LBNL Software for Analyzing Window Thermal Properties and Energy-Efficiency

Transcription

1 LBNL Software for Analyzing Window Thermal Properties and Energy-Efficiency Dariush Arasteh, Robin Mitchell, Christian Kohler, Mike Rubin, Steve Selkowitz, Eleanor Lee, Joe Huang ; Charlie Huizenga, UC Berkeley Charlie Curcija, Carli Inc. John Carmody, U. of Minnesota

2 Glazing and Façade Tools Glazing, Window and Façade Tools Essential for design of new products Supplement, replace testing - virtual product development Window Rating and Labeling Building Design Tools Allow integration strategies to be explored Allows façade performance to be optimized - Daylighting vs Cooling tradeoffs - Energy vs Comfort Tradeoffs HVAC - Façade integration Explore commissioning and operational issues

3 PC Tools (WINDOW+) IGDB (Specular Glass Data Source) Optics (Window Glass) THERM (Window Frame) calculation CGDB (Complex Glazing Data Base) WINDOW (Whole Window) Design / Simulation Tools DOE-2, EnergyPlus Radiance COMFEN (Whole Building Commercial) RESFEN (Whole Building Residential)

4 PC Tools (WINDOW+) Optics Analyze glazing optical properties IGDB Database of glazing materials CGDB Database of complex glazing materials THERM Analyze two-dimensional heat transfer through building products WINDOW Analyze window thermal and optical performance RESFEN Calculate the heating and cooling energy use of windows in residential buildings COMFEN Calculate the heating and cooling energy ue of windows in commercial buildings

5 Objectives and Relevance Modeling Tools are an Enabling Technology 4.7 Quads/yr used by windows [DOE MYP 2/18/05]; Advanced products can reduce this to zero (or better) How does one know what a product s performance is? It is important to know performance potentials before a product is developed. Modeling tools have emerged as the metric to rate products and guide product development. Tools need to lead product development.

6 Tools - History 1980s WINDOW 2, 3 used to guide development of low-e, gas filled products; for reporting product literature NFRC ratings founded on use of WINDOW and FRAME as unbiased, accurate tools 1990s: THERM developed for more versatile 2D analysis RESFEN for residential annual energy simulations IGDB glazing product database Optics for modifying glazing layer properties w/o testing 2003 WINDOW5, THERM5 updates make tools consistent with ISO COMFEN development (not covered here)

7 Why not testing? $ 1 day in a test lab vs. < 1 hr Up to 50K+ to build a prototype before you even know its performance Uncertainty in test results clouds development BUT, software tools must be accurate

8 Understanding Thermal Performance Algorithm Development and Basic Research Software Development User Interface Implementing Technical Algorithms Component Data Quality Assurance of Software Maintenance User Support and Training Validation

9 WINDOW+6 Build on WINDOW+5 universal use Improve technical capabilities so that tools will aid in design of products for Zero Energy Buldings Provide support to industry and other users Ensures tools are used properly Provides feedback on needs With industry, develop underlying component data

10 User Support 7,000 downloads in FY 04 Answer questions and solve problems by and telephone Update Web Knowledge Base

11 How are Tools Used? Design of new products Guidelines for Product Selection Energy Star Compliance and Analysis NFRC Ratings New Product Design Energy Star Map Product Selection Guidelines NFRC Label

12 Optics a Virtual Glass Laboratory Calculate and edit optical properties of glass Change glazing thickness Switch glazing coating Construct glazing with applied films Construct glazing with laminate

13 WINDOW State-of-the-art, Microsoft Windows -based Integrated database of properties Calculates total fenestration product thermal and optical performance indices U-factor Solar Heat Gain Coefficient Visible Transmittance Condensation Resistance NEW: complex glazing systems Venetian Blinds Fritted glass Woven shades calculation

14 Background: Layer types specular diffuse Shading device

15 Why WINDOW 6? Nothing changes for simple products, no change in calculation or modeling Functionality added for complex products, such as: Venetian Blind Woven cloth shades and bug screens Fritted / silk-screened glass

16 Complex Glazing Systems Manufacturers, engineers, architects, builders want to know their performance characteristics Cloth Shades / Bug Screens Venetial Blinds / Integral shades Fritted/Patterned Glass Light Redirecting Products

17 WINDOW6 - Current State Research Version of WINDOW6 and THERM6 available at: A model for complex glazings is in WINDOW6 and THERM6 Venetian blinds and perfect diffusers are implemented Import feature for other complex glazings

18 IGDB WINDOW s Glass Library

19 Shade Material Library Define different materials for shading systems (such as venetian blind slats) Use in the Shading System Library Precursor to Complex Glazing Database calculation CGDB (Complex Glazing Data Base)

20 WINDOW6 - Shading Layers Define different types of shading systems such as venetian blinds Use in the Glazing System Library

21 WINDOW6 Complex Glazing Glazing systems are constructed from glass and gas libraries Shading systems are added to the glazing system Shading Layer

22 WINDOW6 Final Results Construct complete window from glazing system (standard or with complex layers), standard frames and dividers

23 WINDOW6 - Complex Glazings Results RESULTS: Venetian Blind Tilt = 40 o, Window Orientation = South (180 o )

24 THERM6 State-of-the-art, Microsoft Windows -based Two-dimensional heat transfer analysis computer program Calculates fenestration product thermal performance indices (i.e. frame and edge U-factors, temperature data for Condensation Resistance calculations) NEW: Complex glazing Interior Shading Device

25 Background THERM5 Finite element mesh Isotherms Infrared

26 Advantages of THERM Geometry import from CAD programs using DXF. Minimizes the amount of user judgement required in simulating a window. Not limited to windows; heat transfer effects in any building component can be analyzed. NFRC adopted software simulation tool

27 THERM -Technical Approach Use existing algorithms from other applications as available Develop new algorithms as needed from literature, standards, or original research Validate software with comparisons to hot box data MoWiTT measurements IR Thermography other computational results

28 Modeling

29 Modeling Sloped Skylight

30 Spacer Modeling

31 Link to WINDOW Virtual Thermograms can provide a full temperature map of a window's interior surface

32 WINDOW7 and future efforts Dynamic windows with multiple and variable states Extension of complex glazings to integrated facades Modeling of highly insulating systems (R10) with certainty Outputs and interface for Energy Plus to make effective use of complex product output

33 Tools for Assessing Energy Impact of Windows in Buildings Residential Windows Book Efficient Window Collaborative RESFEN Commercial Book Commercial Website COMFEN

34 RESFEN Whole House Impact Calculates the heating and cooling energy use of a building: for a specific house in a specific location with specific window products Consumers have confusing technical information: U, SHGC, AI Can compare different window options Can help select energy-efficient windows RESFEN5 (2005)

35 RESFEN 5 Improvements More locations US and Canadian cities Libraries: Locations can add new locations Window hooks to WINDOW5 Packages can define envelope insulation packages Utility Rate Libraries can define any gas and electric utility prices Database structure for input values and results Results can be exported to spreadsheet Report of results can be generated

36 RESFEN

37 Tools for Assessing Window Energy Impact in Commercial Buildings w/ John Carmody, Univ. of Minnesota Windows for High Performance Commercial Buildings- Book Commercial Fenestration Website Extends book, Pre-calculated data displayed COMFEN Internal EnergyPlus engine Flexible analysis and data display Links to other tools, engines

38 Design Guides/Information Sources Tips for Daylighting Guide: Selective Glazings Application Guide: IEA Daylight in Buildings Source Book: High Performance Building Facades: Window Systems for High Performance Buildings: Norton Press 2004

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43 COMFEN: Optimize Commercial Building Façade Design and Operations Simulation based decision support Project-specific decision making: Designers, owners Address real world issues across design process: energy, demand, glare, comfort, How do I.? What are the consequences of? - Analyze - Compare - Find - Optimize EnergyPlus and Radiance engines ( fast versions) Annual performance: energy, demand Peak, hourly profiles, etc Daylight quantity, quality; glare and visibility Toolkit: Product specific data to support tools Commissioning guidance Case studies, field measurement kit

44 Status DOE-2 building models ported to EnergyPlus Timing runs identified problems with slow speed for the EnergyPlus. Explored mechanisms to speed up output. Developed coefficient based Radiance module that can be added to the tool to do annual Radiance modeling Explored interface options with potential partners and users. Met with industry and other end users to discuss potential partnerships for tool development. Reduced funding will slow effort but working tool expected late 2006