D. Klimenta, M. Jevtic, B. Perovic, D. Tasic, M. Jevtic, J. Klimenta
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This paper proposes procedures for analytical modeling of the heat transfer processes for both laminar and turbulent fl ows from an evacuated tube collector (ETC) and a ground-mounted photovoltaic (PV) panel at tilt angles of 0–90°. Using the data available in the literature for tilted cylinders and plates, appropriate heat transfer correlations are developed using the fundamental dimensionless number for natural
convection. The correlations cover the whole range of Prandtl numbers and they are applied to estimate the heat transfer coeffi cients for natural convection from an ETC and a PV panel, both surrounded by air. The effects of the solar radiation and radiation heat losses from the outer surfaces of the ETC and PV panel are taken into consideration. The fi nite element method (FEM) and available experiments are used
for validation of the analytical procedures. All FEM-based computations are performed using the COMSOL.
Keywords: analytical model, ETC, heat transfer, natural convection, numerical model,
PV panel, tilt angle.
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