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Keywords: heat transfer, computational fluid dynamics, photovoltaic, solar heat gain, heatflow network.

Summary

Free standing photovoltaic modules were investigated to determine how the flow field and the heat transfer coefficients arise in this case. Free standing modules were used in many cases where big arrays are required, and its very similar to modules mounted on large flat roofs.

The efficiency of photovoltaic (PV) devices decreases as the module's temperature increases as a result of that part of the solar irradiance which is not converted into electricity. The placement of the PV modules has a great affect on the natural cooling, due to wind flow-around and the buoyancy driven flows. The effect of the environmental parameters (temperature, irradiation, wind) on the performance of one type of PV module with dimensions 1245 x 637 x 10 mm in terms of the cell temperature and heat transfer coefficient has been determined numerically. The dimensions of the flow field are 20 x 10 m, large enough to obtain the flow already developed near to the modules. The simulation grid was built up using triangular elements and a prism layer at the wall of the modules, to calculate the near-wall flows properly. The PV modules were defined as solid in the calculations with one domain, so we made a thickness weighted average of the density, heat conductivity and of the specific heat capacity. In view of the flow field and the heat transfer, which was calculated numerically, the heat transfer coefficients can be determined. Five inflow rates were set up to determine the trend of the heat transfer coefficient, while this function can be used for the Matlab/Simulink model. To model the free convection flows, the Boussinesq-approximation was used, integrated into the two-dimensional RANS equations and the energy equation.

The surface heat transmission factor of the modules placed in the given environment was defined from the calculations. It has been found that under a constant solar heat gain, the air velocity around the modules increases, proportionately to the wind velocities, and as result the heat transfer coefficient increases linearly.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 94 PROCEEDINGS OF THE SEVENTH INTERNATIONAL CONFERENCE ON ENGINEERING COMPUTATIONAL TECHNOLOGY Edited by: Paper 132 Numerical Determination of the Heat Transfer of Free Standing Solar Modules I.E. Haber¹ and I. Farkas² ¹Department of Information Technology, University of Pécs, Hungary ²Department of Physics and Process Control, Szent Istvan University of Godollo, Hungary doi:10.4203/ccp.94.132 purchase the full-text of this paper Full Bibliographic Reference for this paper I.E. Haber, I. Farkas, "Numerical Determination of the Heat Transfer of Free Standing Solar Modules", in , (Editors), "Proceedings of the Seventh International Conference on Engineering Computational Technology", Civil-Comp Press, Stirlingshire, UK, Paper 132, 2010. doi:10.4203/ccp.94.132 Keywords: heat transfer, computational fluid dynamics, photovoltaic, solar heat gain, heatflow network. Summary Free standing photovoltaic modules were investigated to determine how the flow field and the heat transfer coefficients arise in this case. Free standing modules were used in many cases where big arrays are required, and its very similar to modules mounted on large flat roofs. The efficiency of photovoltaic (PV) devices decreases as the module's temperature increases as a result of that part of the solar irradiance which is not converted into electricity. The placement of the PV modules has a great affect on the natural cooling, due to wind flow-around and the buoyancy driven flows. The effect of the environmental parameters (temperature, irradiation, wind) on the performance of one type of PV module with dimensions 1245 x 637 x 10 mm in terms of the cell temperature and heat transfer coefficient has been determined numerically. The dimensions of the flow field are 20 x 10 m, large enough to obtain the flow already developed near to the modules. The simulation grid was built up using triangular elements and a prism layer at the wall of the modules, to calculate the near-wall flows properly. The PV modules were defined as solid in the calculations with one domain, so we made a thickness weighted average of the density, heat conductivity and of the specific heat capacity. In view of the flow field and the heat transfer, which was calculated numerically, the heat transfer coefficients can be determined. Five inflow rates were set up to determine the trend of the heat transfer coefficient, while this function can be used for the Matlab/Simulink model. To model the free convection flows, the Boussinesq-approximation was used, integrated into the two-dimensional RANS equations and the energy equation. The surface heat transmission factor of the modules placed in the given environment was defined from the calculations. It has been found that under a constant solar heat gain, the air velocity around the modules increases, proportionately to the wind velocities, and as result the heat transfer coefficient increases linearly. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £125 +P&P)
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