TY - RPRT T1 - Demonstration of Energy Efficient Retrofits for Lighting and Daylighting in New York City Office Buildings Y1 - 2017/04// A1 - Eleanor S. Lee A1 - Luis L. Fernandes A1 - Taoning Wang A1 - Stephen E. Selkowitz A1 - Steven Mesh A1 - Yetsuh Frank A1 - Richard Yancey AB - The U.S. Department of Energy's (DOE) Commercial Buildings Integration (CBI) program's mission (and that of the New York State Energy Research & Development Authority (NYSERDA)) is to accelerate the adoption of cost-effective, underutilized building technologies with large energy savings potential. The key question which CBI asks for each high impact technology is: "What can the DOE do to improve the market adoption of this technology?" Answering this relies on an assessment of the most significant barriers, including:A lack of product available in the market to meet current needs;Owner uncertainty about how the technology will perform in real world settings; and,A lack of operational understanding by potential adopters limiting technology acceptance.Innovative, automated shading and LED lighting controls were identified as key technologies that have the potential to significantly reduce perimeter zone energy use and peak demand in existing commercial buildings.  Technological advances in the field of low-cost embedded controls have enabled high-resolution sensing and more optimal control on a per fixture or shade basis. The Lawrence Berkeley National Laboratory (LBNL) partnered with the Building Energy Exchange (BEEx) and a commercial building owner to evaluate leading-edge technologies on a 40,000 ft2 floor in an occupied, high-rise commercial office building in New York, New York. This “Living Laboratory” was monitored for a year prior to and six months following the installation of four sets of lighting and shading technologies and their performance was compared to a parallel reference floor in the same building.The Living Laboratory demonstrated that there were many competitive products on the market, that the products were able to meet current needs, and that the various advanced features provided significant added value over and above that of conventional products. Monitored data provided detailed insights into how and why each technology performed the way it did, and what the impacts were on energy-efficiency, peak demand, visual and thermal comfort, indoor environmental quality, and occupant acceptance and satisfaction within the resultant environment. ER - TY - JOUR T1 - Balancing daylight, glare, and energy-efficiency goals: An evaluation of exterior coplanar shading systems using complex fenestration modeling tools JF - Energy and Buildings Y1 - 2016/01// SP - 279 EP - 298 A1 - Sabine Hoffmann A1 - Eleanor S. Lee A1 - Andrew McNeil A1 - Luis L. Fernandes A1 - Dragan Vidanovic A1 - Anothai Thanachareonkit KW - Complex fenestration systems KW - Discomfort Glare KW - Energy Plus KW - Energy Use Intensity KW - Exterior shades KW - Glare Control KW - radiance AB - Exterior shades are the most effective way to control solar load in buildings. Twelve different coplanar shades with different geometry, material properties and cut-off angles were investigated for two California climates: the moderate San Francisco Bay Area climate and a hot and dry Southern California climate. The presented results distinguish themselves from other simulation studies by a newly developed method that combines three research-grade software programs (Radiance, EnergyPlus and Window 7) to calculate heat transfer, daylight, and glare resulting from optically-complex fenestration systems more accurately. Simulations were run for a case with constant electric lighting and a case with daylighting controls for a prototypical, internal load dominated office building.In the case of daylighting controls, the choice of slat angle and solar cut-off angle of a fixed exterior slat shading system is non trivial. An optimum slat angle was identified for the considered cases. Material properties (e.g., solar and visible reflectance) did not affect energy use if constant electric lighting was assumed, but they did have a significant influence on energy use intensity (EUI) when daylighting controls were assumed. Energy use increased substantially when an additional interior shade was used for glare control. VL - 112 U2 - LBNL-1005092 DO - 10.1016/j.enbuild.2015.12.009 ER - TY - RPRT T1 - Electrochromic Window Demonstration at the Donna Land Port of Entry Y1 - 2015/05// A1 - Luis L. Fernandes A1 - Eleanor S. Lee A1 - Anothai Thanachareonkit AB - The U.S. General Services Administration (GSA) Public Buildings Service (PBS) has jurisdiction, custody or control over 105 land ports of entry throughout the United States, 35 of which are located along the southern border. At these facilities, one of the critical functions of windows is to provide border control personnel with direct visual contact with the surrounding environment. This also can be done through surveillance cameras, but the high value that U.S. Customs and Border Protection (CPB) officers place on direct visual contact can be encapsulated in the following statement by a senior officer regarding this project: “nothing replaces line of sight.” In sunny conditions, however, outdoor visibility can be severely compromised by glare, especially when the orb of the sun is in the field of view. This often leads to the deployment of operable shading devices, such as Venetian blinds. While these devices address the glare, they obstruct the view of the surroundings, negating the visual security benefits of the windows.Electrochromic (EC) windows have the ability to adjust their tint dynamically in response to environmental conditions. This provides the potential to control glare by going to a dark tint at times when extreme glare is likely. In previous studies, these windows have shown that this ability to control glare has the potential to increase the amount of time during which view is unobstructed. This technology is available in the U.S. as a commercial product from two vendors with high-capacity manufacturing facilities, and could be deployed on a nationwide scale if successful in a pilot test.In this project, EC windows were installed at a land port of entry near Donna, Texas. The technical objectives of the study were to determine whether the installation of the EC windows resulted in the following:Reduction in visual discomfort caused by glare from daylight and direct solar orb visibilityReduction or elimination of need for operable shading deploymentImproved tenant satisfaction with visibility to the outsideNo significant negative impact on visibility of the exterior due to the decrease in window transmittance. U2 - LBNL-1001788 ER - TY - RPRT T1 - Angular selective window systems: Assessment of technical potential for energy saving Y1 - 2014/01// SP - 36 A1 - Luis L. Fernandes A1 - Eleanor S. Lee A1 - Andrew McNeil A1 - Jacob C. Jonsson A1 - Thierry Stephane Nouidui A1 - Xiufeng Pang A1 - Sabine Hoffmann KW - angular selective systems KW - Building energy-efficiency KW - daylighting KW - Shading Systems KW - windows AB - Static angular selective shading systems block or filter direct sunlight and admit daylight within a specific range of incident solar angles. They can potentially deliver energy efficient performance within the typical 4.6-m (15-ft) deep perimeter zone of buildings when tailored to a specific façade orientation and latitude. The objective of this study is to quantify the technical potential of these systems to reduce energy use and peak demand in commercial buildings, specifically: a) achieve 30-50% reductions in perimeter zone energy use vs. ASHRAE 90.1-2004, b) constrain peak window loads to less than 43 W/m2-floor (4 W/ft2-floor), and c) to the extent possible, admit useful daylight in the perimeter zone without exceeding the peak solar load constraint. Three distinctly different commercial shading systems were evaluated: a micro-perforated screen, a tubular shading structure (double- and triple-paned configurations), and an expanded metal mesh. This evaluation was performed mainly through computer simulation for a multitude of scenarios, including multiple climates (Chicago, Illinois and Houston, Texas), window-to-wall ratios (0.15-0.60), building codes (ASHRAE 90.1-2004 and 2010) and lighting control configurations (with and without daylighting controls). Angular selective shading systems are optically complex and cannot be modeled accurately using conventional simulation tools, prompting the development of unique versions of the EnergyPlus, Radiance and Window simulation tools. Results show significant potential reductions in perimeter zone energy use, with the best commercially-available system reaching 28% and 47% savings, relative to ASHRAE 90.1- 2004 and respectively without and with daylighting controls, on south facades in Chicago with WWR=0.45, while constraining peak window heat gains to under 43 W/m2-floor, and enabling significant savings from daylighting controls. Results suggest that it is possible that existing systems can be improved to more consistently achieve 30-50% energy savings. Level of angular selectivity, spectral selectivity of low-e coatings and thermal conductance of the angle-selective layer were identified as critical factors for the performance of angular selective systems. Static, angular selective shading systems offer a potentially low-cost option to significantly reduce window heat gains and control glare from visibility of the sun orb, while permitting the admission of useful daylight and access to views to the outdoors. This type of system shows significant potential to contribute towards net-zero energy goals in both new and retrofit construction. N1 -

Submitted to Energy and Buildings, May 27, 2014

U2 - LBNL-187060 ER - TY - JOUR T1 - Asymmetric particle fluxes from drifting ionization zones in sputtering magnetrons JF - Plasma Sources Science and Technology Y1 - 2014/04// SP - 025007 A1 - Matjaž Panjan A1 - Robert Franz A1 - André Anders KW - Instrumentation and measurement KW - Plasma physics KW - Surfaces, interfaces and thin films AB - Electron and ion fluxes from direct current and high-power impulse magnetron sputtering (dcMS and HiPIMS) plasmas were measured in the plane of the target surface. Biased collector probes and a particle energy and mass analyzer showed asymmetric emission of electrons and of singly and doubly charged ions. For both HiPIMS and dcMS discharges, higher fluxes of all types of particles were observed in the direction of the electrons' E x B drift. These results are put in the context with ionization zones that drift over the magnetron's racetrack. The measured currents of time-resolving collector probes suggest that a large fraction of the ion flux originates from drifting ionization zones, while energy-resolving mass spectrometry indicates that a large fraction of the ion energy is due to acceleration by an electric field. This supports the recently proposed hypothesis that each ionization zone is associated with a negative–positive–negative space charge structure, thereby producing an electric field that accelerates ions from the location where they were formed. VL - 23 IS - 2 JO - Plasma Sources Sci. Technol. DO - 10.1088/0963-0252/23/2/025007 ER - TY - RPRT T1 - High Performance Building Façade Solutions-Phase II Y1 - 2014/03// A1 - Eleanor S. Lee A1 - Brian E. Coffey A1 - Luis L. Fernandes A1 - Sabine Hoffmann A1 - Andrew McNeil A1 - Anothai Thanachareonkit A1 - Gregory J. Ward KW - automated shading KW - between-pane shading KW - bidirectional scattering distribution functions KW - building energy simulation tools KW - Complex fenestration systems KW - daylighting KW - daylighting simulation tools KW - electrochromics KW - exterior shading KW - goniophotometer KW - light shelves KW - microprismatic films KW - model predictive controls KW - motorized shading KW - shading KW - solar-optical properties KW - switchable windows KW - thermochromics KW - virtual prototyping KW - window heat transfer AB - The High Performance Building Façade Solutions–Phase II project was initiated through the California Energy Commission’s Public Interest Energy Research (PIER) program in July 2010 to support industry’s development and deployment of both incremental and breakthrough façade technologies in partnership with the U.S. Department of Energy (DOE). The objective of this three-year project was to develop, or support the development and deployment of, promising near-term and emerging zero net energy building façade technologies for solar control and daylighting, addressing two of the largest end uses in California commercial buildings: cooling and lighting. In partnership with industry (such as manufacturers), three classes of technologies were investigated: daylighting systems, angular-selective shading systems, and dynamic façade systems. Commercially available and emerging prototype technologies were developed and evaluated using laboratory tests. Simulations, full-scale outdoor tests in the Advanced Window Testbed, and demonstration projects quantified energy and peak electric demand reductions and occupant satisfaction, acceptance, and comfort associated with the resultant indoor environment. Several new technologies were developed using virtual prototyping tools. Integrated control systems were developed using model predictive controls. Simulation tools were developed to model operable complex fenestration systems such as shades and microprismatic films. A schematic design tool called COMFEN was developed to facilitate evaluation of these advanced technologies in the early design phase. All three classes of technologies resulted in significant reductions in perimeter zone energy use and peak electric demand, providing viable options that can support California’s long-term goal of achieving zero net energy use in the next decade. U2 - LBNL-1004337 ER - TY - JOUR T1 - Monitored lighting energy savings from dimmable lighting controls in The New York Times Headquarters Building JF - Energy and Buildings Y1 - 2014/01// SP - 498 EP - 514 A1 - Luis L. Fernandes A1 - Eleanor S. Lee A1 - Dennis L. DiBartolomeo A1 - Andrew McNeil KW - Building energy-efficiency KW - daylighting KW - lighting control systems AB - Digital addressable, dimmable lighting controls were introduced to the US market in the early 2000s with the promise of facilitating capture of potential energy savings with greater flexibility over their historic, typically unreliable, analog counterpart. The New York Times Company installed this emerging technology, after having tested the system thoroughly prior to procurement, in their new building in New York, New York. Four years after full occupancy in 2007, the owner agreed to participate in a post-occupancy monitored evaluation of the dimmable lighting system to verify actual performance in the field. Annual lighting energy savings from daylighting, setpoint tuning and occupancy controls were determined for the daylit, open-plan office areas on three typical floors (6, 11, and 20th floors) of the 51-story high-rise tower. Energy savings were calculated from ballast control signal and occupancy data recorded by the manufacturer's lighting control system. The ballast data were calibrated with independent measurements of lighting energy consumption. Savings from dimming controls (daylighting and setpoint tuning) were 12.6 kWh/m2-yr (1.17 kWh/ft2-yr) for the daylit spaces on the three floors overall, or 20%, relative to ASHRAE 90.1-2007. Compared to the prescriptive code in effect at the time of the building's construction (ASHRAE 90.1-2001), savings were 21.0 kWh/m2-yr (1.95 kWh/ft2-yr) or 28%. Annual lighting energy use with all lighting control strategies was 33.9 kWh/m2-yr (3.15 kWh/ft2-yr) in the daylit, open plan zones on average for the three floors. A simple payback analysis was conducted. VL - 68 IS - A U2 - LBNL-6171E DO - 10.1016/j.enbuild.2013.10.009 ER - TY - RPRT T1 - Designing improved angular-selective shading systems Y1 - 2013/09// A1 - Luis L. Fernandes A1 - Eleanor S. Lee ER - TY - JOUR T1 - Drifting potential humps in ionization zones: The “propeller blades” of high power impulse magnetron sputtering JF - Applied Physics Letters Y1 - 2013/10// SP - 144103 A1 - André Anders A1 - Matjaž Panjan A1 - Robert Franz A1 - Joakim Andersson A1 - Pavel A. Ni KW - Electric fields KW - ionization KW - plasma ionization KW - sputter deposition KW - sputtering AB - Ion energy distribution functions measured for high power impulse magnetron sputtering show features, such as a broad peak at several 10 eV with an extended tail, as well as asymmetry with respect to E × B, where E and B are the local electric and magnetic field vectors, respectively. Here it is proposed that those features are due to the formation of a potential hump of several 10 V in each of the traveling ionization zones. Potential hump formation is associated with a negative-positive-negative space charge that naturally forms in ionization zones driven by energetic drifting electrons. VL - 103 IS - 14 JO - Appl. Phys. Lett. DO - 10.1063/1.4823827 ER - TY - JOUR T1 - Lighting energy savings potential of split-pane electrochromic windows controlled for daylighting with visual comfort JF - Energy and Buildings Y1 - 2013/06// SP - 8 EP - 20 A1 - Luis L. Fernandes A1 - Eleanor S. Lee A1 - Gregory J. Ward KW - Building energy-efficiency KW - Control optimization KW - daylighting KW - Electrochromic windows AB - A simulation study was conducted to evaluate lighting energy savings of split-pane electrochromic (EC) windows controlled to satisfy key visual comfort parameters. Using the Radiance lighting simulation software, interior illuminance and luminance levels were computed for a south-facing private office illuminated by a window split into two independently-controlled EC panes. The transmittance of these was optimized hourly for a workplane illuminance target while meeting visual comfort constraints, using a least-squares algorithm with linear inequality constraints. Blinds were successively deployed until visual comfort criteria were satisfied. The energy performance of electrochromics proved to be highly dependent on how blinds were controlled. With hourly blind position adjustments, electrochromics showed significantly higher (62% and 53%, respectively without and with overhang)lighting energy consumption than clear glass. With a control algorithm designed to better approximate realistic manual control by an occupant, electrochromics achieved significant savings (48% and 37%, respectively without and with overhang). In all cases, energy consumption decreased when the workplace illuminance target was increased. In addition, the fraction of time during which the occupant had an unobstructed view of the outside was significantly greater with electrochromics: 10 months out of the year versus a handful of days for the reference case. VL - 61 U2 - LBNL-6152E DO - 10.1016/j.enbuild.2012.10.057 ER - TY - RPRT T1 - A Pilot Demonstration of Electrochromic and Thermochromic Windows in the Denver Federal Center, Building 41, Denver, Colorado Y1 - 2013/07// A1 - Eleanor S. Lee A1 - Luis L. Fernandes A1 - Howdy Goudey A1 - Jacob C. Jonsson A1 - Dragan C. Curcija A1 - Xiufeng Pang A1 - Dennis L. DiBartolomeo A1 - Sabine Hoffmann KW - building controls KW - daylighting KW - Demand Side Management KW - electrochromic KW - energy-efficiency KW - Smart windows KW - switchable windows KW - Thermochromic KW - Window AB - Chromogenic glazing materials are emerging technologies that tint reversibly from a clear to dark tinted state either passively in response to environmental conditions or actively in response to a command from a switch or building automation system. Switchable coatings on glass manage solar radiation and visible light while enabling unobstructed views to the outdoors. Building energy simulations estimate that actively controlled, near-term chromogenic glazings can reduce perimeter zone heating, ventilation, and air- conditioning (HVAC) and lighting energy use by 10-20% and reduce peak electricity demand by 20-30%, achieving energy use levels that are lower than an opaque, insulated wall.This project demonstrates the use of two types of chromogenic windows: thermochromic and electrochromic windows. By 2013, these windows will begin production in the U.S. by multiple vendors at high-volume manufacturing plants, enabling lower cost and larger area window products to be specified. Both technologies are in the late R&D stage of development, where cost reductions and performance improvements are underway. Electrochromic windows have been installed in numerous buildings over the past four years, but monitored energy-efficiency performance has been independently evaluated in very limited applications. Thermochromic windows have been installed in one other building with an independent evaluation, but results have not yet been made public. UR - http://gsa.gov/portal/content/187967 N1 -

Completed September 30, 2012, released March 30, 2014.

U2 - LBNL-1005095 ER - TY - RPRT T1 - A Post-Occupancy Monitored Evaluation of the Dimmable Lighting, Automated Shading, and Underfloor Air Distribution System in The New York Times Building Y1 - 2013/01// A1 - Eleanor S. Lee A1 - Luis L. Fernandes A1 - Brian E. Coffey A1 - Andrew McNeil A1 - Robert D. Clear A1 - Thomas L. Webster A1 - Fred S. Bauman A1 - Darryl J. Dickerhoff A1 - David Heinzerling A1 - Tyler Hoyt AB - With aggressive goals to reduce national energy use and carbon emissions, the US Department of Energy will be looking to exemplary buildings that have already invested in new approaches to achieving the energy performance goals now needed at a national level. The New York Times Building, in New York, New York, incorporates a number of innovative technologies, systems and processes and could become a model for widespread replication in new and existing buildings. Post-occupancy data are invaluable in establishing confidence in innovation. A year-long monitored study was conducted to verify energy performance, assess occupant comfort and satisfaction with the indoor environment, and evaluate impacts on maintenance and operations. Lessons learned were derived from the analysis; these lessons could help identify and shape policy, financial, or supporting strategies to accelerate diffusion in the commercial building market. PB - Lawrence Berkeley National Laboratory CY - Berkeley, CA U2 - LBNL-6023E ER - TY - ABST T1 - Electro-Responsive Polymer Glazings For Smart Windows With Dynamic Daylighting Control Y1 - 2012/02// A1 - Georgeta Masson A1 - Rueben Mendlesberg A1 - Irene Fernandez-Cuesta A1 - Stefano Cabrini A1 - Delia J. Milliron A1 - Brett A. Helms A1 - Eleanor S. Lee A1 - Andrew McNeil A1 - Stephen E. Selkowitz AB - In the context of alarming phenomenon of global warming with harmful consequences such as increased green house gases beyond predictions, the development of advanced energy efficient technologies became of a primary importance. Since the building sector accounts for 39% of total US primary energy consumption, fenestration can significantly contribute to lowering the energy use for heating, cooling, and lighting. An estimated 9% reduction in total US building energy use, or 3.47 Q, could be attained by dynamic solar/thermal control and daylighting if these advanced optical technologies were adopted throughout the residential and commercial building sectors. In spite of the great research and engineering efforts in the fast growing area of smart windows, development of glazing devices able to provide efficient, durable, and inexpensive products for dynamic daylight control is in infancy. Like the electrochromic glazings now emerging on the market, microscale, switchable daylight-redirecting glazings have the potential for widespread application if a low-cost, durable coating can be engineered and manufactured with the proper set of attributes.Here we report on the development of a new technology using smart materials for switchable daylight-redirecting glazings. The proposed system consists in a prismatic optical element (POE) fabricated by micro-imprinting of an elastic redox-active polymer network capable to change its geometry and thereby its optical properties in response to an external stimulus. It is expected that the prismatic optical element reversibly collapses in response to an applied potential, thereby modulating the fraction of light which is redirected. The fabrication of the dynamic prismatic optical element from simulation-driven design to materials synthesis and device integration will be described. Investigation of specto-electrochemical characteristics of the redox-active grating and challenges encountered with respect to electromechanical induced structural changes will be also presented. ER - TY - JOUR T1 - The structure and electron energy loss near edge structure of tungsten oxide thin films prepared by pulsed cathodic arc deposition and plasma-assisted pulsed magnetron sputtering JF - Journal of Physics: Condensed Matter Y1 - 2008/04// SP - 175216 A1 - Matthew R. Field A1 - Dougal G. McCulloch A1 - Sunnie H.N. Lim A1 - André Anders A1 - Vicki J. Keast A1 - R.W. Burgess AB - The microstructure and energy-loss near-edge structure (ELNES) of pulsed cathodic arc and pulsed magnetron sputtered WO3 thin films were investigated. It was found that the cathodic arc deposited material consisted of the α-WO3 phase with a high degree of crystallinity. In contrast, the magnetron sputtered material was highly disordered making it difficult to determine its phase. A self-consistent real space multiple scattering approach was used to calculate the NES of the various phases of WO3. Each phase was found to exhibit a unique NES allowing different phases of WO3 to be identified. The real space approach also allowed the origin of the main features in the NES to be investigated as the cluster size increased. The calculated NES for the room temperature γ-WO3 was found to compare well to previous X-ray absorption spectra and to NES obtained by full-potential band structure calculation. VL - 20 U1 -

Windows and Daylighting Group

U2 - LBNL-580E DO - 10.1088/0953-8984/20/17/175216 ER - TY - RPRT T1 - Commissioning and verification procedures for the automated roller shade system at The New York Times Headquarters Y1 - 2007/05// A1 - Eleanor S. Lee A1 - Robert D. Clear A1 - Gregory J. Ward A1 - Luis L. Fernandes AB - This document describes the procedures for verification testing of a newly installed automated roller shade system. The automated roller shade system has been designed to control direct sun and window glare while admitting daylight and permitting view out. Procedures in this document focus on verifying that the glare control aspect of this commercially-available system works prior to building occupancy. A high dynamic range luminance measurement tool, developed for this project, is used to verify that the average window luminance is within acceptable limits. Additional spreadsheet and visualization tools are described. The commissioning agent (CxA) and The New York Times will use these procedures during the commissioning phase of the building to verify that the automated control system is operating as intended. CY - Berkeley ER - TY - RPRT T1 - Daylighting the New York Times Headquarters Building: Final Report: Commissioning Daylighting Systems and Estimation of Demand Response Y1 - 2007/08// A1 - Eleanor S. Lee A1 - Glenn D. Hughes A1 - Robert D. Clear A1 - Luis L. Fernandes A1 - Sila Kiliccote A1 - Mary Ann Piette A1 - Francis M. Rubinstein A1 - Stephen E. Selkowitz KW - automated daylighting controls KW - automated window shades KW - daylighting KW - demand response KW - energy-efficiency KW - visual comfort AB - The technical energy-savings potential for smart integrated window-daylighting systems is excellent and can yield significant reductions in US commercial building energy use if adopted by a significant percentage of the market. However, conventional automated shades and daylighting controls have been commercially available for over two decades with less than 1-2% market penetration in the US. As with many innovations, the problem with accelerating market adoption is one of demonstrating real performance and decreasing risk and cost. The New York Times considered use of such daylighting systems for their new 139,426 m2 (1.5 Mft2) headquarters building in downtown Manhattan.In the initial phase of work, The New York Times employed a unique approach to create a competitive marketplace for daylighting systems and to address their concerns about risk by building a full-scale daylighting mockup and evaluating commercially-available products. This field test formed the strategic cornerstone for accelerating an industry response to the building owners' challenge to a sleepy market. A procurement specification was produced and bids were received that met The Times cost-effective criteria. The Times decided to proceed with using these innovative systems in their new building.This next phase of work consisted of two distinct tasks: 1) to develop and use commissioning tools and procedures to insure that the automated shade and daylighting control systems operate as intended prior to occupancy; and 2) to estimate the peak demand savings resulting from different levels of demand response (DR) control strategies (from moderate to severe load curtailment) and then determine the financial implications given various DR programs offered by the local utility and New York Independent System Operator in the area.Commissioning daylighting control systems is mandatory to insure that design intent is met, that the systems are tuned to optimal performance, and to eliminate problems and errors before occupants move in. Commissioning tools were developed and procedures were defined and then used to verify that the daylighting systems operated according to the technical specifications. For both lighting control and shading systems, the Times and the manufacturers were able to resolve most of the bugs and fine-tune the systems prior to occupancy.The demand response (DR) strategies at the New York Times building involve unique state-of-the-art systems with dimmable ballasts, movable shades on the glass facade, and underfloor air HVAC. The process to develop the demand response strategies, the results of the EnergyPlus model, the activities to implement the DR strategies in the controls design at the New York Times Headquarters building and the evaluation of economics of participating in DR programs are presented and discussed. The DR simulation iv efforts for this building design are novel, with an innovative building owner evaluating DR and future DR program participation strategies during the design and construction phase using advanced simulation tools. CY - Berkeley ER - TY - RPRT T1 - Quick Start Guide: Commissioning and verification procedures for the automated roller shade system at The New York Times Headquarters Y1 - 2007/05// A1 - Eleanor S. Lee A1 - Robert D. Clear A1 - Gregory J. Ward A1 - Luis L. Fernandes AB - This quick start guide summarizes the steps required to verify the performance of a newly installed automated roller shade system. The automated roller shade system at The New York Times Headquarters has been designed to control direct sun and window glare while admitting daylight and permitting view out. Procedures in this guide focus on verifying that the glare control aspect of this commerciallyavailable system works prior to building occupancy. A high dynamic range luminance measurement tool, developed for this project, is used to verify that the average window luminance is within acceptable limits. The commissioning agent (CxA) and The New York Times will use these procedures during the commissioning phase of the building to verify that the automated control system is operating as intended. CY - Berkeley ER - TY - RPRT T1 - Advancement of Electrochromic Windows Y1 - 2006/04// A1 - Eleanor S. Lee A1 - Stephen E. Selkowitz A1 - Robert D. Clear A1 - Dennis L. DiBartolomeo A1 - Joseph H. Klems A1 - Luis L. Fernandes A1 - Gregory J. Ward A1 - Vorapat Inkarojrit A1 - Mehry Yazdanian KW - commercial buildings KW - daylight KW - daylighting controls KW - Electrochromic windows KW - energy efficiency KW - human factors KW - peak demand KW - switchable windows KW - visual comfort AB - This guide provides consumer-oriented information about switchable electrochromic (EC) windows. Electrochromic windows change tint with a small applied voltage, providing building owners and occupants with the option to have clear or tinted windows at any time, irrespective of whether it's sunny or cloudy. EC windows can be manually or automatically controlled based on daylight, solar heat gain, glare, view, energy-efficiency, peak electricity demand response, or other criteria. Window controls can be integrated with other building systems, such as lighting and heating/cooling mechanical systems, to optimize interior environmental conditions, occupant comfort, and energy-efficiency. U1 -

Windows and Daylighting Group

U2 - LBNL-59821 ER - TY - RPRT T1 - A Design Guide for Early-Market Electrochromic Windows Y1 - 2006/ A1 - Eleanor S. Lee A1 - Stephen E. Selkowitz A1 - Robert D. Clear A1 - Dennis L. DiBartolomeo A1 - Joseph H. Klems A1 - Luis L. Fernandes A1 - Gregory J. Ward A1 - Vorapat Inkarojrit A1 - Mehry Yazdanian AB - Switchable variable-tint electrochromic windows preserve the view out while modulating transmitted light, glare, and solar heat gains and can reduce energy use and peak demand. To provide designers objective information on the risks and benefits of this technology, this study offers data from simulations, laboratory tests, and a 2.5-year field test of prototype large-area electrochromic windows evaluated under outdoor sun and sky conditions. The study characterized the prototypes in terms of transmittance range, coloring uniformity, switching speed, and control accuracy. It also integrated the windows with a daylighting control system and then used sensors and algorithms to balance energy efficiency and visual comfort, demonstrating the importance of intelligent design and control strategies to provide the best performance. Compared to an efficient low-e window with the same daylighting control system, the electrochromic window showed annual peak cooling load reductions from control of solar heat gains of 19-26% and lighting energy use savings of 48-67% when controlled for visual comfort. Subjects strongly preferred the electrochromic window over the reference window, with preferences related to perceived reductions in glare, reflections on the computer monitor, and window luminance. The EC windows provide provided the benefit of greater access to view year-round. Though not definitive, findings can be of great value to building professionals. U1 -

Windows and Daylighting Group

U2 - LBNL-59950 ER - TY - JOUR T1 - Smoothing of ultrathin silver films by transition metal seeding JF - Applied Physics Letters Y1 - 2006/ A1 - André Anders A1 - Eungsun Byon A1 - Dong-Ho Kim A1 - Kentaro Fukuda A1 - Sunnie H.N. Lim AB - The nucleation and coalescence of silver islands on coated glass was investigated by in-situ measurements of the sheet resistance. Sub-monolayer amounts of transition metals (Nb, Ti, Ni, Cr, Zr, Ta, and Mo) were deposited prior to the deposition of silver. It was found that some, but not all, of the transition metals lead to coalescence of silver at nominally thinner films with smoother topology. The smoothing effect of the transition metal at sub-monolayer thickness can be explained by a thermodynamic model of surface energies. U1 -

Windows and Daylighting Group

U2 - LBNL-59621 ER - TY - JOUR T1 - In Situ X-Ray Absorption Spectroscopy Study of Hydrogen Absorption by Nickel-Magnesium Thin Films JF - Physical Review B Y1 - 2003/02// A1 - Baker Farangis A1 - Ponnusamy Nachimuthu A1 - Thomas J. Richardson A1 - Jonathan L. Slack A1 - Rupert C.C. Perera A1 - Eric M. Gullikson A1 - Dennis W. Lindle A1 - Michael D. Rubin AB - Structural and electronic properties of co-sputtered Ni-Mg thin films with varying Ni to Mg ratio were studied by in situ x-ray absorption spectroscopy in the Ni L-edge and Mg K-edge regions. Codeposition of the metals led to increased disorder and decreased coordination around Ni and Mg compared to pure metal films. Exposure of the metallic films to hydrogen resulted in formation of hydrides and increased disorder. The presence of hydrogen as a near neighbor around Mg caused a drastic reduction in the intensities of multiple scattering resonances at higher energies. The optical switching behavior and changes in the x-ray spectra varied with Ni to Mg atomic ratio. Pure Mg films with Pd overlayers were converted to MgH2: The H atoms occupy regular sites as in bulk MgH2. Although optical switching was slow in the absence of Ni, the amount of H2 absorption was large. Incorporation of Ni in Mg films led to an increase in the speed of optical switching but decreased maximum transparency. Significant shifts in the Ni L3 and L2 peaks are consistent with strong interaction with hydrogen in the mixed films. VL - 67 IS - 8 U1 -

Windows and Daylighting Group

U2 - LBNL-51067 JO - Phys. Rev. B DO - 10.1103/PhysRevB.67.085106 ER - TY - CONF T1 - Structural and Electronic Properties of Magnesium-3D Transition Metal Switchable Mirrors T2 - Fifth International Meeting on Electrochromism Y1 - 2002/12// A1 - Baker Farangis A1 - Ponnusamy Nachimuthu A1 - Thomas J. Richardson A1 - Jonathan L. Slack A1 - Bruno K. Meyer A1 - Rupert C.C. Perera A1 - Michael D. Rubin KW - EXAFS KW - Hydrogen storage materials KW - NEXAFS KW - thin films KW - x-ray diffraction AB - We have observed reversible mirror-to-transparent state switching in a variety of mixed metal thin films containing magnesium and first-row transition elements including Ni, Fe, Co, Mn, and Ti. The very large changes in both reflectance and transmittance on loading these films with hydrogen are accompanied by significant structural and electronic transformations. The valence states and coordination of metal atoms during hydrogen loading were followed using dynamic in situ transmissionmode X-ray absorption spectroscopy. Time-resolved Mg K-edge and Ni, Co, Mn, and Ti L-edge spectra reflect both reversible and irreversible changes in the metal environments. These spectra are compared to those of reference materials and to predictions from calculations. JF - Fifth International Meeting on Electrochromism CY - Golden, CO U1 -

Windows and Daylighting Group

U2 - LBNL-51415 DO - 10.1016/j.ssi.2003.08.041 ER - TY - JOUR T1 - X-Ray Absorption Spectroscopy of Transition Metal-Magnesium Hydride Thin Films JF - Journal of Alloys and Compounds Y1 - 2003/08// SP - 204 EP - 207 A1 - Thomas J. Richardson A1 - Baker Farangis A1 - Jonathan L. Slack A1 - Ponnusamy Nachimuthu A1 - Rupert C.C. Perera A1 - Nobumichi Tamura A1 - Michael D. Rubin KW - EXAFS KW - Hydrogen storage materials KW - NEXAFS KW - thin films KW - x-ray diffraction AB - Mixed metal thin films containing magnesium and a first-row transition element exhibit very large changes in both reflectance and transmittance on exposure to hydrogen gas. Changes in electronic structure and coordination of the magnesium and transition metal atoms during hydrogen absorption were studied using dynamic in situ transmission mode X-ray absorption spectroscopy. Mg K-edge and Ni, Co, and Ti L-edge spectra reflect both reversible and irreversible changes in the metal environments. A significant shift in the nickel L absorption edge shows it to be an active participant in hydride formation. The effect on cobalt and titanium is much less dramatic, suggesting that these metals act primarily as catalysts for formation of magnesium hydride. VL - 356-357 U1 -

Windows and Daylighting Group

U2 - LBNL-50574 DO - 10.1016/S0925-8388(02)01237-9 ER - TY - RPRT T1 - The Integrated Energy-Efficiency Window-Wall System Y1 - 2001/ A1 - Michael Arney A1 - James Fairman A1 - John Carmody A1 - Dariush K. Arasteh U1 -

Windows and Daylighting Group

U2 - LBNL-51466 ER - TY - JOUR T1 - Mixed Metal Films with Switchable Optical Properties JF - Applied Physics Letters Y1 - 2002/02// SP - 1349 EP - 1351 A1 - Thomas J. Richardson A1 - Jonathan L. Slack A1 - Baker Farangis A1 - Michael D. Rubin AB - Thin, Pd-capped metallic films containing magnesium and first row transition metals (Mn, Fe, Co) switch reversibly from their initial reflecting state to visually transparent states when exposed to gaseous hydrogen or following reduction cathodic polarization in an alkaline electrolyte. Reversion to the reflecting state is achieved by exposure to air or by anodic polarization. The films were prepared by co-sputtering from one magnesium target and one manganese, iron, or cobalt target. Both the dynamic optical switching range and the speed of the transition depend on the magnesium-transition metal ratio. Infrared spectra of films in the transparent, hydrided (deuterided) states support the presence of the intermetallic hydride phases Mg3MnH7, Mg2FeH6, and Mg2CoH5. VL - 80 IS - 8 U1 -

Windows and Daylighting Group

U2 - LBNL-49043 DO - 10.1063/1.1454218 ER - TY - JOUR T1 - Switchable Mirrors Based on Nickel-Magnesium Films JF - Applied Physics Letters Y1 - 2001/05// SP - 3047 EP - 3049 A1 - Thomas J. Richardson A1 - Jonathan L. Slack A1 - Robert D. Armitage A1 - Robert Kostecki A1 - Baker Farangis A1 - Michael D. Rubin AB - An electrochromic mirror electrode based on reversible uptake of hydrogen in nickel magnesium alloy films is reported. Thin, magnesium-rich Ni-Mg films prepared on glass substrates by cosputtering from Ni and Mg targets are mirror-like in appearance and have low visible transmittance. Upon exposure to hydrogen gas or on cathodic polarization in alkaline electrolyte, the films take up hydrogen and become transparent. When hydrogen is removed, the mirror properties are recovered. The transition is believed to result from reversible formation of Mg2NiH4 and MgH2. A thin overlayer of palladium was found to enhance the kinetics of hydrogen insertion and extraction, and to protect the metal surface against oxidation. VL - 78 IS - 20 U1 -

Windows and Daylighting Group

U2 - LBNL-47180 DO - 10.1063/1.1371959 ER - TY - RPRT T1 - THERM 2.1 NFRC Simulation Manual Y1 - 2000/07// SP - 260 A1 - Robin Mitchell A1 - Christian Kohler A1 - Dariush K. Arasteh A1 - Elizabeth U. Finlayson A1 - Charlie Huizenga A1 - Dragan C. Curcija A1 - John Carmody AB - This document, the THERM 2.1 NFRC Simulation Manual, discusses how to use THERM to model products for NFRC certified simulations and assumes that the user is already familiar with the THERM program. In order to learn how to use THERM, it is necessary to become familiar with the material in the THERM User's Manual.In general, this manual references the THERM User's Manual rather than repeating the information.If there is a conflict between the THERM User's Manual and the THERM 2.1 NFRC Simulation Manual, the THERM 2.1 NFRC Simulation Manual takes precedence. U1 -

Windows and Daylighting Group

U2 - PUB-3147 ER - TY - CONF T1 - THERM 2.0: A Building Component Model for Steady-State Two-Dimensional Heat Transfer T2 - Building Simulation 99, International Building Performance Simulation Association (IBPSA) Y1 - 1999/09// A1 - Charlie Huizenga A1 - Dariush K. Arasteh A1 - Elizabeth U. Finlayson A1 - Robin Mitchell A1 - Brent T. Griffith A1 - Dragan C. Curcija AB - THERM 2.0 is a state-of-the-art software program, available without cost, that uses the finite-element method to model steady-state, two-dimensional heat-transfer problems. It includes a powerful simulation engine combined with a simple, interactive interface and graphic results. Although it was developed primarily to model thermal properties of windows, it is appropriate for other building components such as walls, doors, roofs, and foundations, and is useful for modeling thermal bridges in many other contexts, such as the design of equipment. JF - Building Simulation 99, International Building Performance Simulation Association (IBPSA) CY - Kyoto, Japan U1 -

Windows and Daylighting Group

U2 - LBNL-43991 ER - TY - RPRT T1 - Toward a Virtual Building Laboratory Y1 - 1999/03// A1 - Joseph H. Klems A1 - Elizabeth U. Finlayson A1 - Thomas H. Olsen A1 - David W Banks A1 - Jani M. Pallis AB - Buildings account for about one-third of all energy used in the US and about two-thirds of all electricity, with associated environmental impacts.(EIA 1996) After more than 20 years of DOE-supported research universities and national laboratories, a great deal is known about the energy performance of buildings and especially their components and subsystems. The development and market introduction of improved energy efficient technology, such as low-E windows and electronic ballasts, have helped reduce energy use, and the resultant savings will increase, as use of the new technologies becomes more widespread. A variety of approaches to speed market penetration have been and are being pursued, including information dissemination, research to evaluate performance and development of computer tools for making energy performance simulations available to architects and engineers at the earliest design stages. Public-domain computer building energy simulation models, (BLAST_Support_Office 1992; Winkelmann, Birdsall et al. 1993) a controversial idea 20 years ago, have been extremely successful in facilitating the design of more energy-efficient buildings and providing the technical basis for improved state building codes, federal guidelines, and voluntary standards. But the full potential of savings, estimated at 50% of current consumption or $100 billion/year, (Bevington and Rosenfeld 1990; Todesco 1996; Holdren 1997; Kolderup and Syphers 1997; ORNL, LBNL et al. 1997) will require that architects and engineers take an integrated look at buildings beginning in the early design phase, with increasing use of sophisticated, complex and interrelated building systems. This puts a greater burden on the designer and engineer to make accurate engineering decisions. U1 -

Windows and Daylighting Group

U2 - LBNL-43006 ER - TY - CONF T1 - State-of-the-Art Software for Window Energy-Efficiency Rating and Labeling T2 - ACEEE 1998 Summer Study on Energy Efficiency in Buildings Y1 - 1998/08// A1 - Dariush K. Arasteh A1 - Elizabeth U. Finlayson A1 - Yu Joe Huang A1 - Charlie Huizenga A1 - Robin Mitchell A1 - Michael D. Rubin AB - Measuring the thermal performance of windows in typical residential buildings is an expensive proposition. Not only is laboratory testing expensive, but each window manufacturer typically offers hundreds of individual products, each of which has different thermal performance properties. With over a thousand window manufacturers nationally, a testing-based rating system would be prohibitively expensive to the industry and to consumers.Beginning in the early 1990s, simulation software began to be used as part of a national program for rating window U-values. The rating program has since been expanded to include Solar Hear Gain Coefficients and is now being extended to annual energy performance.This paper describes four software packages available to the public from Lawrence Berkeley National Laboratory (LBNL). These software packages are used to evaluate window thermal performance: RESFEN (for evaluating annual energy costs), WINDOW (for calculating a products thermal performance properties), THERM (a preprocessor for WINDOW that determines two-dimensional heat-transfer effects), and Optics (a preprocessor for WINDOWs glass database).Software not only offers a less expensive means than testing to evaluate window performance, it can also be used during the design process to help manufacturers produce windows that will meet target specifications. In addition, software can show small improvements in window performance that might not be detected in actual testing because of large uncertainties in test procedures. JF - ACEEE 1998 Summer Study on Energy Efficiency in Buildings CY - Pacific Grove, CA U1 -

Windows and Daylighting Group

U2 - LBNL-42151 ER - TY - JOUR T1 - Teaching Students about Two-Dimensional Heat Transfer Effects in Buildings, Building Components, Equipment, and Appliances Using THERM 2.0 JF - ASHRAE Transactions Y1 - 1999/01// A1 - Charlie Huizenga A1 - Dariush K. Arasteh A1 - Elizabeth U. Finlayson A1 - Robin Mitchell A1 - Brent T. Griffith AB - THERM 2.0 is a state-of-the-art software program, available for free, that uses the finite-element method to model steady-state, two-dimensional heat-transfer effects. It is being used internationally in graduate and undergraduate laboratories and classes as an interactive educational tool to help students gain a better understanding of heat transfer. THERM offers students a powerful simulation engine combined with a simple, interactive interface and graphic results. Although it was developed to model thermal properties of building components such as windows, walls, doors, roofs, and foundations, it is useful for modeling thermal bridges in many other contexts, such as the design of equipment. These capabilities make THERM a useful teaching tool in classes on: heating, ventilation, and air-conditioning (HVAC); energy conservation; building design; and other subjects where heat-transfer theory and applications are important. THERMs state-of-the-art interface and graphic presentation allow students to see heat-transfer paths and to learn how changes in materials affect heat transfer. THERM is an excellent tool for helping students understand the practical application of heat-transfer theory. CY - Chicago, IL VL - 105, Part 1 U1 -

Windows and Daylighting Group

U2 - LBNL-42102 ER - TY - RPRT T1 - THERM 2.0: a PC Program for Analyzing Two-Dimensional Heat Transfer through Building products Y1 - 1998/ A1 - Elizabeth U. Finlayson A1 - Robin Mitchell A1 - Dariush K. Arasteh A1 - Charlie Huizenga A1 - Dragan C. Curcija AB - THERM is a state-of-the-art, Microsoft Windows?-based computer program developed at Lawrence Berkeley National Laboratory (LBNL) for use by building component manufacturers, engineers, educators, students, architects, and others interested in heat transfer. Using THERM, you can model two-dimensional heat-transfer effects in building components such as windows, walls, foundations, roofs, and doors; appliances; and other products where thermal bridges are of concern. THERM's heat-transfer analysis allows you to evaluate a product?s energy efficiency and local temperature patterns, which may relate directly to problems with condensation, moisture damage, and structural integrity.This version of THERM includes several new technical and user interface features; the most significant is a radiation view-factor algorithm. This feature increases the accuracy of calculations in situations where you are analyzing non-planar surfaces that have different temperatures and exchange energy through radiation heat transfer. This heat-transfer mechanism is important in greenhouse windows, hollow cavities, and some aluminum frames. U1 -

Windows and Daylighting Group

U2 - LBL-37371R ER - TY - JOUR T1 - Guidelines for Modeling Projecting Fenestration Products JF - ASHRAE Transactions Y1 - 1998/01// A1 - Dariush K. Arasteh A1 - Elizabeth U. Finlayson A1 - Dragan C. Curcija A1 - Jeff Baker A1 - Charlie Huizenga AB - Heat transfer patterns in projecting fenestration products (greenhouse windows, skylights, etc.) are different than those with typical planar window products. The projecting surfaces often radiate to each other, thereby invalidating the commonly used assumption that fenestration product interior surfaces radiate to a uniform room air temperature. The convective portion of the surface heat transfer coefficient is also significantly different from the one used with planar geometries, and is even more dependent on geometry and location. Projecting fenestration product profiles must therefore be modeled in their entirety. This paper presents the results of complete cross section, variable film-coefficient, 2-D heat transfer modeling of two greenhouse windows using the next generation of window specific heat transfer modeling tools. The use of variable film-coefficient models is shown to increase the accuracy with which simulation tools can compute U-factors. Simulated U-factors are also determined using conventional constant film coefficient algorithms. The results from both sets of simulations are compared with measured values. CY - San Francisco, CA VL - 104, Part 1 U1 -

Windows and Daylighting Group

U2 - LBNL-40707 ER - TY - JOUR T1 - Pressure Controlled GaN MBE Growth Using a Hollow Anode Nitrogen Ion Source JF - Materials Research Society Proceedings Y1 - 1997/ A1 - Michael S.H. Leung A1 - Ralf Klockenbrink A1 - Christian F. Kisielowski A1 - Hiroaki Fujii A1 - Joachim Krüger A1 - Sudhir G. Subramanya A1 - André Anders A1 - Zuzanna Liliental-Weber A1 - Michael D. Rubin A1 - Eicke R. Weber ED - Joachim Krüger AB - GaN films were grown on sapphire substrates at temperatures below 1000 K utilizing a Hollow Anode nitrogen ion source. A Ga flux limited growth rate of ~0.5 μm/h is demonstrated. Active utilization of strain and the assistance of a nitrogen partial pressure during buffer layer growth are found to be crucial issues that can improve the film quality. The best films exhibit a full width at half maximum of the x-ray rocking curves of 80 arcsec and 1.85 meV for the excitonic photoluminescence measured at 4 K. A Volmer-Weber three dimensional growth mode and the spontaneous formation of cubic GaN inclusions in the hexagonal matrix are observed in the investigated growth temperature range. It is argued that this growth mode contributes to a limitation of the carrier mobility in these films that did not exceed 120 cm2/Vs through a minimum canier concentration of ~1015 cm-3 was achieved. VL - 449 IS - 221 N1 -

1996 MRS Fall Meeting

U1 -

Windows and Daylighting Group

U2 - LBNL-39851 JO - MRS Proceedings DO - 10.1557/PROC-449-221 ER - TY - JOUR T1 - The Significance of Bolts in the Thermal Performance of Curtain-Wall Frames for Glazed Façades JF - ASHRAE Transactions Y1 - 1998/01// A1 - Brent T. Griffith A1 - Elizabeth U. Finlayson A1 - Mehry Yazdanian A1 - Dariush K. Arasteh AB - Curtain walls are assemblies of glazings and metal frames that commonly form the exterior glass façades of commercial buildings. Evaluating the thermal performance of the bolts that hold curtain wall glazings in place is necessary to accurately rate the overall thermal performance of curtain walls. Using laboratory tests and computer simulations, we assessed the thermal performance of several different configurations of bolts and glazings. Curtain-wall samples were tested in the infrared thermography laboratory at the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California. Experimental results were compared to two-dimensional simulations approximating the thermal effect of the bolts using the parallel path and the isothermal planes calculation methods. We conclude that stainless steel bolts minimally affect curtain-wall thermal performance (approximately 18%) when spaced at least nine inches apart, which is the industry standard. Performance is increasingly compromised when there is less than nine inches between bolts or when steel bolts are used. We also show that the isothermal planes method of approximating curtain wall thermal performance can be used with 2-D heat transfer software typical of that used in the window industry to give conservative results for the thermal bridging effect caused by bolts. CY - San Francisco, CA VL - 104, Part 1 U1 -

Windows and Daylighting Group

U2 - LBNL-40690 ER - TY - Generic T1 - Impact of Growth Temperature, Pressure and Strain on the Morphology of GaN Films T2 - Materials Research Society Symposium N – III-V Nitrides Y1 - 1996/ SP - 227 A1 - Hiroaki Fujii A1 - Christian F. Kisielowski A1 - Joachim Krüger A1 - Michael S.H. Leung A1 - Ralf Klockenbrink A1 - Michael D. Rubin A1 - Eicke R. Weber ED - Joachim Krüger AB - GaN films grown on sapphire at different temperatures are investigated. A Volmer-Weber growth mode is observed at temperatures below 1000K that leads to thin films composed of oriented grains with finite size. Their size is temperature dependent and can actively be influenced by strain. Largest grains are observed in compressed films. It is argued that diffusing Ga ad-atoms dominate the observed effects with an activation energy of 2.3 ± 0.5 eV. Comparably large grain sizes are observed in films grown on off-axes sapphire substrates and on bulk GaN. This assures that the observed size limitation is a consequence of the 3D growth mode and not dependent on the choice of the substrate. In addition, the grain size and the surface roughness of the films depend on the nitrogen partial pressure in the molecular beam epitaxy (MBE) chamber,most likely due to collisions between the reactive species and the background gas molecules. This effect is utilized to grow improved nucleation layers on sapphire. JF - Materials Research Society Symposium N – III-V Nitrides VL - 449 U1 -

Windows and Daylighting Group

U2 - LBNL-39850 DO - 10.1557/PROC-449-227 ER - TY - CONF T1 - The National Energy Requirements of Residential Windows in the U.S.: Today and Tomorrow T2 - ACEEE 1996 Summer Study on Energy Efficiency in Buildings: Profiting from Energy Efficiency Y1 - 1996/08// A1 - Karl J. Frost A1 - Joseph H. Eto A1 - Dariush K. Arasteh A1 - Mehry Yazdanian AB - This paper describes an end-use analysis of the national energy requirements of U.S. residential window technologies. We estimate that the current U.S. stock of 19 billion square feet of residential windows is responsible for 1.7 quadrillion BTUs (or quads) per year of energy use - 1.3 quads of heating and 0.4 quads of cooling energy - which represents about 2% of total U.S. energy consumption. We show that national energy use due to windows could be reduced by 25% by the year 2010 through accelerated adoption of currently available, advanced window technologies such as low-e and solar control low-e coatings, vinyl and wood frames, and superwindows. We evaluate the economics of the technologies regionally, considering both climatic and energy price variations, and find that the technologies would be cost effective for most consumers. JF - ACEEE 1996 Summer Study on Energy Efficiency in Buildings: Profiting from Energy Efficiency CY - Pacific Grove, CA UR - http://aceee.org/files/proceedings/1996/data/papers/SS96_Panel10_Paper07.pdf#page=1 U1 -

Windows and Daylighting Group

U2 - LBNL-39692 ER - TY - CONF T1 - Origin of Strain in GaN Thin Films T2 - 23rd International Conference on the Physics of Semiconductors Y1 - 1996/ SP - 513 A1 - Christian F. Kisielowski A1 - Joachim Krüger A1 - Michael S.H. Leung A1 - Ralf Klockenbrink A1 - Hiroaki Fujii A1 - Tadeusz Suski A1 - Sudhir G. Subramanya A1 - Joel W. Ager III A1 - Michael D. Rubin A1 - Eicke R. Weber ED - Joachim Krüger AB - Photoluminescence measurements are used to determine the strain in GaN thin films grown by Molecular Beam Epitaxy. The strain which originates from growth on lattice mismatched substrates and from differences in thermal expansion coefficients is found to be greatly relaxed. Residual strains are shown to depend on the thickness of GaN buffer layers and the III/V flux ration during main layer growth. The results strongly suggest that the residual biaxial strain caused by the post-growth cooling can be modified by the incorporation of point defects during the main layer growth which introduce an additional hydrostatic strain field. The effect allows for strain engineering of GaN crystals. JF - 23rd International Conference on the Physics of Semiconductors CY - Singapore VL - 4 U1 -

Windows and Daylighting Group

U2 - LBNL-39853 ER - TY - CONF T1 - Advances in Thermal and Optical Simulations of Fenestration Systems: The Development of WINDOW 5 T2 - Thermal Performance of the Exterior Envelopes of Buildings VI Conference Y1 - 1995/12// A1 - Elizabeth U. Finlayson A1 - Dariush K. Arasteh A1 - Michael D. Rubin A1 - John Sadlier A1 - Robert Sullivan A1 - Charlie Huizenga A1 - Dragan C. Curcija A1 - Mark Beall AB - WINDOW is a personal-computer-based computer program used by manufacturers, researchers, and consumers to evaluate the thermal performance properties (U-factors, solar heat gain and shading coefficients, and visible transmittances) of complete windows and other fenestration systems. While WINDOW is used by thousands of users in the United States and internationally and is at the foundation of the National Fenestration Rating Council's U-factor and solar heat gain property procedures, improvements to the program are still necessary for it to meet user needs. Version 5, intended for release in late 1995, is being developed to meet these needs for increased accuracy, a flexible and state-of-the-art user interface, and the capabilities to handle more product types.WINDOW 5 includes the capabilities to define and model the thermal performance of frames/dividers and their associated edge effects. Currently, such an analysis must be performed outside of WINDOW and requires simplifications to be made to frame profiles or is based on the use of generic frame and edge correlations. WINDOW's two-dimensional thermal model is composed of four sections: a graphical input, automatic grid generation, an finite-element analysis (FEA) solution, and the display of results. In the graphical input section, users are able to directly import a computer-aided design (CAD) drawing or a scanned image of a window profile, replicate its exact geometry, and assign material types and boundary conditions. The automatic grid generation is transparent to the user, with the exception of the requirement that complex shapes (i.e., an aluminum extrusion) be broken down into simpler polyshapes. Inclusion of an automatic grid generation makes detailed "true geometry" frame-and-edge heat-transfer analysis accessible to users without extensive knowledge of numerical methods of heat-transfer analysis. After the cross section is meshed it is sent to the FEA engine for solution and the results are returned. A postprocessor allows for the visual display of temperature and heat flux plots. Note that while this two-dimensional heat-transfer tool is being developed specifically for fenestration products, it also can be used to analyze other building envelope components.WINDOW 5 also will include a built-in version of a national laboratory's program that allows the user to estimate the orientation-dependent annual energy impacts of a given window in a typical residence in various U.S. climates. This program is based on regressions to a database of DOE2.1 runs. Future versions will include a similar feature for commercial buildings.Other technical additions include an improved angular/ spectral model for coated and uncoated glazings, the ability to analyze the optical properties of nonhomogeneous layers, and the ability to model the effects of laminated glazing layers. A door module permits the user to compute the total U-factors of exterior doors based on component U-factors calculated using the two-dimensional FEA module. JF - Thermal Performance of the Exterior Envelopes of Buildings VI Conference CY - Clearwater Beach, FL U1 -

Windows and Daylighting Group

U2 - LBL-37283 ER - TY - JOUR T1 - The Influence of Nitrogen Ion Energy on the Quality of GaN Films Grown with Molecular Beam Epitaxy JF - Journal of Electronic Materials Y1 - 1995/04// SP - 249 EP - 255 A1 - T.C. Fu A1 - Nathan Newman A1 - Erin C. Jones A1 - James S. Chan A1 - Xiaohong Liu A1 - Michael D. Rubin A1 - Nathan W. Cheung A1 - Eicke R. Weber KW - Activated nitrogen KW - GaN KW - molecular beam epitaxy (MBE) KW - nitrogen ion energy AB - Since the growth of GaN using molecular beam epitaxy (MBE) occurs under metastable growth conditions, activated nitrogen is required to drive the forward synthesis reaction. In the process of exciting the nitrogen using a plasma or ion-beam source, species with large kinetic energies are generated. Impingement on the growth surface by these species can result in subsurface damage to the growing film, as well as an enhancement of the reverse decomposition reaction rate. In this study, we investigate the effect of the kinetic energy of the impinging nitrogen ions during growth on the resulting optical and structural properties of GaN films. Strong band-edge photoluminescence and cathodoluminescence are found when a kinetic energy of ~10 eV are used, while luminescence is not detectable when the kinetic energies exceeds 18 eV. Also, we find that the use of conductive SiC substrates results in more homogeneous luminescence than the use of insulating sapphire substrates. This is attributed to sample surface charging in the case of sapphire substrates and subsequent variation in the incident ion flux and kinetic energy across the growth surface.This study clearly shows that the quality of GaN films grown by MBE are presently limited by damage from the impingement of high energy species on the growth surface. VL - 24 IS - 4 U1 -

Windows and Daylighting Group

U2 - LBL-37223 DO - 10.1007/BF02659683 ER - TY - CONF T1 - Recent Technical Improvements to the WINDOW Computer Program T2 - Window Innovations 95 Y1 - 1995/06// A1 - Dariush K. Arasteh A1 - Elizabeth U. Finlayson A1 - Michael D. Rubin A1 - John Sadlier AB - The WINDOW series of computer programs has been used since 1985 to model the thermal and optical properties of windows. Each succeeding version of WINDOW has brought its user base new technical capabilities, improvements to the user interface, and greater accuracy. Technical improvements to the current version, which will be released as version 5, are at first being released as stand-alone programs. This paper summarizes the capabilities and algorithms of two of these programs, THERM and LAMINATE. A third stand alone program, RESFEN, which calculates the annual energy effects of specific windows in a typical house throughout the US, will also be incorporated into WINDOW 5; because this program is already in use and documented, it is not discussed in this paper. THERM allows the user to evaluate two dimensional (2-D) heat transfer effects through the solid elements of a window while LAMINATE determines the optical properties of an individual glazing layer with an applied film. Both of these programs are undergoing final development at the time of this writing and will be released as separate programs before they are incorporated into WINDOW 5. JF - Window Innovations 95 CY - Toronto, Canada U1 -

Windows and Daylighting Group

U2 - LBNL-41680 ER - TY - CONF T1 - Fundamental Materials-Issues Involved in the Growth of GaN by Molecular Beam Epitaxy Y1 - 1994/ A1 - Nathan Newman A1 - T.C. Fu A1 - Z. Liu A1 - Zuzanna Liliental-Weber A1 - Michael D. Rubin A1 - James S. Chan A1 - Erin C. Jones A1 - Jennifer T. Ross A1 - Ian M. Tidswell A1 - Kin Man Yu A1 - Nathan W. Cheung A1 - Eicke R. Weber AB - Gallium nitride is one of the most promising materials for ultraviolet and blue light-emitting diodes and lasers. Both Molecular Beam Epitaxy (MBE) and Metal-Organic Chemical Vapor Deposition (MOCVD) have recently made strong progress in fabricating high-quality epitaxial GaN thin films. In this paper, we review materials-related issues involved in MBE growth. We show that a strong understanding of the unique meta-stable growth process allows us to correctly predict the optimum conditions for epitaxial GaN growth. The resulting structural, electronic and optical properties of the GaN films are described in detail. U2 - LBL-37296 ER - TY - CONF T1 - Simulating the Energy Performance of Holographic Glazings T2 - 13th SPIE International Symposium on Optical Materials Technology for Energy Efficiency and Solar Energy Conversion Y1 - 1994/04// A1 - Konstantinos M. Papamichael A1 - Liliana O. Beltran A1 - Reto A. Furler A1 - Eleanor S. Lee A1 - Stephen E. Selkowitz A1 - Michael D. Rubin AB - The light diffraction properties of holographic diffractive structures present an opportunity to improve the daylight performance in side-lit office spaces by redirecting and reflecting sunlight off the ceiling, providing adequate daylight illumination up to 30 ft (9.14 m) from the window wall. Prior studies of prototypical holographic glazings, installed above conventional view windows, have shown increased daylight levels over a deeper perimeter area than clear glass, for selected sun positions. In this study, we report on the simulation of the energy performance of prototypical holographic glazings assuming a commercial office building in the inland Los Angeles climate.The simulation of the energy performance involved determination of both luminous and thermal performance. Since the optical complexity of holographic glazings prevented the use of conventional algorithms for the simulation of their luminous performance, we used a newly developed method that combines experimentally determined directional workplane illuminance coefficients with computer-based analytical routines to determine a comprehensive set of daylight factors for many sun positions. These daylight factors were then used within the DOE-2.1D energy simulation program to determine hourly daylight and energy performance over the course of an entire year for four window orientations.Since the prototypical holographic diffractive structures considered in this study were applied on single pane clear glass, we also simulated the performance of hypothetical glazings, assuming the daylight performance of the prototype holographic glazings and the thermal performance of double-pane and low-e glazings. The results of our analyses show that these prototypical holographic glazings did not save significant electric energy or reduce peak electricity demand compared to conventional energy-efficient window systems in inland Los Angeles office buildings, mainly because of their low diffraction efficiency. Finally, we address various design and implementation issues towards potential performance improvement. JF - 13th SPIE International Symposium on Optical Materials Technology for Energy Efficiency and Solar Energy Conversion CY - Freiburg, Germany U1 -

Windows and Daylighting Group

U2 - LBL-35382R ER - TY - RPRT T1 - WINDOW 4.1: Program Description Y1 - 1994/ A1 - Dariush K. Arasteh A1 - Elizabeth U. Finlayson A1 - Charlie Huizenga AB - WINDOW 4.1 is a publicly available IBM PC compatible computer program developed by the Windows and Daylighting Group at Lawrence Berkeley Laboratory for calculating total window thermal performance indices (i.e. U-values, solar heat gain coefficients, shading coefficients, and visible transmittances). WINDOW 4.1 provides a versatile heat transfer analysis method consistent with the rating procedure developed by the National Fenestration Rating Council (NFRC). The program can be used to design and develop new products, to rate and compare performance characteristics of all types of window products, to assist educators in teaching heat transfer through windows, and to help public officials in developing building energy codes.WINDOW 4.1 is an update to WINDOW 4.0. The WINDOW 4 series is a major revision to previous versions of WINDOW. We strongly urge all users to read this manual before using the program. Users who need professional assistance with the WINDOW 4.1 program or other window performance simulation issues are encouraged to contact one or more of the NFRC-accredited Simulation Laboratories. U1 -

Windows and Daylighting Group

U2 - LBL-35298 ER - TY - CONF T1 - Comparison of AIN Films Grown by RF at Magnetron Sputtering and Ion-Assisted Molecular Beam Epitaxy T2 - Materials Research Society Y1 - 1993/04// A1 - James S. Chan A1 - T.C. Fu A1 - Nathan W. Cheung A1 - Jennifer T. Ross A1 - Nathan Newman A1 - Michael D. Rubin AB - Crystalline aluminum nitride (AlN) thin films were formed on various substrates by using RF magnetron sputtering of an A1 target in a nitrogen plasma and also by ion-assisted molecular beam epitaxy (IAMBE). Basal-oriented AlN/(111) Si showed a degradation of crystallinity with increased substrate temperature from 550 to 770 °C, while the crystallinity of AlN/(0001) Al2O3 samples improved from 700 to 850 °C. The optical absorption characteristics of the AlN/(0001) Al2O3 films as grown by both deposition methods revealed a decrease in sub-band gap absorption with increased substrate temperature. JF - Materials Research Society CY - San Francisco, CA VL - 300 U1 -

Windows and Daylighting Group

U2 - LBL-35660 ER - TY - RPRT T1 - The Energy Performance of Prototype Holographic Glazings Y1 - 1993/02// A1 - Konstantinos M. Papamichael A1 - Liliana O. Beltran A1 - Reto A. Furler A1 - Eleanor S. Lee A1 - Stephen E. Selkowitz A1 - Michael D. Rubin AB - We report on the simulation of the energy performance of prototype holographic glazings in commercial office buildings in a California climate. These prototype glazings, installed above conventional side windows, are designed to diffract the transmitted solar radiation and reflect it off the ceiling, providing adequate daylight illumination for typical office tasks up to 10m from the window. In this study, we experimentally determined a comprehensive set of solar-optical properties and characterized the contribution of the prototype holographic glazings to workplane illuminance in a scale model of a typical office space. We then used the scale model measurements to simulate the energy performance of the holographic glazings over the course of an entire year for four window orientations (North, East, South and West) for the inland Los Angeles climate, using the DOE-2.lD building energy analysis computer program. The results of our experimental analyses indicate that these prototype holographic glazings diffract only a small fraction of the incident light. The results of this study indicate that these prototype holographic glazings will not save energy in commercial office buildings. Their performance is very similar to that of clear glass, which, through side windows, cannot efficiently illuminate more than a 4m - 6m depth of a building`s perimeter, because the cooling penalties due to solar heat gain are greater than the electric lighting savings due to daylighting. U1 -

Windows and Daylighting Group

U2 - LBL-34367 ER - TY - JOUR T1 - P-Type Gallium Nitride by Reactive Ion-Beam Molecular Beam Epitaxy with Ion Implantation, Diffusion or Coevaporation of Mg JF - Applied Physics Letters Y1 - 1993/ SP - 64 EP - 66 A1 - Michael D. Rubin A1 - Nathan Newman A1 - James S. Chan A1 - T.C. Fu A1 - Jennifer T. Ross KW - carrier density KW - carrier mobility KW - crystal doping KW - diffusion KW - evaporation KW - gallium nitrides KW - ion implantation KW - magnesium additions KW - molecular beam epitaxy KW - p−type conductors AB - Gallium nitride is one of the most promising materials for ultraviolet and blue light‐emitting diodes and lasers. The principal technical problem that limits device applications has been achieving controllable p‐type doping. Molecular beam epitaxy assisted by a nitrogen ion beam produced p‐type GaN when doped via ion implantation, diffusion, or coevaporation of Mg. Nearly intrinsic p‐type material was also produced without intentional doping, exhibiting hole carrier concentrations of 5×1011 cm−3 and hole mobilities of over 400 cm2/V/s at 250 K. This value for the hole mobility is an order of magnitude greater than previously reported. VL - 64 IS - 1 U1 -

Windows and Daylighting Group

U2 - LBL-34413 JO - Appl. Phys. Lett. DO - 10.1063/1.110870 ER - TY - RPRT T1 - Savings from Energy Efficient Windows: Current and Future Savings from New Fenestration Technologies in the Residential Market Y1 - 1993/ A1 - Karl J. Frost A1 - Dariush K. Arasteh A1 - Joseph H. Eto AB - Heating and cooling energy lost through windows in the residential sector (estimated at two-thirds of the energy lost through windows in all sectors) currently accounts for 3 percent (or 2.8 quads) of total US energy use, costing over $26 billion annually in energy bills. Installation of energy-efficient windows is acting to reduce the amount of energy lost per unit window area. Installation of more energy efficient windows since 1970 has resulted in an annual savings of approximately 0.6 quads. If all windows utilized existing cost effective energy conserving technologies, then residential window energy losses would amount to less than 0.8 quads, directly saving $18 billion per year in avoided energy costs. The nationwide installation of windows that are now being developed could actually turn this energy loss into a net energy gain. Considering only natural replacement of windows and new construction, appropriate fenestration policies could help realize this potential by reducing annual residential window energy losses to 2.2 quads by the year 2012, despite a growing housing stock. N1 -

A version of this report was presented at the 4th Global Warming International Conference. Chicago, IL, April 5-8, 1993.

U1 -

Windows and Daylighting Group

U2 - LBL-33956 ER - TY - RPRT T1 - Window 4.0: Documentation of Calculation Procedures Y1 - 1993/ A1 - Elizabeth U. Finlayson A1 - Dariush K. Arasteh A1 - Charlie Huizenga A1 - Michael D. Rubin A1 - M. Susan Reilly AB - WINDOW 4.0 is a publicly available IBM PC compatible computer program developed by the Building Technologies Group at the Lawrence Berkeley Laboratory for calculating the thermal and optical properties necessary for heat transfer analyses of fenestration products. This report explains the calculation methods used in WINDOW 4.0 and is meant as a tool for those interested in understanding the procedures contained in WINDOW 4.0. All the calculations are discussed in the International System of units (SI). U1 -

Windows and Daylighting Group

U2 - LBL-33943 ER - TY - RPRT T1 - Window U-Value Effects on Residential Cooling Load Y1 - 1993/ A1 - Robert Sullivan A1 - Karl J. Frost A1 - Dariush K. Arasteh A1 - Stephen E. Selkowitz AB - This paper presents the results of a study investigating the effects of window U-value changes on residential cooling loads. We used the DOE-2.1D energy analysis simulation program to analyze the hourly, daily, monthly, and annual cooling loads as a function of window U-value. The performance of a prototypical single-story house was examined in three locations: hot and humid, Miami FL; hot and dry, Phoenix AZ; and a heating-dominated location with a mildly hot and humid summer, Madison WI. Our results show that when comparing windows with identical orientation, size, and shading coefficient, higher U-value windows often yield lower annual cooling loads, but lower U-value windows yield lower peak cooling loads. This occurs because the window with the higher U-value conducts more heat from inside the residence to the outside during morning and evening hours when the outside air temperature is often lower than the inside air temperature; and, a lower U-value window conducts less heat from outside to inside during summer afternoon peak cooling hours. The absolute effects are relatively small when compared to total annual cooling which is typically dominated by window solar heat gain effects, latent loads, and internal loads. The U-value effect on cooling is also small when compared to both the effects of U-value and solar heat gain on heating load. Our modeling assumed that U-value and solar heat gain could be independently controlled. In fact, reducing window conductance to the levels used in this study implies adding a second glazing layer which always reduces solar heat gain, thus reducing annual cooling. Thus, when we compare realistic options, e.g., single pane clear to double pane clear, or single pane tinted to double pane tinted, the double pane unit shows lower annual cooling, as well as lower peak loads. U1 -

Windows and Daylighting Group

U2 - LBL-34648 ER -