Summer vs Winter UValues

[Faron Morris]

LBNL,

I have modeled a vision unit and spandrel shadow box in Window and find the following:

The vision unit summer uvalue (0.26) is lower than the winter (0.29).  But the reverse is true for the spandrel:  winter uvalue (0.065) is slightly lower than the summer (0.068).

I would expect both summer uvalues to be lower than both winter uvalues.  Why isn't this the case?  Does it have to do with the multiple air spaces in the spandrel versus just one in the vision?  Something else?

Regards,

Faron

PS.  I'm trying to attached .pdf output but isn't letting me.  Will try posting then replying with the attachment.

[Faron Morris]

Here's the output.  Still won't let me attach a file.  Faron

Window v6.3.72.0 Glazing System Thermal and Optical Properties 12/05/13 11:10:51

 

ID      : 3

Name    : Winter - Spandrel

Tilt    : 90.0

Glazings: 4

KEFF    : 0.0653

Width   : 7.008

Uvalue  : 0.065

SHGCc   : 0.08

SCc     : 0.10

Vtc     : 0.00

RHG     : 19.99

 

 

Layer Data for Glazing System '3 UValue - Spandrel'

ID     Name            D( ") Tsol  1 Rsol 2 Tvis  1 Rvis 2  Tir  1 Emis 2 Keff

------ --------------- ----- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----

Outside

  6046 VE12M.VIR      #0.223 .383 .286 .449 .792 .060 .047 .000 .840 .040 .578 

       1 Air           0.540                                                   

   103 CLEAR_6.DAT    #0.225 .771 .070 .070 .884 .080 .080 .000 .840 .840 .578 

       1 Air           3.440                                                    

 30004 0.125" Alum Pan 0.125 .000 .001 .001 .000 .001 .001 .000 .900 .200 92.4 

       1 Air           0.375                                                   

 30001 2" insul + alum 2.080 .000 .001 .001 .000 .001 .001 .000 .900 .900 .021 

Inside

 

 

Environmental Conditions: 1 NFRC 100-2001

          Tout   Tin  WndSpd   Wnd Dir   Solar  Tsky  Esky

          (F)    (F)   (mph)            (Btu/h-ft2)  (F)

         -----  ----  ------  --------  ------  ----  ----

Uvalue    -0.4  69.8   12.30  Windward     0.0  -0.4  1.00

Solar     89.6  75.2    6.26  Windward   248.2  89.6  1.00

 

 

 

Temperature Distribution (degrees F)

        Winter         Summer

       Out   In       Out   In

      ----  ----     ----  ----

Lay1   0.5   0.6    130.3 133.8  

Lay2  14.3  14.5    262.7 264.8  

Lay3  20.2  20.2    289.7 289.7  

Lay4  27.9  66.1    271.6  90.4  

 

 

 

Window v6.3.72.0 Glazing System Thermal and Optical Properties 12/05/13 11:10:02

 

ID      : 7

Name    : Summer - Spandrel

Tilt    : 90.0

Glazings: 4

KEFF    : -0.0028

Width   : 7.008

Uvalue  : 0.068

SHGCc   : 0.08

SCc     : 0.10

Vtc     : 0.00

RHG     : 19.97

 

 

Layer Data for Glazing System '7 Summer - Spandrel'

ID     Name            D( ") Tsol  1 Rsol 2 Tvis  1 Rvis 2  Tir  1 Emis 2 Keff

------ --------------- ----- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----

Outside

  6046 VE12M.VIR      #0.223 .383 .286 .449 .792 .060 .047 .000 .840 .040 .578 

       1 Air           0.540                                                    

   103 CLEAR_6.DAT    #0.225 .771 .070 .070 .884 .080 .080 .000 .840 .840 .578 

       1 Air           3.440                                                   

 30004 0.125" Alum Pan 0.125 .000 .001 .001 .000 .001 .001 .000 .900 .200 92.4 

       1 Air           0.375                                                   

 30001 2" insul + alum 2.080 .000 .001 .001 .000 .001 .001 .000 .900 .900 .021 

Inside

 

 

Environmental Conditions: 3 NFRC 100-2001 Summer

          Tout   Tin  WndSpd   Wnd Dir   Solar  Tsky  Esky

          (F)    (F)   (mph)            (Btu/h-ft2)  (F)

         -----  ----  ------  --------  ------  ----  ----

Uvalue    89.6  75.2    6.15  Windward   248.2  89.6  1.00

Solar     89.6  75.2    6.15  Windward   248.2  89.6  1.00

 

 

 

Temperature Distribution (degrees F)

        Winter         Summer

       Out   In       Out   In

      ----  ----     ----  ----

Lay1 130.7 134.2    130.7 134.2  

Lay2 263.1 265.2    263.1 265.2  

Lay3 290.1 290.1    290.1 290.1  

Lay4 272.0  91.0    272.0  91.0  

 

Window v6.3.72.0 Glazing System Thermal and Optical Properties 12/05/13 11:51:16

 

ID      : 1

Name    : Winter - Vision

Tilt    : 90.0

Glazings: 2

KEFF    : 0.0193

Width   : 0.988

Uvalue  : 0.29

SHGCc   : 0.38

SCc     : 0.44

Vtc     : 0.70

RHG     : 91.13

 

 

Layer Data for Glazing System '1 UValue - Vision'

ID     Name            D( ") Tsol  1 Rsol 2 Tvis  1 Rvis 2  Tir  1 Emis 2 Keff

------ --------------- ----- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----

Outside

  6046 VE12M.VIR      #0.223 .383 .286 .449 .792 .060 .047 .000 .840 .040 .578 

       1 Air           0.540                                                   

   103 CLEAR_6.DAT    #0.225 .771 .070 .070 .884 .080 .080 .000 .840 .840 .578 

Inside

 

 

Environmental Conditions: 1 NFRC 100-2001

          Tout   Tin  WndSpd   Wnd Dir   Solar  Tsky  Esky

          (F)    (F)   (mph)            (Btu/h-ft2)  (F)

         -----  ----  ------  --------  ------  ----  ----

Uvalue    -0.4  69.8   12.30  Windward     0.0  -0.4  1.00

Solar     89.6  75.2    6.26  Windward   248.2  89.6  1.00

 

 

 

Temperature Distribution (degrees F)

        Winter         Summer

       Out   In       Out   In

      ----  ----     ----  ----

Lay1   3.6   4.3    110.1 111.2  

Lay2  52.7  53.4     88.6  88.2  

 

 

 

Window v6.3.72.0 Glazing System Thermal and Optical Properties 12/05/13 11:51:43

 

ID      : 8

Name    : Summer - Vision

Tilt    : 90.0

Glazings: 2

KEFF    : 0.0075

Width   : 0.988

Uvalue  : 0.26

SHGCc   : 0.38

SCc     : 0.44

Vtc     : 0.70

RHG     : 91.05

 

 

Layer Data for Glazing System '8 Summer - Vision'

ID     Name            D( ") Tsol  1 Rsol 2 Tvis  1 Rvis 2  Tir  1 Emis 2 Keff

------ --------------- ----- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----

Outside

  6046 VE12M.VIR      #0.223 .383 .286 .449 .792 .060 .047 .000 .840 .040 .578 

       1 Air           0.540                                                   

   103 CLEAR_6.DAT    #0.225 .771 .070 .070 .884 .080 .080 .000 .840 .840 .578 

Inside

 

 

Environmental Conditions: 3 NFRC 100-2001 Summer

          Tout   Tin  WndSpd   Wnd Dir   Solar  Tsky  Esky

          (F)    (F)   (mph)            (Btu/h-ft2)  (F)

         -----  ----  ------  --------  ------  ----  ----

Uvalue    89.6  75.2    6.15  Windward   248.2  89.6  1.00

Solar     89.6  75.2    6.15  Windward   248.2  89.6  1.00

 

 

 

Temperature Distribution (degrees F)

        Winter         Summer

       Out   In       Out   In

      ----  ----     ----  ----

Lay1 110.4 111.4    110.4 111.4  

Lay2  89.1  88.6     89.1  88.6  

[Robin Mitchell]

Faron

 

I would like to look at your WINDOW database.

 

Can you make a Project database, which will be much smaller than the entire database, zip it up and email it to me ?

 

Here are instructions about how to make a Project Database:

 

http://windows.lbl.gov/software/window/FAQ/ProjectDB.htm

 

Also, please let me know what version of WINDOW you are running.

 

Robin

***

Robin Mitchell

Windows & Envelope Materials Group

Lawrence Berkeley National Laboratory

--
You can view the THERM forum online at: http://windows.lbl.gov/software/THERM/forum
---
You received this message because you are subscribed to the Google Groups "THERM" group.
To unsubscribe from this group and stop receiving emails from it, send an email to LBNL-THERM+...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

[D. Charlie Curcija/LBNL]

To close the loop on this issue, SHGC is dependent on solar transmittance and heat transfer in the structure. Solar transmittance does not change from summer to winter conditions (at least not under our assumptions in this modeling). Heat transfer portion changes and convection heat transfer (and sometimes radiation heat transfer) could switch direction of change depending on the configuration of the system.

[Anupama]

 

Hi

 

I am also simulating for spandrel panel. And I wanted to know the surface temperatures of the spandrel glass, insulation and back panel.

 

-->The centre of glass result, I get from WINDOWS 7.2 is as below:

 

 

"Layer 1" is 8mm clear glass, "Layer 2" 2mm Aluminium alloy, and "layer 3" is 50mm Rockwool.

 

-- >Environmental condition I am using is as below:

 

       

 

 

 

 

--> My Question: Simulation shows high temperature 114.7oC in layer 2 and layer 3 during Summer. Is this high temperature, possible/ correct value? Am I simulating correctly?

I am also attaching project database for this spandrel panel, and a screenshot of the spandrel build-up , kindly please let me know if I am doing anything wrong.

 

Thank you

Anupama

[Anupama]

 

 

Hi

 

For the same spandrel panel, I have also tried to generate report for "whole spandrel with simple frames". I imported frames and edge values from Therm model ( I have attached the therm sill, jambs and head models).

 

--> My Question: the temperature values I get from Windows 7.2 "Glazing system  " for the spandrel panel is different from the report generated for the "whole spandrel with simple frames". Why are the temperature different in the two reports?

 

Thank you

Anupama

[D. Charlie Curcija/LBNL]

Hi,

In one of earlier posts, Robin asked for your WINDOW mdb file. Can you please post that file?

Charlie

[Anupama]

Hi Charlie

I am attaching the WINDOW mdb file.

 

Thank you

Anupama