Advanced Glazing and Window Technologies
Brandon Tinianov, Ph.D., P.E., LEED AP
Chief Technology Off icerSerious Materials
Our Mission: to reduce carbon dioxide emissions by one billion tons annually
• Building Energy Consumption• 62% goes to light ing, plugs, equipment• 38% goes to goes to condit ioning (heating and
cooling)
• Residential heating: 6.2 Q BTU• Residential cooling: 2.5 Q BTU
• Commercial heating: 2.1 Q BTU• Commercial cooling: 1.6 Q BTU
Breakdow n of the Opportunity
• Much of the condit ioning consumption is due to loss through the building envelope.
• More heat is lost is lost through the building envelope than is generated by the heating systems, • Solar heat gain and internal loads from equipment add up to
50%
• Reducing the envelope heat loss by 29% can save 30% heating energy
• Up to 80% of res. and 40% of comm. loads are due to solar heat gain via roof and w indows
Breakdow n of the Opportunity
The vast majority of energy loss is through the windows
Residential Examples
Envelope performance – IR Images
Superwindows’ ten hidden benefits
1. Saved heating energy (4–7x double glazing’s insulating value)—* the only benefit normally counted *
2. Save cooling energy, + fan/pump energy is proportional to flow3
3. Radiant comfort (half of comfort sensation) 4. Downsize/eliminate space-conditioning capacity5. Lower construction cost (avoids ducts, etc.)6. No perimeter zone heating7. Reduced fading from ~20less UV <380 nm8. Reduced noise9. Less/no condensation and sash rot10. Improved daylighting11. Human productivity
Benefits courtesy Amory Lovins
• High Thermal insulat ion – Advanced w indows and glazingsneed to move beyond the norm to deliver full frame thermal performance that is 2-10X better
• Dynamic glazings – These include both dynamic vision and dynamic thermal control. Viable technology w ill be in the market in 1-5 years.
• Building Integrated Photovoltaics (BIPV) – The f inal advancement for w indow technology. Viability and benefit is TBD.
Three Generations of Window s
Courtesy Amory Lovins ref. NYT 2008
Double Glaze: U = 0.5
+ Gain
- Loss
1973 1980 2010 2020
Single Glaze: U = 1
1990
Low “e” U = .35 (Energy Star)
2000
R6 Window U = 0.17(Dynamic Niche)R10 Window U = 0.10(Dynamic Wide Spread)
Three Generations of Window s
Source: Marc LeFrance, DOE
High Thermal Performance Glazing
DOUBLE GLASS PATENT, Thomas Stetson – 1865
Key elements to thermal performance
Image courtesy Serious Materials
Triple pane (SCF) thermal performance
Center of glass performance for one current IGU/w indow manufacturer
Image courtesy Serious Materials
Triple pane (SCF) thermal performance
Center of glass performance for one current IGU/w indow manufacturer
Image courtesy Serious Materials
Incorporating high performance frames
Typical Aluminum, Dual Pane Low-E
FG insulated frame ,Triple pane
Note: Modeled via THERM 6.1 Simulation software, Lawrence Berkeley National Labs
Models of window cross sections – aluminum vs fiberglass
• U factor (FF) = 0.151• U-factor (COG) = 0.14• SHGC = 0.27• Tvis = 0.49
• U factor (FF) = 0.399• U-factor (COG) = 0.24• SHGC = 0.45• Tvis = 0.64
Image courtesy Serious Materials
Air infiltration as the final piece
• Air inf ilt rat ion is a topic of grow ing focus.
• Minimally tested – AAMA only requires a pass / no pass level of performance at this t ime.
• Passive House more thoroughly addresses this w ith a limits. This theme may gain tract ion in the future.
Dynamic glazing
• A dynamic glazing is one that can act ively change its physical propert ies of either:• Visual Transmission (Tvis)• Thermal/Infrared transmission (SHGC)• Or both
• A dynamic glazing is one that can act ively change its physical propert ies via:• Electrical/user control - actively• Environmental condit ions - passively• Or both
Active dynamic glazing - electrochromics
• Sage page
•Selkowitz study
Images courtesy SAGE Electrochromics
Typical embodiment with visible light transmission (Tvis) switching between 5 and 65% (LBNL)
Benefits:• Dynamic daylight control• Reduced HVAC loads
Concerns:• High cost (> $80/sf)• “ Clear” mode still somew hat
hazy w ith some electrochromic technologies
Active dynamic glazing - electrochromics
Images courtesy SAGE Electrochromics
Passive dynamic glazing
Benefits:• Dynamic daylight control• Reduced HVAC loads• Low er installed cost (~
$20/sf)• Possible as a retrofit
Concerns:• Availability• Unw anted activation • Service life
Images courtesy RavenBrick LLC
Passive dynamic glazing
Benefits:• Dynamic daylight control• Reduced HVAC loads• Low er installed cost (~ $20/sf)• Possible as a retrof it
Concerns:• Availability• Unw anted activation • Service life• Spotty visual f ield
Images courtesy RavenBrick LLC
Other dynamic glazing
• Hybrid dynamic glazing - Sw itches on per environmental condit ions, off w ith voltage:• Similar cost to tradit ional EC systems• Wiring and controls are required• Better tuned to energy savings than pure active types
• ‘ IR specif ic’ passive glazing:• Extremely low cost compared to other technologies• Pure passive, no controls • No change to Tvis• Available as a retrofit solution
Dynamic glazing - $ benefits
• A 2003 ASHRAE study found that buildings with low-E glass saved an average of 8-15% total annual energy (heating, cooling, and ventilation) costs,
• Addition of dynamic glazing (where SHGC varied from 0.26 and 0.40) saved an additional 6-19%.
• Low-E glass reduced peak cooling loads by 2-14%, and dynamic glazing an additional 5-38% reduction in peak cooling load, allowing downsizing of the building’s AC system.
• The report concluded that dynamic glazings “offer the potential for significantly greater HVAC savings than can be achieved with currently available high-performance windows”
• For large buildings across multiple climate zones, the pay-back is about 5-8 years (@ $25/sf).
Source: Energy Savings of EC Windows in the US Commercial Buildings Sector, LBNL, 2004
Source: Performance Criteria for Residential Zero Energy Windows, 2007
• A residential study w ith two teachings:
• Dynamic glazing can have a signif icant posit ive energy impact
• Effective dynamic w indows require a low u-factor to work
Dynamic glazing - research
BIPV glazing
courtesy SunTech Corp.,
Building integrated photovoltaics represent the third generat ion of high performance glazings
• Depending on the format, BIPV provides moderate power generation (avg. 45W - 100W/m² )
• May be integrated into required structures such as atria, shades, aw nings
• In some cases, can be used for view ing surfaces
• Is not f inancially viable at this t ime
BIPV glazing – light transmitting
Images courtesy SunTech Corp.,
Light transmitt ing surfaces w ith energy output of approximately 100 W / m²
Current state-of-the-art PV generates approx 1000 W / m²
•Crystal ball multiple technologies
•$/$ has to work out
10% light transmission44 W /m²
BIPV glazing – viewable
•Crystal ball multiple technologies
•$/$ has to work out
5% light transmission50 W /m²
BIPV glazing – viewable
•Crystal ball multiple technologies
•$/$ has to work out
Images courtesy SunTech Corp.,
1% light transmission55 W /m²
BIPV glazing – viewable
Advanced Glazing Case study - Retro
• SG 8 3/16_SB60• R-value: 7.7, SHGC: 0.34, VT: 0.63• Interior Glazing retrofit, $4/sqft labor• Product cost in volume, $7.21/sqft
The Situation The Solution
• Circa 1962 windows, 6 inches deep• R-value: 1.75, SHGC: 0.50, VT: 0.47• 1662 windows, 60,000 sqft total
SCF IGU Package
Image courtesy Serious Materials
Two energy model results
Base case
Modeled improvements
Advanced Glazing Case study - Retro
Advanced Glazing Case study- Retro
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
Post Energy Efficiency Retrofit with Current
Windows
Serious Windows Retrofit, R7.7
Gas Consumption / Year(BTU x000,000,000)
33% Reduction
0.00
500,000.00
1,000,000.00
1,500,000.00
2,000,000.00
2,500,000.00
Energy Savings (NPV) Investment in Serious Windows
SCF Cost-Effectiveness
SCF Retrofit R 7.7
SCF Retrofit R 7.7
Case study – New hi-rise office
• 20 story structure
• 400,000 ft2. total area
• Window-Wall-Ratio is 50%
while the
• Lighting density is 0.8 W/ft2
• Equipment power density is
0.5 W/ft2
Image source: http://www.mysketchuprenderings.com/riverpointe-office-building
Case study – New hi-rise office
Office Energy Cost Savings (compared to PPG SB60)
0%
2%
4%
6%
8%
10%
12%
14%
16%
P1-
AT
L
P3-
AT
L
P4-
AT
L
P5-
AT
L
P1-
MIN
P3-
MIN
P4-
MIN
P5-
MIN
P1-
PH
X
P3-
PH
X
P4-
PH
X
P5-
PH
X
P1-
SE
A
P3-
SE
A
P4-
SE
A
P5-
SE
A
En
erg
y C
ost
Sav
ing
s [%
]
Source: Architectural Energy Corporation, 2009.
Case study – Example hi-rise office
25-year Life Cycle Savings(over single clear glazing, 7% fuel escalation rate)
$9
$10
$11
$12
$13
$14
$15
$16
ATL
- SB6
0
ATL
-SB
70XL
ATL
- SG
-6
ATL
- SG
-8&
9
ATL
- SG
-20
MIN
- SB
60
MIN
-SB
70XL
MIN
- SG
-6
MIN
- SG
-8&
9
MIN
- SG
-20
Life
Cyc
le S
avin
gs [m
illio
ns o
f $]
Source: Architectural Energy Corporation, 2009.
25-year Rate of Return (over single clear glazing)
0%
5%
10%
15%
20%
25%
ATL - SB70XL ATL - SG-6 MIN - SB70XL MIN - SB-6
Rat
e of
Ret
urn
[%]
3% escalation
5% escalation
7% escalation
Source: Architectural Energy Corporation, 2009.
Case study – Example hi-rise office
A last glazing case study - sound the alarms
Source: McGraw-Hill, Green Building Retrofit and Renovation: SmartMarket Report, 2009.
A last glazing case study - sound the alarms
Source: McGraw-Hill, Green Building Retrofit and Renovation: SmartMarket Report, 2009.
Summary
Source: Mike Noble, BKL Consultants, Ltd.
• Glazing is a classic design problem that requires balance of– Thermal comfort, energy efficiency, light quality– View, daylight, connectivity with the outdoors
• First priority to building envelope performance, national energy efficiency
• 50% by 2030 would have– Saved 3 Q BTUs– Reduced GHG equal to 150 M metric tons of CO2 (28M cars)
• 50% by 2050 would – Saved 100 Quad BTUs– Reduced GHG equal to 6 B metric tons of CO2