ISEC2005-76140 ......(5)

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NUMERICAL STUDY OF CONJUGATE HEAT TRANSFER IN A BIPV-THERMAL SYSTEM(5)

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    Based on experimental measurements, the flow has been established as two-dimensional and primarily turbulent. This situation is expected to be representative of practical application of the systems shown in Fig. 1. The system in Fig. 1 includes a motorized blind in the double fa-ade cavity above the PV section, but this portion of the system is beyond the scope of this paper. The air flow cavity has width, L=0.092m and height, H=1m as shown in Fig. 2. The outside air is drawn from the bottom inlet of the cavity and the air intake temperature is measured. The flow is assumed to be quasisteady. The PV panel is heated by the solar radiation and cooled by the air flow in the cavity so its surface temperature is a function of the height. The right hand surface in Fig. 2 is assumed to be adiabatic (thermal insulation) but exchanges heat with the PV through longwave radiation. A control volumebased finite difference method is used to simulate the flow region in the cavity. The realizable k-ε model employed by FLUENT [8] is utilized with constant fluid properties except for the buoyancy term of the momentum equations, where the Boussinesq approximation is used to account for the density variation. The full buoyancy effect is also considered in the k-ε turbulent model. For the longwave radiation heat transfer, view factors and radiosity are computed and it was assumed that the surfaces are gray-diffuse and the fluid is transparent to radiation. Since detailed analysis is desired near the boundaries, a finer grid is employed in those regions in addition to the enhanced wall treatment that is utilized for the k-ε turbulent model.绿色建筑博客l N"?!o$o q@;u&Zf

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