TY - JOUR T1 - Regional performance targets for transparent near-infrared switching electrochromic window glazings JF - Building and Environment Y1 - 2013/03// SP - 160 EP - 168 A1 - Nicholas DeForest A1 - Arman Shehabi A1 - Guillermo Garcia A1 - Jeffery B. Greenblatt A1 - Eric R. Masanet A1 - Eleanor S. Lee A1 - Stephen E. Selkowitz A1 - Delia J. Milliron KW - Dynamic windows KW - Electrochromic glazings KW - NIR-switching KW - Performance targets KW - Solar heat gain AB - With building heating and cooling accounting for nearly 14% of the national energy consumption, emerging technologies that improve building envelope performance have significant potential to reduce building energy consumption. Actual savings from these technologies will depend heavily upon their performance in diverse climate and operational conditions. In many cases, early-stage research can benefit from detailed investigation in order to develop performance thresholds and identify target markets. One example, a dynamic, highly transparent, near-infrared switching electrochromic (NEC) window glazing, is the focus of this investigation. Like conventional electrochromics, the NEC glazing can dynamically tune its optical properties with a small applied voltage. Consequently, the glazing can block or transmit solar heat to reduce cooling or heating loads, respectively. Unlike conventional electrochromics, NEC glazings remain transparent to visible light, causing no adverse effect to daylighting or building aesthetics. This study utilizes the software COMFEN to simulate a broad range of NEC performance levels, for commercial and residential buildings in 16 climate-representative reference cities. These simulations are the basis for identifying performance levels necessary to compete with existing static technologies. These results indicate that energy savings are strongly influenced by blocking-state performance. Additionally, residential applications have lower performance requirements due to their characteristic internal heat gains. Finally, the most dynamic NEC performance level is simulated in competition with high performing static alternatives. Here heating and cooling energy savings range from 5 to 11 kWh/m2 yr for commercial and 8–15 kWh/m2 yr for residential, in many regions on the order of 10%. VL - 61 JO - Building and Environment DO - 10.1016/j.buildenv.2012.12.004 ER - TY - JOUR T1 - U.S. energy savings potential from dynamic daylighting control glazings JF - Energy and Buildings Y1 - 2013/11// SP - 415 EP - 423 A1 - Arman Shehabi A1 - Nicholas DeForest A1 - Andrew McNeil A1 - Eric R. Masanet A1 - Jeffery B. Greenblatt A1 - Eleanor S. Lee A1 - Georgeta Masson A1 - Brett A. Helms A1 - Delia J. Milliron KW - Clerestories KW - daylighting KW - Dynamic prismatic optical elements (dPOE) KW - energy efficiency KW - Glare KW - indoor environmental quality KW - radiance KW - windows AB - Daylighting controls have the potential to reduce the substantial amount of electricity consumed for lighting in commercial buildings. Material science research is now pursuing the development of a dynamic prismatic optical element (dPOE) window coating that can continuously readjust incoming light to maximize the performance and energy savings available from daylighting controls. This study estimates the technical potential for energy savings available from vertical daylighting strategies and explores additional savings that may be available if current dPOE research culminates in a successful market-ready product. Radiance daylight simulations are conducted with a multi-shape prismatic window coating. Simulated lighting energy savings are then applied to perimeter floorspace estimates generated from U.S. commercial building stock data. Results indicate that fully functional dPOE coatings, when paired with conventional vertical daylight strategies, have the potential to reduce energy use associated with U.S. commercial electric lighting demand by as much as 930 TBtu. This reduction in electric lighting demand represents an approximately 85% increase in the energy savings estimated from implementing conventional vertical daylight strategies alone. Results presented in this study provide insight into energy and cost performance targets for dPOE coatings, which can help accelerate the development process and establish a successful new daylighting technology. VL - 66 DO - 10.1016/j.enbuild.2013.07.013 ER -