02120nas a2200169 4500008004100000022001400041245009400055210006900149260001200218300001400230490000800244520157100252100001901823700002101842700002301863856006401886 2017 eng d a0360-132300aDaylight performance of a microstructured prismatic window film in deep open plan offices0 aDaylight performance of a microstructured prismatic window film c02/2017 a280–2970 v1133 a
Daylight redirecting systems with vertical windows have the potential to offset lighting energy use in deep perimeter zones. A microstructured prismatic film designed for such use was characterized using goniophotometric measurements and ray tracing simulations. The synthetically-generated bidirectional scattering distribution function (BSDF) data were shown to have good agreement with limited measured data for normal incident angles (0–60°). Measured data indicated that the prismatic film was most efficient when vertical angles of incidence were between 18 and 35° and within ±45° of normal incidence to the plane of the window so maximum energy savings across the full depth of the zone occurred over the equinox to winter solstice period. Annual lighting energy use and visual comfort in a deep open plan office zone were evaluated using the Radiance three-phase method in several climates and for south and east-facing window orientations. Lighting energy savings were 39–43% for a 12 m (40 ft) deep south-facing perimeter zone compared to the same zone with no lighting controls. The prismatic film with and without a diffuser controlled glare for views parallel to the window but produced glare for seated viewpoints looking toward the window. At mature market costs, the system was projected to have a simple payback of 2–6 years. Technical challenges encountered throughout the evaluation led to improvements in measurement and modeling tools and stressed the importance of having accurate input data for product development.
1 aMcNeil, Andrew1 aLee, Eleanor, S.1 aJonsson, Jacob, C. uhttps://facades.lbl.gov/publications/daylight-performance-002919nas a2200181 4500008004100000245011300041210006900154260001200223520228500235100002102520700002402541700001802565700002702583700001702610700001802627700002002645856007202665 2017 eng d00aDemonstration of Energy Efficient Retrofits for Lighting and Daylighting in New York City Office Buildings0 aDemonstration of Energy Efficient Retrofits for Lighting and Day c04/20173 aThe 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:
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.
1 aLee, Eleanor, S.1 aFernandes, Luis, L.1 aWang, Taoning1 aSelkowitz, Stephen, E.1 aMesh, Steven1 aFrank, Yetsuh1 aYancey, Richard uhttps://facades.lbl.gov/publications/demonstration-energy-efficient02275nas a2200277 4500008003900000245015300039210006900192260001200261300001200273490000800285520134500293653003301638653002101671653001601692653002501708653002001733653001801753653001301771100002101784700002101805700001901826700002401845700002201869700002901891856007701920 2016 d00aBalancing daylight, glare, and energy-efficiency goals: An evaluation of exterior coplanar shading systems using complex fenestration modeling tools0 aBalancing daylight glare and energyefficiency goals An evaluatio c01/2016 a279-2980 v1123 aExterior 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.
10aComplex fenestration systems10aDiscomfort Glare10aEnergy Plus10aEnergy Use Intensity10aExterior shades10aGlare Control10aradiance1 aHoffmann, Sabine1 aLee, Eleanor, S.1 aMcNeil, Andrew1 aFernandes, Luis, L.1 aVidanovic, Dragan1 aThanachareonkit, Anothai uhttps://facades.lbl.gov/publications/balancing-daylight-glare-and-energy00763nas a2200205 4500008003900000245011500039210006900154260003100223653002400254653003300278653002400311653002100335653002500356653001300381100002100394700001900415700002100434700002300455856007900478 2015 d00aDiscomfort glare with complex fenestration systems and the impact on energy use when using daylighting control0 aDiscomfort glare with complex fenestration systems and the impac aBern, Switzerlandc11/201510abuilding simulation10aComplex fenestration systems10adaylighting control10aDiscomfort Glare10aEnergy Use Intensity10aradiance1 aHoffmann, Sabine1 aMcNeil, Andrew1 aLee, Eleanor, S.1 aKalyanam, Raghuram uhttps://facades.lbl.gov/publications/discomfort-glare-complex-fenestration03492nas a2200253 4500008003900000245009000039210006900129260001200198300000700210520268100217653003002898653003102928653001602959653002002975653001202995100002403007700002103031700001903052700002303071700003103094700001803125700002103143856007403164 2014 d00aAngular selective window systems: Assessment of technical potential for energy saving0 aAngular selective window systems Assessment of technical potenti c01/2014 a363 aStatic 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.
10aangular selective systems10aBuilding energy-efficiency10adaylighting10aShading Systems10awindows1 aFernandes, Luis, L.1 aLee, Eleanor, S.1 aMcNeil, Andrew1 aJonsson, Jacob, C.1 aNouidui, Thierry, Stephane1 aPang, Xiufeng1 aHoffmann, Sabine uhttps://facades.lbl.gov/publications/angular-selective-window-systems04341nas a2200157 4500008003900000245008100039210006900120260001200189520378700201100002703988700002604015700002004041700002304061700002204084856007704106 2014 d00aCOMFEN – Early Design Tool for Commercial Facades and Fenestration Systems0 aCOMFEN Early Design Tool for Commercial Facades and Fenestration c03/20143 aCalifornia leads the nation in building energy efficiency standards and is a leader in the United States for legislation to reduce greenhouse gas emissions. Achieving these goals in practice requires that design teams and owners have access to technologies, systems and decision support tools that support their design work. This California Energy Commission funded work on the COMFEN software tool, which gives building practitioners, such as architects and engineers, the ability to assess the energy consequences of building design decisions, is thus a key enabling element that supports the AEC community in achieving ever more stringent performance requirements. COMFEN can provide needed building design guidance to not achieve the shorter term code goals but supports more aggressive achievement of the net-zero energy performance and peak load reduction required for all new buildings by 2030 as well as supporting deep retrofit of existing building stock.
Achieving a net-zero energy building cannot be done solely by improving the efficiency of the engineering systems (HVAC, lighting, equipment). It also requires consideration of the essential nature of the building starting early in the design process, including factors such as architectural form, massing, orientation and enclosure. Making informed decisions about the fundamental character of a building requires continuous assessment of the effects of the complex interaction of these factors on the resulting performance of the building as the design evolves. The complexity of these interactions necessitates the use of modeling and simulation tools to dynamically analyze the effects of the relationships. Decisions about the building fundamentals are often made in the earliest stages of design, before a complete 'building' exists to model so that a focus on representative spaces in the building allows earlier guidance for the decision making.
COMFEN, an early-design energy modeling tool developed by LBNL, is designed specifically to make informed decisions about building fundamentals by considering the design of the building envelope, orientation and massing on building performance. It supports exploratory work early in the process by architects but is also useful for engineers and consultants later in the design process. It also supports innovation broadly as it allows teams to model new technologies and systems that are becoming available but have not yet reached mainstream status.
COMFEN focuses on the concept of a "space" or "room" and uses the EnergyPlus and Radiance™ engines and a simple, graphic user interface to allow the user to explore the effects of changing key early-design input variables for the façade, internal loads, lighting controls and HVAC system on energy consumption, peak energy demand, and thermal and visual comfort. COMFEN also provides the ability to import glazing systems that have been developed in Window7, utilizing the International Glazing DataBase (IGDB) for glass choices. Comparative results are rapidly presented in a variety of graphic and tabular formats to help users move toward optimal façade and fenestration design choices.
While the underlying simulation engines were developed over time as part of DOE's national windows and daylighting program, the specific design features of COMFEN were evolved over a several year period by consulting with a series of largely California-based architectural and engineering firms who provided important guidance and feedback on desirable features and then on functionality once the features were implemented.
COMFEN is available at no charge on the LBNL website.
1 aSelkowitz, Stephen, E.1 aHitchcock, Robert, J.1 aMitchell, Robin1 aMcClintock, Maurya1 aSettlemyre, Kevin uhttps://facades.lbl.gov/publications/comfen-early-design-tool-commercial03205nas a2200421 4500008003900000245005700039210005600096260001200152520188100164653002202045653002502067653005202092653003702144653003302181653001602214653003302230653002002263653002102283653002002304653001802324653002502342653003002367653002202397653001202419653002902431653002302460653001902483653002402502653002502526100002102551700002202572700002402594700002102618700001902639700002902658700002202687856007402709 2014 d00aHigh Performance Building Façade Solutions-Phase II0 aHigh Performance Building Façade SolutionsPhase II c03/20143 aThe 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.
10aautomated shading10abetween-pane shading10abidirectional scattering distribution functions10abuilding energy simulation tools10aComplex fenestration systems10adaylighting10adaylighting simulation tools10aelectrochromics10aexterior shading10agoniophotometer10alight shelves10amicroprismatic films10amodel predictive controls10amotorized shading10ashading10asolar-optical properties10aswitchable windows10athermochromics10avirtual prototyping10awindow heat transfer1 aLee, Eleanor, S.1 aCoffey, Brian, E.1 aFernandes, Luis, L.1 aHoffmann, Sabine1 aMcNeil, Andrew1 aThanachareonkit, Anothai1 aWard, Gregory, J. uhttps://facades.lbl.gov/publications/high-performance-building-fa-ade07924nas a2200265 4500008003900000245004800039210004800087260006500135520707300200653002507273653001607298653003807314653002107352653001507373653002207388653002507410653002107435653002007456653001907476100001907495700002207514700002107536700002707557856007407584 2014 d00aHigh Performance Building Mockup in FLEXLAB0 aHigh Performance Building Mockup in FLEXLAB aBerkeley, CAbLawrence Berkeley National Laboratoryc12/20143 aGenentech has ambitious energy and indoor environmental quality performance goals for Building 35 (B35) being constructed by Webcor at the South San Francisco campus. Genentech and Webcor contracted with the Lawrence Berkeley National Laboratory (LBNL) to test building systems including lighting, lighting controls, shade fabric, and automated shading controls in LBNL's new FLEXLAB facility. The goal of the testing is to ensure that the systems installed in the new office building will function in a way that reduces energy consumption and provides a comfortable work environment for employees.
LBNL tested three facades of the new office building in the rotating FLEXLAB testbed: west, south and east. External shading, lighting, and internal shading control was configured for each orientation to replicate the conditions of B35. The three facades were each tested for one week three times between July and October 2014. Changes were made between each test to improve the performance of the systems.
Linear pendant LED light fixtures will illuminate the open office areas of the office building. These fixtures were installed in FLEXLAB. The wide spacing between rows of light fixtures results in a low lighting power density of 0.57 W/ft2 in the open office areas, while still meeting the average illuminance criteria of 300 lux (28 footcandles). A combination of the wide spacing and optics of the light fixture creates a nonuniform lighting pattern on the ceiling of the space. Changing to a diffuse lens on the uplight will help reduce abrupt changes in luminance on the ceiling but non-uniformity will persist due to the wide spacing.
The pendant light fixtures allow separate control of the downward and upward light. The lighting control design aims to enhance the quality of space by dimming upward light unison providing uniform patterns of electric light on the ceiling. The downward light of each fixture dims to provide just enough light to meet illuminance criteria below the fixture.
Webcor installed two lighting control systems manufactured by Enlighted and Encelium for testing in FLEXLAB. The Encelium system uses an open loop control architecture with a ceiling-mounted photosensor at each facade (inside of the automated shade). While there is greater variation in workplane illuminance provided by the Encelium system, the system is better able to control upward versus downward lighting and is able to control the lighting according to the lighting design intent. The architecture of the Encelium system offers more functional flexibility by allowing any input (sensors, switches etc.) or multiple inputs to affect any fixture.
The Enlighted control system uses closed loop architecture with two photosensors per fixture (one for upward light and one for downward light). The Enlighted system controlled the lights more precisely than the Encelium system to meet workplane illuminance requirements, however the upward versus downward light control did not behave according to the lighting design intent.
MechoSystems provided motorized window shades and automated control. The shades in each window had a different color fabric, one dark grey and one medium grey. Both shade fabrics were an open weave with 3% openness. Genentech selected the dark colored shade because it provides a better view of the exterior compared to the lighter colored shade. Anecdotal evidence suggests that some occupants may experience direct glare with 3% open fabric while other occupants will not experience glare under the same conditions. Visual discomfort during the worst case sunny winter condition was not evaluated. However, the east-facing orientation during the equinox period was exposed to low sun angles in the third test period so findings of just acceptable visual discomfort are expected to be similar to what might be experienced during the winter.
The shades operated as expected on sunny days (which was the predominant condition during the test period). The testing identified substantial potential energy savings for the lighting systems by stopping the shade above the sill, preventing the shade from completely covering the window and allowing the sun to shine deeper into the space through the bottom few inches of the window. On partly cloudy days, which occurred more frequently after our testing concluded, anecdotal evidence suggests that the shades could be raised more often. LBNL suggests that a second threshold be implemented which drops the shade partway to prevent direct glare from bright sun, but doesn't close the shade down to the height required to limit sunshine depth.
Thermal comfort analysis suggests that occupants seated near the shaded window will be comfortable around 80% of the time. The 20% of time where the observed conditions fall outside the ASHRAE Standard 55 are almost always due to occupants being cold in the morning. This discomfort is mostly driven by cold surrounding surfaces causing a low mean radiant temperature and overcooling from outside air during economizer mode. Only one thermal comfort station, located near the facade, was used for the experiment. Thermal comfort further from the facade is unknown but is likely to be better due to the increased distance from the relatively cold facade.
Visual comfort studies indicated that occupants could sit as close as 3.5 feet to the east and west facade and 2.5 feet to the south facade when facing parallel to the window. Occupants must sit further away from the window to be comfortable when facing the window directly. Occupants should be 3.5 feet away when facing the south facade, 4.5 feet away when facing the west facade and 5.5 feet away when facing the east facade. Thermal comfort studies show that sitting within 30 inches of the facade has a negligible effect on comfort ratings.
Daylighting controls reduced lighting energy use in FLEXLAB by 46% for east facade, 34% for south facade and 35% for west facade over 30 feet deep perimeter zone between 7 AM and 7 PM local time at autumn equinox. Occupancy controls will further reduce lighting energy use, though they were not implemented for the test due to the cell being tested unoccupied.
Genentech, Webcor, and the architectural and engineering team had access to the FLEXLAB during and for a month following the test period to observe, work, and discuss operational issues with employees and staff. The project team made their own qualitative observations about the space in terms of view, adequacy of lighting and daylight levels, color, furniture placement, etc. The project team worked collaboratively with the LBNL team to fine tune details of component design, control settings, troubleshooting, and operations. Because Genentech is introducing a new model for their work environment, a non-assigned workplace, there were detailed discussions on how to educate the occupants about the new technologies and their operational modes. Commissioning and tuning procedures were also discussed.
10acommercial buildings10adaylighting10aenergy management control systems10aexterior shading10afield test10alighting controls10amonitored evaluation10ashading controls10athermal comfort10avisual comfort1 aMcNeil, Andrew1 aKohler, Christian1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/high-performance-building-mockup02421nas a2200205 4500008003900000245011400039210006900153260001200222300001200234490000700246520171800253653003101971653001602002653002902018100002402047700002102071700002902092700001902121856007502140 2014 d00aMonitored lighting energy savings from dimmable lighting controls in The New York Times Headquarters Building0 aMonitored lighting energy savings from dimmable lighting control c01/2014 a498-5140 v683 aDigital 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.
10aBuilding energy-efficiency10adaylighting10alighting control systems1 aFernandes, Luis, L.1 aLee, Eleanor, S.1 aDiBartolomeo, Dennis, L.1 aMcNeil, Andrew uhttps://facades.lbl.gov/publications/monitored-lighting-energy-savings01785nas a2200193 4500008003900000245016500039210006900204520103800273653002701311653002901338653003801367653001101405653002301416100001601439700001901455700002001474700002101494856007601515 2013 d00aAcceleration of the matrix multiplication of Radiance three phase daylighting simulations with parallel computing on heterogeneous hardware of personal computer0 aAcceleration of the matrix multiplication of Radiance three phas3 aBuilding designers are increasingly relying on complex fenestration systems to reduce energy consumed for lighting and HVAC in low energy buildings. Radiance, a lighting simulation program, has been used to conduct daylighting simulations for complex fenestration systems. Depending on the configurations, the simulation can take hours or even days using a personal computer. This paper describes how to accelerate the matrix multiplication portion of a Radiance three-phase daylight simulation by conducting parallel computing on heterogeneous hardware of a personal computer. The algorithm was optimized and the computational part was implemented in parallel using OpenCL. The speed of new approach was evaluated using various daylighting simulation cases on a multicore central processing unit and a graphics processing unit. Based on the measurements and analysis of the time usage for the Radiance daylighting simulation, further speedups can be achieved by using fast I/O devices and storing the data in a binary format.
10adaylighting simulation10agraphics processing unit10amulticore central processing unit10aOpenCL10aparallel computing1 aZuo, Wangda1 aMcNeil, Andrew1 aWetter, Michael1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/acceleration-matrix-multiplication02440nas a2200157 4500008003900000245011900039210006900158520181800227653005202045653003202097653001602129653002502145100001902170700002102189856007202210 2013 d00aAnnual daylighting performance of a passive optical light shelf in sidelit perimeter zones of commercial buildings0 aAnnual daylighting performance of a passive optical light shelf 3 aSunlight redirecting systems have the potential to significantly offset electric lighting energy use in deep perimeter zones of buildings where the windows are subject to high daylight availability. New Radiance modeling tools have recently been developed and validated, enabling accurate and timely simulation analysis of the annual energy and comfort performance of these optically-complex, anisotropic systems. A parametric study was conducted using these tools to evaluate the performance of a commercially-available passive optical light shelf (OLS) in a 17.4 m deep (57 ft), south-facing open plan office zone in three climates. Daylighting efficiency, discomfort glare, and lighting energy savings with continuous dimming and bi-level switching controls were determined at varying depths within the zone. The OLS decreased lighting energy use significantly throughout the depth of the space and achieved these savings with minimal discomfort glare in the area near the window. Annual lighting energy use intensity was reduced to 1.71-1.82 kWh/ft2-yr (22-27%) over the full depth of the perimeter zone across the three climates modeled (Phoenix, Washington DC, and Minneapolis) compared to a non-daylit zone at 2.34 kWh/ft2-yr. There was a greater occurrence of discomfort glare (3-7% during daytime work hours) if the occupant was in a seated view position looking at the window from the back of the room. The system is passive, needing no adjustment during the day and over the seasons and can be used as a retrofit measure in existing buildings. These results are encouraging and demonstrate how the primary daylit sidelit area can be extended well beyond the defined limits provided by the newly adopted ASHRAE 90.1-2010 code (i.e., 1.0 times the head height of the window).
10abidirectional scattering distribution functions10abuildings energy efficiency10adaylighting10aRadiance simulations1 aMcNeil, Andrew1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/annual-daylighting-performance00580nas a2200133 4500008003900000245015800039210006900197260001200266100002200278700001900300700003100319700002100350856007500371 2013 d00aAutomated Production of Optimization-Based Control Logics for Dynamic Façade Systems, with Experimental Application to Two-Zone External Venetian Blinds0 aAutomated Production of OptimizationBased Control Logics for Dyn c09/20131 aCoffey, Brian, E.1 aMcNeil, Andrew1 aNouidui, Thierry, Stephane1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/automated-production-optimization00649nas a2200109 4500008004100000245007100041210006900112260001200181520026300193100001900456856006400475 2013 eng d00aBSDFViewer: A utility for interactive exploration of BSDF datasets0 aBSDFViewer A utility for interactive exploration of BSDF dataset c09/20133 aBSDFViewer is a utility for interactive exploration of BSDF datasets. With BSDF view you can load a BSDF xml file and view the outgoing distribution for user-selectable incident directions. You can look at transmission or reflection for front or back.
1 aMcNeil, Andrew uhttp://www.radiance-online.org/download-install/bsdf-viewer01223nas a2200133 4500008004100000245009400041210006900135260001200204520073200216100001900948700002100967700002300988856007801011 2013 eng d00aDaylight performance of a microstructured prismatic window film in deep open plan offices0 aDaylight performance of a microstructured prismatic window film c09/20133 aDaylight redirecting systems with vertical windows have the potential to offset lighting energy use in deep perimeter zones. A microstructured prismatic film was designed and fabricated by a manufacturer to redirect sunlight to the ceiling plane when the film was installed in the upper portion of a window. Energy simulations based on the raytracing program, Radiance, were performed to evaluate the annual lighting energy use and discomfort glare in a deep open plan office zone in several climates and for south and east-facing window orientations. These simulations showed that when the prismatic film was combined with a light diffusing film, the system was able to deliver significant energy savings without glare.
1 aMcNeil, Andrew1 aLee, Eleanor, S.1 aJonsson, Jacob, C. uhttps://facades.lbl.gov/publications/daylight-performance-microstructured02991nas a2200217 4500008003900000245010400039210006900143260004200212300001000254490000700264520225800271653003202529653001602561653002402577653001902601653001202620100002902632700002102661700001902682856007202701 2013 d00aEmpirical Assessment of a Prismatic Daylight-Redirecting Window Film in a Full-Scale Office Testbed0 aEmpirical Assessment of a Prismatic DaylightRedirecting Window F aHuntington Beach, Californiac10/2013 a19-450 v103 aDaylight redirecting systems with vertical windows have the potential to offset lighting energy use in deep perimeter zones. Microstructured prismatic window films can be manufactured using low-cost, roll-to-roll fabrication methods and adhered to the inside surface of existing windows as a retrofit measure or installed as a replacement insulating glass unit in the clerestory portion of the window wall. A clear film patterned with linear, 50-250 micrometer high, four-sided asymmetrical prisms was fabricated and installed in the south-facing, clerestory low-e, clear glazed windows of a full-scale testbed facility. Views through the film were distorted. The film was evaluated in a sunny climate over a two-year period to gauge daylighting and visual comfort performance. The daylighting aperture was small (window-to-wall ratio of 0.18) and the lower windows were blocked off to isolate the evaluation to the window film. Workplane illuminance measurements were made in the 4.6 m (15 ft) deep room furnished as a private office. Analysis of discomfort glare was conducted using high dynamic range imaging coupled with the evalglare software tool, which computes the daylight glare= probability and other metrics used to evaluate visual discomfort.
The window film was found to result in perceptible levels of discomfort glare on clear sunny days from the most conservative view point in the rear of the room looking toward the window. Daylight illuminance levels at the rear of the room were significantly increased above the reference window condition, which was defined as the same glazed clerestory window but with an interior Venetian blind (slat angle set to the cut-off angle), for the equinox to winter solstice period on clear sunny days. For partly cloudy and overcast sky conditions, daylight levels were improved slightly. To reduce glare, the daylighting film was coupled with a diffusing film in an insulating glazing unit. The diffusing film retained the directionality of the redirected light= spreading it within a small range of outgoing angles. This solution was found to reduce glare to imperceptible levels while retaining for the most part the illuminance levels achieved solely by the daylighting film.
10abuildings energy efficiency10adaylighting10amicrostructure film10aprismatic film10awindows1 aThanachareonkit, Anothai1 aLee, Eleanor, S.1 aMcNeil, Andrew uhttps://facades.lbl.gov/publications/empirical-assessment-prismatic00864nas a2200109 4500008003900000245007600039210006900115260001200184520046100196100001900657856007800676 2013 d00aThe Five-Phase Method for Simulating Complex Fenestration with Radiance0 aFivePhase Method for Simulating Complex Fenestration with Radian c09/20133 aThe "five-phase method" is an extension of the three-phase method that more closely follows the standard daylight coefficient model for dynamic daylight simulations proposed by Bourgeois et al (2008). More specifically, the five-phase method handles the direct solar component separately from the sky and interreflected solar component to achieve better accuracy of the distribution of direct solar light in a room for complex glazing systems (CFS).
1 aMcNeil, Andrew uhttps://facades.lbl.gov/publications/five-phase-method-simulating-complex01199nas a2200253 4500008003900000245007500039210006900114260001200183300001400195490000600209520041200215653002400627653002100651653001600672653002800688653002000716100002200736700002500758700001800783700002600801700001800827700002400845856007600869 2013 d00aNear-Infrared Spectrally Selective Plasmonic Electrochromic Thin Films0 aNearInfrared Spectrally Selective Plasmonic Electrochromic Thin c03/2013 a215 - 2200 v13 aA plasmonic electrochromic effect in which electrochemical doping reversibly modulates near-infrared surface plasmon absorption of aluminium-doped zinc oxide and tin-doped indium oxide nanocrystals is reported. Optical performance, switching kinetics, and cycling durability point to high-performance NIR selective plasmonic electrochromic coatings based on earth-abundant materials.
10aaluminum zinc oxide10aindium tin oxide10ananocrystal10aspectroelectrochemistry10asurface plasmon1 aGarcia, Guillermo1 aBuonsanti, Raffaella1 aLlordes, Anna1 aRunnerstrom, Evan, L.1 aBergerud, Amy1 aMilliron, Delia, J. uhttps://facades.lbl.gov/publications/near-infrared-spectrally-selective01789nas a2200217 4500008003900000245015800039210006900197260006500266520094400331100002101275700002401296700002201320700001901342700002201361700002401383700002101407700002701428700002301455700001601478856007701494 2013 d00aA Post-Occupancy Monitored Evaluation of the Dimmable Lighting, Automated Shading, and Underfloor Air Distribution System in The New York Times Building0 aPostOccupancy Monitored Evaluation of the Dimmable Lighting Auto aBerkeley, CAbLawrence Berkeley National Laboratoryc01/20133 aWith 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.
1 aLee, Eleanor, S.1 aFernandes, Luis, L.1 aCoffey, Brian, E.1 aMcNeil, Andrew1 aClear, Robert, D.1 aWebster, Thomas, L.1 aBauman, Fred, S.1 aDickerhoff, Darryl, J.1 aHeinzerling, David1 aHoyt, Tyler uhttps://facades.lbl.gov/publications/post-occupancy-monitored-evaluation02791nas a2200289 4500008003900000022001300039245010400052210006900156260001200225300001400237490000700251520187700258653002002135653002802155653001802183653002402201653002002225100002302245700001902268700002202287700002802309700002202337700002102359700002702380700002402407856007002431 2013 d a0360132300aRegional performance targets for transparent near-infrared switching electrochromic window glazings0 aRegional performance targets for transparent nearinfrared switch c03/2013 a160 - 1680 v613 aWith 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%.
10aDynamic windows10aElectrochromic glazings10aNIR-switching10aPerformance targets10aSolar heat gain1 aDeForest, Nicholas1 aShehabi, Arman1 aGarcia, Guillermo1 aGreenblatt, Jeffery, B.1 aMasanet, Eric, R.1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E.1 aMilliron, Delia, J. uhttps://facades.lbl.gov/publications/regional-performance-targets00448nas a2200109 4500008003900000245010200039210006900141260001200210100001900222700002100241856007600262 2013 d00aSimulated daylight performance of a new prototype prismatic window film in deep open plan offices0 aSimulated daylight performance of a new prototype prismatic wind c09/20131 aMcNeil, Andrew1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/simulated-daylight-performance-new01617nas a2200109 4500008004100000245007700041210006900118260001200187520121000199100001901409856007901428 2013 eng d00aThe three-phase method for simulating complex fenestration with Radiance0 athreephase method for simulating complex fenestration with Radia c08/20133 aThe "three-phase method" is a means to perform annual simulation of complex and/or dynamic fenestration systems. Flux transfer is broken into the following three phases for independ ent simulation:
Rather than simulate a specific daylight condition, the three-phase method calculates normalized coefficients that relate flux input to output for each phase. A result for a specific daylight condition is computed by multiplying the coefficient matrices by the input values (sky luminance values). Matrix calculation can be performed very quickly enabling the user to simulate many sky conditions and fenestration transmission properties.
This document starts with a brief overview of the three-phase method. Following is a detailed discussion of each phase of flux transfer including an explanation of new tools that were develop ed for the three - phase method, explained in detail. Two examples follow the detailed discussion, the first a simple space with one south facing window, the second a space with south and east facing windows.
1 aMcNeil, Andrew uhttps://facades.lbl.gov/publications/three-phase-method-simulating-complex02476nas a2200325 4500008003900000245007600039210006900115260001200184300001200196490000700208520149100215653001701706653001601723653004601739653002201785653001001807653003301817653001301850653001201863100001901875700002301894700001901917700002201936700002801958700002101986700002102007700002102028700002402049856007702073 2013 d00aU.S. energy savings potential from dynamic daylighting control glazings0 aUS energy savings potential from dynamic daylighting control gla c11/2013 a415-4230 v663 aDaylighting 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.
10aClerestories10adaylighting10aDynamic prismatic optical elements (dPOE)10aenergy efficiency10aGlare10aindoor environmental quality10aradiance10awindows1 aShehabi, Arman1 aDeForest, Nicholas1 aMcNeil, Andrew1 aMasanet, Eric, R.1 aGreenblatt, Jeffery, B.1 aLee, Eleanor, S.1 aMasson, Georgeta1 aHelms, Brett, A.1 aMilliron, Delia, J. uhttps://facades.lbl.gov/publications/us-energy-savings-potential-dynamic02197nas a2200229 4500008003900000245013800039210006900177260001200246300001200258490000700270520138900277653005201666653003301718653001601751653002001767100001901787700002301806700002101829700002201850700002101872856007401893 2013 d00aA validation of a ray-tracing tool used to generate bi-directional scattering distribution functions for complex fenestration systems0 avalidation of a raytracing tool used to generate bidirectional s c12/2013 a404-4140 v983 aFenestration attachments are anticipated to produce significant reductions in building energy use because they can be deployed quickly at low-cost. New software tools enable users to assess the building energy impacts of optically complex fenestration systems (CFS) such as shades, Venetian blinds, or daylighting systems. However, such tools require users to provide bi-directional scattering distribution function (BSDF) data that describe the solar-optical performance of the CFS. A free, open-source Radiance tool genBSDF enables users to generate BSDF data for arbitrary CFS. Prior to genBSDF, BSDF data for arbitrary fenestration systems could only be produced using either expensive software or with expensive equipment. genBSDF outputs CFS data in the Window 6 XML file format and so can be used with CFS-enabled software tools to model multi-layered window systems composed of glazing and shading layers.
We explain the basis and use of the genBSDF tool and validate the tool by comparing results for four different cases to BSDF data produced via alternate methods. This validation demonstrates that BSDFs created with genBSDF are comparable to BSDFs generated analytically using TracePro and by measurement with a scanning goniophotometer. This tool is expected to support accelerated adoption of fenestration attachments and daylighting technologies.
10aBi-directional scattering distribution function10aComplex fenestration systems10adaylighting10aSolar heat gain1 aMcNeil, Andrew1 aJonsson, Jacob, C.1 aAppelfeld, David1 aWard, Gregory, J.1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/validation-ray-tracing-tool-used00787nas a2200133 4500008003900000245009500039210006900134260001200203300000600215520032200221100001900543700002100562856007000583 2012 d00aOn the benefits of a variable-resolution bidirectional scattering distribution data format0 abenefits of a variableresolution bidirectional scattering distri c09/2012 a53 aThis summary report adds context to the recent development of a new format for variable-resolution bi-directional scattering data. Specifically we discuss why a high resolution BSDF format is needed, the advantages of a variable resolution data format, and the new capabilities that stem from this development.
1 aMcNeil, Andrew1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/benefits-variable-resolution01397nas a2200145 4500008004100000245013200041210006900173260001200242300000700254520084000261100003101101700001901132700002101151856007901172 2012 eng d00aDevelopment of a simulation-based controls framework for implementation of controls algorithms for complex fenestration systems0 aDevelopment of a simulationbased controls framework for implemen c09/2012 a153 aEffectively controlled dynamic windows can substantially reduce the energy consumption of buildings. Unfortunately, modular and extensible frameworks for testing and evaluating window system control algorithms that include the effects of thermal mass are missing in the research community.
This paper describes a modular and extensible simulation-based framework that uses different simulation tools such as EnergyPlus, Modelica, Radiance, and the Building Controls Virtual Test Bed (BCVTB) to develop and evaluate the performance of integrated façade control strategies. We present a simulation framework and a proof-of concept application using the framework to control a venetian blind in a physical test cell in order to reduce its zone thermal load based on solar inputs and internal gains measured at the test cell.
1 aNouidui, Thierry, Stephane1 aMcNeil, Andrew1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/development-simulation-based-controls02762nas a2200205 4500008004100000245009100041210006900132260001200201520206000213100002102273700002402294700002802318700002102346700002402367700002102391700002102412700001902433700002702452856007702479 2012 eng d00aElectro-Responsive Polymer Glazings For Smart Windows With Dynamic Daylighting Control0 aElectroResponsive Polymer Glazings For Smart Windows With Dynami c02/20123 aIn 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.
1 aMasson, Georgeta1 aMendlesberg, Rueben1 aFernandez-Cuesta, Irene1 aCabrini, Stefano1 aMilliron, Delia, J.1 aHelms, Brett, A.1 aLee, Eleanor, S.1 aMcNeil, Andrew1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/electro-responsive-polymer-glazings01798nas a2200193 4500008003900000245013300039210006900172490000700241520111100248653003501359653003201394653001301426653001201439653001601451100002101467700001901488700002001507856007701527 2012 d00aAn Hourly-Based Performance Comparison of an Integrated Micro-Structural Perforated Shading Screen with Standard Shading Systems0 aHourlyBased Performance Comparison of an Integrated MicroStructu0 v503 aThis article evaluates the performance of an integrated micro structural perforated shading screen (MSPSS). Such a system maintains a visual connection with the outdoors while imitating the shading functionality of a venetian blind. Building energy consumption is strongly influenced by the solar gains and heat transfer through the transparent parts of the fenestration systems. MSPSS is angular-dependent shading device that provides an effective strategy in the control of daylight, solar gains and overheating through windows. The study focuses on using direct experimental methods to determine bi-directional transmittance properties of shading systems that are not included as standard shading options in readily available building performance simulation tools. The impact on the indoor environment, particularly temperature and daylight were investigated and compared to three other static complex fenestration systems. The bi-directional description of the systems was used throughout the article. The simulations were validated against outdoor measurements of solar and light transmittance.
10abuilding performance modelling10acomplex fenestration system10adaylight10ashading10asolar gains1 aAppelfeld, David1 aMcNeil, Andrew1 aSvendsen, Svend uhttps://facades.lbl.gov/publications/hourly-based-performance-comparison01539nas a2200241 4500008003900000022001400039245011000053210006900163260001100232300001400243490000700257520076200264653003001026653002201056653002601078100001701104700002801121700002201149700001501171700001601186700001901202856007601221 2012 d a0884-291400aImproved structural and electrical properties of thin ZnO:Al films by dc filtered cathodic arc deposition0 aImproved structural and electrical properties of thin ZnOAl film c3/2012 a857 - 8620 v273 aTransparent conducting oxide films are usually several 100-nm thick to achieve the required low sheet resistance. In this study, we show that the filtered cathodic arc technique produces high-quality low-cost ZnO:Al material for comparably smaller thicknesses than achieved by magnetron sputtering, making arc deposition a promising choice for applications requiring films less than 100-nm thick. A mean surface roughness less than 1 nm is observed for ZnO:Al films less than 100-nm thick, and 35-nm-thick ZnO:Al films exhibit Hall mobility of 28 cm2/Vs and a low resistivity of 6.5 × 10−4 Ωcm. Resistivity as low as 5.2 × 10−4 Ωcm and mobility as high as 43.5 cm2/Vs are obtained for 135-nm films.
10aphysical vapor deposition10aPlasma deposition10aTransparent conductor1 aZhu, Yuankun1 aMendelsberg, Rueben, J.1 aLim, Sunnie, H.N.1 aZhu, Jiaqi1 aHan, Jiecai1 aAnders, André uhttps://facades.lbl.gov/publications/improved-structural-and-electrical01241nas a2200181 4500008003900000022001400039245012000053210006900173260001200242300001100254490000700265520064300272100001900915700001900934700001800953700002000971856006800991 2012 d a0022-372700aThe ‘recycling trap’: a generalized explanation of discharge runaway in high-power impulse magnetron sputtering0 arecycling trap a generalized explanation of discharge runaway in c01/2012 a0120030 v453 aContrary to paradigm, magnetron discharge runaway cannot always be related to self-sputtering. We report here that the high density discharge can be observed with all conducting targets, including low sputter yield materials such as carbon. Runaway to a high density discharge is therefore generally based on self-sputtering in conjunction with the recycling of gas atoms in the magnetic field-affected pre-sheath. A generalized runaway condition can be formulated, offering a pathway to a time-dependent model for high-power impulse magnetron sputtering that includes rarefaction and an explanation for the termination of runaway.
1 aAnders, André1 aČapek, Jiří1 aHála, Matêj1 aMartinu, Ludvik uhttps://facades.lbl.gov/publications/recycling-trap-generalized00422nas a2200109 4500008004100000245007600041210006900117260001200186100001900198700002100217856007400238 2012 eng d00aUsing Radiance and GenOpt to design static daylight redirection systems0 aUsing Radiance and GenOpt to design static daylight redirection c09/20121 aMcNeil, Andrew1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/using-radiance-and-genopt-design00704nas a2200181 4500008003900000245014600039210006900185260001200254490001500266653005200281653003200333653001600365653001300381653001500394100001900409700002100428856007300449 2012 d00aA validation of the Radiance three-phase simulation method for modeling annual daylight performance of optically-complex fenestration systems0 avalidation of the Radiance threephase simulation method for mode c05/20120 vApril 201210abidirectional scattering distribution functions10abuildings energy efficiency10adaylighting10aradiance10avalidation1 aMcNeil, Andrew1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/validation-radiance-three-phase01204nas a2200157 4500008004100000245009300041210006900134260003100203300001500234520064900249100001600898700001900914700002000933700002100953856007200974 2011 eng d00aAcceleration of Radiance for Lighting Simulation by using Parallel Computing with OpenCL0 aAcceleration of Radiance for Lighting Simulation by using Parall aSydney, Australiac11/2011 ap. 110-1173 aThis study attempted to accelerate annual daylighting simulations for fenestration systems in Radiance ray-tracing program. The algorithm was optimized to reduce both the redundant data input/output operations and floating-point operations. To further accelerate the simulation speed, calculation for matrices multiplications was implemented in parallel on a graphics processing unit using OpenCL, a cross-platform parallel programming language. Numerical experiments show that combination of above measures can speed up the annual daylighting simulations 101.7 times or 28.6 times when sky vector has 146 or 2306 elements, respectively.
1 aZuo, Wangda1 aMcNeil, Andrew1 aWetter, Michael1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/acceleration-radiance-lighting01830nas a2200181 4500008003900000245010000039210006900139300001800208490000700226520121300233100002801446700002201474700001701496700001601513700002401529700001901553856007601572 2011 d00aAchieving high mobility ZnO:Al at very high growth rates by dc filtered cathodic arc deposition0 aAchieving high mobility ZnOAl at very high growth rates by dc fi a232003-2320070 v443 aAchieving a high growth rate is paramount for making large-area transparent conducting oxide coatings at a low cost. Unfortunately, the quality of thin films grown by most techniques degrades as the growth rate increases. Filtered dc cathodic arc is a lesser known technique which produces a stream of highly ionized plasma, in stark contrast to the neutral atoms produced by standard sputter sources. Ions bring a large amount of potential energy to the growing surface which is in the form of heat, not momentum. By minimizing the distance from cathode to substrate, the high ion flux gives a very high effective growth temperature near the film surface without causing damage from bombardment. The high surface temperature is a direct consequence of the high growth rate and allows for high-quality crystal growth. Using this technique, 500–1300 nm thick and highly transparent ZnO : Al films were grown on glass at rates exceeding 250 nm min−1 while maintaining resistivity below 5 × 10−4 Ω cm with electron mobility as high as 60 cm2 V−1 s−1.
1 aMendelsberg, Rueben, J.1 aLim, Sunnie, H.N.1 aZhu, Yuankun1 aWallig, Joe1 aMilliron, Delia, J.1 aAnders, André uhttps://facades.lbl.gov/publications/achieving-high-mobility-znoal-very02631nas a2200169 4500008004100000245009900041210007000140260002400210520201600234100002702250700002002277700002302297700002202320700001902342700002102361856007902382 2011 eng d00aCOMFEN 3.0: Evolution of an Early Design Tool for Commercial Façades and Fenestration Systems0 aCOMFEN 30 Evolution of an Early Design Tool for Commercial Façad aPomona, CAc03/20113 aAchieving a net-zero energy building cannot be done solely by improving the efficiency of the engineering systems. It also requires consideration of the essential nature of the building including factors such as architectural form, massing, orientation and enclosure. Making informed decisions about the fundamental character of a building requires assessment of the effects of the complex interaction of these factors on the resulting performance of the building. The complexity of these interactions necessitates the use of modeling and simulation tools to dynamically analyze the effects of the relationships, yet decisions about the building fundamentals are often made in the earliest stages of design, before a 'building' exists to model.
To address these issues, Lawrence Berkeley National Laboratory (LBNL) has developed an early-design energy modeling tool (COMFEN) specifically to help make informed decisions about building façade fundamentals by considering the design of the building envelope, orientation and massing on building performance. COMFEN focuses on the concept of a "space" or "room" and uses the EnergyPlus, and Radiance™ engines and a simple, graphic user interface to allow the user to explore the effects of changing key early-design input variables on energy consumption, peak energy demand, and thermal and visual comfort. Comparative results are rapidly presented in a variety of graphic and tabular formats to help users move toward optimal façade and fenestration design choices.
While COMFEN 1.0 utilized an Excel™–based user interface, COMFEN 3.0 has been reworked to include a simple, more intuitive, yet powerful Graphic User Interface (GUI), a broader range of libraries for associated system and component choices and deliver a wider range of graphic outputs and options.
This paper (and presentation) outlines the objectives in developing and further refining COMFEN, the mechanics of the program, and plans for future development.
1 aSelkowitz, Stephen, E.1 aMitchell, Robin1 aMcClintock, Maurya1 aMcQuillen, Daniel1 aMcNeil, Andrew1 aYazdanian, Mehry uhttps://facades.lbl.gov/publications/comfen-30-evolution-early-design-tool01433nas a2200289 4500008003900000022001400039245009300053210006900146260001200215300001600227490000700243520053600250653001100786653002100797653001600818653002800834653002000862100002200882700002500904700002600929700002800955700001800983700001901001700002701020700002401047856007201071 2011 d a1530-698400aDynamically Modulating the Surface Plasmon Resonance of Doped Semiconductor Nanocrystals0 aDynamically Modulating the Surface Plasmon Resonance of Doped Se c10/2011 a4415 - 44200 v113 aLocalized surface plasmon absorption features arise at high doping levels in semiconductor nanocrystals, appearing in the near-infrared range. Here we show that the surface plasmons of tin-doped indium oxide nanocrystal films can be dynamically and reversibly tuned by postsynthetic electrochemical modulation of the electron concentration. Without ion intercalation and the associated material degradation, we induce a > 1200 nm shift in the plasmon wavelength and a factor of nearly three change in the carrier density.
10adoping10aindium tin oxide10ananocrystal10aspectroelectrochemistry10asurface plasmon1 aGarcia, Guillermo1 aBuonsanti, Raffaella1 aRunnerstrom, Evan, L.1 aMendelsberg, Rueben, J.1 aLlordes, Anna1 aAnders, André1 aRichardson, Thomas, J.1 aMilliron, Delia, J. uhttps://facades.lbl.gov/publications/dynamically-modulating-surface00572nas a2200145 4500008003900000245011600039210006900155260001200224100003100236700001900267700002200286700002200308700002100330856007500351 2011 d00aModeling solar heat gains of complex fenestration systems using bidirectional scattering distribution functions0 aModeling solar heat gains of complex fenestration systems using c09/20111 aNouidui, Thierry, Stephane1 aMcNeil, Andrew1 aKohler, Christian1 aCoffey, Brian, E.1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/modeling-solar-heat-gains-complex01669nas a2200121 4500008004100000245015500041210006900196260001200265300000700277520117000284100001901454856007401473 2011 eng d00aOn the sensitivity of daylight simulations to the resolution of the hemispherical basis used to define bidirectional scattering distribution functions0 asensitivity of daylight simulations to the resolution of the hem c09/2011 a193 aThe Radiance simulation program includes new tools that enable daylight modeling of complex fenestration systems (CFS) using bi-directional transmission distribution functions (BTDF). The tools use the Klems angle basis to define the number of paired incoming and outgoing data values. However, the Klems angle basis was developed for thermal simulations and may be too low of a resolution for some types of daylight systems, particularly those that exhibit peaky, specular transmission. This study evaluates the sensitivity of the angle basis resolution by comparing simulation results for the Klems angle basis against results using two higher resolution angle bases. The first evaluation compares results for specific points in time. The second evaluation compares simulation results using annual performance metrics. Annual lighting energy data were found to agree to within 1%. Annual assessments of discomfort glare were found to disagree by 7% because high resolution basis resolved glare sources into smaller, more intense sources. We concluded that high resolution bases are appropriate for specific types of CFS and performance metrics.
We describe two methods which rely on bidirectional scattering distribution functions (BSDFs) to model the daylighting performance of complex fenestration systems (CFS), enabling greater flexibility and accuracy in evaluating arbitrary assemblies of glazing, shading, and other optically-complex coplanar window systems. Two tools within Radiance enable a) efficient annual performance evaluations of CFS, and b) accurate renderings of CFS despite the loss of spatial resolution associated with low-resolution BSDF datasets for inhomogeneous systems. Validation, accuracy, and limitations of the methods are discussed.
10abidirectional scattering distribution function (BSDF)10aComplex fenestration systems10adaylighting systems10aenergy10aRadiance software10aShading Systems10awindows1 aWard, Gregory, J.1 aMistrick, Richard, G.1 aLee, Eleanor, S.1 aMcNeil, Andrew1 aJonsson, Jacob, C. uhttps://facades.lbl.gov/publications/simulating-daylight-performance01087nas a2200157 4500008004100000245004000041210004000081260001200121300001200133490000700145520063800152100002200790700001900812700002100831856007700852 2009 eng d00aDaylight metrics and energy savings0 aDaylight metrics and energy savings c09/2009 a261-2830 v413 aThe drive towards sustainable, low-energy buildings has increased the need for simple, yet accurate methods to evaluate whether a "daylit" building meets minimum standards for energy and human comfort performance. Current metrics do not account for the temporal and spatial aspects of daylight, nor of occupants comfort or interventions. This paper reviews the historical basis of current compliance methods for achieving daylit buildings, proposes a technical basis for development of better metrics, and provides two case study examples to stimulate dialogue on how metrics can be applied in a practical, real-world context.
1 aMardaljevic, John1 aHeschong, Lisa1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/daylight-metrics-and-energy-savings05111nas a2200217 4500008004100000245007400041210006900115260001200184520439000196100002104586700002704607700002904634700002204663700002204685700002004707700002604727700002104753700002004774700002504794856007404819 2009 eng d00aHigh Performance Building Facade Solutions: PIER Final Project Report0 aHigh Performance Building Facade Solutions PIER Final Project Re c12/20093 aBuilding façades directly influence heating and cooling loads and indirectly influence lighting loads when daylighting is considered, and are therefore a major determinant of annual energy use and peak electric demand. façades also significantly influence occupant comfort and satisfaction, making the design optimization challenge more complex than many other building systems.
This work focused on addressing significant near-term opportunities to reduce energy use in California commercial building stock by a) targeting voluntary, design-based opportunities derived from the use of better design guidelines and tools, and b) developing and de ploying more efficient glazings, shading systems, daylighting systems, façade systems and integrated controls.
This two-year project, supported by the California Energy Commission PIER program and the US Department of Energy, initiated a collaborative effort between The Lawrence Berkeley National Laboratory (LBNL) and major stakeholders in the façades industry to develop, evaluate, and accelerate market deployment of emerging, high-performance, integrated façade solutions. The LBNL Windows Testbed Facility acted as the primary cata lyst and mediator on both sides of the building industry supply-user business transaction by a) aiding component suppliers to create and optimize cost effective, integrated systems that work, and b) demonstrating and verifying to the owner, designer, and specifier community that these integrated systems reliably deliver required energy performance. An industry consortium was initiated amongst approximately seventy disparate stakeholders, who unlike the HVAC or lighting industry, has no single representative, multi-disciplinary body or organized means of communicating and collaborating. The consortium provided guidance on the project and more importantly, began to mutually work out and agree on the goals, criteria, and pathways needed to attain the ambitious net zero energy goals defined by California and the US.
A collaborative test, monitoring, and reporting protocol was also formulated via the Windows Testbed Facility in collaboration with industry partners, transitioning industry to focus on the import ance of expecting measured performance to consistently achieve design performance expectations. The facility enables accurate quantification of energy use, peak demand, and occupant comfort impacts of synergistic façade-lighting-HVAC systems on an apples-to-apples comparative basis and its data can be used to verify results from simulations.
Emerging interior and exterior shading technologies were investigated as potential near-term, low-cost solutions with potential broad applicability in both new and retrofit construction. Commercially-available and prototype technologies were developed, tested, and evaluated. Full-scale, monitored field tests were conducted over solstice-to-solstice periods to thoroughly evaluate the technologies, uncover potential risks associated with an unknown, and quantify performance benefits. Exterior shading systems were found to yield net zero energy levels of performance in a sunny climate and significant reductions in summer peak demand. Automated interior shading systems were found to yield significant daylighting and comfort-related benefits.
In support of an integrated design process, a PC-based commercial fenestration (COMFEN) software package, based on EnergyPlus, was developed that enables architects and engineers to x quickly assess and compare the performance of innovative façade technologies in the early sketch or schematic design phase. This tool is publicly available for free and will continue to improve in terms of features and accuracy. Other work was conducted to develop simulation tools to model the performance of any arbitrary complex fenestration system such as common Venetian blinds, fabric roller shades as well as more exotic innovative façade systems such as optical louver systems.
The principle mode of technology transfer was to address the key market barriers associated with lack of information and facile simulation tools for early decisionmaking. The third party data generated by the field tests and simulation data provided by the COMFEN tool enables utilities to now move forward toward incentivizing these technologies in the marketplace.
1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E.1 aDiBartolomeo, Dennis, L.1 aKlems, Joseph, H.1 aClear, Robert, D.1 aKonis, Kyle, S.1 aHitchcock, Robert, J.1 aYazdanian, Mehry1 aMitchell, Robin1 aKonstantoglou, Maria uhttps://facades.lbl.gov/publications/high-performance-building-facade01581nas a2200181 4500008004100000050001500041245011400056210006900170520095200239100001901191700002201210700001701232700002201249700002001271700002001291700001601311856007201327 2009 eng d aLBNL-1881E00aHigh quality ZnO:Al transparent conducting oxide films synthesized by pulsed filtered cathodic arc deposition0 aHigh quality ZnOAl transparent conducting oxide films synthesize3 aAluminum-doped zinc oxide, ZnO:Al or AZO, is a well-known n-type transparent conducting oxide with great potential in a number of applications currently dominated by indium tin oxide (ITO). In this study, the optical and electrical properties of AZO thin films deposited on glass and silicon by pulsed filtered cathodic arc deposition are systematically studied. In contrast to magnetron sputtering, this technique does not produce energetic negative ions, and therefore ion damage can be minimized. The quality of the AZO films strongly depends on the growth temperature while only marginal improvements are obtained with post-deposition annealing. The best films, grown at a temperature of about 200°C, have resistivities in the low to mid 10-4Ω cm range with a transmittance better than 85% in the visible part of the spectrum. It is remarkable that relatively good films of small thickness (60 nm) can be fabricated using this method.
1 aAnders, André1 aLim, Sunnie, H.N.1 aYu, Kin, Man1 aAndersson, Joakim1 aRosén, Johanna1 aMcFarland, Mike1 aBrown, Jeff uhttps://facades.lbl.gov/publications/high-quality-znoal-transparent01914nas a2200253 4500008004100000245013900041210006900180260002500249490000800274520105500282653001901337653000801356653003601364653001601400653000801416100002201424700002001446700002901466700003101495700001901526700002301545700001901568856007301587 2008 eng d00aFunctionalization of Hydrogen-free Diamond-like Carbon Films using Open-air Dielectric Barrier Discharge Atmospheric Plasma Treatments0 aFunctionalization of Hydrogenfree Diamondlike Carbon Films using aBoulder, COc08/20080 v2543 aA dielectric barrier discharge (DBD) technique has been employed to produce uniform atmospheric plasmas of He and N2 gas mixtures in open air in order to functionalize the surface of filtered-arc deposited hydrogen-free diamond-like carbon (DLC) films. XPS measurements were carried out on both untreated and He/N2 DBD plasma-treated DLC surfaces. Chemical states of the C 1s and N 1s peaks were collected and used to characterize the surface bonds. Contact angle measurements were also used to record the short- and long-term variations in wettability of treated and untreated DLC. In addition, cell viability tests were performed to determine the influence of various He/N2 atmospheric plasma treatments on the attachment of osteoblast MC3T3 cells. Current evidence shows the feasibility of atmospheric plasmas in producing long-lasting variations in the surface bonding and surface energy of hydrogen-free DLC and consequently the potential for this technique in the functionalization of DLC-coated devices.
10aCell viability10aDLC10aIon implantation and deposition10awettability10aXPS1 aEndrino, Jose, L.1 aMarco, Jose, F.1 aPoolcharuansin, Phitsanu1 aPhani, Ayalasomayajula, R.1 aAllen, Matthew1 aAlbella, José, M.1 aAnders, André uhttps://facades.lbl.gov/publications/functionalization-hydrogen-free01696nas a2200193 4500008004100000245018300041210006900224260001200293300001100305490000700316520097400323100002301297700002601320700002201346700001901368700002101387700001801408856007601426 2008 eng d00aThe structure and electron energy loss near edge structure of tungsten oxide thin films prepared by pulsed cathodic arc deposition and plasma-assisted pulsed magnetron sputtering0 astructure and electron energy loss near edge structure of tungst c04/2008 a1752160 v203 aThe 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.
1 aField, Matthew, R.1 aMcCulloch, Dougal, G.1 aLim, Sunnie, H.N.1 aAnders, André1 aKeast, Vicki, J.1 aBurgess, R.W. uhttps://facades.lbl.gov/publications/structure-and-electron-energy-loss02585nas a2200205 4500008004100000245005400041210005100095260006100146300001000207520191200217100002002129700002202149700002202171700002302193700002502216700002202241700001602263700002402279856007602303 2008 eng d00aWINDOW 6.2/THERM 6.2 Research Version User Manual0 aWINDOW 62THERM 62 Research Version User Manual aBerkeleybLawrence Berkeley National Laboratoryc01/2008 a1-1263 aWINDOW 6 and THERM 6 Research Versions are software programs developed at Lawrence Berkeley National Laboratory (LBNL) for use by manufacturers, engineers, educators, students, architects, and others to determine the thermal and solar optical properties of glazing and window systems.
WINDOW 6 and THERM 6 are significant updates to LBNL's WINDOW 5 and THERM 5 computer program because of the added capability to model complex glazing systems, such as windows with shading systems, in particular venetian blinds. Besides a specific model for venetian blinds and diffusing layers, WINDOW 6 also includes the generic ability to model any complex layer if the Transmittance and Reflectance are known as a function of incoming and outgoing angles.
The algorithms used in these versions of the programs to determine the properties of windows with shading layers are relatively new and should be considered as informative but not definitive.
As such, for windows with shading layers, the results are intended for research purposes only. Pending further validation efforts, results for windows with sh ading layers should not be used for NFRC certified calculations of design decisions in real buildings.
All calculations for products without shading layers are identical to those from WINDOW 5.2.
WINDOW 6 Research Version includes all of the WINDOW 5 capabilities with the addition of shading algorithms from ISO15099 which are incorporated into the program, as well as an extension of those algorithms with the matrix calculation method.
THERM 6 Research Version includes all of the THERM 5 capabilities with the addition of being able to import and model WINDOW 6 glazing systems with shading devices. Those THERM 6 files with shading devices can them be imported into the WINDOW 6 Frame Library and whole windows with shading devices can then be modeled in WINDOW 6.
1 aMitchell, Robin1 aKohler, Christian1 aKlems, Joseph, H.1 aRubin, Michael, D.1 aArasteh, Dariush, K.1 aHuizenga, Charlie1 aYu, Tiefeng1 aCurcija, Dragan, C. uhttps://facades.lbl.gov/publications/window-62therm-62-research-version01259nas a2200157 4500008004100000245004400041210004300085260003400128300001200162490000800174520077700182100002200959700002200981700002001003856007801023 2007 eng d00aField Evaluation of Low-E Storm Windows0 aField Evaluation of LowE Storm Windows aClearwater Beach, FLc12/2007 a228-2360 v2773 aA field evaluation comparing the performance of low emittance (low-e) storm windows with both standard clear storm windows and no storm windows was performed in a cold climate. Six homes with single pane windows were monitored over the period of one heating season. The homes were monitored with no storm windows and with new storm windows. The storm windows installed on four of the six homes included a hard coat, pyrolitic, low-e coating while the storm windows for the other two homes had traditional clear glass. Overall heating load reduction due to the storm windows was 13% with the clear glass and 21% with the low-e windows. Simple paybacks for the addition of the storm windows were 10 years for the clear glass and 4.5 years for the low-e storm windows.
1 aDrumheller, Craig1 aKohler, Christian1 aMinen, Stefanie uhttps://facades.lbl.gov/publications/field-evaluation-low-e-storm-windows01644nas a2200205 4500008004100000245011300041210006900154260001200223300001400235490000800249520093200257653003001189653002701219653002401246653002301270653002501293100002301318700001901341856007801360 2007 eng d00aPhysical properties of erbium implanted tungsten oxide films deposited by reactive dual magnetron sputtering0 aPhysical properties of erbium implanted tungsten oxide films dep c05/2007 a5264-52690 v5153 aAmorphous and partially crystalline WO3 thin films were prepared by reactive dual magnetron sputtering and successively implanted by erbium ions with a fluence in the range from 7.7 x 1014 to 5 x 1015 ions/cm2. The electrical and optical properties were studied as a function of the film deposition parameters and the ion fluence. Ion implantation caused a strong decrease of the resistivity, a moderate decrease of the index of refraction and a moderate increase of the extinction coefficient in the visible and near infrared, while the optical band gap remained almost unchanged. These effects could be largely ascribed to ion-induced oxygen deficiency. When annealed in air, the already low resistivities of the implanted samples decreased further up to 70°C, whereas oxidation, and hence a strong increase of the resistivity, was observed at higher annealing temperatures
10aDual magnetron sputtering10aelectrical resistivity10aEr ion implantation10aoptical properties10atungsten oxide films1 aMohamed, Sodky, H.1 aAnders, André uhttps://facades.lbl.gov/publications/physical-properties-erbium-implanted01614nas a2200169 4500008003900000245009500039210006900134260001200203520102300215100001901238700002201257700001701279700002501296700002501321700002101346856007701367 2006 d00aExperimental Validation of Daylighting Simulation Methods for Complex Fenestration Systems0 aExperimental Validation of Daylighting Simulation Methods for Co c05/20063 aThe objective of this paper is to assess the capability of existing lighting simulation methods to predict the performance of complex fenestration systems, which are becoming a commonly used component in buildings construction domain. A specific experimental protocol was conducted to collect reliable reference data based on illuminance measurements inside a black box with (and without) one complex glazing sample facing a measured external luminance distribution. Two types of simulation methods were tested and compared: The first is based on modeling the glazing sample in a ray-tracing simulation program and the second is based on use of the samples' BTDF data. The BTDF data sets were combined with the external luminance distribution to predict the flux distribution inside the room and the resulting illuminance values at the reference points. The comparison between the experimental reference data and the simulation results showed that the influence of the CFS could be predicted with good accuracy.
1 aMaamari, Fawaz1 aAndersen, Marilyn1 ade Boer, Jan1 aCarroll, William, L.1 aDumortier, Dominique1 aGreenup, Phillip uhttps://facades.lbl.gov/publications/experimental-validation-daylighting01286nas a2200169 4500008004100000050001500041245006100056210006100117260002400178520073100202100002500933700001800958700001900976700002200995700002001017856007901037 2006 eng d aLBNL-5919000aPerformance Criteria for Residential Zero Energy Windows0 aPerformance Criteria for Residential Zero Energy Windows aDallas, TXc01/20073 aThis paper shows that the energy requirements for today's typical efficient window products (i.e. ENERGY STAR products) are significant when compared to the needs of Zero Energy Homes (ZEHs). Through the use of whole house energy modeling, typical efficient products are evaluated in five US climates and compared against the requirements for ZEHs. Products which meet these needs are defined as a function of climate. In heating dominated climates, windows with U-factors of 0.10 Btu/hr-ft2-F (0.57 W/m2-K) will become energy neutral. In mixed heating/cooling climates a low U-factor is not as significant as the ability to modulate from high SHGCs (heating season) to low SHGCs (cooling season).
1 aArasteh, Dariush, K.1 aGoudey, Howdy1 aHuang, Yu, Joe1 aKohler, Christian1 aMitchell, Robin uhttps://facades.lbl.gov/publications/performance-criteria-residential-zero02166nas a2200193 4500008004100000245011300041210006900154300001400223490000800237520149200245653003001737653001501767653002301782653001501805653003501820100002301855700001901878856007501897 2006 eng d00aStructural, optical and electrical properties of WOxNy films deposited by reactive dual magnetron sputtering0 aStructural optical and electrical properties of WOxNy films depo a2977-29830 v2013 aThin films of tungsten oxynitrides were prepared by dual magnetron sputtering of tungsten using argon/oxygen/nitrogen gas mixtures with various nitrogen/oxygen ratios. The presence of even relatively small amounts of oxygen led to close-to-stoichiometric WO3, with little incorporation of nitrogen, therefore the films were labeled as WOx(Ny). Oxygen had a great effect not only on the composition but on the structure of WOx(Ny) films, as shown by Rutherford backscattering and X-ray diffraction, respectively. Significant incorporation of nitrogen occurred only when the nitrogen partial pressure exceeded 89% of the total reactive gas pressure. Sharp changes in the stoichiometry, deposition rate, room temperature resistivity, electrical activation energy and optical band gap were observed when the nitrogen/oxygen ratio was high. The deposition rate increased from 0.31 to 0.89 nm/s, the room temperature resistivity decreased from 1.65 × 108 to 1.82 × 10− 2 Ω cm, the electrical activation energy decreased from 0.97 to 0.067 eV, and the optical band gap decreased from 3.19 to 2.94 eV upon nitrogen incorporation into the films. WOx(Ny) films were highly transparent as long as the nitrogen incorporation was low, and were brownish (absorbing) and partially reflecting as nitrogen incorporation became significant.
10aDual magnetron sputtering10aelectrical10aoptical properties10astructural10atungsten oxynitride thin films1 aMohamed, Sodky, H.1 aAnders, André uhttps://facades.lbl.gov/publications/structural-optical-and-electrical02657nas a2200265 4500008003900000245007100039210006900110260001200179520181700191653003502008653002802043653001602071653002202087653001902109100002102128700002702149700002202176700002202198700002202220700002202242700001402264700002102278700002402299856006802323 2005 d00aDaylighting the New York Times Headquarters Building: Final Report0 aDaylighting the New York Times Headquarters Building Final Repor c06/20053 aThe 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 all innovations, the problem with accelerating market adoption is one of decreasing risk. As the building owner researches technology options, the usual questions surface that concern the purchase of any new product: how will it work for my application, are the vendor claims valid, what risks are incurred, and will the performance benefits be sustained over the life of the installation? In their effort to create an environment that "enhances the way we work" in their new 139 km2 (1.5 Mft2) headquarters building in downtown Manhattan, The New York Times employed a unique approach to create a competitive marketplace for daylighting systems. A monitored field test formed the strategic cornerstone for accelerating an industry response to the building owners' challenge to a sleepy market (i.e., US automated shading and daylighting control products have had few major technical advances over the past 10 years). Energy, control system, and environmental quality performance of commercially-available automated roller shade and daylighting control systems were evaluated. Procurement specifications were produced. Bids were received that met The Times cost-effective criteria. The Times will proceed with the use of these systems in their final building. Competitively-priced new products have been developed as a result of this research and are now available on the market.
10aautomated daylighting controls10aautomated window shades10adaylighting10aenergy-efficiency10avisual comfort1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E.1 aHughes, Glenn, D.1 aClear, Robert, D.1 aWard, Gregory, J.1 aMardaljevic, John1 aLai, Judy1 aInanici, Mehlika1 aInkarojrit, Vorapat uhttps://facades.lbl.gov/publications/daylighting-new-york-times01869nas a2200157 4500008004100000245003300041210003200074260005100106520137600157100002001533700001901553700002501572700002201597700002301619856006901642 2005 eng d00aRESFEN5: Program Description0 aRESFEN5 Program Description bLawrence Berkeley National Laboratoryc05/20053 aA computer tool such as RESFEN can help consumers and builders pick the most energy-efficient and cost-effective window for a given application, whether it is a new home, an addition, or a window replacement. It calculates heating and cooling energy use and associated costs as well as peak heating and cooling demand for specific window products. Users define a specific scenario by specifying house type (single-story or two-story), geographic location, orientation, electricity and gas cost, and building configuration details (such as wall, floor, and HVAC system type). Users also specify size, shading, and thermal properties of the window they wish to investigate. The thermal properties that RESFEN requires are: U-factor, Solar Heat Gain Coefficient, and air leakage rate. RESFEN calculates the energy and cost implications of the window compared to an insulated wall. The relative energy and cost impacts of two different windows can be compared.
RESFEN 3.0 was a major improvement over previous versions because it performs hourly calculations using a version of the DOE 2.1E (LBL 1980, Winkelmann et al. 1993) energy analysis simulation program. RESFEN 3.1 incorporates additional improvements including input assumptions for the base case buildings taken from the National Fenestration Rating Council (NFRC) Annual Energy Subcommittee's efforts.
1 aMitchell, Robin1 aHuang, Yu, Joe1 aArasteh, Dariush, K.1 aHuizenga, Charlie1 aGlendenning, Steve uhttps://facades.lbl.gov/publications/resfen5-program-description01188nas a2200145 4500008004100000245007500041210006900116490000700185520069000192100002000882700001900902700002100921700002600942856007400968 2004 eng d00aCharge-State-Resolved Ion Energy Distributions of Aluminum Vacuum Arcs0 aChargeStateResolved Ion Energy Distributions of Aluminum Vacuum 0 v973 aThe charge-state-resolved ion energy distributions of metal ions present in a cathodic arc plasma have been measured and analyzed. Contrary to literature data, lower energies were observed for higher charged ions. The observations were explained by opposing acceleration by pressure gradient and electron-ion coupling, and deceleration by part of the discharge voltage. The distributions were well fitted by shifted Maxwellian distributions, giving additional information on plasma parameters. These results are of importance for an improved understanding of the evolution of ion energy distributions, and is hence instrumental for future progress in thin film growth modelling.
1 aRosén, Johanna1 aAnders, André1 aMráz, Stanislav1 aSchneider, Jochen, M. uhttps://facades.lbl.gov/publications/charge-state-resolved-ion-energy01246nas a2200169 4500008004100000050001500041245006200056210006100118260002500179520069000204100001900894700002000913700002700933700002500960700002200985856006901007 2004 eng d aLBNL-5551700aDevelopment of Trade-Off Equations for EnergyStar Windows0 aDevelopment of TradeOff Equations for EnergyStar Windows aBoulder, COc08/20043 aThe authors explore the feasibility of adding a performance option to DOE's EnergyStar© Windows program whereby windows of differing U-factors and SHGCs can qualify so long as they have equivalent annual energy performance. An iterative simulation procedure is used to calculate trade-off equations giving the change in SHGC needed to compensate for a change in U-factor. Of the four EnergyStar© Window climate zones, trade-off equations are possible only in the Northern and Southern zones. In the North/Central and South/Central zones, equations are not possible either because of large intrazone climate variations or the current SHGC requirements are already near optimum.
1 aHuang, Yu, Joe1 aMitchell, Robin1 aSelkowitz, Stephen, E.1 aArasteh, Dariush, K.1 aClear, Robert, D. uhttps://facades.lbl.gov/publications/development-trade-equations01095nas a2200169 4500008004100000245008300041210006900124260003000193520049900223653002000722653002200742653002400764653001500788100001900803700002400822856007900846 2003 eng d00aSurface Engineering of Glazing Materials and Structures Using Plasma Processes0 aSurface Engineering of Glazing Materials and Structures Using Pl aTampere, Finlandc06/20033 aA variety of coatings is commercially produced on a very large scale, including transparent conducting oxides and multi-layer silver-based low-emissivity and solar control coatings. A very brief review of materials and manufacturing process is presented and illustrated by ultrathin silver films and chevron copper films. Understanding the close relation between manufacturing processes and bulk and surface properties of materials is crucial for film growth and self-assembly processes.
10anano-structures10aplasma processing10asurface engineering10athin films1 aAnders, André1 aMonteiro, Othon, R. uhttps://facades.lbl.gov/publications/surface-engineering-glazing-materials01448nas a2200169 4500008004100000050001500041245004400056210004300100520093100143100002001074700002201094700002501116700001801141700002201159700002401181856007301205 2003 eng d aLBNL-4825500aTHERM 5/WINDOW 5 NFRC Simulation Manual0 aTHERM 5WINDOW 5 NFRC Simulation Manual3 aThis document, the THERM 5 / WINDOW 5 NFRC Simulation Manual, discusses how to use the THERM and WINDOW programs to model products for NFRC certified simulations and assumes that the user is already familiar with those programs. In order to learn how to use these programs, it is necessary to become familiar with the material in both the THERM Users Manual and the WINDOW Users Manual. In general, this manual references the Users Manuals rather than repeating the information.
If there is a conflict between either of the User Manual and this THERM 5 / WINDOW 5 NFRC Simulation Manual, the THERM 5 / WINDOW 5 NFRC Simulation Manual takes precedence. In addition, if this manual is in conflict with any NFRC standards, the standards take precedence. For example, if samples in this manual do not follow the current taping and testing NFRC standards, the standards not the samples in this manual, take precedence.
1 aMitchell, Robin1 aKohler, Christian1 aArasteh, Dariush, K.1 aCarmody, John1 aHuizenga, Charlie1 aCurcija, Dragan, C. uhttps://facades.lbl.gov/publications/therm-5window-5-nfrc-simulation02700nas a2200217 4500008004100000050001500041245009700056210006900153260003100222520195900253100002102212700002702233700001902260700002202279700002002301700002302321700002302344700001902367700002302386856007302409 2002 eng d aLBNL-5085500aActive Load Management with Advanced Window Wall Systems: Research and Industry Perspectives0 aActive Load Management with Advanced Window Wall Systems Researc aPacific Grove, CAc08/20023 aAdvanced window wall systems have the potential to provide demand response by reducing peak electric loads by 20-30% in many commercial buildings through the active control of motorized shading systems, switchable window coatings, operable windows, and ventilated double-skin facade systems. These window strategies involve balancing daylighting and solar heat gains, heat rejection through ventilation, and night-time natural ventilation to achieve space-conditioning and lighting energy use reductions without the negative impacts on occupants associated with other demand responsive (DR) strategies.
This paper explores conceptually how advanced window systems fit into the context of active load management programs, which cause customers to directly experience the time-varying costs of their consumption decisions. Technological options are suggested. We present pragmatic criteria that building owners use to determine whether to deploy such strategies. A utility's perspective is given. Industry also provides their perspectives on where the technology is today and what needs to happen to implement such strategies more broadly in the US.
While there is significant potential for these advanced window concepts, widespread deployment is unlikely to occur with business-as-usual practice. Technologically, integrated window-lighting-HVAC products are underdeveloped. Implementation is hindered by fragmented labor practices, non-standard communication protocols, and lack of technical expertise. Design tools and information products that quantify energy performance, occupant impacts, reliability, and other pragmatic concerns are not available. Interest within the building industry in sustainability, energy-efficiency, and increased occupant amenity, comfort, and productivity will be the driving factors for these advanced facades in the near term — at least until the dust settles on the deregulated electricity market.
1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E.1 aLevi, Mark, S.1 aBlanc, Steven, L.1 aMcConahey, Erin1 aMcClintock, Maurya1 aHakkarainen, Pekka1 aSbar, Neil, L.1 aMyser, Michael, P. uhttps://facades.lbl.gov/publications/active-load-management-advanced01488nas a2200169 4500008004100000245011300041210006900154260001200223300001400235490000700249520089100256100002401147700001901171700002701190700002301217856007801240 2002 eng d00aCalculation of Thermodynamic, Electronic, and Optical Properties of Monoclinic Mg2NiH40 aCalculation of Thermodynamic Electronic and Optical Properties o c04/2002 a4879-48850 v913 aAb initio total-energy density functional theory is used to investigate the low temperature (LT) monoclinic form of Mg2NiH4. The calculated minimum energy geometry of LT Mg2NiH4 is close to that determined from neutron diffraction data, and the NiH4 complex is close to a regular tetrahedron. The enthalpies of the phase change to high temperature (HT) pseudo-cubic Mg2NiH4 and of hydrogen absorption by Mg2Ni are calculated and compared with experimental values. LT Mg2NiH4 is found to be a semiconductor with an indirect band gap of 1.4 eV. The optical dielectric function of LT Mg2NiH4 differs somewhat from that of the HT phase. A calculated thin film transmittance spectrum is consistent with an experimental spectrum.
1 aMyers, Whittier, R.1 aWang, Lin-Wang1 aRichardson, Thomas, J.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/calculation-thermodynamic-electronic01573nas a2200241 4500008004100000245009300041210006900134260002400203520077100227653001000998653003101008653001101039653001501050653002201065100002001087700002601107700002701133700002401160700002101184700002501205700002301230856007801253 2002 eng d00aStructural and Electronic Properties of Magnesium-3D Transition Metal Switchable Mirrors0 aStructural and Electronic Properties of Magnesium3D Transition M aGolden, COc12/20023 aWe 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.
10aEXAFS10aHydrogen storage materials10aNEXAFS10athin films10ax-ray diffraction1 aFarangis, Baker1 aNachimuthu, Ponnusamy1 aRichardson, Thomas, J.1 aSlack, Jonathan, L.1 aMeyer, Bruno, K.1 aPerera, Rupert, C.C.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/structural-and-electronic-properties00811nam a2200241 4500008004100000050001500041245007900056210006900135100001600204700002300220700001900243700002500262700002000287700001700307700002000324700003000344700002000374700002100394700002000415700002800435700002700463856007900490 2001 eng d aLBNL-4749300aDaylight in Buildings. A Source Book on Daylighting Systems and Components0 aDaylight in Buildings A Source Book on Daylighting Systems and C1 aRuck, Nancy1 aAschehoug, Øyvind1 aAydinli, Sirri1 aChristoffersen, Jens1 aCourret, Gilles1 aEdmonds, Ian1 aJakobiak, Roman1 aKischkoweit-Lopin, Martin1 aKlinger, Martin1 aLee, Eleanor, S.1 aMichel, Laurent1 aScartezzini, Jean-Louis1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/daylight-buildings-source-book-daylighting-systems02156nas a2200169 4500008004100000050001500041245008000056210006900136260003400205520156000239100002501799700002001824700002201844700002201866700002401888856007401912 2001 eng d aLBNL-4814700aImproving Information Technology to Maximize Fenestration Energy Efficiency0 aImproving Information Technology to Maximize Fenestration Energy aClearwater Beach, FLc12/20013 aAnnual heating and cooling energy loads through fenestration products in both residential and commercial buildings are a significant fraction of national energy requirements. In the residential sector, 1.34 and 0.37 quads are required for heating and cooling respectively (DOE Core Data Book, 2000). In commercial buildings, cooling energy use to compensate for fenestration product solar heat gain is estimated at 0.39 quads; heating energy use to compensate for heat loss through fenestration products is estimated at 0.19 quads. Advanced products offer the potential to reduce these energy uses by at least 50% (Frost et. al. 1993). Potential electric lighting savings from fenestration products are estimated at 0.4 quads if daylight can be used effectively so that electric lighting in commercial building perimeter zones can be reduced.
Software has begun to make an impact on the design and deployment of efficient fenestration products by making fenestration product performance ratings widely available. These ratings, which are determined in part using software programs such as WINDOW/THERM/Optics, VISION/FRAME, and WIS, can now easily be used by architects, engineers, professional fenestration product specifiers, and consumers. Information on the properties of fenestration products has also influenced state and national codes (IECC, ASHRAE 90.1) and aided voluntary market transformation programs, such as the Efficient Windows Collaborative and the Energy Star Windows program, which promote efficient fenestration products.
1 aArasteh, Dariush, K.1 aMitchell, Robin1 aKohler, Christian1 aHuizenga, Charlie1 aCurcija, Dragan, C. uhttps://facades.lbl.gov/publications/improving-information-technology01132nas a2200157 4500008004100000245008800041210006900129260003200198300001200230490001600242520057600258100002200834700002500856700002000881856007300901 2001 eng d00aTHERM Simulations of Window Indoor Surface Temperatures for Predicting Condensation0 aTHERM Simulations of Window Indoor Surface Temperatures for Pred aAtlantic City, NJc01/ 2002 a593-5990 v109, Part 13 aAs part of a round robin project, the performance of two wood windows and a Calibrated Transfer Standard was modeled using the THERM heat-transfer simulation program. The resulting interior surface temperatures can be used as input to condensation resistance rating procedures. The Radiation and Condensation Index features within THERM were used to refine the accuracy of simulation results. Differences in surface temperatures between the Basic calculations and those incorporating the Radiation and/or Condensation Index features are demonstrated and explained.
1 aKohler, Christian1 aArasteh, Dariush, K.1 aMitchell, Robin uhttps://facades.lbl.gov/publications/therm-simulations-window-indoor00496nas a2200133 4500008004100000245006800041210006700109100002000176700002200196700002500218700002200243700002400265856007300289 2001 eng d00aWINDOW 5.0 User Manual for Analyzing Window Thermal Performance0 aWINDOW 50 User Manual for Analyzing Window Thermal Performance1 aMitchell, Robin1 aKohler, Christian1 aArasteh, Dariush, K.1 aHuizenga, Charlie1 aCurcija, Dragan, C. uhttps://facades.lbl.gov/publications/window-50-user-manual-analyzing01204nas a2200193 4500008004100000245003700041210003600078260001200114300000800126520064300134100002000777700002200797700002500819700002900844700002200873700002400895700001800919856007300937 2000 eng d00aTHERM 2.1 NFRC Simulation Manual0 aTHERM 21 NFRC Simulation Manual c07/2000 a2603 aThis 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.
1 aMitchell, Robin1 aKohler, Christian1 aArasteh, Dariush, K.1 aFinlayson, Elizabeth, U.1 aHuizenga, Charlie1 aCurcija, Dragan, C.1 aCarmody, John uhttps://facades.lbl.gov/publications/therm-21-nfrc-simulation-manual01238nas a2200169 4500008004100000050001500041245008000056210006900136260002700205520065300232100002500885700001900910700002000929700002200949700002200971856007500993 1999 eng d aLBNL-4402000aA Database of Window Annual Energy Use in Typical North American Residences0 aDatabase of Window Annual Energy Use in Typical North American R aDallas, Texasc02/20003 aThis paper documents efforts by the National Fenestration Rating Council to develop a database on annual energy impacts of windows in a typical new, single family, single story residence in various U.S. and Canadian climates. The result is a database of space heating and space cooling energies for 14 typical windows in 52 North American climates. (Future efforts will address the effects of skylights.) This paper describes how this database was created, documents the assumptions used in creating this database, elaborates on assumptions, which need further research, examines the results, and describes the possible uses of the database.
1 aArasteh, Dariush, K.1 aHuang, Yu, Joe1 aMitchell, Robin1 aClear, Robert, D.1 aKohler, Christian uhttps://facades.lbl.gov/publications/database-window-annual-energy-use01128nas a2200205 4500008004100000245008600041210006900127260001200196300001000208490000700218520044500225653003000670653002000700653002300720653003500743100001900778700002400797700002300821856007800844 1999 eng d00aEvaluation of the Plasma Distribution of a Quasi-Linear Constricted Plasma Source0 aEvaluation of the Plasma Distribution of a QuasiLinear Constrict c02/1999 a82-830 v273 aThe quasi-linear constricted plasma source is a downstream plasma source with ten linearly aligned discharge cells. Each cell operates on the basis of a constricted glow discharge. The plasma output can easily be monitored by the plasma-emitted light. The information is not only intuitive but can also be used to operate on-line feedback control of the plasma source which is important for large-area plasma processing of materials.
10aConstricted plasma source10agas plasma flow10aplasma diagnostics10aplasma processing of materials1 aAnders, André1 aMacGill, Robert, A.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/evaluation-plasma-distribution-quasi02024nas a2200169 4500008004100000024001100041245011600052210006900168260006100237520137600298100002001674700001901694700002501713700002101738700002101759856007401780 1999 eng d aBS-37100aRESFEN 3.1: A PC Program for Calculating the Heating and Cooling Energy Use of Windows in Residential Buildings0 aRESFEN 31 A PC Program for Calculating the Heating and Cooling E aBerkeleybLawrence Berkeley National Laboratoryc08/19993 aA computer tool such as RESFEN can help consumers and builders pick the most energy-efficient and cost-effective window for a given application, whether it is a new home, an addition, or a window replacement. It calculates heating and cooling energy use and associated costs as well as peak heating and cooling demand for specific window products. Users define a specific scenario by specifying house type (single-story or two-story), geographic location, orientation, electricity and gas cost, and building configuration details (such as wall, floor, and HVAC system type). Users also specify size, shading, and thermal properties of the window they wish to investigate. The thermal properties that RESFEN requires are: U-factor, Solar Heat Gain Coefficient, and air leakage rate. RESFEN calculates the energy and cost implications of the window compared to an insulated wall. The relative energy and cost impacts of two different windows can be compared.
RESFEN 3.0 was a major improvement over previous versions because it performs hourly calculations using a version of the DOE 2.1E (LBL 1980, Winkelmann et al. 1993) energy analysis simulation program. RESFEN 3.1 incorporates additional improvements including input assumptions for the base case buildings taken from the National Fenestration Rating Council (NFRC) Annual Energy Subcommittee's efforts.
1 aMitchell, Robin1 aHuang, Yu, Joe1 aArasteh, Dariush, K.1 aSullivan, Robert1 aPhillip, Santosh uhttps://facades.lbl.gov/publications/resfen-31-pc-program-calculating02582nas a2200157 4500008004100000050001500041245006700056210006600123260003400189520203200223100001902255700002002274700002502294700002702319856007802346 1999 eng d aLBNL-4287100aResidential Fenestration Performance Analysis Using RESFEN 3.10 aResidential Fenestration Performance Analysis Using RESFEN 31 aClearwater Beach, FLc12/19983 aThis paper describes the development efforts of RESFEN 3.1, a PC-based computer program for calculating the heating and cooling energy performance and cost of residential fenestration systems. The development of RESFEN has been coordinated with ongoing efforts by the National Fenestration Rating Council (NFRC) to develop an energy rating system for windows and skylights to maintain maximum consistency between RESFEN and NFRCs planned energy rating system. Unlike previous versions of RESFEN, that used regression equations to replicate a large data base of computer simulations, Version 3.1 produces results based on actual hour-by-hour simulations. This approach has been facilitated by the exponential increase in the speed of personal computers in recent years. RESFEN 3.1 has the capability of analyzing the energy performance of windows in new residential buildings in 52 North American locations. The user describes the physical, thermal and optical properties of the windows in each orientation, solar heat gain reductions due to obstructions, overhangs, or shades, and the location of the house. The RESFEN program then models a prototypical house for that location and calculates the energy use of the house using the DOE-2 program. The user can vary the HVAC system, foundation type, and utility costs. Results are presented for the annual heating and cooling energy use, energy cost, and peak energy demand of the house, and the incremental energy use or peak demand attributable to the windows in each orientation. This paper describes the capabilities of RESFEN 3.1, its usefulness in analyzing the energy performance of residential windows and its development effort and gives insight into the structure of the computer program. It also discusses the rationale and benefits of the approach taken in RESFEN in combining a simple-to-use graphical front-end with a detailed hour-by-hour simulation engine to produce an energy analysis tool for the general public that is user-friendly yet highly accurate.
1 aHuang, Yu, Joe1 aMitchell, Robin1 aArasteh, Dariush, K.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/residential-fenestration-performance01203nas a2200181 4500008004100000050001500041245008900056210006900145260002600214520056200240100002200802700002500824700002900849700002000878700002400898700002400922856007500946 1999 eng d aLBNL-4399100aTHERM 2.0: A Building Component Model for Steady-State Two-Dimensional Heat Transfer0 aTHERM 20 A Building Component Model for SteadyState TwoDimension aKyoto, Japanc09/19993 aTHERM 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.
1 aHuizenga, Charlie1 aArasteh, Dariush, K.1 aFinlayson, Elizabeth, U.1 aMitchell, Robin1 aGriffith, Brent, T.1 aCurcija, Dragan, C. uhttps://facades.lbl.gov/publications/therm-20-building-component-model01659nas a2200193 4500008004100000050001500041245009400056210006900150260002500219520098200244100002301226700002301249700002101272700002501293700002701318700002401345700002101369856007501390 1998 eng d aLBNL-4227700aEffect of Hydrogen Insertion on the Optical Properties of PD-Coated Magnesium Lanthanides0 aEffect of Hydrogen Insertion on the Optical Properties of PDCoat aLondon, U.K.c9/19983 aMetallic magnesium lanthanide thin films upon insertion of hydrogen transform to a highly transparent hydride phase. With a Pd overlayer, the transformation can be produced either by electrochemical insertion of hydrogen or by exposing the film to hydrogen gas. Unlike amorphous oxide electrochromics, the transformation is accompanied by a large change in visible reflectance (about 50%). The optical switching effect in these materials is investigated in terms of changes in the complex refractive index as determined by variable-angle spectroscopic ellipsometric and normal-incidence radiometric measurements over the solar spectrum. Furthermore the optical effect of converting the Pd caplayer to Pd-H was determined. It is shown that the pd layer limits the visible transmittance of the hyrdrided stack to about 35-40%. Whereas the extinction coefficient of the dehydrided LnMg-layers at 550 nm is between 2.2 and 3.1, it is as low as 10-4 in the transparent state.
1 avon Rottkay, Klaus1 aRubin, Michael, D.1 aMichalak, Franck1 aArmitage, Robert, D.1 aRichardson, Thomas, J.1 aSlack, Jonathan, L.1 aDuine, Peter, A. uhttps://facades.lbl.gov/publications/effect-hydrogen-insertion-optical01510nas a2200181 4500008004100000050001500041245010000056210006900156300001400225490000700239520088500246100002101131700002301152700002701175700002401202700002301226856007901249 1998 eng d aLBNL-4227600aElectrochromic Lithium Nickel Oxide Thin Films by RF-Sputtering from a LiNiO2 Target0 aElectrochromic Lithium Nickel Oxide Thin Films by RFSputtering f a3085-30920 v443 aThin films of lithium nickel oxide were deposited by rf sputtering from a stoichiometric LiNiO2 target. The composition and structure of these films depended on the oxygen pressure during deposition (sputtering gas is Argon), and, to a certain extent, the target history. The sputtering geometry, i.e. the substrate to target distance and the sputtering angle were also critical. the films exhibit excellent reversibility in the potential range 1.1V to 3.8 V vs Li/Li+ and could be cycled in a liquid electrolyte half cell for more than 3000 cycles with a switching range ΔTvis close to 70%. The coloration efficiency in the visible was typically -30 to -40 cm2 C-1. The switching performance of a device utilizing a lithium nickel oxide film as counter electrode for a tungsten oxide electrochromic film is reported.
1 aMichalak, Franck1 avon Rottkay, Klaus1 aRichardson, Thomas, J.1 aSlack, Jonathan, L.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/electrochromic-lithium-nickel-oxide-102194nas a2200181 4500008004100000050001500041245007900056210006900135260003100204520156500235100002501800700002901825700001901854700002201873700002001895700002301915856007401938 1998 eng d aLBNL-4215100aState-of-the-Art Software for Window Energy-Efficiency Rating and Labeling0 aStateoftheArt Software for Window EnergyEfficiency Rating and La aPacific Grove, CAc08/19983 aMeasuring 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.
1 aArasteh, Dariush, K.1 aFinlayson, Elizabeth, U.1 aHuang, Yu, Joe1 aHuizenga, Charlie1 aMitchell, Robin1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/state-art-software-window-energy01900nas a2200181 4500008004100000050001500041245014300056210006900199260002500268490001600293520122000309100002201529700002501551700002901576700002001605700002401625856006901649 1998 eng d aLBNL-4210200aTeaching Students about Two-Dimensional Heat Transfer Effects in Buildings, Building Components, Equipment, and Appliances Using THERM 2.00 aTeaching Students about TwoDimensional Heat Transfer Effects in aChicago, ILc01/19990 v105, Part 13 aTHERM 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.
1 aHuizenga, Charlie1 aArasteh, Dariush, K.1 aFinlayson, Elizabeth, U.1 aMitchell, Robin1 aGriffith, Brent, T. uhttps://facades.lbl.gov/publications/teaching-students-about-two01730nas a2200157 4500008004100000050002100041245009800062210006900160520114800229100002901377700002001406700002501426700002201451700002401473856007501497 1998 eng d aLBL-37371 Rev. 200aTHERM 2.0: a PC Program for Analyzing Two-Dimensional Heat Transfer through Building products0 aTHERM 20 a PC Program for Analyzing TwoDimensional Heat Transfer3 aTHERM 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.
1 aFinlayson, Elizabeth, U.1 aMitchell, Robin1 aArasteh, Dariush, K.1 aHuizenga, Charlie1 aCurcija, Dragan, C. uhttps://facades.lbl.gov/publications/therm-20-pc-program-analyzing-two01511nas a2200181 4500008004100000050001500041245007100056210006900127260002400196490001000220520090600230100002701136700002301163700002401186700002101210700002301231856007501254 1998 eng d aLBNL-4238100aTungsten-Vanadium Oxide Sputtered Films for Electrochromic Devices0 aTungstenVanadium Oxide Sputtered Films for Electrochromic Device aBoston, MAc11/19980 v98-263 aMixed vanadium and tungsten oxide films with compositions ranging from 0 to 100% vanadium (metals basis) were prepared by reactive sputtering from metallic vanadium and tungsten targets in an atmosphere of argon and oxygen. The vanadium content varied smoothly with the fraction of total power applied to the vanadium target. Films containing vanadium were more color neutral than pure tungsten oxide films, tending to gray-brown at high V fraction. The electrochromic switching performance of these films was investigated by in situ monitoring of their visible transmittance during lithium insertion/extraction cycling in a non-aqueous electrolyte (1M LiClO4 in PC). the solar transmittance and reflectance was measured ex-situ. Films with vanadium content greater than about 15%, exhibited a marked decrease in switching range. The coloration efficiencies followed a similar trend.
1 aRichardson, Thomas, J.1 avon Rottkay, Klaus1 aSlack, Jonathan, L.1 aMichalak, Franck1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/tungsten-vanadium-oxide-sputtered02619nas a2200169 4500008003900000024001100039245011600050210006900166260005100235300000700286520199700293100001902290700002102309700002502330700002002355856007402375 1997 d aBS-37100aRESFEN 3.0: A PC Program for Calculating the Heating and Cooling Energy Use of Windows in Residential Buildings0 aRESFEN 30 A PC Program for Calculating the Heating and Cooling E bLawrence Berkeley National Laboratoryc12/1997 a383 aToday's energy-efficient windows can dramatically lower the heating and cooling costs associated with windows while increasing occupant comfort and minimizing window surface condensation problems. However, consumers are often confused about how to pick the most efficient window for their residence. They are typically given window properties such as U-factors or R-values, Solar Heat Gain Coefficients or Shading Coefficients, and air leakage rates. However, the relative importance of these properties depends on the site and building specific conditions. Furthermore, these properties are based on static evaluation conditions that are very different from the real situation the window will be used in. Knowing the energy and associated cost implications of different windows will help consumers and builders make the best decision for their particular application, whether it is a new home, an addition, or a window replacement.
A computer tool such as RESFEN can help consumers and builders pick the most energy-efficient and cost-effective window for a given application. It calculates the heating and cooling energy use and associated costs as well as the peak heating and cooling demand for specific window products. Users define a problem by specifying the house type (single story or two story), geographic location, orientation, electricity and gas cost, and building configuration details (such as wall type, floor type, and HVAC systems). Window options are defined by specifying the window`s size, shading, and thermal properties: U-factor, Solar Heat Gain Coefficient, and air leakage rate. RESFEN calculates the energy and cost implications of the windows compared to insulated walls. The relative energy and cost impacts of two different windows can be compared against each other.
RESFEN 3.0 is a major improvement over previous versions of RESFEN because it performs hourly calculations using a version of the DOE 2.1E energy analysis simulation program.
1 aHuang, Yu, Joe1 aSullivan, Robert1 aArasteh, Dariush, K.1 aMitchell, Robin uhttps://facades.lbl.gov/publications/resfen-30-pc-program-calculating01975nas a2200169 4500008004100000024001200041245007400053210006900127260003100196520140100227100001801628700002101646700002301667700002101690700002701711856006701738 1996 eng d aUC-160000aVisual Quality Assessment of Electrochromic and Conventional Glazings0 aVisual Quality Assessment of Electrochromic and Conventional Gla aFreiburg, Germanyc09/19963 aVariable transmission, switchable electrochromic glazings are compared to conventional static glazings using computer simulations to assess the daylighting quality of a commercial office environment where paper and computer tasks are performed. RADIANCE simulations were made for a west-facing commercial office space under clear and overcast sky conditions. This visualization tool was used to model different glazing types, to com-pute luminance and illuminance levels, and to generate a parametric set of photorealistic im-ages of typical interior views at various times of the day and year. Privacy and visual dis-play terminal (VDT) visibility is explored. Electrochromic glazings result in a more consis-tent glare-free daylit environment compared to their static counterparts. However, if the glazing is controlled to minimize glare or to maintain low interior daylight levels for critical visual tasks (e.g., VDT), occupants may object to the diminished quality of the outdoor view due to its low transmission (Tv=0.08) during those hours. RADIANCE proved to be a very powerful tool to better understand some of the design tradeoffs of this emerging glazing technology. Our ability to draw specific conclusions about the relative value of dif-ferent technologies or control strategies is limited by the lack of agreed upon criteria or standards for lighting quality and visibility.
1 aMoeck, Martin1 aLee, Eleanor, S.1 aRubin, Michael, D.1 aSullivan, Robert1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/visual-quality-assessment01843nas a2200181 4500008004100000050001400041245009300055210006900148300000800217520124200225100002101467700002201488700002101510700001801531700001801549700002701567856006701594 1993 eng d aLBL-3314400aCharacteristics of Laminated Electrochromic Devices Using Polyorganodisulfate Electrodes0 aCharacteristics of Laminated Electrochromic Devices Using Polyor a1433 aThe use of polyorganodisulfides as optically passive counterelectrodes in a variety of electrochromic devices are discussed. Characteristic data is presented for electrochmmic devices using proton, and lithium coloration ions with polyethylene oxide electrolyte and polydimercaptothiadiazole positive electrodes. Solid state devices consisting of molybdenum doped W03, amorphous polyethylene oxide electrolyte (a-PEO), and a polyorganodisulfide counter-electrode colored rapidly from a pale yellow to a deep blue-green, upon application of 1.2 V d.c. The photopic transmittance changed from 61 to 98, and the solar transmittance from 45 to 5% during the coloration process. Also, our experiments with polyimidazole are detailed. This family of compounds due to its unique electrical and ion conduction properties allow a single composite ion storage and ion conductor electrode to be made, simplifying the device construction. Devices rnade from this family of compounds color to deep blue-gray upon application of 1.2-1.5 V. Bleaching occurs at -0.4 to -0.5 s. The photopic transmittance changed from 55 to 9%. and the solar transmittance from 34 to 4% during coloration. Both coloration and bleaching are quite rapid.
1 aLampert, Carl, M1 aVisco, Steven, J.1 aDoeff, Marca, M.1 aMa, Yan, Ping1 aHe, Yongxiang1 aGiron, Jean-Christophe uhttps://facades.lbl.gov/publications/characteristics-laminated01773nas a2200181 4500008004100000245006900041210006800110260001200178490001500190520118600205100002501391700002201416700002001438700002001458700002301478700002001501856007001521 1993 eng d00aPhase I Results of the NFRC U-Value Procedure Validation Project0 aPhase I Results of the NFRC UValue Procedure Validation Project c08/19930 v100, Pt. 13 aThe NFRC U-Value Procedure Validation Project was undertaken by a collaborative group of industry, public utility, trade associations, and government researchers in order to validate the testing and calculational methods of the NFRC 100-91: Procedure for Determining Fenestration Product Thermal Properties (Currently Limited to U-Values). This paper summarizes the validation projects goals and test methodology, the results of the data analysis, and the recommendations following completion of Phase I of the project. Simulations performed according to NFRC 100-91 are shown to agree with each other, to within the NFRC tolerance, in 100% of the cases. Window test results with perpendicular wind performed according to NFRC 100-91 are shown to agree with each other, to within the NFRC tolerance, in 84% of the cases. Simulations and perpendicular wind window test results are shown to agree with each other, to within the NFRC tolerance, in 80% of the cases. Testing of skylights was shown to be problematic under the procedure as written at the time. Agreement between tests and simulations will improve as a result of a strong NFRC education and accreditation program.
1 aArasteh, Dariush, K.1 aBeck, Fredric, A.1 aStone, Nehemiah1 aDuPont, William1 aMathis, Christophe1 aKoenig, Michael uhttps://facades.lbl.gov/publications/phase-i-results-nfrc-u-value