Exergy analysis of a PVT system having fins in air cooled channel
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Date
2021-03
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Photovoltaic thermal (PVT) systems are systems are used to generate electrical energy and remaining energy lost as heat. One of the most critical parameters influencing the performance and life of PV panels is the temperature of photovoltaic (PV) cells. Higher cell temperature increases the waste heat that is not extracted, thus cell voltage/power decreases with an increase in cell temperature. By cooling the solar cell with a fluid stream like air/water/nano fluids, the electricity conversion can be increased. In addition to this, heat energy can be used for other applications such as space heating, drying of agricultural products, paint spraying and related processes. In present work, exergy analysis is done for a solar PVT system having fins in an air-cooled channel attached at the back of the PVT system. For this a 3-D numerical model is developed. Numerical simulations are achieved using ANSYS-Fluent software. The comparative study of air cooled channels with fins and without fins are performed considering two mass flow rates of air of 0.0085 kg/s and 0.0137 kg/s. The parameters such as panel temperature, inlet and outlet air flow temperatures in the air cooling channels are analyzed. Effect of duct depth on the panel temperature, thermal efficiency and exergy efficiency is analyzed. Also, roughness of the duct and fins surfaces on the panel temperature, thermal efficiency and exergy efficiency is analyzed. The results of the PVT system showed considerable improvement in thermal performance with using fin in air cooled channel. The maximum thermal performance observed 8.54 % at a mass flow rate of 0.0085 kg/s and 15.24 % at a mass flow rate of 0.0137 kg/s for the air cooled channel with fins. Subsequently, the maximum exergy efficiency was attained as 3.73 % at a mass flow rate of 0.0085 kg/s and 8.14 % at a mass flow rate of 0.0137 kg/s in air cooled channel with fins. However, the increment in duct depth decreases the thermal efficiency decreased by 0.6 % and exergy efficiency decreased by 0.5%.