changing the world; one window, building, city, country at a time…. effective solar shading: from...
TRANSCRIPT
Changing the World; One Window, Building, City, Country at a Time….
Effective Solar Shading: From Components to Measured Whole Building Energy Impacts
Steve Selkowitz, Charlie CurcijaWindows and Envelope Materials GroupBuilding Technology and Urban Systems February 29th 2012
Overview
• U.S. Window Energy Situation and Goals
• Characterizing Energy Efficient Windows– Components to Systems– Systems to Performance
• Markets: Residential, Commercial– Ratings, Standards – Education and Deployment Programs
• Collaboration Opportunities
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Bloomberg BusinessWeek Magazine 2/27/2012
Innovation Pathways
ZX
Y
+ + + +
Tools and Knowledge Base
Enabling Technologies: Simulation and Testing
Innovative Products
High Perf BuildingsManuf.
A/E Firms
Fenestration Impacts on Building Energy ConsumptionBuildings consume 40% of total U.S. energy
• 71% of electricity and 54% of natural gasWindows Do Not Directly Consume Energy• Allocating Impact on End Use Energy is a Challenge
42%
57%
Business and Policy “Energy” Context• Severe downturn in New Construction Markets -> More
Retrofit
• Future energy costs trends?, unclear policy on carbon??
• “Technologies” reaching inflection points– E.g. Double glazing Triple: new factory investment– New technologies: “smart glass”– Shift from “Components” to focus on “Integrated Systems”
• Updates to Mandatory Codes and Standards
• Updates to Voluntary Programs: e.g LEED, EnergyStar
• New State, Federal Energy Savings Requirements– E.g. California: “all new buildings net-zero by 2030”
• New Performance Disclosure requirements like EPBD– City, State now; will likely spread; How is Envelope Assessed?
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• U.S. Windows Context– Windows cost Building Owners ~ $50B/yr in Energy Bills
– Highly “visible” component- window selection is “complex”
– Long-Lived Component- one chance to make the right decision!
– Vision: change windows from net loss to net supply
• LBNL Program Supports Zero Energy Window Vision– Comprehensive program: spans materials science to product R&D to
systems integration
– Technology – Policy - Codes/Standards – Education/Training
– Research – Development – Demonstration – Deployment
– All Climates, All Building Types, New and Retrofit
– Significant Industry Collaboration and Cost Share
– Measurable impact on technology, products, energy savings
– International Collaboration
Windows, Facades and Daylighting
Program Vision: “Zero-Energy Window”Energy Losers --> Neutral --> Net Suppliers
• Heating climates– Reduce heat losses so that ambient solar energy
balances and exceeds loss– Need lower heat loss technologies
• Cooling climates– Reduce cooling loads– Static control -> dynamic control
• All climates– Replace electric lighting with daylight
• Electricity supply optionsElectricity supply options– Photovoltaics-building skin as power source
Successes in U.S. Window Markets (Example: Improved Insulating Properties in Residential market)
• 1973: Typical Window:– clear, single glazed,– double or storm window in north,– Uaverage = 4.8 W/m2-K
• 2003: Typical Window:– 95% double glazed– 50% have a low-E coating – 30-65% energy savings vs. 1973– Uaverage = 2.5 W/m2-K
• 2030: Future Window:– Zero net energy use (typical)
• Net winter gain; 80% cooling savings– Uaverage = .6 W/m2-K
– Dynamic solar control
• Starting Today– Window -> Window System w/Shading– Annual Performance; Operations
Challenge for Window Shading/Attachments
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Next Steps/Challenges in U.S. (Globally)• Well Developed and Accepted (accurate) Methods to
characterize “Window Properties”– New Technologies Can Be Added
• Extend to Shading/Insulating Attachments• Properties-> Performance
– Metrics, Ratings and Standards
• Applications– Residential: New, Retrofit– Commercial: New, Retrofit
• Deployment– Market based programs– Education Materials
FROM COMPONENTS TO SYSTEMS
SystemLayerMaterial Building
SHADING DEVICE LOCATION
IndoorOutdoor Integral
USE OF REAL-TIME DETAILED COMPUTER MODELING • Optical modeling by ray-tracing of geometrical shapes
that have base material properties already measured• Optical modeling of material properties based on
detailed description of material structure• Thermal modeling (convection heat transfer) by
computational fluid dynamics/heat transfer (CFD/CHT) numerical modeling
Optical Thermal
• Conduction
• Convection• Visible & Solar• Far Infrared
EXISTING MODELING METHODS –
• Horizontal louvered blinds (Venetian blinds)• Vertical louvered blinds• Woven Shades• Perforated Screens
MISSING MODELING METHODS
• Horizontal and vertical projecting attachments• Honeycomb (cellular) shade.• General scattering shade. • Projecting attachments consisting of irregular
patterns type of materials
COMPLEX GLAZING DATABASE (CGDB)
• Conceptually comparable to International Glazing Database (IGDB)
• Designed for optically complex materials and devices– Venetian Blind slats– Woven Shades– Scattering (Diffusing) Interlayers– Scattering glass– Fritted Glass– Cellular shades– Other scattering layers/systems
EXISTING PRODUCT DATA in CGDB (2011)
• Initial CGDB content:– 100 Woven Shade screens– 14 Frits– 7 Venetian Blinds– 3 Diffusing Laminates
• WINDOW 6.3 and WINDOW 7
• Available at: http://windows.lbl.gov/software/CGDB
• Shared Global Database?
SHADING DEVICES WITH KNOWN ANALYTICAL MODELS
EachAngle of incidence
CGDBM(Scattering Material Database)
Example Work Flow for Venetian Blinds
• Measure slat material in spectrophotometer• Create XML data file and submit to LBNL
• LBNL adds to CGDB• Create Blind Geometry in WINDOW
Slat spacing, width, angle• Create Glazing System
• Perform Calculation
Angular U-factor, SHGC, VT
COMFEN/RESFEN/EnergyPlus input
Radiance input file
Not Implemented Yet
Manufacturer / Optical Lab
Simulator
Rating Info U-factor, SHGC, VT,
Tvis vs Hour/Month of year
Tvis vs Altitude/Azimuth
Transmittance Properties of a
45 Degree venetian blind in Stuttgart
Tvis vs Profile Angle
OTHER SCATTERING AND DIFFUSING PRODUCTS
CGDB (Scattering Layer Database
Scope of WINDOW 7/THERM 7
• Specular glazing
• Scattering glazing
• Vacuum Glazing
• Perforated screens
• Horizontal and Vertical louvered blinds
• Woven shades
• Glazing deflection
• IGDB/CGDB
• Third party developers interface
Extending Glazing and Façade Decision Support Tools to Include Shading/Attachments
Download http://windows.lbl.gov/software/ FY10 ~ 37,000 Downloads
Radiance Lighting /Daylighting
THERM(WindowFrame)
Optics(Window
Glass)
WINDOW+
Shading Systems
(Whole Window)
IGDB(Specular Glass Data Source)
CGDB(Complex Glazing Data Base)
RESFEN(Whole Building
Residential)
COMFEN(Whole Building
Commercial)
Commercial Windows Website Efficient Windows Website Design /Simulation Tools
Angular SHGC/U/VT
(Rating/Lableling)
?
EnergyStar
MEASUREMENT METHODS • Measurement of bi-directional transmittance and
reflectance of scattering products• Measurement of bi-directional transmittance and
reflectance of scattering materials (“thin” material coupon size)
• Thermal measurements of window attachments stand-alone and attached to prime windows
• Thermal measurements of products with complex geometrical surfaces
• Optical measurements of projecting attachments• Thermal measurements of projecting
attachments
Tools for Glazing/Shading/Daylighting Measurement + Validation • Façade/daylighting test facility
• Integrated Systems testbeds• Mobile Thermal Test Facility • IR Thermography chamber
• Large integrating sphere• Optics laboratory• Scanning Goniophotometer• HDR Imaging• Field Data Collection systems• Commissioning systems
• Virtual Building Controls Testbed• Daylighting controls laboratory
MEASUREMENT OPTIONS FOR OPTICAL PROPERTIES• Goniophotometer:
– Detailed angular resolution – Slow/expensive and only available at LBNL and a few other
places. – Limited number of wavelengths.
• Spectrophotometer: – Only normal incidence– Full spectral resolution
• Spectrophotometer + angle tubes:– Limited number of angles (9 currently)– Full spectral resolution
• Integrating sphere
MEASUREMENT DEVICES FOR OPTICAL MEASUREMENTS
• Spectrophotometer– Venetian blind slats– Fritted glass– Diffusing laminates
• Angle Tubes– Woven shades / insect screens
• Large Integrating Sphere – Tvis, large sample• Goniophotometer
– All Other Complex systems– BSDF
VIRTUAL GONIOPHOTOMETER (VGP)
ZX
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Virtual Goniospectroradiometer in Ray Trace software Ray Traced Geometric / Optical model
STANDARD METHODS OF EXPRESSING PRODUCT PERFORMANCE
• Indices of performance (U, SHGC, VT)
• Detailed performance information (angular SHGC, angular VT, BSDF, breakdown of convection and radiation heat transfer)
• Annual energy use (EP)
• Model any house/office, could form basis for seasonal or annual metrics– RESFEN, COMFEN in U.S.
BUILDING ENERGY SIMULATION OUTPUT
• Output to COMFEN
• Output to RESFEN
• Model any house/office, could form basis for seasonal or annual metrics
EDUCATION MATERIALS
• Information for building professionals– Designers: Architects, Engineers– Standards, Code Officials
• Information for consumers
• Information dissemination mechanisms– Web site– Fact sheets– Regional guides
• Product selection tools– Qualitative– Quantitative
Residential Window Market Education Material• www.efficientwindows.org- daily visitors > 2,000 in 2009
• Residential Windows: A Guide to New Technology and Energy Performance
Three editions: 1996, 2000, 2007
• Fact sheets, guides
• Online Window Selection ToolProduct data from EWC members
• Windows and Skylights but no Attachments
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BROCHURES FOR CONSUMERS, CONTRACTORS AND BUILDERS
Exterior Shades and Roller Shutters
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- Accurate performance prediction
- Improved simulation tools - Product Performance data- Validation of window retrofits through field testing
Field testing protocol for winter and summer performance
-Energy Star Ratings?-Voluntary Programs-Code Programs
-Information Programs, Websites-Tools for Purchase Decisions
WEB-BASED QUALITATIVE PRODUCT SELECTION TOOL
0.27 0.36
0.38
Best WindowWood Ultimate Double HungLow-e / AIR
SMART LABELS – Product Selection with Smart Phone AppsSelect Optimized Windows in your Local Building Supply Center
Commercial Buildings: Controlling Dynamic Shading
Advanced Technologies: Sensors;Controls;Hi R windows,Cool coatings;Switchable coatings;Automated Shading; Daylight-redirectingOperable windows,
Advanced Technologies: Sensors;Controls;Hi R windows,Cool coatings;Switchable coatings;Automated Shading; Daylight-redirectingOperable windows,
Program Activities:Simulation
Optimization
Lab test
Field Test
Demonstrations
Standards
Program Activities:Simulation
Optimization
Lab test
Field Test
Demonstrations
Standards
Human Factors: Thermal comfortVisual comfortSatisfactionPerformance
Human Factors: Thermal comfortVisual comfortSatisfactionPerformance
Business CaseManufacturingInstallationCommissioningReliabilityCost
Business CaseManufacturingInstallationCommissioningReliabilityCost
Advanced Facades and Daylighting:Program Goals:Net Zero Energy Balance for New and Retrofit
Enhanced View and Thermal Comfort
Reliable, cost effective operations
Tools to design, optimize, specify, control
Adoption/diffusion throughout industry
Advanced Facades and Daylighting:Program Goals:Net Zero Energy Balance for New and Retrofit
Enhanced View and Thermal Comfort
Reliable, cost effective operations
Tools to design, optimize, specify, control
Adoption/diffusion throughout industry
Application:All climatesAll Building typesNew-Replacement-Retrofit
Application:All climatesAll Building typesNew-Replacement-Retrofit
Decision ToolsBooks, GuidesWebsitesSimulation ToolsTestbeds
Decision ToolsBooks, GuidesWebsitesSimulation ToolsTestbeds
PartnersManufacturersOwnersArchitectsEngineersSpecifiersCode officialsContractorsUtilities
PartnersManufacturersOwnersArchitectsEngineersSpecifiersCode officialsContractorsUtilities
LBNL Façade Testbed Facility
2007-2009Automated
Shading
2003-2006Electrochromic
windows
Industry Advisory Groups:ManufacturersGlazing, ShadingFraming, LightingControlsDesignersArchitects, EngineersSpecifiersOwner/OperatorsPublic, PrivateUtilities
• Berkeley, South facing3 Rooms
• Changeable façade• Lighting, HVAC• Heavily instrumented• Static/Dynamic• Occupant Studies• Controls/Automation
Comparative Shading System Performance
Time Lapse from Tests in LBNL Façade Test Facility: Interior Daylight Luminance Patterns with Dynamic ShadingAutomated Shading Controls Glare Throughout the Day
LBNL Façade Test Facility
1 2 3654
321
FLEXLAB Testbed Facility - 2013
Exploring Intelligent Control Systems
Maximum performance requires full integration with building systems
Dynamic windows: Model-Based Controls (MBC)
• Need:– Real-time control of operable façade
components enables more optimal whole building systems integration
– Conventional open-loop or closed-loop PID control of commercial systems produce sub-optimal impacts on HVAC and lighting systems
• Goal: – Create low-cost, reliable, performance
based control solutions to optimize energy and peak demand savings, minimize discomfort, and improve IEQ
– Target: 30-50% annual energy use savings
– Determine value of MBC for industry: Aerospace & transportation model for rapidly prototyping complex control systems; does it work for facades?
Automated awning system with MBC to optimize daylight and solar control
Research on Daylighting and Advanced Facades
System Integration: Investment Tradeoffs
Heating
Cooling
Lighting
PeakCoolingLoad
ChillerSize
LightingDesignStrategy
Energy,PeakElectricDemand
CentralPower
Generation$
$$
$
$
Initial Cost Annual Cost
Office Eq.
Onsite Power
Generation
$
$
• Dimmable lighting– Addressable– Affordable (1/3 original cost estimate) – Multifunctional
• Automated Shading– Cooling load control– Glare control
New York Times HQ New York Times HQ
New York Times office with dimmable lights and automated shading
Occupied 2007
From Test Labs to From Test Labs to Large BuildingsLarge Buildings
Approach: Test Shade System Performance in a Full-Scale Mockup
• Shading, daylighting, employee feedback and constructability: ~4500 sf mockup
• Concerns with glass facade:— Window glare (Tv=0.75)
— Control of solar gain/cooling
— Daylight harvesting potential
• Real sun and sky conditions near construction site, 12-month monitored period
• Extend to all orientations with simulation
North
A
B
PG&E @ LBNL 2/16/2012
Website and On-Line Tools;Custom Design Guides
COMFEN:Façade Early Design ToolWebsite: www.commercialwindows.org
- Models Shading Systems: Thermal and Daylighting Impacts- Energy, Carbon, Comfort…- European Cities included
COMFEN 4.0 – FAÇADE OPTIMIZATION
Light Redirecting Louver system:Hourly/Monthly energy savings performance by depth in room
10 ft
30 ft
50 ft
– Lighting energy savings in 60-ft deep space: 40% (LightLouver), 28% (45° blind)
– Glare: 1-5% (LightLouver), 0% (45° blind)
– Optimized for 10AM-2PM, south, winter & summer altitude angles, clear sky
Hourly/Monthly glare index
COLLABORATIVE RESEARCH New IEA Task?? or….
• Hold kick-off meeting at LBNL: 6-9 months?• Define subtasks
– Define Scope and Priority– Optical properties of complex products– Thermal performance of complex products– Harmonized standards and rating procedures– Tools, Data- basis for ACTION
• Support from institutions and government• Support from trade associations and other
relevant public/private organizations
IMPROVE STANDARDIZATION
• Establish new ISO WG for windows• AHG for windows established 9/2011• Unify thermal calculations under TC 163• Unify optical calculations under TC 205• Change ISO 10077 with new science• Develop new ISO standard for modeling
complex glazing and shading devices,• Develop new standard for measuring optical
properties of complex products• Develop new thermal measurement standard for
window attachments
HARMONIZE RATING SYSTEMSBEST PRACTICE for MARKET IMPACTS
• Identify established rating systems and rating systems under current development
• Harmonized comparative product ratings, detailed ratings– Develops specific formats and infrastructure to allow
for easy access to more detailed product information
• Harmonize labeling systems?• Market-based Programs
– Assess global programs– Share best practice– Coordinate global activity
Saving the Planet with High Performance Windows and Shading Systems
ImproveOccupant Comfort,
Satisfaction and Performance
Add Value, Reduce Operating
Costs
Reduce Energy,
Greenhouse Gas Emissions
OccupantBuilding Owner Planet