why Fin or Overhang Projection impact are not similar than shading objet ?

asked 2019-10-25 10:54:38 -0500

Lefort-Antoine gravatar image

updated 2019-10-27 10:15:47 -0500

Hello,

I've studied the impact of "Shading:Overhang:Projection" and ""Shading:Fin:Projection". I have set tilt angle to 90°and the fractions of window door equal to 1 and I compare it to manual shading objects similar to projection description. The result are not equal and I wondering why ?

Secondly I have detected than using depth shading element have a big impact on solar window transmitted value ?!


Results:

Variable "Zone Windows Total Transmitted Solar Radiation Energy" image description

Detail of models/simulations: Energyplus version 9.2 Manual shading object : "Shading:Building:Detailed"

Simulations is on a simple model without control or uses.

Building,
 in.idf,                        ! Name
 0.0,                           ! North Axis
 suburbs,                       ! Terrain
 0.04,                          ! Loads Convergence Tolerance Value
 0.4,                           ! Temperature Convergence Tolerance Value
 fullexterior,                  ! Solar Distribution
 25,                            ! Maximum Number of Warmup Days
 6;                             ! Minimum Number of Warmup Days

ShadowCalculation, 
 AverageOverDaysInFrequency,
 20,  
 15000, 
 SutherlandHodgman, 
 SimpleSkyDiffuseModeling;

Shading:Overhang:Projection,
 opening|double_pane_window_oh_1|s-4j63bdze2|overhang,    ! Name
 s-4j63bdze2,                   ! Window or Door Name
 ,                              ! Height above Window or Door
 90.0,                          ! Tilt Angle from Window/Door
 ,                              ! Left extension from Window/Door Width
 ,                              ! Right extension from Window/Door Width
 1.0;                           ! Depth as Fraction of Window/Door Height 

Shading:Fin:Projection,
 opening|double_pane_window_fin_1|s-4j63bdze2|fin,    ! Name
 s-4j63bdze2,                   ! Window or Door Name
 ,                              ! Left Extension from Window/Door
 ,                              ! Left Distance Above Top of Window
 ,                              ! Left Distance Below Bottom of Window
 90.0,                          ! Left Tilt Angle from Window/Door
 1.0,                           ! Left Depth as Fraction of Window/Door Width
 ,                              ! Right Extension from Window/Door
 ,                              ! Right Distance Above Top of Window
 ,                              ! Right Distance Below Bottom of Window
 90.0,                          ! Right Tilt Angle from Window/Door
 1.0;                           ! Right Depth as Fraction of Window/Door Width

image description image description image description image description

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Comments

Hello everyone, I investigated the problem and it seems that there is a problem with horizontal shade.

I compare manual flate shade impact with two geometry's rule convention: clockwise and counterclockwise (I manage the vertex order). The result is : with clockwise convention the solar tranmistted is twice reduce than with counterclokwise convention ! I suppose problem is with counterclockwise convention. In my previous post, the thickness of the shade block has big impact. It expect that because vertical shades have impact while it must not.

Lefort-Antoine gravatar imageLefort-Antoine ( 2019-11-19 02:38:27 -0500 )edit