Design and performance evaluation of an improved photovoltaic thermal (PVT) collector powered dryer
Date
2022-01
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Federal University of Technology, Owerri
Abstract
This work involves the design, construction and testing of an improved Photovoltaic thermal collector (PVT) powered dryer used in the drying of agricultural products. The setup consists of a 0.989m2 PV panel, an air flow channel modified by fitting twenty curved aluminium vanes, each of height 50mm with a curvature radius of 31mm, thus covering a distance of 37mm from its base, a charge controller, temperature probes, thermo-couple temperature reader, a DC fan, a 12V battery and a 0.078m3 drying chamber constructed using a ply-wood. The PVT collector is formed by the assembly of the modified air-flow channel and the PV panel. The PVT collector outlet is connected to the drying chamber at an angle of 8.48 for maximum harvesting of solar radiation at the test location, with the setup facing due south. Air is drawn beneath the PV panel and subjected to a serpentine flow pattern through the configuration of the aluminium vanes in the air-flow channel. The air flow regime is aided by the use of a DC fan installed directly on the exit vent of the drying chamber thereby enabling the heated air drawn in from the PVT collector to be used for drying 5kg of cassava from the
initial moisture content of 65% to the final moisture content of 15% wet basis. Temperature probes are fitted to the inlet and outlet region of the air flow channel, likewise in the drying chamber and the temperature readings are displayed on the digital thermo-couple temperature reader. The 12V battery powers the fan and the temperature reader during periods of low solar insolation while the charge controller ensures that the battery is continuously charged and at the same time protects the battery from being over charged. The PVT powered solar dryer was tested for a total of thirteen days: five days unloaded test and eight days of loaded test under the meteorological conditions of FUTO from 8:00h to 17:00h daily. The maximum recorded PV surface temperature for the loaded and unloaded tests are 49°C and 50°C respectively. The upper and lower regions of the drying chamber recorded identical maximum temperatures readings of 49°C during the unloaded test which corresponds to an 11°C rise from ambient temperature. Also, during the loaded test, the upper and lower region of the drying chamber recorded maximum temperatures of 47°C and 46°C respectively, corresponding to 9°C and 8°C rise in ambient temperature respectively. The PVT collector recorded an average thermal efficiency of 48.52% while the drying chamber efficiency ranged from 44.96 – 82.72% at a moisture removal rate of 0.07 – 0.21Kg/hr. Therefore addition of the curved aluminium vanes in the air-flow channel has significantly improved waste heat recovery efficiency from PV panel leading to overall PVT powered dryer performance improvement.
Description
A Master's thesis on performance evaluation of an improved photovoltaic thermal (PVT)
Keywords
PVT collector, air-flow channel, drying chamber, temperature, thermal efficiency, drying chamber efficiency., Department of Mechanical Engineering
Citation
Munkailu, A. A. S. (2022). Design and performance evaluation of an improved photovoltaic thermal (PVT) collector powered dryer . (Unpublished Master's Thesis). Federal University of Technology, Owerri.