Changing the World; One Window, Building, City, Country at a Time…. Effective Solar Shading: From Components to Measured Whole Building Energy Impacts.

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)

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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