THERM 7 / WINDOW 7 NFRC Simulation Manual

1 THERM 7 / WINDOW 7 NFRC Simulation Manual National Fenestration Rating Council, Inc. Publication Version: July 2017 DISCLAIMER This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor The Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or The Regents of the University of California.

2 The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof, or The Regents of the University of California or the University of Minnesota. This Manual is derived from the original Simulation Manual that had been authored by an author at Lawrence Berkeley National Laboratory under Contract No. DE-AC02-05CH11231 with the Department of Energy. The Government retains, and the publisher, by accepting the article for publication, acknowledges that the Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this Manual and original Manual , or allow others to do so, for Government purposes. THERM 7 / WINDOW 7 NFRC Simulation Manual NFRC Publication Dates: May 2015, January 2016, July 2016 Original Simulation Manual , NFRC Simulation Manual , Publication Dates by the following Original Authors: Publication Dates.

3 January 2011, June 2013, July 2013, and January 2014 Robin Mitchell, Christian Kohler, Dragan Curcija, Ling Zhu, Simon Vidanovic, Stephen Czarnecki and Dariush Arasteh windows and Daylighting Group Building Technologies Department Environmental Energy Technologies Division Lawrence Berkeley National Laboratory John Carmody College of Architecture and Landscape Architecture University of Minnesota Charlie Huizenga Center for Environmental Design Research University of California Prior versions (up to ) of this Simulation Manual were supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technology, Building Technologies Program of the Department of Energy under Contract No. DE-AC03-76SF00098, and the Original Simulation Manual was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technology, State and Community Programs of the Department of Energy under Contract No.

4 DE-AC02-05CH11231. Subsequent versions, including the current version, are developed by NFRC members and staff. NFRC has a license to all copyrights in the Simulation Manual and a license to use, modify, and create derivative works of this Simulation Manual and NFRC retains the copyright for such derivative works. THERM7 / WINDOW7 NFRC Simulation Manual July 2016 Contents 1. INTRODUCTION .. 1 1 Overview .. 1 1 2. FENESTRATION PRODUCTS .. 2 1 Overview .. 2 1 Fenestration Product Sash Operation .. 2 1 Projected or Hinged windows .. 2 2 Sliding windows .. 2 2 Sliding Glass Doors .. 2 2 French Doors and Folding Patio Doors .. 2 2 Skylights and Roof windows .. 2 2 Performance Implications of Basic Fenestration Types .. 2 3 Hinged windows .. 2 3 Sliding windows .. 2 3 Sliding Glass and French Doors .. 2 4 Frame Materials .. 2 4 Wood Frames .. 2 4 Aluminum Frames .. 2 4 Vinyl Frames .. 2 5 Fiberglass and Engineered 2 5 Wood Composites.

5 2 5 Hybrid and Composite Frames .. 2 5 Basic Glazing Materials .. 2 5 Glass .. 2 6 Plastics .. 2 6 Improved Glazing Products .. 2 7 Tinted Glazing .. 2 7 Reflective Coatings and Films .. 2 8 Double Glazing .. 2 8 Glass Coatings and Tints in Double Glazing .. 2 8 Gap Width in Multiple Glazed Units .. 2 9 Divided Lights .. 2 9 Special Products .. 2 10 Multiple Panes or Films .. 2 10 Low Emittance Coatings .. 2 11 Coating Placement .. 2 12 Coating 2 12 Gas Fills .. 2 13 Thermally Improved Edge Spacers .. 2 13 Contents THERM7 / WINDOW7 NFRC Simulation Manual July 2016 3. FENESTRATION HEAT TRANSFER BASICS .. 3 1 Overview .. 3 1 Energy Flow Mechanisms .. 3 1 Temperature Driven Heat Transfer .. 3 2 Conduction .. 3 3 Convection .. 3 3 Radiation .. 3 3 U 3 3 Total Product U factor .. 3 4 Center of Glazing U factor .. 3 4 Edge Effects .. 3 4 Frames and Sashes .. 3 4 Overall U factor.

6 3 4 Solar Heat Gain and Visible Transmittance .. 3 5 Determining Solar Heat Gain .. 3 5 Solar Heat Gain Coefficient (SHGC) .. 3 6 Visible Transmittance .. 3 6 Condensation Resistance .. 3 7 Impact of Glazing Type and Spacers on 3 8 Condensation Resistance .. 3 9 Outdoor Condensation .. 3 9 Condensation Between Glazings .. 3 9 Infiltration .. 3 10 Solar Properties of Glazing Materials .. 3 10 Transmittance .. 3 11 Reflectance .. 3 12 Absorptance .. 3 13 Infrared Properties of Glazing Materials (Emittance) .. 3 13 4. SUMMARY OF ALGORITHMS .. 4 1 THERM and WINDOW Algorithms .. 4 1 WINDOW .. 4 1 THERM : .. 4 1 WINDOW Computational Method .. 4 1 THERM Computational Methods .. 4 4 Total Product Calculations .. 4 6 U 4 6 Solar Heat Gain Coefficient (SHGC) .. 4 7 Visible Transmittance .. 4 7 Condensation Resistance .. 4 8 5. MODELING CENTER OF GLAZING WITH WINDOW .. 5 1 Overview.

7 5 1 Glass Library .. 5 2 Updating Glass Library from the IGDB .. 5 3 Glazing System Library Center of Glazing U fa ctor .. 5 4 Contents THERM7 / WINDOW7 NFRC Simulation Manual July 2016 Environmental Conditions .. 5 7 Coatings .. 5 9 Gas Fill .. 5 10 Laminated Glass / Applied Films .. 5 11 Solar Heat Gain Coefficient and Visible Transmittance .. 5 11 6. MODELING FRAME AND EDGE HEAT TRANSFER WITH THERM .. 6 1 Overview .. 6 1 Cross Sections to be Modeled .. 6 1 Draw the Cross Sections .. 6 4 Getting Started Drawings and DXF Files .. 6 4 File Properties Cross Section Type .. 6 4 Cross Section Orientation .. 6 5 What is Not Modeled .. 6 7 Deformable Parts .. 6 7 Frame Cavities .. 6 8 Slightly Ventilated Exterior Cavities .. 6 13 Modeling Sloped and Curved Surfaces .. 6 14 Modeling Sloped Sills .. 6 15 Importing Glazing Systems .. 6 16 Overview .. 6 16 Inserting Glazing Systems.

8 6 17 Multiple Glazing Options .. 6 18 Linking Glazing Cavities .. 6 21 Condensation Resistance .. 6 24 Defining Boundary Conditions .. 6 28 Overview .. 6 28 Assigning Boundary Conditions and U factor Surface Tags .. 6 32 Voids, Overlaps and Bad Points .. 6 37 Calculating Results .. 6 38 Meshing .. 6 38 Error Estimator .. 6 38 Required Settings for NFRC Simulations .. 6 39 Calculations .. 6 40 Results .. 6 42 Custom Frame Len gth .. 6 43 Importing Results into WINDOW .. 6 44 7. TOTAL PRODUCT CALCULATIONS USING WINDOW .. 7 1 Overview .. 7 1 Frame and Edge U factors from THERM .. 7 1 Center of Glazing U factors from WINDOW .. 7 2 Overall Product U factor, SHGC, VT, and CR Calculations .. 7 4 Individual Product SHGC and VT (SHGC 0 & 1, VT 0 & 1) .. 7 6 Sightline Grouping 7 8 Whole Product U factor With Dividers .. 7 10 Project Databases .. 7 11 Contents THERM7 / WINDOW7 NFRC Simulation Manual July 2016 8.

9 SPECIAL CASES .. 8 1 Overview .. 8 1 Meeting Rails .. 8 2 Modeling Meeting Rails .. 8 2 Steps for Meeting Rail U factor Calculation .. 8 3 Steps for Meeting Rail Condensation Resistance Calculation .. 8 8 Dividers .. 8 10 Internal Dividers (Suspended Grilles) .. 8 10 Modeling Steps .. 8 10 Air Flled Glazing Systems .. 8 11 Gas Filled Glazing Systems .. 8 18 Simulated Divided Lites .. 8 22 True Divided Lites .. 8 31 Door Caming .. 8 39 Storm windows .. 8 45 Modeling Steps .. 8 45 Storm WINDOW Example .. 8 48 Storm WINDOW Meeting Rails .. 8 53 Steps for Storm WINDOW Condensation Resistance Calculation 8 54 Skylights .. 8 57 Skylight Modeling Steps .. 8 57 Skylight Mounting Details .. 8 59 Example Flush Mounted Skylight Problem .. 8 60 Domed Skylights / Glass Block .. 8 70 Sloped Glazing Systems with Large Gaps: .. 8 72 Doors .. 8 73 Boundary Conditions for Steel Skin Doors .. 8 73 Spacers.

10 8 74 Overview .. 8 74 Linking Glazing Cavity properties (imported from WINDOW ) for Open Spacers .. 8 75 Non Continuous Thermal Bridge Elements .. 8 77 Modeling Steps .. 8 78 Equations .. 8 79 Example 1: Bolts in Curtain Wall .. 8 80 Example 2: Thermally slotted cross section .. 8 84 Example 3: Skip and debridge: .. 8 87 Site Built Fenestration Products (Curtain Walls, WINDOW Walls and Sloped Glazing) .. 8 90 Curtain Walls, WINDOW Walls, and Sloped Glazing .. 8 90 Curtain Wall Modeling Procedure .. 8 92 Garage / Rolling Doors .. 8 104 Sectional Garage Door (Insulated and Non Insulated) .. 8 104 Rolling Door .. 8 111 Creating a Laminate in Optics for NFRC .. 8 117 Overview .. 8 117 Laminate Interlayer Data .. 8 11 8 Constructing a Laminate in Optics .. 8 119 Contents THERM7 / WINDOW7 NFRC Simulation Manual July 2016 Creating an Applied Film Layer in Optics for NFRC Certification .. 8 131 Overview.