Assessment of a heat storage system within an indirect solar dryer to improve the efficiency and the dynamic behavior

The development and performance analysis of an indirect solar dryer (ISD) was investigated. The whole system studied was integrated with a heat storage system in form of copper tubes filled with PCM, placed in the side-mounted plenum chamber. The Ansys Fluent software was used to predict the thermal and the dynamic behavior of the solar dryer, under the meteorological conditions of Oujda city (Eastern of Morocco), in order to study the solar dryer realistically. To do so, a subroutine code written in C++ was integrated into Ansys Fluent. The effect of PCM tubes on the dynamic and thermal behavior was investigated, as well the effect of the number of tube layers, and the effect of different phase change materials that have different properties. A new concept of dryer efficiency is introduced in this paper, based on the temperature required to dry the product. The results showed that the solar dryer with a heat storage system increases the efficiency by about 3.12% at night compared to the case without storage. Regarding the multiple materials studied, the Paraffin RT58 showed a better performance, where the temperature differences between the two cases with and without PCM reach 11 degrees at night.