THERM -- Knowledge Base THERM 5.2

	Pentium class or better.
	At least 64 MB of random access memory (RAM). For optimal operation, 128 MB or more of RAM is preferrable.
	Microsoft Windows 98^TM, Windows 2000^TM, Windows ME^TM, Windows NT^TM.or Windows XP^TM, (The program WILL NOT run with Windows 3.1^TM, Windows NT 3.51^TM or Windows 95^TM).
	Hard disk drive with at least 40 MB of available disk space
	Printer supported by Microsoft Windows (serial, parallel, or shared over a network).

Installation Problems
In order to install the program with the Microsoft NT (4.0), 2000, and XP, you must be Administrator or part of the Administrators Group on your machine. To check if you are Administrator, do the following:

	Go to Control Panel, then "Users and Password" in Microsoft 2000, or "User Accounts" in Microsoft XP
	Find the current username (yours) and look in the group column. It should say: Administrators
	If the current username does NOT say Administrators, contact your IT department to become Administrator, or to have someone with Administrator privileges install the program on the machine.

BUG FIXES / NEW FEATURES

Projected Frame Dimension:
There are 2 new options for the projected dimension for U-factors:

	Projected in Glass Plane
	Custom Rotation

If there is a glazing system in the THERM file, Projected in Glass Plane is now the default. This allows you to rotate the glazing system without changing the U-factor, other than artifacts of the mesh since the mesh works on a 90 degree grid. Custom Rotation allows you to project the U-factor lengths onto an arbitrary angle from vertical. This currently requires a recalculation to update the results

MODELING GUIDELINES FOR NFRC 100-2002:

Documentation:
The THERM5 / WINDOW 5 NFRC Training Simulation Manual is available in PDF format from this website. It contains much more detailed information about NFRC modeling rules than this FAQ.

Interior Frame Boundary Conditions:
After a detailed analysis of the new ISO15099 THERM/WINDOW modeling assumptions (used just prior to the NFRC meeting in Snowbird, Utah), we have concluded that revisions to these modeling assumptions are necessary. One of the modeling changes was partially redundant with another modeling change (the use of partially ventilated cavities on interior surfaces with the radiation model) and a second change (the use of glass convective film coefficients on frames) was not consistent with how test results would be standardized nor necessarily what we would recommend without future research. Thus, the modeling procedures we are recommending are:

Use the radiation model on the interior surfaces of THERM cross-sections, as proposed prior to Utah;
Eliminate the use of partially ventilated cavities on interior surfaces;

Use the following updated list of convective film coefficients on frame surfaces

Table 1

Boundary Condition Name	Convective Film Coefficient (hc) W/m2K
Interior Wood/Vinyl Frame (convection only)	2.44
Interior Thermally Broken Aluminum Frame (convection only)	3.00
Interior Thermally Improved Aluminum Frame (convection only)	3.12
Interior Aluminum Frame (convection only)	3.29

All other modeling shall be consistent with NFRC procedures, WINDOW5 and ISO15099 procedures, and the latest version of NFRC's "The Application of ISO 15099 to NFRC 100 and 200".

Glazing Systems: Import glazing systems with the following settings:

	Actual Cavity Height: only matters for CI modeling
	Edge of Glass Dimension: 63.5 mm (2.5 inches)
	Glazing System Height: 152.4 mm (6.0 inches)
	Exterior Boundary Conditions: Use convection plus blackbody radiation
	Interior Boundary Condition: Use convection plus enclosure radiation

Frame Cavities: Set all frame cavities to either "Frame Cavity NFRC 100-2002" or "Frame Cavity Slightly Ventilated NFRC 100-2002". The settings for this frame cavity definition are the following:

	Material Type: Simplified
	Cavity Model: "ISO 15099" for unventilated cavities "ISO 15099 ventilated" for slightly ventilated cavities
	Gas Fill: Air
	Emissivities: Side 1: 0.90 Side 2: 0.90 (these values are initial defaults, and the program calculates the final values during the simulation)

The following values are calculated automatically by the program for each frame cavity during the simulation so the default values do not need to be changed before the simulation:

	Heat flow direction
	Side 1 and Side 2 Temperature
	Emissivity

Boundary Conditions: Set the boundary conditions for the cross section as follows:

Exterior Boundary Conditions: set all exterior boundary conditions to "NFRC 100-2002 Exterior".

	The program should automatically get the emissivities of the adjacent materials for the Boundary Conditions.
	The Radiation Model is set to "Blackbody"

Interior Boundary Conditions: set all interior Glazing System boundary conditions to the <THERM5 file name>:<WINDOW5 glazing system name> U-factor Inside Film, and the Frame boundary conditions to the values listed above in Table 1

	The program should automatically get the emissivities of the adjacent materials for the Boundary Conditions.
	The Radiation Model is set by default to "AutoEnclosure" if the glazing system was imported with the Interior Boundary Condition set to "Use convection plus enclosure radiation"

U-factor Tags: Set the U-factor tags in a similar manner as with THERM 2.1a, except for the 88.900 mm (3.5 inches) above the 63.5 mm (2.5 inch) Edge-of-glass, which should be set to None.

Radiation Enclosure: a radiation enclosure should be modeled for all cross sections, but with the new AutoEnclosure feature, the actual enclosure does not have to be drawn. See the Automatic Radiation Enclosure explanation below under New Features.

File Properties: It is extremely important to set the Cross Section Type for each file before importing the glazing systems, in order for the program to model the frame cavities and CI glazing cavity correctly.

CONVERT A THERM 2.1a FILE TO A THERM 5.0 FILE:

In WINDOW 5.1

Make the glazing system in WINDOW 5.1
(double click on the glazing system in THERM to see the properties (glass ID, gap width etc))

In THERM 5.1

	Delete the glazing system
	Save the file, close it, and re-open it (this guarantees that the boundary conditions from the new glazing system will be in the Boundary Condition Library)
	Import the new WINDOW 5.1 glazing system with the following settings:

interior BC: use Convection plus Enclosure Radiation

exterior BC: NFRC 100-2002 Exterior

Check "Use CI Model for Window Glazing Systems" if you want to model Condensation Resistance

	Select a frame cavity
	Go to Edit, Select Special, and click OK
	Now all the �old-style� frame cavities have been selected
	Pick �Frame Cavity NFRC 100-2002� from the Materials pulldown
	Assign the appropriate "Interior <frame type> Convection Only" BC(s) on the interior frame
	Assign �NFRC 100-2002 Exterior� on the exterior frame sections
	Assign u-factor tags, including the "SHGC Exterior" tag on the exterior frame components

NEW FEATURES

Automatic Radiation Enclosure:
THERM 5.0 now has a feature that allows the radiation enclosure model to be activated without actually drawing the radiation enclosure geometry. When WINDOW 5 glazing systems are imported into a THERM file, at the bottom of the Insert Glazing System dialog box, the Interior Boundary Condition can be set to "Use convection plus enclosure radiation". When this choice is selected, and the boundary conditions are generated for the glazing system, double clicking on a boundary condition segment will show a Radiation Model setting of "AutoEnclosure". This means that the program will model a radiation enclosure that includes all the boundary segments that have this setting. It is also possible to change the Radiation Model setting after boundary conditions have been generated by going into the Boundary Condition Library (either from the Library menu or by double clicking on a boundary condition segment and clicking on the Boundary Condition Library button), and change the Radiation Model to "AutoEnclosure" if it is set to "Manual Enclosure Model". The Boundary Condition Model field must be set to "Comprehensive" in order for the Radiation Model choices to be active. The "AutoEnclosure" feature includes the same features as the "Manual Enclosure Model" which are:

	THERM automatically sets the film coefficients for boundary conditions inside a radiation enclosure, so these values no longer need to be calculated by hand.
	If multiple glazing options are defined, THERM automatically changes the interior film coefficients for each file and simulation.

Combined U-factor and Condensation Resistance Calculations:
If the Condensation Resistance model is activated, either at the time a glazing system is imported, or later (using the Options menu, Preferences menu choice, THERM File Options tab), THERM 5.0 will automatically calculate both the U-factor and CI results in one run, and store the results for both in the same file. At the time of the simulation, the program will first run the U-factor simulation, and then automatically run the Condensation Resistance calculation (you will see in the status bar that a temporary file is created, which is the THERM file name with "_ci" appended to it.) It is possible to toggle between viewing each set of runs in the Calculation menu, Display Options menu choice -- when the Condensation Resistance results are available, there will be two radio buttons at the bottom of the screen, one for each set of results.

If you want to run only the U-factor results, simply turn off the CI option by unchecking the "Use CI Model for Glazing Systems" in the Options menu, Preferences menu choice, THERM File Options tab.

NOTE: THERM will not perform the Condensation Resistance simulation for vertical components, such as Jambs, Vertical Meeting Rails or Vertical Dividers. The following message will be displayed

Gas Library: THERM 5.0 now saves the gas properties in the THERM file, so that it is not necessary to first import them into the THERM Gas Library from the WINDOW 5 Gas Library. They function in a similar manner to the Boundary Condition and Material Libraries in they are added to the Gas Library when the file is opened, and are saved with the file when the file is closed.

Gravity Arrow: From the View menu, select Gravity Arrow, to see a graphic representation of the gravity vector the program is using for the simulation, relative to the computer screen. This gravity vector is based on the Cross Section Type set in the File/Properties menu, as well as the direction the glazing system is imported (except for Cross Section Type = Jamb, which will always have the gravity arrow pointing into the computer screen)

Glazing System Feedback: More information about the WINDOW 5 glazing system has been added to the Glazing System Info screen, such as individual glazing layer and gap information. Double click on a glazing system to view this information.

TROUBLESHOOTING

Array Overflow in Mesher:
When the Quad Tree Mesh Parameter (set in Options/Preferences/Therm File Options) is set too high (usually greater than 9), THERM will display the following message:

To fix this problem, set the Quad Tree Mesh Parameter to a lower number in Options/Preferences/Therm File Options. You may have to simplify your geometry in order for the model to mesh.

Boundary Condition U-factor Tags:
Always check the interior boundary condition U-factor tags to make sure that they are set correctly. THERM will assign them correctly in most cases, but there are some situations where they will not be generated correctly automatically. The two circumstances where this can happen are:

	When selecting all the boundary conditions on the interior of the model, and assigning them to the same boundary condition, the program will assign the U-factor tags to "None" for all these boundary conditions.
	If there is no "Frame" segment on the glazing system, the program will not assign the U-factor tags correctly. Frame will get assigned to the Edge area, and Edge will get assigned to the None area.

Boundary Conditions Error Message -- Inconsistent boundary condition data:
THERM will give an error message if triangular Frame Cavities are defined:

The solution is to add at least one more point in the frame cavity and move it to make a 4th surface in the frame cavity

Boundary Conditions from older WINDOW5 glazing systems:
If you open a file that has a glazing system in it with "old-style" combined boundary conditions, and you delete the glazing system, and reimport a new WINDOW5 glazing system with the same name (that has the new boundary condition settings in the glazing system import screen), THERM will not use the new ones, but instead will use the old ones. The solution is to delete the glazing system, delete the boundary conditions, save and close the file, reopen the file, then import the glazing system.

Boundary Conditions that are not set to AutoEnclosure:
For files made with THERM 5.0 Beta 2 and glazing systems imported from WINDOW 5.01 Beta, the Radiation Model in the boundary conditions (in almost all cases these boundary conditions will be the glazing system boundary conditions imported from WINDOW 5) will probably be set to "Enclosure". This can be changed to the "AutoEnclosure" setting by going into the Boundary Condition Library and editing the boundary condition. In the Radiation section of the Boundary Conditions definition, click on the "Automatic Enclosure Model" and that change will then be reflected in all the boundary condition segments that are set to this boundary condition.

Calculation does not work -- "Trouble opening file:" message appears

This may occur the first time you try to do a calculation after installing the program. When you press the Calculate button, a message appears saying "Trouble opening file" but is otherwise blank and does not say what file is causing the problem. It is probably due to the fact that you do not have Administrator privileges on your computer which will allow the program to create the SIM directory (a subdirectory of the THERM directory which contains intermediate files created during the calculation) the first time a simulation is run, where it will write temporary files created during simulations. The solution is to either become Administrator on your computer, or reinstall the computer in a location where you do have write priveleges, so that the SIM directory can be created by THERM and intermediate files can be written to that directory.

Check Gravity Vector on Condensation Resistance Files Before Simulating:
Use the View/Gravity Arrow feature to make sure that the gravity vector is pointing in the correct direction in files that are to be used to calculate the Condensation Resistance values. The gravity vectors should be the following:

Cross Section Type File/Preferences Setting	File orientation	Gravity Vector Orientation
Sill	glazing system pointing up	pointing down
Head	glazing system pointing down	pointing down
Head	glazing system pointing up	pointing up
Jamb	glazing system pointing up	pointing into the screen, ie, you will see what looks like an X
Meeting Rail (vertical) such as for a horizontal slider	glazing systems pointing up and down	pointing into the screen, ie, you will see what looks like an X
Meeting Rail (horizontal) such as for a vertical slider	glazing systems pointing up and down	pointing down
Divider (vertical)	glazing systems pointing up and down	pointing into the screen, ie, you will see what looks like an X
Divider (horizontal)	glazing systems pointing up and down	pointing down

An indication that something may be wrong in the Condensation Resistance (CR) calculation is if the gravity vector is not set according to the table above. Also check the temperatures and "sides" of the CR boundary conditions inside the glazing system cavity (by double clicking on them) to make sure that "Left" is really the left side of the cavity and "Right" is the right side of the cavity, and that the temperature settings make sense. If either or both the sides or the temperatures are wrong, delete the glazing system, check to make sure the File/Properties Cross Section Type is set correctly, realign the gravity vector, and reimport the glazing system.

Combined Condensation Resistance and U-factor Calculations:
Before simulating a file that has the Condensation Model activated (ie, there are red boundary conditions inside the glazing system), go to the Options menu, Preferences menu choice, THERM File Options tab and make sure the checkbox labeled "Use CI Model for Glazing Systems" is checked. In some instances, even though the glazing system was imported with the Condensation Resistance model turned on, and there are red boundary conditions in the glazing system cavity, the "Use CI Model for Glazing Systems" box will NOT be checked in the Options/Preferences/THERM File Options tab. This will be fixed in future versions so that this step is not necessary.

Condensation Resistance Calculations in WINDOW 5:
In WINDOW5, in order to do correct condensation resistance calculations and use the temperature map feature, the WINDOW 5.0 program requires files in the Frame and Divider Libraries that were generated with either THERM version 5.1 (version 5.1.00) or 5.2 (5.2.04).

Glazing Systems:
Although THERM 5.1 can read files with WINDOW 4.1 glazing systems in them, you are strongly advised to create that glazing system in WINDOW 5.1 and reimport it into the THERM 5.1 file. If this is not done, there is no guarantee that THERM 5.1 will be able to generate the appropriate boundary conditions, or calculate the correct result.

Importing THERM file into WINDOW generates "unnamed file has a bad format" error message:
If importing a file into WINDOW generates the error message:

"Unnamed file has a bad format"

this means that there is a problem with the THERM file, in that the file results are spanning a buffer when being read. One work around to try is to add comments to one of the input fields in the File/Properties menu -- it shouldn't take more than 15 characters.

Material Library Update:
The Material Library has been updated (with THERM 5.2) to match the NFRC 101-2001 Procedure for Determining Thermo-Physical Properties of Materials for Use in NFRC-Approved Software Programs.

	View the NFRC technical documents (go to the NFRC 101-2006 or 101-2001 link on this page
	Download updated Material.lib file (dated 3/18/2003 -- included in current THERM 5 installations) -- This file should be put in the THERM program directory (c:\Program Files\LBNL\WINDOW). Rename your old material.lib if you want to prevent it from being overwritten by this updated version.

Mesh Error -- Mesh appears to have gaps:

After a simulation, if the program displays the Warning message below that "the mesh appears to have gaps", it means that one or more polygons have not been meshed properly. It is necessary to find the polygon that has not meshed (turn on the mesh display from the Calculation/Display Options menu, and select "Finite Element Mesh"). You should see one or more polygons that do not have a mesh drawn in them.

Delete the unmeshed polygons and redraw them, changing the position (even very slightly) of one point. Regenerate the boundary conditions and resimulate the problem. Changing the position of a point should solve the problem.

Nominal Thickness:
THERM 5 is shipped with the nominal thickness settings from the NFRC 100-2002 standards document, which are different from the THERM 2.1a settings.

Print and Print Preview Does Not Show A Model

There are some circumstances where the Print or Print Preview options do not produce a picture of the THERM model. Instead you just get a blank page with a header on it.

The most likely cause for this problem is that the model is very small relative to the size of the drawing, and so it is just an invisible speck on the paper.

One way to fix this problem is to select the entire model (Edit/Select All), then copy (Edit/Copy) this model and paste it into a new model (File/New, then Edit/Paste). Then do a Print Preview (File/Print Preview) and see if the model appears.

You can see that the "drawing size" is most likely the problem -- in one example, where the model did not appear in Print Preview, the drawing size (Options/Preferences/Drawing Options) was 14884 mm hight x 18678 mm wide, while the actual model was 247 mm high and 67 mm wide. After copying the model into a new document, the drawing size was 500 mm x 500 mm, and the model image appeared in the Print Preview.

Changing the drawing size in the original drawing to a more reasonable size does not "stick" -- the program reverts back to the large size, or close to it.

One possible cause of the large drawing size is to use a DXF as an underlay that is very large. So one prevention measure would be to use an appropriately sized DXF file.

Program Crashes when Zooming with Windows 95 or Windows 98 Operating Systems:
If the program is crashing when you use the Zoom feature, go to Options/Preferences and "check" the "Windows 95" box. This should solve the problem.

If this is happening even when you reduce the Mesh Parameter, go to Options/Preferences/Simulation, and make sure that the "Automatically increment mesh parameter" is turned OFF, ie, "unchecked". If this option is checked, the program will keep increasing the mesh parameter automatically until it can either simulate the problem or the array overflow occurs, even if you reset the mesh parameter to a smaller number.

Report Does Not Print

THERM needs the file RICHTX32.OCX in order for the Report feature to work. This file is used by many programs so it may already be installed on your computer, and THERM will display the Report properly. However, if the Report button doesn't display anything, you need to the following:

Download the RICHTX32.ocx file by clicking here.

and save or copy it into your system directory. The standard system directories for the various versions of MS Windows are listed below:

For MS NT/2000:

copy file into c:\winnt\system32

For MS Windows XP:

copy file into c:\windows\system32

You also need to "register" the file by doing the following:

Go to the Start menu, click on Run

In the Run dialog box, type the following, depending on your operating system:

For Windows NT or 2000, type:

regsvr32 \WINNT\system32\RICHTX32.OCX

For Windows XP, type:

regsvr32 \windows\system32\RICHTX32.OCX

Make sure you put a space between regsvr32 and the directory path.

You should get a dialog box saying the registration was successful

Steady solution is diverging in ConRad:
If this message appears at the end of a simulation, the program will not have been able to calculate a solution to the model. Go to the Options menu, select Preferences, and go to the Simulation tab. Changing the Relaxation Parameter will probably allow the file to simulate. The default setting for Relaxation Parameter should be 1.0 and that is the setting to try first. If that does not allow the program to simulate, increment that value down in 0.01 increments until the problem simulates, without going below a value of 0.90. For example, if the problem didn't converge at 1.0, the next Relaxation Parameter to try is 0.99, then 0.98, until you reach 0.90.

THERM 2.1a cannot read THERM 5 files:
THERM 5 can read THERM 2.1a files, but once saved as a THERM 5 file, 2.1a will not be able to read the file.

Underlays with AutoCAD 2000 and 2002:
THERM cannot read DXF files from AutoCAD versions 2000 and 2002, so in the File/Save As dialog box in either of those AutoCADversions, set the Type to either AutoCAD12 or AutoCAD13 DXF format files.

Exporting sections or parts of a file (Autocad 2000):

To prepare an AutoCAD dxf section for use in Therm, follow the steps below. Note that you may want to use only part of the drawing. You can save each section in a separate file or save the entire vertical or horizontal section in a single file.

Select and copy the section you want to save as a dxf file.
Create a new page (click on the "new" button and press return).
Delete any hatching, dimension lines, screws, hardware or other unnecessary parts.
At this point, if the section needs to be rotated or flipped, use the AutoCAD features to do this.
Select the section you want to export to a dxf and completely explode it (several times if necessary). When it's completely exploded, you'll typically see the cursor change to a small square.
Select File � "Save As."
Under "Tools" and "Options" on the "Save drawing as" dialog box, select the "Dxf Options" tab.
Check the "Select Objects" box (from previous step).
Under the "Options" button, check the box for "Selected Objects" & click OK.
Choose the file type as "AutoCAD R12/LT2 DXF."
Name the file & click OK.
You'll be returned to the drawing in a "selection mode" where you will select the section to be exported.
Select the section and press "Enter."
You are now ready to import the file into Therm.

Note that parts in a drawing may not be able to be completely exploded and may not appear in Therm. You may have to go back to the originator of the file and ask them to make sure that the parts are able to be exploded.

Whole product SHGC calculations:
The ISO 15099 formula for the frame Solar Heat Gain Coefficient (SHGC) specifies that the surface area (Asurf) should be the outdoor wetted surface, while the frame area (Af) should be the indoor projected surface area. By default, if there are no exterior U-factor tags, THERM passes the inside wetted length to WINDOW5 for the SHGC calculation. In order for THERM to pass the exterior wetted surface length, tag the exterior frame boundary conditions with the U-factor tag of "SHGC Exterior". In the latest installation of THERM, this tag is in the default U-factor tag library, but if it is not there, you can be added to the library.

KNOWN BUGS

Frame Cavity Emissivities
There are some circumstances where the program will assign frame cavity surface emissivities based on the emissivities of the glazing system layers, rather than the emissivities of the surrounding surfaces. This problem occurs only with frame cavities using the advanced radiation model or the iso model, and is partly based on the geometry of the frame cavity as it relates to the glazing system. It is hard to predict when it will happen, and so the best way to make sure this is not happening in a particular file is to print out the Report for the file (File/Report), and examine the emissivities of all the frame cavities to see if there are any that do not seem to make sense.

If some questionable values are found, it is possible to then example the frame cavity in question (the Polygon ID is listed in the report in the first column, and that polygon can be selected in the THERM file by using the Edit/Select Special menu and then typing the Polygon ID number in the ID field). Once the problem polygon is selected, double click on each frame cavity surface and the emissivity of that surface will be displayed. In general, unless overridden by the user, these emissivities should be the emissivities of the materials the surface is touching. If these emissivities are found to be incorrect (if the problem is from this bug, the emissivities will be set to one of the glass layer emissivities, so it should be obvious if that is the problem), then the emissivity can be changed by inputting the correct value into this dialog box, and rerunning the file.

Boundary Conditions Changed from Comprehensive to Simplified
If a Boundary Condition is initially defined with the Model = Comprehensive in the Boundary Condition Library and applied to a cross section surface, an then is later changed to Model = Simplified in the Boundary Condition Library, if the applied boundary condition is "clicked on", the Radiation model will still be set to "AutoEnclosure" even though it shouldn't be. The solution is to make a completely new Boundary Condition with the Model = Simplified, rather than taking one that was originally defined with the Model = Comprehensive.


Boundary Condition is originally defined as Model = Comprehensive		Boundary Condition is changed to Model = Simplified

		When a boundary condition segment is clicked on, the Radiation Model is still set to AutoEnclosure, even though it shouldn't be.

Two Automatic Radiation Enclosures in the Same Model
If there are two Automatic Radiation Enclosures in the same THERM cross section, the program will not necessarily calculate the results correctly. The solution until this bug is fixed is to set one set of boundary conditions to "Blackbody" and the other to "Automatic Radiation Enclosure". If you have a model where you want to do this and have questions about to set up the model, send email to THERMHelp@lbl.gov.

	interior BC: use Convection plus Enclosure Radiation
	exterior BC: NFRC 100-2002 Exterior
	Check "Use CI Model for Window Glazing Systems" if you want to model Condensation Resistance