Image Source : Colt, Google Images
Reducing Energy Consumption & Improving Indoor Environmental Quality through Dynamic Shading Uma Patwardhan – MS in Sustainable Design – August 2012
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TABLE OF CONTENTS 1. Topic Justification 2. Case studies & Commercially Available Products 3. Health & Productivity Benefits 4. Hypotheses 5. Scope of work 6. Field experiments 7. Controls Decision flow chart
8. Simulation & Energy Savings 9. Triple Bottom Line calculations 10. Conclusion
11. Future Research
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WHY OFFICES ..... According to 2003 Commercial Buildings Energy Consumption Survey (CBECS): • 4,859,000 total commercial buildings in USA • 19% of total energy consumed by commercial sector • 57% energy consumed in heating, cooling and lighting in commercial buildings. • 30% of commercial buildings are offices comprising 33% of total floor space • 33% of total energy in commercial sector consumed in office buildings
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Indoor Environmental Quality Issues Images Source : Google Images
RADIANT TEMPERATURES
LIGHTING LOADS
GLARE
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Dynamic facades can help reduce energy loads and improve occupant comfort
Image Source : www.lowenergyfacades.gov (LBNL)
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SUCCESSFUL INSTALLATIONS % reduction in energy consumption represents reduction due to all sustainable design solutions including solar shading devices Project Name
Terry Thomas
SBL Offices
Alley 24
Bank of America
LOTT Clean Water Alliance
Heifer International Headquarters
Manitoba Hydro
Interserve
Function
Commercial
Commercial
Mixed Use (Retail, Office, Residential)
Commercial
Commercial
Commercial
Commercial
Commercial
Location
Seattle, WA
Linz, Austria
Seattle, WA
New York
Olympia, WA
Little Rock, AR
Winnipeg, Canada
Leicester, England
KPMB Architects
CPMG Architects
Architect
Weber Thompson
Helmut Schimek, Linzli
NBBJ
Cook +Fox
Miller Hull Patnership LLC
Polk Stanley Rowland Curzon Porter Architects, Ltd
LEED GOLD for core and shell and LEED PLATINUM for commercial interiors
NA
LEED Silver
LEED Platinum
COTE Award
LEED Platinum
LEED Gold
Passivhaus accredition
5" & 3" Louvers
Sun shades & Light shelves
Venetian blinds
3" Motorized Venetian Blinds
View
Recognition
Type of Solar Shading Device
2" Chained & 4" Motorized Motorized venetian Venetian Blinds Blinds with sun with Sun Tracking tracking
Automated louvers
Louvers
Position (Interior / Exterior )
Interior + Exterior
Exterior
Exterior
Interior
Interior + Exterior
Interior + Exterior
Interior + Exterior
Exterior
Manufacturer
NA
Colt
Nysan, Hunter Douglas
Nysan, Hunter Douglas
Nysan, Hunter Douglas
Kawneer
Nysan, Hunter Douglas
Levolux
Special features
Operable windows along with automated louvers
PV cells on louvers
NA
Motorized or manual
NA
NA
Daylight blinds perforated
NA
% reduction in energy consumption
30%
40%
49%
50%
50%
52%
65%
Upto 90%
Data & Image Source
Weber Thompson
Colt
Hunter Douglas
Hunter Douglas
Hunter Douglas
Kawneer
Hunter Douglas
Levolux
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ENERGY, HEALTH & PRODUCTIVITY BENEFITS
•
In 2001 simulation study by Carbonari et al identify 8.6% annual energy savings due to application of adjustable louvers as compared to fixed louvers or no shading devices to south façade in moderate climate. They also identify 12.5% - 20.8% reduced energy consumption for buildings with southern orientation in climate that demands both heating and cooling .
•
In 1990 building case study in California, Benton & Fountain identified 50% savings in annual lighting, cooling and ventilation energy consumption and 15% reduced absenteeism with daylighting design which integrates layout, orientation, window placement, type of glazing, light shelves and ceiling.
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HIGH PERFORMANCE PRODUCTS Performance Criteria
Manufacturer Materials
1
Type
2
Location
3
Application
4
Fixed Adjustable / Dynamic (Manual, Automatic, Sensors, Timer, Computer) Interior (I) Exterior (EX) New Construction Retrofit Both
Additional Strategies required / Special Features
7 8 9 10 11
Aluminum
P P P
Satisfaction
P
Maintenance factor Ease of installation / operation Cost ($) Payback period (years)
Hunter Douglas Aluminum, Steel, Wood P P
Speciality Louvers
Bright Shelf
Retrolux U
RetroFlex
Retrolux A
Specialist Venetian Blinds
InLighten Light Shelf
Hunter Douglas
Hunter Douglas
Hunter Douglas
Retro Solar
Retro Solar
Retro Solar
Levolux
Kawneer
Steel
Wood, Glass, Metal
Aluminum
Aluminum
Aluminum
Aluminum
Aluminum
Aluminum
P
P
P
P
P
P
P P
P P
P
P
P
P
P
Concave up shape helps light redirection
Reflects most of solar incidence back before admitting light indoor
Dynamic Louvers Brise Soleil
Hunter Douglas Aluminum, Wood, Glass P
P
P
P P
P P P
P P P
P P
P
P
P
Perforated slats to permit view even when closed P P P P
Quality of light / glare - no glare
Aerofoil Louvers
P
Day Lighting / Light redirection Glare Reduction Solar Gain Control Access to nature when fully closed (% of view) Indoor Temperature Control Occupant
5 Results achieved 6
Interior MakroBlind Louvered Shade Hunter Douglas
Permits view Highly while reflecting reflective maximum solar mirrored finish incidence back preventing glare P P P
P P
P P 100%
P P
P
P P
P
P P
P P P P P
P
P
P
P
P P
P P P P
Effortless tilting for cleaning
P P P
P P 100% P Easy
P
P
Note : This is not an exhaustive list of products available commercially today, nationally and internationally. Similar type of products are available with various manufacturers with slight difference in specifications.
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HYPOTHESES Blinds with dynamic control (different slats positions as per orientation, seasonal & daily variation) 1. Reduces operative temperatures and radiant surface asymmetry thus reducing energy loads
2. Acts as dynamic insulating layer to faรงade 3. Prevents glare while maintaining the desired daylight levels even on cloudy days thus reducing lighting loads 4. Provides access to view 5. Improves occupant health and productivity by providing thermal and visual comfort 9
SCOPE OF WORK 1. Case Study : To identify energy efficient projects 2. Online market survey : To identify high performance commercially available products 3. Field experiments and Energy Plus simulation : To quantify energy loads reduction due to blinds deployment 4. Literature review : To identify occupant health and productivity benefits with shading strategy 5. Triple Bottom Line calculations 6. LEED credits 10
FIELD EXPERIMENTS 11
EXPERIMENTS LOCATION
Image Source : Google Images
12 Center for Building Performance & Diagnostics, CMU
Equipment & Sensors 1. 2. 3. 4.
1
2
3
4
Black Globe Thermometer HOBO Sensor Nikon Coolpix, Fish Eye lens Thermographic Camera
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Experiments Summary SOUTH EAST & SOUTH WEST BAY EXPERIMENTS Blinds Open vs Blinds Closed – Sunny Warm Blinds Open vs Blinds Horizontal (0°) Blinds Open vs Blinds 45° Blinds Closed vs Blinds Horizontal (0°) – Cloudy Hot Day Blinds Closed vs Blinds 45° Blinds Horizontal (0°) vs Blinds 45° - Partly Sunny Hot Day
WEST BAYS SIDE BY SIDE EXPERIMENTS Blinds Open (Control) vs Blinds Closed Blinds Open (Control) vs Blinds Horizontal (0°) Blinds Open (Control) vs Blinds 45° Blinds Closed (Control) vs Blinds Horizontal (0°)
Blinds Closed (Control) vs Blinds 45° Blinds Horizontal 0° (Control) vs Blinds 45°
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Methodology for Field Experiments •
Calibrated the HOBO sensors by keeping them next to each other on sunny and cloudy days and comparing the readings
•
In South bays, conducted experiments with blinds open and close to calibrate the two bays but found that the readings were different due to the influence of East and West and therefore side by side experiments were not possible.
•
Conducted experiments in South East and South West bays with blinds slats in different positions for seven days each. To normalize the data, identified days with similar outdoor conditions with respect to outdoor temperature and solar radiation and compared the effects of different blinds positions
•
Since these experiments were conducted during Swing season, finding comparable days was difficult. So, the experiment setup was moved to West bays where side by side experiments were conducted
•
Thermographic camera was used to analyze the surface radiant temperatures with the blinds intervention
•
Results from the field experiment were used in simulation to achieve percentage energy savings 15
Limitations •
Tests done in existing building with existing installations
•
Open plan office with partitions not upto the ceiling allows heat dispersion between adjoining bays
•
Unequal number and different types of blinds installed internally as well as externally. Difficult to quantify the impact of a specific type and location
•
Clerestory has light redirection devices allowing daylight penetration even with other blinds closed.
•
External louvers always closed thus blocking a considerable amount of direct solar incidence on glazing
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South Test Bays
SOUTH EAST
SOUTH WEST 17
BLINDS OPEN VS BLINDS CLOSED SOUTH EAST •
Blinds Closed maintain up to 2°F lower ambient temperature with no peak at morning and 8°F lower radiant temperature
•
Daylight levels sustained at 100 – 150 lux with blinds closed
•
Upto 3°F free cooling at night with blinds open
•
Blinds Closed maintain 8°F lower radiant temperature with no peak in afternoon
•
Daylight levels sustained at 150 – 300 lux with blinds closed
•
Upto 3°F free cooling at night with blinds open
SOUTH WEST
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BLINDS HORIZONTAL (0°) VS BLINDS 45° SOUTH EAST
•
Blinds 45° maintain 1° - 2°F lower ambient temperature with no peak at morning and 6°F lower radiant temperature
•
Daylight levels sustained at 200 lux with blinds 45°
•
Upto 1°F free cooling at night with blinds horizontal
SOUTH WEST
0°
45°
•
Blinds 45° maintain 0.5° - 1°F lower ambient temperature with no peak in afternoon
•
Daylight levels sustained at 400 – 600 lux with blinds closed
•
Upto 1°F free cooling at night with blinds open 19
BLINDS CLOSED VS BLINDS HORIZONTAL (0°) SOUTH EAST •
Daylight levels sustained at 200 lux with blinds closed
•
Upto 2° F free cooling at night with blinds horizontal
0°
CLOSED
SOUTH WEST
Since the day with blinds horizontal began at much warmer temperature than the day with blinds closed, early morning indoor temperature comparison is not done
•
Daylight levels sustained at 300 lux with blinds closed except for slight peak in the afternoon
•
Upto 1° F free cooling at night with blinds open
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KEY FINDINGS SUMMARY SOUTH EAST OPERATIVE TEMP RADIANT PEAK SHAVING NIGHT TIME FREE COOLING BLINDS OPEN VS CLOSED
2° F
8° F
3° F
BLINDS HORIZONTAL VS 45°
1 - 2° F
6° F
1° F
BLINDS CLOSED VS HORIZONTAL
NA
NA
2° F
SOUTH WEST OPERATIVE TEMP RADIANT PEAK SHAVING NIGHT TIME FREE COOLING BLINDS OPEN VS CLOSED
NA
8° F
3° F
BLINDS HORIZONTAL VS 45°
0.5 - 1° F
NA
1° F
BLINDS CLOSED VS HORIZONTAL
NA
NA
1° F
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SURFACE RADIANT TEMPERATURES ANALYSIS 1 : 79.7 °F
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2 : 80.5 °F External louvers keep lower temperature on upper field of glass
2
1 : 81.1 °F 2 : 85.4 °F 2
1
External blinds keep lower temperature than interior blinds
1 : 83 °F 2 : 84.1 °F 2
1
Sophisticated light redirection blinds keep lower temperature than upward concave blinds 22
West Test Bays
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BLINDS CLOSED (CONTROL) – AMBIENT TEMPS
•
Blinds Open show maximum heat gain
•
Blinds 45 ° show some heat gain as compared to blinds closed
Base Case
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BLINDS CLOSED (CONTROL) – RADIANT TEMPS
•
Blinds Open show maximum heat gain
•
Blinds 45° shows slight peak in radiant temperature unlike blinds closed
•
Trade-off between energy savings and outdoor view
•
Blinds 45° can be proposed instead of blinds closed to provide access to view
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SURFACE RADIANT TEMPERATURES ANALYSIS MORNING
BLINDS CLOSED
1
BLINDS OPEN
2
78.4 °F
1 : 75.6 °F 2 : 77.4 °F AFTERNOON
BLINDS CLOSED
1
BLINDS OPEN
2
1 : 82.3 °F 2 : 87.4 °F External louvers [1] maintains lower temperature than internal blinds
88.6 °F Blinds Open increase the surface radiant temperature by 1° F as compared to Blinds Closed 26
CONTROLS DECISION FLOW CHART
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ENERGY PLUS SIMULATION
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SIMULATIONS & ENERGY SAVINGS
BASE MODEL
SOUTH BAYS April 10th To 13th : Blinds Open vs Closed
12.46% May 1st To 31st
: Blinds Horizontal vs 45°
3.94% WEST BAYS May To August : Blinds Open vs Closed
2.24%
MODIFICATIONS • • •
• • •
PNNL prototype model for small office building in Climate Zone 5A Based on DOE reference model, updated with ASHRAE 90.1.2010 standards Four perimeter zones (16.4 ft deep) and core Window to Wall Ratio: South – 24.4% Other orientations – 19.8% Unitary HVAC system Daylighting controls as per ASHRAE 90.1 standards
•
Matched building orientation to the existing
•
Used Pittsburgh weather file
•
Changed the set point schedules zone wise according to the results from the field tests
•
Results reflect only cooling energy savings and does not include lighting loads 29
TRIPLE BOTTOMLINE CALCULATIONS WEST Total Building investment costs Initial investment costs
$ 261 Per sq ft $ 0.36
Per employee $ 261
$ 0.01
$ 3.16
First year savings:
First Tier Considerations
ECONOMIC Second Tier Considerations
ECONOMICS + ENVIRONMENT Third Tier Considerations
ECONOMICS + ENVIRONMENT + EQUITY
Energy savings
4.85 %
ROI (Economic) 15 year Net Present Value (Economic only) Energy savings
$ 96 0.12 kWh
25 kWh
$ 0.01
$ 1.22
First year Savings : Air pollution emissions Cumulative ROI (Economic + Environment)
7%
Cumulative 15 year Net Present Value (Economic + Environment)
$ 133
First year savings: Health benefits Productivity increase (3% x 35% x 45,000) Absenteeism Annual Baseline Savings Cumulative ROI (Economic + Environment + Equity) Cumulative 15 year Net Present Value (Economic + Environment + Equity)
-
-
$ 2.36
$ 473
-
-
$ 2.38
$ 477
732 % $ 14,509 30
LEED 2009 NEW CONSTRUCTION CREDITS
Energy & Atmosphere (EA) Credit 1: Optimize Energy Performance Indoor Environmental Quality (IEQ) Credit 7.1: Thermal Comfort—Design
Indoor Environmental Quality (IEQ) Credit 8.1 & 8.2: Daylight and Views Innovation in Design (ID) Credit 1 – Possibility can be explored
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USE SOLAR SHADING DEVICES WITH DYNAMIC CONTROLS TO SAVE ENERGY AND INCREASE OCCUPANT COMFORT !!
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FUTURE RESEARCH
•
Complete the remaining set of experiments
•
Perform controlled field experiments
•
Test single type of blinds at a time on different locations (internal & external)
•
Develop model of existing structure and simulate using real time weather data
•
Triple Bottom Line Calculation for the entire project
•
Studies relating health & productivity benefits with blinds intervention
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Special Thanks to ‌‌
Synthesis Advisors : - Vivian Loftness - Azizan Aziz - Erica Cochran EEB HUB Team Members: - Bertrand Lasternas - Flore Marion Energy Modeling expert : - Omer Karaguzel
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