material can be used to solve the above mentioned disadvantages. To solve this problem, energy-saving batteries containing phase-change material can be
used to store additional daily heat and use it during the night. In this paper, different drying methods and a different kinds of solar dryers will be described. The special solar panels and solar complexes used in
drying and the methods of connecting different solar dryers are also reviewed. The latest applied examples are also presented.