Thermal performance enhancement of tube-type alternative indirect solar dryer with iron mesh modification

Abstract

Clean and sustainable energy generation is a substantial necessity for developing world. Solar energy is an extensively utilized renewable energy resource and it can be utilized for both electricity and thermal energy generation. Solar thermal applications could be utilized in various processes like space heating and drying. In this study, two cost-effective and simple-structured solar air heaters were designed and manufactured. The first heater is a hollow tube-type heater. Second heater has the same basic properties but iron meshes were added in the flow channel to extend its heat transfer surface area. The mesh modified tube-type heater was manufactured regarding to numerical simulation findings using Ansys Fluent software. Both heaters were integrated with a drying chamber and drying tests were conducted at three air mass flow rates (0.014, 0.011 and 0.009 kg/s). The maximum instantaneous thermal efficiency in iron mesh modified solar heater was obtained as 74.71%. Utilizing mesh modification enhanced thermal efficiency of the tube-type heater up to 11%. Also, the highest values of the average energy efficiency of the drying system was achieved as 50.85% as well in iron mesh modified solar assisted dryer. It is observed that this tubular SAH design is promising in view of renewable hot air generation with its simple and cost-effective structure since it includes no casing, no insulation material and fabricated from sheet metal.