How we can change interior floor reflectivity of the building model in the eQuest?

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Dear Friends,

I want to change interior floor reflectivity of the building model in the
eQuest. To do this I am opting to detailed edit model and going to " EL1IFLr
Construction " but there shows ext. colour ( abs).

So my question is - How we can change interior floor reflectivity of the
building model in the eQuest?

Thanks,

Nimesh Prajapati

Thanks, Nimesh Prajapati (+91 9687133492) Design Engineer & Energy Modeller
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Joined: 2012-03-03
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Dear Nimesh,
Select the emissivity of the surface and then use the below table for inside
film resistance value in surface construction> layers tab in terms of inside
film resistance that shows the reflectivity of the surface faces to inner
side of the space.

Regards
Uday Kumar
INSIDE-FILM-RES
Specifies the combined convective and radiative air film resistance for the
inside wall surface. The default of 0.68 hr-ft2-F/Btu (0.1198 m2-K/W) is an
appropriate value for vertical walls. For horizontal surfaces, such as
ceilings and floors, the suggested inside film resistance can be found in
Table 12 . Because only one value is allowed
for each surface, you should decide which is more important, cooling or
heating.
For radiant barriers having a low-emissivity surface (for example, aluminum
foil or insulation with aluminum coating) facing the interior of the space,
select the emissivity from Table 13 and
then determine the INSIDE-FILM-RES value by interpolating the e=0.09, e=0.20
and e=0.05 columns of Table 12 .
Table 12
INSIDE-FILM-RES values for position of surface, direction of heat flow and
insidesurface emissivity.

Position of surface

Direction of heat flow
Surface emissivity

0.90*
0.20**
0.05***

Ceiling in the heating mode
or Floor in the cooling mode

Horizontal
Up
0.61 (0.11)
1.10 (0.19)
1.32 (0.23)

45( slope
Up
0.62 (0.11)
1.14 (0.20)
1.37 (0.24)

Vertical
Horizontal
0.68 (0.12)
1.35 (0.24)
1.70 (0.30)

45( slope
Down
0.76 (0.13)
1.67 (0.29)
2.22 (0.39)

Ceiling in the cooling mode
or Floor in the heating mode

Horizontal
Down
0.92 (0.16)
2.70 (0.48)
4.55 (0.80)

*Regular building materials: wood, masonry, non-metallic paints, paper
**Polished aluminum coated paper, for example
***Bright aluminum foil, for example

If you cannot decide which is more important, cooling or heating, you can
use the average of the heating and cooling values. For exterior walls and
roofs, the outside-film-resistance is calculated by the program depending on
wind speed. For interior walls, the air film described in INSIDE-FILM-RES is
the film on the side of the wall that is in the SPACE where the wall is
specified. For the calculation of the U-Value of an INTERIOR-WALL, the
INSIDE-FILM-RES is duplicated on the other surface (opposite side).
Table 13 IR Emissivity of Different Interior Surfaces

Surface
Emissivity

Aluminum foil, bright
0.05

Aluminum sheet
0.12

Aluminum coated paper, polished
0.20

Steel, galvanized, bright
0.25

Aluminum paint
0.50

Regular glass
0.84

Building materials
(wood, masonry, non-metallic paints)
0.90

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Nimesh,

For opaque surfaces the absorptivity is 1 - reflectivity.

For transparent objects, the incoming light is partially reflected, partially absorbed, and partially transmitted through. The total for each of those equals the whole...reflectivity + absorptivity + transmissivity = 1. For opaque objects transmissivity is zero, so you get absorptivity = 1 - reflectivity.

Keith Swartz, PE, LEED AP

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Nimesh,

I misunderstood your question. I believe you are looking for the interior reflectivity instead of the exterior reflectivity (absorptivity), which is shown in your screenshot.

In the Building Shell module double-click on the desired floor surface. If it's on the ground floor, click on the "Daylighting - Solar" tab. There you will find "Inside Visible Reflectance" in the top field.

[cid:image003.png at 01CDA78B.0B1FF970]

If it's on a higher floor, click on the "Surface Properties" tab, where you will find "Inside Visible Reflectance" in the middle field.

[cid:image004.png at 01CDA78B.8FB97080]

Keith Swartz, PE, LEED AP

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