Developing the Next Three Generations of Zero-Energy

Transcription

1 Developing the Next Three Generations of Zero-Energy Windows Brandon Tinianov, Ph.D., P.E., LEED AP Chief Technology Officer Serious Materials Our Mission: to reduce carbon dioxide emissions by one billion tons annually

2 Envelope performance IR Images

3 Alaska Pipeline Energy Goes Out the Window Residential heating: 6.2 Q BTU Residential cooling: 2.5 Q BTU Commercial heating: 2.1 Q BTU Commercial cooling: 1.6 Q BU Comparison courtesy Amory Lovins

4 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 flow 3 3. Radiant comfort (half of comfort sensation) 4. Downsize/eliminate space-conditioning capacity 5. Lower construction cost (avoids ducts, etc.) 6. No perimeter zone heating 7. Reduced fading from ~20% less UV <380 nm 8. Reduced noise 9. Less/no condensation and sash rot 10. Improved daylighting 11. Human productivity it Benefits courtesy Amory Lovins

5 Three Generations of Windows High Thermal insulation Advanced windows and glazings g need 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 will be in the market in 1-5 years. Building Integrated Photovoltaics (BIPV) The final advancement for window technology. Viability and benefit is TBD.

6 Three Generations of Windows Single Glaze: U = 1 Double Glaze: U = 0.5 Low e U =.35 (Energy Star) - Loss R6 Window U = 0.17(Dynamic Niche) R10 Window U = 0.10 (Dynamic Wide Spread) + Gain Courtesy Amory Lovins ref. NYT Source: Marc LeFrance, DOE

7 High Thermal Performance Glazing DOUBLE GLASS PATENT, Thomas Stetson 1865

8 Key elements to thermal performance Image courtesy Serious Materials

9 Incorporating high performance frames Typical Aluminum, Dual Pane Low-E FG insulated frame, Triple pane U factor (FF) = U factor (FF) = U-factor (COG) = 0.24 U-factor (COG) = 0.14 SHGC = 0.45 SHGC = 0.27 Tvis = 0.64 Tvis = 0.49 Models of window cross sections aluminum vs fiberglass Note: Modeled via THERM 6.1 Simulation software, Lawrence Berkeley National Labs Image courtesy Serious Materials

10 Triple pane (SCF) thermal performance Center of glass performance for one current IGU/window manufacturer Image courtesy Serious Materials

11 Triple pane (SCF) thermal performance Center of glass performance for one current IGU/window manufacturer Image courtesy Serious Materials

12 SCF Technology Triple pane (SCF) thermal performance

13 Air infiltration as the final piece Air infiltration is a topic of growing g focus. Minimally tested AAMA only requires a pass / no pass level of performance at this time. Passive House more thoroughly addresses this with a limits. This theme may gain traction in the future.

14 Dynamic glazing A dynamic glazing g is one that can actively change its physical properties of either: Visual Transmission (Tvis) Thermal/Infrared transmission (SHGC) Or both A dynamic glazing is one that can actively change its physical properties via: Electrical/user control - actively Environmental conditions - passively Or both

15 Active dynamic glazing - electrochromics Sage page Selkowitz study Images courtesy SAGE Electrochromics

16 Active dynamic glazing - electrochromics Benefits: Dynamic daylight control Reduced HVAC loads Concerns: High cost (> $80/sf) Clear mode still somewhat hazy with some electrochromic technologies Typical embodiment with visible light transmission (Tvis) switching between 5 and 65% (LBNL) Images courtesy SAGE Electrochromics

17 Benefits: Dynamic daylight control Reduced d HVAC loads Lower installed cost (~ $20/sf) Possible as a retrofit Passive dynamic glazing Concerns: Availability Unwanted activation Service life Images courtesy RavenBrick LLC

18 Benefits: Dynamic daylight control Reduced HVAC loads Lower installed cost (~ $20/sf) Possible as a retrofit Passive dynamic glazing Concerns: Availability Unwanted activation Service life Spotty visual field Images courtesy RavenBrick LLC

19 Other dynamic glazing Hybrid dynamic glazing g - Switches on per environmental conditions, off with voltage: Similar cost to traditional EC systems Wiring and controls are required Better tuned to energy savings than pure active types IR specific passive glazing: p p g g Extremely low cost compared to other technologies Pure passive, no controls No change to Tvis Available as a retrofit solution

20 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 i 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

21 Dynamic glazing - research A residential study with two teachings: Dynamic glazing can have a significant positive energy impact Effective dynamic windows require a low u-factor to work Source: Performance Criteria for Residential Zero Energy Windows, 2007

22 BIPV glazing Building integrated photovoltaics represent the third generation 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, awnings In some cases, can be used for viewing surfaces Is not financially viable at this time courtesy SunTech Corp.,

23 BIPV glazing light transmitting Light transmitting surfaces with energy output of approximately 100 W / m² Current state-of-the-art the art PV generates approx 1000 W / m² Images courtesy SunTech Corp.,

24 BIPV glazing viewable Crystal ball multiple technologies $/$ has to work out 10% light transmission 44 W /m²

25 BIPV glazing viewable Crystal ball multiple technologies $/$ has to work out 5% light transmission 50 W /m²

26 BIPV glazing viewable Crystal ball multiple technologies $/$ has to work out Images courtesy SunTech Corp., 1% light transmission 55 W /m²

27 Image courtesy SunTech Corp., BIPV glazing viewable

28 Summary Glazing is a classic design problem that requires balance of Thermal comfort, energy efficiency, light quality View, daylight, yg 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 d GHG equal to 6 B metric tons of CO2 Source: Mike Noble, BKL Consultants, Ltd.