Re: [EnergyPlus_Support] Interior windows, opaque surfaces

[Rob Hitchcock <RJHitchcock@xxxxxxx>]

Regarding Interior Window Solar:

"Initial Transmitted Diffuse Solar Transmitted Out through Inside of 
Window Surface" is only the diffuse solar initially transmitted through 
exterior windows that is then incident on and transmitted out through 
another window in the zone (either to the outdoors for an exterior 
window or to an adjacent zone for an interior window).  You will need to 
sum this value for all interior windows into the zone of interest.

For the adjacent zone on the other side of an interior window, you 
should then add "Zone Beam Solar from Interior Windows" to account for 
the beam solar that entered a zone through an exterior window and was 
then incident on and transmitted through interior windows into the 
adjacent zone.  This radiation is considered diffuse once it has been 
transmitted through an interior window.

And, you should also add "Zone Diff Solar from Interior Windows", which 
is the combination of beam and diffuse solar that first entered a zone 
through an exterior window, was subsequently reflected from interior 
surfaces in that zone (becoming diffuse through that reflection), and 
then transmitted through interior windows into the adjacent zone.  In 
answering this question I have realized that this output variable is 
incorrectly defined in the EnergyPlus Input/Output Reference as of 
Version 2.1 when the treatment of diffuse solar distribution was modified.

Rob
=======
coolshadow10a wrote:

> Why does Opaque Surface Inside Face Conduction not balance out over
> the course of a few days? Am I understanding correctly that this
> variable represents basically the energy transferred into a mass each
> time step? If all my opaque surfaces are adiabatic, shouldn't the
> energy balance of those surfaces remain within a reasonable margin?
>
> Interior windows:
>
> Solar through interior windows
> - From previous commentary, it was suggested to use Initial
> Transmitted Diffuse Solar Transmitted Out through Inside of Window
> Surface to get a measure of solar that has entered through exterior
> windows and is falling on/passing out through an interior window.
> This value is associated with an interior window. But it is much less
> than would be expected. It appears to be only the diffuse portion of
> solar through the exterior windows that passes out through the
> interior window. How can I get a measure of the full solar load on
> the interior zone (and thus a measure of the performance of the
> interior window)
> - Zone Diff Solar From Interior Windows gives a value much closer to
> what is expected, but I was cautioned about this variable previously.
> What are the caveats to using this value to analyze solar gains
> through interior windows?
>
> Window Heat Gain
> - This is defined in the docs as solar plus conductive for an Exterior
> window, but there are values for interior windows as well. For
> interior windows, this value is mostly less than the expected value
> for solar that should be coming through that window even when Tout is
> much higher then Tin. The solar component seems to be NOT part of
> interior Window Heat Gain values. Can this then be taken as
> conductive loads through interior windows? If not, any suggestions
> for calculating conductive loads through an interior window?
> - Window heat gain and window heat loss values do not balance out
> across adjacent window surfaces. Not even close. Is solar discounted
> at some point in the generation of these variables?
> - Zone Window Heat Gain is always Zero for interior zones, even though
> interior window Window Heat Gain is non-zero.
>
> Thanks,
> r3
>
>  




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