Environmentally Controlled Dynamic Glazing. Christopher D. Anderson, Ph.D. Pleotint, LLC

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1 Environmentally Controlled Dynamic Glazing Christopher D. Anderson, Ph.D. Pleotint, LLC

2 Commercial Dynamic Glazing Landscape Electronically Controlled Voltage induces a color change Environmentally Controlled Direct solar irradiance increases glass pane temperature causing a change in light transmission

3 Environmentally Controlled Dynamic Glazing Two types based on width of switching range Thermotropic Narrow Switching Range Distinct threshold temperature divides high and low light transmission states Specular below threshold temperature: large %LT above threshold temperature: small %LT Scattering below threshold temperature: weak light scattering above threshold temperature: significant light scattering

4 Environmentally Controlled Dynamic Glazing Two Classes distinguished by width of switching range Thermochromic broad switching range Continuous change in transmission with increase and decrease in temperature Specular Low Glass Temperature: large %LT Increasing Glass Temperature: progressively smaller %LT

5 Thermochromic ECDG Glazing in Action No direct sunlight = Clear Direct sunlight = Tinted

6 Residential Installations

7 Residential Installations

8 Commercial Installations

9 Commercial Installations

10 Benefits of Environmentally Controlled Dynamic Glazing No Wiring No Control Systems No Added Maintenance Sun is the only power supply Installation identical to conventional IGU/Window Laminated Glass Benefits Balances Daylighting with desire for low SHGC Currently available in dimensions in excess of 5 x 10 Pairs with glass from any manufacturer

11 LBNL Evaluations Denver A Pilot Demonstration of Electrochromic and Thermochromic Windows in the Denver Federal Center, Building 41, Denver, Colorado Eleanor S. Lee, Principal Investigator With thermochromic windows annual HVAC electricity use due to cooling equipment (e.g., chiller, fans, and pumps) decreased 22%, from 2.48 to 1.93 kwh/ft2 yr Peak cooling load decreased 47%...which, in turn, could enable downsizing of HVAC cooling equipment (chiller and cooling tower) by 21%, from 50.1 tons to 39.8 tons Annual boiler gas consumption for heating by the C TC window decreased 17%...

12 LBNL Evaluations Berkeley An empirical study of a full scale polymer thermochromic window and its implications on material science development objectives Lee, E. et al. Published in Solar Energy Materials & Solar Cells 116 (2013) Annual energy savings in the...perimeter zones were 20 43% in the hot/cold climate of Chicago compared to the ASHRAE Standard prescriptive window. The TC window was able to produce energy savings that were greater than an advanced low e dual pane window... Savings were due to reductions in HVAC energy use and did not include lighting energy use savings due to daylight dimming.

13 Methods for Determining Solar Optical Properties of Environmentally Controlled Dynamic Glazing Lawrence Berkeley National Laboratory Edge Heating System Jacob C. Jonsson, Howdy Goudey, Charlie Curcija

14 Modeling in LBNL Software Energy Plus models thermochromic windows using spectral data that have been input at regular temperature intervals over the switching range. Window 7 Window 7 incorporates this interpolation capability within the software, enabling the end user to generate spectral data for any arbitrary window configuration and at user specified temperature intervals Solar Energy Materials & Solar Cells 116 (2013)

15 IGDB Thermochromics have been available in the IGDB since version 31 Data available across operable temperature range 5 C, 15 C, 25 C, 45 C, 65 C, 85 C and 95 C Validated algorithms determine spectra and properties at intermediate temperatures is implemented in Window 7 Thermochromic interlayer data with NFRC Acceptance (Approved Interlayer List) is anticipated in IGDB 38

16 Current Dynamic Glazing Label Environmentally controlled dynamic glazings fit the current form of the NFRC dynamic label The Off state corresponds to the maximum VLT condition of an ECDG The On state corresponds to the minimum VLT condition of the ECDG.

17 Iowa Energy Center Iowa State University US DOE Grant DE EE Year round real world evaluation Two thermochromic double pane constructions tested Clear Glass Spectrally selective Glass Six 1 week periods Approximately every other month Paired rooms oriented E, S & W Temperatures monitored on thermochromic windows

18 Iowa Energy Center East Windows

19 Iowa Energy Center South Windows

20 Iowa Energy Center West Windows

21 LBNL Installation and Evaluation

22 Environmentally Controlled Dynamic Glazing and NFRC Ratings/Labeling ECDG endpoints (5 C = Off and 65 C = On ) supported by data Using 5 C and 65 C interlayer spectral data allows for straightforward calculation solar optical and thermal properties for both Fully ON and Fully OFF states with LBNL Optics and Window.

23 What does ECDG Need Going Forward? Clarity on how to obtain NFRC rating/certificate Commercial (CMA) State and Local Building code compliance CEC Title 24 Residential Clarity on procedure for establishing dynamic ratings for ECDG

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25 Environmentally Controlled Dynamic Glazing and NFRC Items for longer term consideration Language in NFRC documents should be broadened to better accommodate ECDG ON/OFF and OPEN/CLOSED are not perfect descriptors for ECDG Maximum VLT/SHGC and Minimum VLT/SHGC would cover all DG Incorporate means of differentiating between electronically controlled DG and ECDG on labels

26 Thermochromic Laminate Transmission vs. Temperature

27 How Thermochromic Glazings Work Thermochromic Interlayer 7/16 Spacer with Insulating Gas Low Emissivity Coating SHGC Tsol Tvis Clear Outside Glass* * Optional Tint Glass Glass Tdw ISO Glass Laminate Assembly

28 Environmentally Controlled Dynamic Glazing and NFRC Ratings/Labeling Needed to inform consumers Residential and Commercial code compliance & possible tax benefits Who benefits? Customers Dynamic Glazing Manufacturers both electrochromic and ECDG Glass Producers Glass Fabricators Glaziers