7.2.2 Thermal Analysis Tool

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The Thermal Analysis Tool provides detailed analysis of curtain panels where there are sub-panels or several materials in the panel family.   This Tool is only suitable for Revit versions of 2019 and later as the libraries and classes required for functionality are not present in earlier versions.

The Thermal Analysis Tool does not require FenestraPro to operate or that Solar Loads to have been calculated. It is used to identify materials and assign thermal properties to panel elements, mullions, frames, spandrels and set boundary conditions. This data may then be imported into FenestraPro to inform the results.

The Thermal Analysis Tool can query curtain wall panels to find dependent elements’ geometry and materials.

The Tool will extrapolate an overall U-value of complex or composite windows and curtain wall family elements within Revit, in accordance with National Fenestration Rating Council Incorporated (NFRC) guidelines.    

The Glazing Tool works by listing the materials found in the family. The user is then asked to categorize each material. Categories include Frame, Glazed, Solid as well as an Excluded category to remove that material from calculations. The user is also asked to apply a thermal performance R-value or U-value for each usable material.

This allows the Tool to organize exposed geometry into performance zones. Each zone can be further refined with Edge-of-glazing U-Factors and an edge condition performance value and category (Frame or Divider). The area weighted average assembly U-value can now be calculated for that family type.

The assembly U-values can be exported to CSV format, with more options in development. FenestraPro can use these exported assembly R-value/U-values to provide an accurate picture of the unit’s performance within the building envelope.

FenestraPro’s Thermal Analysis Tool can query curtain wall panels to find dependent element’s geometry and materials.

You are provided with a list of families in the model and may then assign a category for each material and assign a U-value or R-value. This information may then be passed back to FenestraPro to be included into the breakdown details for glazing elements. These properties will then affect the results for Solar Loads and Overall R-value / U-value. The data may then be exported to a CSV file for review.

Each curtain wall will have a CSV file with a breakdown of all panels within. An overview CSV file contains the Revit ID’s for each curtain wall as well as the panel and sub-panel Revit ID’s for reference.

Units will display automatically appropriate for your model (metric or imperial).

Glazing Tool for Nested Panels

1. Open the Thermal Analysis Tool from the Add-Ins Menu in Revit.

Thermal Analysis Tool may be accessed from the Revit Menu under the FenestraPro section

2. The Add-in opens a new window.  Select a panel in the Revit model to begin (use the Tab key on your keyboard to select a panel element on the model). There is a list of Steps to guide you through the workflow.

The Revit ID of the element is displayed in the Tool as well as the orientation on the dial. The thermal properties have not yet been set.  Some values may be displayed if they have been assigned in Revit materials but these may be overridden.

3.  For each material that has been identified in the panel family, a category should be selected or excluded.

‘None’ will display if no material has been set when the Revit family was created but this should not be left to remain as ‘None’.  Materials may be created in Revit for the project and you may assign these in the Tool.

Options are: Glazed Unit, Solid Unit, Frame, Transom, Mullion, Divider or Excluded.

For Glazed Materials, the Glass Database drop-down list is provided to select a sample glass type or a product from the included vendors. You may toggle the list from Revit to the full FenestraPro Database.

4.  Once all materials are assigned to a category (the value should not be left as ‘None’ for any material),  Refresh the exposed performance zones by clicking on the button shown. A weighted average is used based on NFRC guidelines.

The Viewer will display the relevant panel. You may orbit in the viewer also.

The Exposed Faces are also displayed in the lower panel with areas and properties. These are the surface elevation areas which are in the same plane as the curtain wall.

Note: Version 6.1 includes a Linear Heat Loss calculation option as well as the Area Heat Loss option in Settings (wheel icon).

5.  Clicking on the question mark icon or the buttons which contain the materials will highlight these locations on the model and in the Viewer.

The Dashboard will then display a U-value for this panel. This is a weighted average using the areas and properties of the various materials in the panel.

6.  The Solar Heat Gain Coefficient and Visual Light Transmission on the Dashboard may also be overridden if you wish. The Exposed Area provides a value where the materials are parallel to the curtain panel. In situations where materials are angled, there is a separate workflow, described below.

The Tool provides the ability to go into more detail with panel conditions and uses guidelines from the NFRC (National Fenestration Rating Council). Different areas and conditions on the panel are identified and analyzed. For instance, the Center of Panel U-factor is separated from the Edge of Panel where it borders onto a frame.

Typical Schematic of Fenestration (guidelines from NFRC 2013)

Where a material touches the surface and divides it but does not break the Surface, a Divider is identified. Here, an Center Pane U-factor is identified as well as an Edge of Panel U-factor. Users should input values in these cases provided by third party tools such as Therm (LBNL).

Clicking on the Tabs (Center and Sides) will highlight the item in the Viewer and in the Revit model. If a frame breaks through the Surface, you may input a value. If it does not break the exposed Surface, it is a divider and will be treated differently. You may still input a value for this type of condition.

Edge of Panel default U-factors are set as 1 (imperial) or 5.678 (metric). A U-factor may be set for the panel and a material category may be set for the surrounding items (Frame etc).

This should be done for each material listed in the section on the left hand side of the application.

Once values are set for a panel type, this will apply to other instances of this family in the Revit model (this does not need to be repeated for each instance).

Another Panel type in the model may then be selected and the process repeated until all family types in use in the model are dealt with. Once a new panel is selected in the model, the items contained in the family are displayed and you may set values for each material type.

Very small Surface areas (edge of materials etc) may be excluded if they will not have a large effect on the results.

Note: Areas are currently rounded to two decimal places, so larger windows may not always display significantly greater values than smaller windows.

Orientations of Panels

If orientations appear to display incorrectly (data supplied by Revit), you may use the arrow beside the Materials heading to open the list of family types. 

Here, you can make a selection and options will then display to Show Orientation and Populate Curtain Wall.

Click on Show Orientation to check how the curtain panel is facing. If this does not seem correct (a globe will appear to indicate which side the panels face. 

If the globe appears inside the building, you may need to use the Flip Orientation button so that the orientation is reversed for calculation purposes. 

Click on the Show Orientation button again. This will then display the Globe outside the building (correct) indicating that the panels face outwards.

To return to the Materials window (to modify material properties/glass types), select the panel family again in Revit.

7.  When all Curtain Panel types have been dealt with, you may export the data to a CSV file which will be used by FenestraPro to calculate results.

To do this, select the Curtain Wall itself in Revit.  Note: this CSV file can be exported and saved in v6.2 but has yet to be added in version 7.0. In the meantime for v7.0, the assembly values from the Glazing Analysis Dashboard may be noted and added to the family type properties in Revit using the User Defined method.

The dialog window will ask you to Populate the Curtain Wall. This means that all panel types in that wall will be set to the properties that you have defined.

Note: This is a manual process, since an automatic loading of large models with many panel types may take some time, the User will then need to wait until all elements are loading. This way, the user chooses when they are ready to proceed. Click on ‘Populate Curtain Wall’ to proceed.

8. The Curtain Wall frame property may then be set by inputting a value

9.  You can also select a Curtain Wall from the list by using the arrow and getting a list of all windows and curtain walls in the model.

Clicking on one of these will select it on the model (1) and you may populate this window or curtain wall using the button in the upper panel (2).

Note: Window families are also listed since they are glazed elements in the model. These may also be modified in this Tool if required.

10.  Curtain Walls/Windows that have had their panel properties assigned using the Tool, may then be saved to a report from which FenestraPro can read.  Click on the camera icon button to save the report.

The report is the mechanism for sending this data to FenestraPro. Panel ID’s in these files are searched when FenestraPro is opened and if they are listed, these properties will be used to override any Revit properties when calculations are made.

Note: The original panel properties set in Revit will remain displayed and are not modified there. These properties relate to the entire panel and are not useful in the case of Nested families inside Curtain Panels.

CSV files will be created in the FenestraPro folder with data produced using the Tool.

Files exported from the Tool are as follows:

  1. Curtain Wall Panels CSV file
  2. A file for each populated Curtain Wall
  3. Windows CSV file

If you wish to review the data, it may be imported into an Excel file.  Note: It is not necessary to do this for the data to be read or used in FenestraPro.  Once the data is exported from the Tool, FenestraPro will be able to use the data.

11.  To view the Data in the CSV file, a few steps are required.

Open MS Excel or similar application, go to the Data tab and click the  ‘From Text/CSV‘ button.

CSV File exported from the Glazing Tool

The CSV files will be saved in your FenestraPro local folder under the model name along with a numeric string.

For example: ‘C:\Users\(YourName)\AppData\Local\FenestraPro\TEST MODEL123′

  1. Select a file in the folder list to import
  2. From the pop-up window that opens, select ‘Edit‘ (1 in the image)

Click the ‘Use First Row as Headers’ twice, so that the numbers are imported as numbers and not text.

12.  To use the outputted results in FenestraPro:

  1. Exporting data from the Glazing Tool creates a local file
  2. FenestraPro will monitor this location and if there is a saved file found for that model, FenestraPro will load the calculated overall U-Value results and use them for its analytical calculations.
  3. In the Settings of FenestraPro (under the Detailed Models Tab), please make sure that the option Read cached U-Factor, SHGC and VLT from Glazing App is checked. If this is not checked, FenestraPro for Revit will read only the parameters of the panel families directly in the model.

Note: that access to these parameters may not always be successful due to various limitations of nested components.

Option in Settings to identify changes made using the Glazing Tool

13. The Settings button provides extra information for debugging and is generally not required to be modified.




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