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Multiple Phase Change Materials for Performance Enhancement of a Solar Dryer with Double Pass Collector

Ahmed J. Hamad*, Fawziea M. Hussien, Johain J. Faraj

Engineering Technical College, Middle Technical University, Baghdad, Iraq

* Corresponding Author: Ahmed J. Hamad. Email: email

(This article belongs to this Special Issue: Advanced Materials and Technologies for Sustainable Energy)

Energy Engineering 2021, 118(5), 1483-1497.


The fluctuation in drying temperature influences the food products’ quality and drying time significantly during the drying process using an indirect solar dryer. One of the effective methods to reduce these variations in the temperature is based on thermal storage materials to control the drying temperature. An experimental investigation is presented in this study to evaluate the performance of an indirect solar dryer with air double pass using multiple phase change materials (PCM) as thermal storage materials. Two PCMs with different melting points are used to store the available heat energy during peak sunshine periods and reduce the drying temperature fluctuations. Drying tests on a food product sample are conducted in three cases, the first was without PCMs using natural convection. The second and third cases are based on forced convection with and without using multiple PCMs under Baghdad city conditions. The results showed that; approximately a steady temperature of hot drying air was obtained during relatively low ambient temperatures when the dryer was incorporated with multiple PCMs. The drying time of the product sample for the natural, forced convection without PCMs and forced with PCMs was 87, 72 and 47 h, respectively. The higher performance of the dryer was for the forced convection with PCMs. The reduction percentage in drying time was about 17.2% and 46% for the forced convection without and with PCMs respectively compared with natural convection. The average drying rate for the natural, forced without PCMs and forced convection with PCMs was 0.0093, 0.0135 and 0.0172 kg/h, respectively. The enhancement in thermal efficiency of the solar collector and drying chamber with multiple PCMs was 43% and 25.5%, respectively, compared with a typical solar dryer.


Cite This Article

Hamad, A. J., Hussien, F. M., Faraj, J. J. (2021). Multiple Phase Change Materials for Performance Enhancement of a Solar Dryer with Double Pass Collector. Energy Engineering, 118(5), 1483–1497.

cc This work is licensed under a Creative Commons Attribution 4.0 International License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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