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Re: [EnergyPlus_Support] Interior windows, opaque surfaces
David,
I see non-zero values for "Zone Beam Solar from Interior Windows" in my
runs. Be sure you are requesting this for the interior zone, and that
you are looking at days and times when direct beam solar through the
exterior window can hit the interior window (e.g., winter low sun angles
for south-facing windows in the northern hemisphere).
"Zone Diff Solar from Interior Windows" as of Version 2.1 is only the
diffuse solar that has been reflected from interior surfaces in the
exterior zone before being transmitted through the interior window into
the adjacent zone. So it is no longer analogous to the above variable
for beam solar. Request this for the same interior zone as "Zone Beam
Solar from Interior Windows".
Whereas "Initial Transmitted Diffuse Solar Transmitted Out through
Inside of Window Surface" is the diffuse solar transmitted through an
exterior window that is incident on, and then transmitted through, an
interior window. Request this for the interior window that is hosted by
the interior wall in the exterior zone (i.e., not the interior window
from the interior zone side).
Clear as mud, right?
Rob
========
David Scheer - L+U wrote:
> Rob.
> Thanks, but not quite sure I understand the naming convention, and my
> results have always been at odds with that description:
>
> "Zone Beam Solar from Interior Windows" is a variable for the interior
> zone, correct? It reports the component of beam solar that falls on
> the outside of the interior zone window that enters the zone (entering
> as diffuse and being distrubuted to all interior surfaces). I don't
> think this variable is implemented yet, as it has always been, and
> still is Null in all my models.
>
> I am running FullInteriorAndExterior.
>
> "Initial Transmitted Diffuse Solar Transmitted Out through Inside of
> Window Surface" - for an interior zone with only one window onto an
> exterior zone, this value associated with the interior window in the
> adjacent exterior zone should be the same as "Zone Diff Solar from
> Interior Windows" for the interior zone, less absorbed radiation,
> correct? This is not at all the case (it is about 25x larger), thus my
> assumption that "Zone Diffuse Solar from Interior Windows" also
> included beam solar, which is considered diffuse when passing though
> the second window and is therefore called Diffuse, though a bit
> misleadingly. In any case, the total of all the "Zone Diff..." values
> is much larger than the total Window Transmitted Diffuse Solar into
> the exterior zone.
>
> Also, a hand calc of exterior Window Transmitted Solar (beam and
> diffuse) through the SHGC of the interior window yields approximatly
> the same value as Zone Diff Solar from Interior Windows.
>
> What about "Initial Transmitted BEAM Solar Transmitted Out through
> Inside of Window Surface"? Since this variable doesn't exist, I was
> assuming that the beam component was considered in the Diffuse
> variable because it was considered diffuse after it passed through a
> second window.
>
> Other things:
> - The variable "Beam Sol Amount from Ext Windows on Inside of Surface"
> is Null for the interior window that is definitely in full sun. Same
> for "Beam Sol Intensity from Ext...." Same for "Window Solar Absorbed
> All Glass Layers", which is more expected for interior windows.
>
> At some point these numbers have to add up.
>
> Thanks.
> r3
>
> ----- Original Message -----
> From: Rob Hitchcock
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> Sent: Wednesday, May 21, 2008 5:16 PM
> Subject: Re: [EnergyPlus_Support] Interior windows, opaque surfaces
>
> 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
> >
> >
>
> [Non-text portions of this message have been removed]
>
> [Non-text portions of this message have been removed]
>
>
--
Robert J. Hitchcock, Ph.D.
Lawrence Berkeley National Laboratory
1 Cyclotron Road, Mailstop 90-3111
Berkeley, CA 94720
RJHitchcock@xxxxxxx
530.295.9433 (telecommute office)
[Non-text portions of this message have been removed]
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