light tubes and light wells

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Hi,

I'm trying to model a light tube and a light well in eQuest. I'd like to
bring light into the core and maybe a lower level and have this reduce the
lighting required.

so, I create a window in the roof, change the window to "Tubular
Daylighting device" and have a daylighting sensor in the space below (a
core zone).
But there is no effect on the lighting energy. This is the same if I use a
skylight (aka a light well).

Has anyone used this successully?

thanks
Norm

norman wheatley's picture
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Norm,
Is your simulation going through successfully? Typically, just creating
a skylight in an existing roof (which I am guessing is currently
attached to your core plenum space) gives you an error.
You will have to create a new roof for the core space, use 'Skylt Roof
Construction' as the construction, and then create the skylight in this
new roof. See if this works.
Regards,
Umesh

Umesh Atre's picture
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Umesh/Norm:

An extra thought: Don't count on daylight moving between/across
spaces... If your window is in roof surface that's a child of a plenum
space, I believe the light will only be measurable in the plenum for
daylighting control purposes.

An approach for detailed mode that may be instructive for core spaces
remote from the exterior: If your core space does not already have an
exterior surface defined, you will want to create one to host the
window. It could be a wall/roof... don't think it really matters. Play
with this exterior surface's location/dimensions/orientation until it is
situated above and parallel to your roof surface above, then create a
window within this remote exterior surface. Light should then "jump" to
the core space, bypassing any plenums or other spaces along the way.

Best of luck!

~Nick

NICK CATON, P.E.

Nick-Caton's picture
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I was thinking exactly along the lines of Nick - if you have a plenum you need to create a dummy roof to house you light tube. Just another thing to add - the wall that you host this light tube on is going to behave like it was a roof to the space (in terms of conductance) so you probably want to create a material that makes it close to adiabatic (high R-value material)

Vikram Sami, LEED AP BD+C

Sami, Vikram's picture
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Vikram & Nick, you are both correct.
I suggested creating the new roof surface with the 'Skylt Roof
Construction' (this is a construction in the library with U-value
0.001), and
attaching it to the core space vs the plenum for the same reasons that
you mention.
Thanks

Umesh Atre's picture
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