Re: [EnergyPlus_Support] Multiple sys/common return, deep daylighting ?s

[Rob Hitchcock <RJHitchcock@xxxxxxx>]

Regarding your question #2 on daylighting: The daylighting calculation 
in EnergyPlus *does* account for daylight passing through interior 
windows in interior walls.  This would allow you to place a window wall 
at the boundary of your thermal zone, and define a daylighting zone in 
the "interior" thermal zone.  A complication is that this "virtual" 
window wall, dividing the open office plan into different thermal zones, 
will influence the heat balance within what are now two zones.  But this 
is also true for the case where you place what you refer to as an "air 
wall" to separate your thermal zones.

Perhaps someone with more insight into the impact of your "air wall" on 
thermal zone heat balance calculations can respond to this issue in more 
detail.

Rob Hitchcock
========
Kristin Field wrote:

> Hello, EP folks. Two questions for you:
>
> (1) A proposed underfloor & displacement air system will utilize
> multiple VVT systems, which share a common return plenum and shaft.
> Can this be modeled explicitly in E+ using air nodes (roomair or
> other)? The designer claims that during heating the return
> temperatures in the core will be higher than on the perimeter. As the
> perimeter VVT systems provide warm air directly they can utilize all
> warmth in the RA to reduce the heat added to the SA, so it is
> important to have a valid determination of this mixed RA temperature,
> and to have distinct systems with separate SA temperature control on
> each perimeter. Any advice on whether and/or how this could be
> implemented in EP?
>
> (2) One situation we struggle with regularly is the daylighting
> calculation where the daylit zone is deeper than the thermal zone.
> This is typical in large open office configurations, with very tall
> daylight glass (or light-redirecting devices) and dimming ballasts
> installed to the interior. The daylight zone may be 30' deep, but the
> thermal zone is typically only 15' deep. The zones are separated in
> the model by an air wall. Is there a way to explicitly model daylight
> which passes into this interior zone, without declaring "virtual"
> exterior walls & windows, etc., at that 15' boundary? I remember that
> daylight doesn't pass through interior windows, but I'm wondering if
> there's another way to get it to cross through zones.
>
> Thanks for your help!
>
> Kristin Field
>
> 




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