Define exterior thermal conditions in an AEC model

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To prepare for running an AEC simulation in Autodesk CFD, you must first specify the physical characteristics of the model.

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This includes defining boundary conditions, such as external thermal conditions.

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In this example, a boundary condition is assigned to nine exterior surfaces of an office model using an applied U value,

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also known as a film coefficient or convection condition.

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Begin by selecting Boundary Conditions on the Setup tab of the ribbon.

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Left-click the roof surface to select it.

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Next, left-click to select the eight exterior and interior surfaces of the four walls.

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To rotate the model and access the surfaces on the other side, press SHIFT and the middle mouse button, while moving the mouse.

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You should have nine surfaces selected.

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On the Setup tab of the ribbon, in the Boundary Conditions context panel, click Edit.

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In the Boundary Conditions quick edit dialog, expand the Type drop-down and select Film Coefficient,

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the equivalent of a U-value, near the bottom of the list.

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Next, set the Coefficient Units to BTU/ft2/h/R and enter a Film Coefficient of 3.5.

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Verify that the Temperature Units are set to Fahrenheit.

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Then, enter a Ref Temperature of 85.

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Click Apply.

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To verify that the boundary condition is correctly applied to the exterior surfaces,

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in the Design Study bar, ensure that the Film Coefficient condition appears with values of 3.5 BTU/ft2/h/R and 85 Fahrenheit.

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Also, in the graphics window, ensure that the color of the stripes on the exterior surfaces corresponds to the legend.

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With the exterior thermal boundary conditions properly set, the next step is to configure the heat generated by an occupant.