[Equest-users] U value (Building envelope Construction)

[pranita kothuru]

I am  re-phrasing my question:

* *

*In "Building Envelope Constructions" window (3 of 25) I put an Overall
R-Value of 30 h-ft2-°F/Btu...*

*But, when I go into the .inp file in the roof construction details, I see a
U Value of 30 Btu/h-ft2-°F!?*

*It is not the same thing!*

* *

*Does it mean I enter the U value though eQuest is asking for R-value (DD
wizard). *

*Why is eQuest not converting the R-value entered to U-value.*

* *

*Please let me know.*

* *

*Thanks in advance!*


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On Tue, Oct 12, 2010 at 3:15 PM, Alex Krickx
<akrickx at seriousmaterials.com>wrote:

>  Hi Pranita,
>
>
>
> U-value is the inverse of R value. A U-30 is the equivalent of R-0.03.
> Likewise, if you have an R-30 roof, you would have a U-(1/30) = U-0.03. Is
> it possible you entered in R-value where you were meant to enter U? I would
> check, and maybe try to change what you’ve entered.
>
>
>
> Be careful about which units you’re using, though. I think the wizards use
> IP units, but the INP file has metric? Not sure.
>
>
>
> Good luck!
>
> Alex
>
>
>
>
>
> Alex Krickx
>
> Building Energy Specialist
>
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> 1250 Elko Dr, Sunnyvale, CA 94089
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> (t) 408.541.8124
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> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *pranita kothuru
> *Sent:* Tuesday, October 12, 2010 11:47 AM
> *To:* equest-users
> *Subject:* [Equest-users] U value (Building envelope Construction)
>
>
>
> Hello All -
>
> I don't know whether I am understanding the R value input in eQuest in the
> way its supposed to be.
>
> In the Building Envelope Constructions *(3-25) in the DD Wizard:*
>
> Construction: Custom, layer by layer construction
>
> Layer-by layer: Arena Roof (name of the roof I have created)
>
> In the layer by layer window I use the 'Specify Resistance' (under the spec
> method) option and insert the overall R value of the roof directly below in
> the box.
>
> When I go to the.inp file, I see the following -
>
> "EL1 Roof Construction" = CONSTRUCTION
>    TYPE             = U-VALUE
>    U-VALUE          = 30
>    ABSORPTANCE      = 0.6
>    ROUGHNESS        = 1
>
> It says the U -value is 30 which is really low. Am I missing something here
> in understanding the U-value and R value. (I have inserted the r value as 30
> not the U value)
>
> Thank you for your comments in advance.
> --
>
> *Pranita.*
>
>
>



-- 

*Pranita Kothuru
*

'The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it.' Michelangelo
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