03134nas a2200241 4500008004100000022001300041245011500054210006900169260001200238300001400250490000800264520230200272653005802574653001602632653002102648653002102669653004902690653001302739100001802752700001802770700002102788856008302809 2018 eng d a0378778800aEfficient modeling of optically-complex, non-coplanar exterior shading: Validation of matrix algebraic methods0 aEfficient modeling of opticallycomplex noncoplanar exterior shad c09/2018 a464 - 4830 v1743 a

It has long been established that shading windows with overhangs, fins, and other types of non-coplanar systems (NCS) is one of the most effective ways of controlling solar heat gains in buildings because they intercept solar radiation prior to entry into the building. Designers however often specify non-opaque materials (e.g., louvers, fritted glass, expanded metal mesh) for these systems in order to admit daylight, reduce lighting energy use, and improve indoor environmental quality. Most simulation tools rely on geometric calculations and radiosity methods to model the solar heat gain impacts of NCS and cannot model optically-complex materials or geometries. For daylighting analysis, optically-complex NCS can be modeled using matrix algebraic methods, although time-efficient parametric analysis has not yet been implemented. Determining the best design and/or material for static or operable NCS that minimize cooling, heating, and lighting energy use and peak demand requires an iterative process. This study describes and validates a matrix algebraic method that enables parametric energy analysis of NCS. Such capabilities would be useful not only for design but also for development of prescriptive energy-efficiency standards, rating and labeling systems for commercial products, development of design guidelines, and development of more optimal NCS technologies.

A facade or "F" matrix, which maps the transfer of flux from the NCS to the surface of the window, is introduced and its use is explained. A field study was conducted in a full-scale outdoor testbed to measure the daylight performance of an operable drop-arm awning. Simulated data were compared to measured data in order to validate the models. Results demonstrated model accuracy: simulated workplane illuminance was within 11-13%, surface luminance was within 16-18%, and the daylight glare probability was within 6-9% of measured results. Methods used to achieve accurate results are discussed. Results of the validation of daylighting performance are applicable to solar heat gain performance. Since exterior shading can also significantly reduce peak demand, these models enable stakeholders to more accurately assess HVAC and lighting impacts in support of grid management and resiliency goals.

10abidirectional scattering distribution function (BSDF)10adaylighting10aexterior shading10asolar heat gains10avalidation; building energy simulation tools10awindows.1 aWang, Taoning1 aWard, Gregory1 aLee, Eleanor, S. uhttps://www.sciencedirect.com/science/article/pii/S0378778818302457?via%3Dihub02717nas a2200133 4500008003900000245007200039210006900111260001200180520224000192100002402432700002102456700002902477856007702506 2015 d00aElectrochromic Window Demonstration at the Donna Land Port of Entry0 aElectrochromic Window Demonstration at the Donna Land Port of En c05/20153 a

The U.S. General Services Administration (GSA) Public Buildings Service (PBS) has jurisdiction, custody or control over 105 land ports of entry throughout the United States, 35 of which are located along the southern border. At these facilities, one of the critical functions of windows is to provide border control personnel with direct visual contact with the surrounding environment. This also can be done through surveillance cameras, but the high value that U.S. Customs and Border Protection (CPB) officers place on direct visual contact can be encapsulated in the following statement by a senior officer regarding this project: “nothing replaces line of sight.” In sunny conditions, however, outdoor visibility can be severely compromised by glare, especially when the orb of the sun is in the field of view. This often leads to the deployment of operable shading devices, such as Venetian blinds. While these devices address the glare, they obstruct the view of the surroundings, negating the visual security benefits of the windows.

Electrochromic (EC) windows have the ability to adjust their tint dynamically in response to environmental conditions. This provides the potential to control glare by going to a dark tint at times when extreme glare is likely. In previous studies, these windows have shown that this ability to control glare has the potential to increase the amount of time during which view is unobstructed. This technology is available in the U.S. as a commercial product from two vendors with high-capacity manufacturing facilities, and could be deployed on a nationwide scale if successful in a pilot test.

In this project, EC windows were installed at a land port of entry near Donna, Texas. The technical objectives of the study were to determine whether the installation of the EC windows resulted in the following:

1 aFernandes, Luis, L.1 aLee, Eleanor, S.1 aThanachareonkit, Anothai uhttps://facades.lbl.gov/publications/electrochromic-window-demonstration02991nas 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 a

Daylight 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-prismatic02354nas a2200229 4500008003900000245013200039210006900171260001200240300001000252490000800262520159100270653003201861653001801893653001801911653001201929100002101941700001801962700002101980700001802001700002902019856007602048 2013 d00aAn empirical study of a full-scale polymer thermochromic window and its implications on material science development objectives0 aempirical study of a fullscale polymer thermochromic window and  c09/2013 a14-260 v1163 a

Large-area polymer thermochromic (TC) laminated windows were evaluated in a full-scale testbed office. The TC interlayer film exhibited thermochromism through a ligand exchange process, producing a change in solar absorption primarily in the visible range while maintaining transparent, undistorted views through the material. The film had a broad switching temperature range and when combined to make an insulating window unit had center-of-glass properties of Tsol=0.12-0.03, Tvis=0.28-0.03 for a glass temperature range of 24-75°C. Field test measurements enabled characterization of switching as a function of incident solar irradiance and outdoor air temperature, illustrating how radiation influences glass temperature and thus effectively lowers the critical switching temperature of TC devices. This was further supported by EnergyPlus building energy simulations. Both empirical and simulation data were used to illustrate how the ideal critical switching temperature or temperature range for TC devices should be based on zone heat balance, not ambient air temperature. Annual energy use data are given to illustrate the energy savings potential of this type of thermochromic. Based on observations in the field,a broad switching temperature range was found to be useful in ensuring a uniform appearance when incident irradiance is non-uniform across the facade. As indicated in prior research, a high visible transmittance in both the switched and unswitched state is also desirable to enable reduction of lighting energy use and enhance indoor environmental quality.

10abuildings energy efficiency10aSolar control10aThermochromic10awindows1 aLee, Eleanor, S.1 aPang, Xiufeng1 aHoffmann, Sabine1 aGoudey, Howdy1 aThanachareonkit, Anothai uhttps://facades.lbl.gov/publications/empirical-study-full-scale-polymer02907nas a2200157 4500008003900000245014300039210006900182260002200251520231100273653001602584653002702600653003502627653002102662100002002683856004602703 2012 d00aEffective Daylighting: Evaluating Daylighting Performance in the San Francisco Federal Building from the Perspective of Building Occupants0 aEffective Daylighting Evaluating Daylighting Performance in the  aBerkeleyc01/20123 a

Commercial office buildings promoted as “sustainable,” “energy efficient,” “green,” or “high performance” often reference use of daylight as a key strategy for reducing energy consumption and enhancing indoor environmental quality. However, buildings are rarely studied in use to examine if the design intent of a sufficiently daylit and a visually comfortable work environment is achieved from the perspective of building occupants or how occupant use of shading devices may affect electrical lighting energy reduction from photocontrols. This dissertation develops a field-based approach to daylighting performance assessment that pairs repeated measures of occupant subjective response using a novel desktop polling station device with measurements of the physical environment acquired using High Dynamic Range (HDR) imaging and other environmental sensors with the objective of understanding the physical environmental conditions acceptable to occupants. The approach is demonstrated with a 6-month field study involving (N=44) occupants located in perimeter and core open-plan office spaces in the San Francisco Federal Building1 (SFFB). Over 23,100 subjective assessments paired with physical measures were analyzed to develop models of visual discomfort and shade control and to examine the assumptions of existing daylighting performance indicators. The analysis found that existing daylight performance indicators overestimated the levels of daylight illuminance required by occupants to work comfortably without overhead ambient electrical lighting. Time-lapse observation of interior roller shades showed that existing shade control models overestimated the frequency of shade operation and underestimated the level of facade occlusion due to interior shades. Comparison of measured results to the daylighting objectives of the SFFB showed that available daylight enabled electrical lighting energy reduction in the perimeter zones but not in the open-plan core zones. The results extend existing knowledge regarding the amount of daylight illuminance acceptable for occupants to work comfortably without overhead electrical lighting and for the physical variables (and stimulus intensities) associated with visual discomfort and the operation of interior shading devices.

10adaylighting10aperformance assessment10aSan Francisco Federal Building10ashading controls1 aKonis, Kyle, S. uhttps://escholarship.org/uc/item/7q35m7nq02762nas 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 a

In the context of alarming phenomenon of global warming with harmful consequences such as increased green house gases beyond predictions, the development of advanced energy efficient technologies became of a primary importance. Since the building sector accounts for 39% of total US primary energy consumption, fenestration can significantly contribute to lowering the energy use for heating, cooling, and lighting. An estimated 9% reduction in total US building energy use, or 3.47 Q, could be attained by dynamic solar/thermal control and daylighting if these advanced optical technologies were adopted throughout the residential and commercial building sectors. In spite of the great research and engineering efforts in the fast growing area of smart windows, development of glazing devices able to provide efficient, durable, and inexpensive products for dynamic daylight control is in infancy. Like the electrochromic glazings now emerging on the market, microscale, switchable daylight-redirecting glazings have the potential for widespread application if a low-cost, durable coating can be engineered and manufactured with the proper set of attributes.

Here we report on the development of a new technology using smart materials for switchable daylight-redirecting glazings. The proposed system consists in a prismatic optical element (POE) fabricated by micro-imprinting of an elastic redox-active polymer network capable to change its geometry and thereby its optical properties in response to an external stimulus. It is expected that the prismatic optical element reversibly collapses in response to an applied potential, thereby modulating the fraction of light which is redirected. The fabrication of the dynamic prismatic optical element from simulation-driven design to materials synthesis and device integration will be described. Investigation of specto-electrochemical characteristics of the redox-active grating and challenges encountered with respect to electromechanical induced structural changes will be also presented.

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-glazings02357nas a2200229 4500008003900000245008900039210006900128260001200197300001200209490000700221520162300228653003201851653002001883653001601903653002701919653002301946653002601969100002101995700002402016700001902040856006802059 2012 d00aEnd User Impacts of Automated Electrochromic Windows in a Pilot Retrofit Application0 aEnd User Impacts of Automated Electrochromic Windows in a Pilot  c04/2012 a267-2840 v473 a

Automated electrochromic (EC) windows, advanced thermally-improved window frames, and a dimmable lighting system were installed in a single, west-facing conference room in Washington DC. The EC windows were commercially-available, tungsten-oxide switchable devices, modulated automatically between either fully clear or fully tinted transparent states to control solar gains, daylight, and discomfort glare. Occupants were permitted to manually override the automated EC controls. The system was monitored over a 15-month period under normal occupied conditions. The last six months were used in the analysis. Manual override data were analyzed to assess the EC control system design and user satisfaction with EC operations. Energy and comfort were evaluated using both monitored data and simulations.

Of the 328 meetings that occurred over the six month period, the automatic system was manually overridden on 14 or 4% of the meetings for reasons other than demonstration purposes. When overridden, occupants appeared to have switched the individual zones with deliberation, using a combination of clear and tinted zones and the interior Venetian blinds to produce the desired interior environment. Monitored weekday lighting energy savings were 91% compared to the existing lighting system, which was less efficient, had a higher illuminance setpoint, and no controls. Annual performance was estimated using EnergyPlus, where the existing condition met the ASHRAE 90.1-2007 prescriptive requirements except for a higher window U-value. Annual energy savings were 48% while peak demand savings were 35%.

10abuildings energy efficiency10acontrol systems10adaylighting10aElectrochromic windows10aIntegrated systems10aIntelligent buildings1 aLee, Eleanor, S.1 aClaybaugh, Erin, S.1 aLaFrance, Marc uhttps://facades.lbl.gov/publications/end-user-impacts-automated02589nas a2200289 4500008004100000245010600041210006900147260003400216520165800250653001701908653001701925653001701942653002701959653001201986653002801998653002602026653001202052653001802064100002102082700001602103700002502119700001802144700002202162700002102184700002602205856006802231 2010 eng d00aExperimental and Numerical Examination of the Thermal Transmittance of High Performance Window Frames0 aExperimental and Numerical Examination of the Thermal Transmitta aClearwater Beach, FLc09/20103 a

While window frames typically represent 20-30% of the overall window area, their impact on the total window heat transfer rates may be much larger. This effect is even greater in low-conductance (highly insulating) windows which incorporate very low conductance glazings. Developing low-conductance window frames requires accurate simulation tools for product research and development.

The Passivhaus Institute in Germany states that windows (glazing and frames, combined) should have U-values not exceeding 0.80 W/(m2 K). This has created a niche market for highly insulating frames, with frame U-values typically around 0.7-1.0 W/(m2 K). The U-values reported are often based on numerical simulations according to international simulation standards. It is prudent to check the accuracy of these calculation standards, especially for high performance products before more manufacturers begin to use them to improve other product offerings.

In this paper the thermal transmittance of five highly insulating window frames (three wooden frames, one aluminum frame and one PVC frame), found from numerical simulations and experiments, are compared. Hot box calorimeter results are compared with numerical simulations according to ISO 10077-2 and ISO 15099. In addition CFD simulations have been carried out, in order to use the most accurate tool available to investigate the convection and radiation effects inside the frame cavities.

Our results show that available tools commonly used to evaluate window performance, based on ISO standards, give good overall agreement, but specific areas need improvement.

10aexperimental10aFenestration10aframe cavity10aheat transfer modeling10ahot box10ainternational standards10athermal transmittance10aU-value10awindow frames1 aGustavsen, Arlid1 aTalev, Goce1 aArasteh, Dariush, K.1 aGoudey, Howdy1 aKohler, Christian1 aUvsløkk, Sivert1 aJelle, Bjørn, Petter uhttps://facades.lbl.gov/publications/experimental-and-numerical01524nas a2200157 4500008004100000050001500041245011400056210006900170260003600239490000600275520094200281100001901223700002401242700002701266856007301293 2008 eng d aLBNL-1089E00aElectrochromically switched, gas-reservoir metal hydride devices with application to energy-efficient windows0 aElectrochromically switched gasreservoir metal hydride devices w aEindhoven, Netherlandsc08/20030 v13 a

Proof-of-principle gas-reservoir MnNiMg electrochromic mirror devices have been investigated. In contrast to conventional electrochromic approaches, hydrogen is stored (at low concentration) in the gas volume between glass panes of the insulated glass units (IGUs). The elimination of a solid state ion storage layer simplifies the layer stack, enhances overall transmission, and reduces cost. The cyclic switching properties were demonstrated and system durability improved with the incorporation a thin Zr barrier layer between the MnNiMg layer and the Pd catalyst. Addition of 9% silver to the palladium catalyst further improved system durability. About 100 full cycles have been demonstrated before devices slow considerably. Degradation of device performance appears to be related to Pd catalyst mobility, rather than delamination or metal layer oxidation issues originally presumed likely to present significant challenges.

1 aAnders, André1 aSlack, Jonathan, L.1 aRichardson, Thomas, J. uhttps://facades.lbl.gov/publications/electrochromically-switched-gas02703nas a2200205 4500008004100000245008300041210006900124260001200193300001400205490000700219520204000226653002402266653002302290653001602313653002702329653002202356100002102378700001902399856007902418 2007 eng d00aEnergy and visual comfort performance of electrochromic windows with overhangs0 aEnergy and visual comfort performance of electrochromic windows  c06/2007 a2439-24490 v423 a

DOE-2 building energy simulations were conducted to determine if there were practical architectural and control strategy solutions that would enable electrochromic (EC) windows to significantly improve visual comfort without eroding energy-efficiency benefits. EC windows were combined with overhangs since opaque overhangs provide protection from direct sun which EC windows are unable to do alone. The window wall was divided into an upper and lower aperture so that various combinations of overhang position and control strategies could be considered. The overhang was positioned either at the top of the upper window aperture or between the upper and lower apertures. Overhang depth was varied. EC control strategies were fully bleached at all times, modulated based on incident vertical solar radiation limits, or modulated to meet the design work plane illuminance with daylight. The EC performance was compared to a state-of-the-art spectrally selective low-e window with the same divided window wall, window size, and overhang as the EC configuration. The reference window was also combined with an interior shade which was manually deployed to control glare and direct sun. Both systems had the same daylighting control system to dim the electric lighting. Results were given for south-facing private offices in a typical commercial building.

In hot and cold climates such as Houston and Chicago, EC windows with overhangs can significantly reduce the average annual daylight glare index (DGI) and deliver significant annual energy use savings if the window area is large. Total primary annual energy use was increased by 2-5% for moderate-area windows in either climate but decreased by 10% in Chicago and 5% in Houston for large-area windows. Peak electric demand can be reduced by 7-8% for moderate-area windows and by 14-16% for large-area windows in either climate. Energy and peak demand reductions can be significantly greater if the reference case does not have exterior shading or state-of-the-art glass.

10abuilding simulation10aControl algorithms10adaylighting10aElectrochromic windows10aenergy efficiency1 aLee, Eleanor, S.1 aTavil, Aslihan uhttps://facades.lbl.gov/publications/energy-and-visual-comfort-performance01648nas a2200121 4500008004100000050001500041245007000056210006900126520122000195100001901415700002101434856007101455 2006 eng d aLBNL-6113700aEffects of Overhangs on the Performance of Electrochromic Windows0 aEffects of Overhangs on the Performance of Electrochromic Window3 a

In this study, various facade designs with overhangs combined with electrochromic (EC) window control strategies were modeled for a typical commercial office building in a hot and cold climate using the DOE 2.1E building energy simulation program. EC windows were combined with overhangs since opaque overhangs provide protection from direct sun which EC windows are unable to do alone. The window wall was divided into an upper and lower aperture so that various combinations of overhang position and control strategies could be considered. The overhang was positioned either at the top of the upper window aperture or between the upper and lower apertures. Overhang depth was varied. EC control strategies were fully bleached at all times, modulated based on incident vertical solar radiation limits, or modulated to meet the design work plane illuminance with daylight. Annual total energy use (ATE), peak electric demand (PED), average daylight illuminance (DI), and daylight glare index (DGI) for south-facing private offices were computed and compared to determine which combinations of façade design and control strategies yielded the greatest energy efficiency, daylight amenity, and visual comfort.

1 aTavil, Aslihan1 aLee, Eleanor, S. uhttps://facades.lbl.gov/publications/effects-overhangs-performance01885nas a2200169 4500008004100000050001500041245008600056210006900142260002700211520128600238100002501524700002401549700001901573700002201592700002201614856007901636 2006 eng d aLBNL-6124900aEvaluating Fenestration Products for Zero-Energy Buildings: Issues for Discussion0 aEvaluating Fenestration Products for ZeroEnergy Buildings Issues aCambridge, MAc08/20063 a

Computer modeling to determine fenestration product energy properties (U-factor, SHGC, VT) has emerged as the most cost-effective and accurate means to quantify them. Fenestration product simulation tools have been effective in increasing the use of low-e coatings and gas fills in insulating glass and in the widespread use of insulating frame designs and materials. However, for more efficient fenestration products (low heat loss products, dynamic products, products with non-specular optical characteristics, light redirecting products) to achieve widespread use, fenestration modeling software needs to be improved.

This paper addresses the following questions:

1) Are the current properties (U, SHGC, VT) calculated sufficient to compare and distinguish between windows suitable for Zero Energy Buildings and conventional window products? If not, what data on the thermal and optical performance, on comfort, and on peak demand of windows is needed.

2) Are the algorithms in the tools sufficient to model the thermal and optical processes? Are specific heat transfer and optical effects not accounted for? Is the existing level of accuracy enough to distinguish between products designed for Zero Energy Buildings? Is the current input data adequate?

1 aArasteh, Dariush, K.1 aCurcija, Dragan, C.1 aHuang, Yu, Joe1 aHuizenga, Charlie1 aKohler, Christian uhttps://facades.lbl.gov/publications/evaluating-fenestration-products-zero01614nas a2200169 4500008003900000245009500039210006900134260001200203520102300215100001901238700002201257700001701279700002501296700002501321700002101346856007701367 2006 d00aExperimental Validation of Daylighting Simulation Methods for Complex Fenestration Systems0 aExperimental Validation of Daylighting Simulation Methods for Co c05/20063 a

The 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-daylighting02708nas a2200109 4500008003900000245010700039210006900146260002300215520227300238100001902511856006802530 2005 d00aEnergetic or Not Energetic: Considerations for Fabricating Nanostructures by Physical Vapor Deposition0 aEnergetic or Not Energetic Considerations for Fabricating Nanost aSingaporec06/20053 a

Physical vapor deposition (PVD) has greatly matured in terms of growth modeling and equipment available. For this reason, and the often-required limitation to low-temperature processing, it is app ealing to utilize PVD methods not only for thin films but also for the synthesis of nanostructures. This is true even as many other methods enjoy the advantage of not needing high vacuum equipment.

PVD techniques are traditionally classified by the method of vapor generation, though here it is argued that a physically meaningful classification can be based on the energetics of film-forming species. At the low end of the energy scale, evaporation methods can be used to produce columnar structures with significant porosity. Sputtering at high pressure results in similar properties. This regime is preferred for sculptured structures, which involves moving tilted substrates (chiral films, chevrons, etc. [1]). As the energy is increased, so is the mobility of surface atoms, and we enter an energy regime that is widely used in thin film deposition by magnetron sputtering. Recently, high power pulsed sputtering has evolved as an energetic extension of conventional sputtering [2]. The enhanced degree of ionization enables the efficient application of bias techniques. Additionally, species seem to have higher kinetic energy. Ultimately, one would like to have fully ionized plasmas to fully exploit biasing, which can be done by using filtered cathodic arc plasmas [3]. Considering the high-energy range, substrates can be ion-treated by immersing them in a plasma and applying high voltage pulses, a technique known as plasma-based ion implantation.

Nanostructures are preferentially fabricated at either the low energy (< 1 eV, e.g. for sculptured films) or very high energy (> 1 keV, e.g. metal filling of lithographically produced nanotrenches [4], or formation of precipitates or bubbles by ion implantation [5]). At the intermediate energy range, ~ 100 eV, nanoscale processing of interfaces is used to obtain coatings with superior adhesion. Subplantation growth is facilitated at this energy, which is especially important for tuning the structure and properties of diamond-like carbon and a range of nitride and oxide materials.

1 aAnders, André uhttps://facades.lbl.gov/publications/energetic-or-not-energetic01808nas a2200241 4500008004100000022001500041245010500056210006900161260001200230300001200242490000700254520105000261653001501311653002401326653002201350653002501372653002101397100001801418700001801436700001901454700001901473856007401492 2004 eng d a0093-3813 00aEffect of Ion Mass and Charge State on Transport Vacuum Arc Plasmas Through a Biased Magnetic Filter0 aEffect of Ion Mass and Charge State on Transport Vacuum Arc Plas c04/2004 a433-4390 v323 a

The effect of ion mass and charge state on plasma transport through a 90 deg.-curved magnetic filter is experimentally investigated using a pulsed cathodic arc source. Graphite, copper, and tungsten were selected as test materials. The filter was a bent copper coil biased via the voltage drop across a low-ohm, selfbias resistor. Ion transport is accomplished via a guiding electric field, whose potential forms a trough shaped by the magnetic guiding field of the filter coil. Evaluation was done by measuring the filtered ion current and determination of the particle system coefficient, which can be defined as the ratio of filtered ion current, divided by the mean ion charge state, to the arc current. It was found that the ion current and particle system coefficient decreased as the mass-to-charge ratio of ions increased. This result can be qualitatively interpreted by a very simple model of ion transport that is based on compensation of the centrifugal force by the electric force associated with the guiding potential trough.

10aArc plasma10acathodic vacuum arc10aion charge states10amacroparticle filter10aplasma transport1 aByon, Eungsun1 aKim, Jong-Kuk1 aKwon, Sik-Chol1 aAnders, André uhttps://facades.lbl.gov/publications/effect-ion-mass-and-charge-state02280nas a2200133 4500008004100000050001500041245009700056210006900153520178900222100002102011700002102032700002702053856006602080 2004 eng d aLBNL-5496600aThe Energy-Savings Potential of Electrochromic Windows in the US Commercial Buildings Sector0 aEnergySavings Potential of Electrochromic Windows in the US Comm3 a

Switchable electrochromic (EC) windows have been projected to significantly reduce the energy use of buildings nationwide. This study quantifies the potential impact of electrochromic windows on US primary energy use in the commercial building sector and also provides a broader database of energy use and peak demand savings for perimeter zones than that given in previous LBNL simulation studies. The DOE-2.1E building simulation program was used to predict the annual energy use of a three-story prototypical commercial office building located in five US climates and 16 California climate zones. The energy performance of an electrochromic window controlled to maintain daylight illuminance at a prescribed setpoint level is compared to conventional and the best available commercial windows as well as windows defined by the ASHRAE 90.1-1999 and California Title 24-2005 Prescriptive Standards. Perimeter zone energy use and peak demand savings data by orientation, window size, and climate are given for windows with interior shading, attached shading, and horizon obstructions (to simulate an urban environment).

Perimeter zone primary energy use is reduced by 10-20% in east, south, and west zones in most climates if the commercial building has a large window-to-wall area ratio of 0.60 compared to a spectrally selective low-e window with daylighting controls and no interior or exterior shading. Peak demand for the same condition is reduced by 20-30%. The emerging electrochromic window with daylighting controls is projected to save approximately 91.5-97.3 1012 Btu in the year 2030 compared to a spectrally selective low-E window with manually-controlled interior shades and no daylighting controls if it reaches a 40% market penetration level in that year.

1 aLee, Eleanor, S.1 aYazdanian, Mehry1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/energy-savings-potential01165nas a2200121 4500008004100000050001500041245008200056210006900138520072800207100002100935700001600956856007100972 2004 eng d aLBNL-5754500aEvaluation of High Dynamic Range Photography as a Luminance Mapping Technique0 aEvaluation of High Dynamic Range Photography as a Luminance Mapp3 a

The potential, limitations, and applicability of the High Dynamic Range (HDR) photography technique is evaluated as a luminance mapping tool. Multiple exposure photographs of static scenes are taken with a Nikon 5400 digital camera to capture the wide luminance variation within the scenes. The camera response function is computationally derived using the Photosphere software, and is used to fuse the multiple photographs into HDR images. The vignetting effect and point spread function of the camera and lens system is determined. Laboratory and field studies have shown that the pixel values in the HDR photographs can correspond to the physical quantity of luminance with reasonable precision and repeatability.

1 aInanici, Mehlika1 aGalvin, Jim uhttps://facades.lbl.gov/publications/evaluation-high-dynamic-range02094nas a2200133 4500008004100000050001500041245010000056210006900156260002300225520159700248100001801845700001901863856007801882 2003 eng d aLBNL-5156800aEffect of Underlayer on Coalescence of Silver Islands Grown by Filtered Cathodic Arc Deposition0 aEffect of Underlayer on Coalescence of Silver Islands Grown by F aSan Diegoc05/20033 a

Ultrathin silver films that are not continuous show relatively high absorption in the visible and low reflection in the infrared. For low-emissivity application on window glass, coalescence of silver islands is crucial for obtaining the desired optical properties of the coating, namely high transparence in the visible and high reflectivity in the infrared. It is well known that the energy of ions arriving at the substrate and the type of underlayer affect nucleation and growth of silver islands. There are a number of studies on nucleation and growth, but little is known about coalescence of silver islands synthesized by more energetic condensation, e.g. filtered cathodic vacuum arc (FCVA). In this work, the effect of underlayer on nucleation and growth of silver films deposited by FCVA was investigated by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results arescompared with data obtained by magnetron sputtering.

From the results, plane and titanium-oxide-coated glass requires more material to achieve the same value of resistance than for the zinc oxide coated glass. It is related with the energy of interaction between the surface and the silver atom. Silver films made by cathodic arc deposition show an earlier onset of island coalescence and formation of short links. It was found that silver islands in energetic deposition exhibit a reduced aspect ratio when compared to evaporation and sputtering. Nb underlayer affects nucleation and growth of coalescence of silver only in the case of few monolayer of Nb was introduced.

1 aByon, Eungsun1 aAnders, André uhttps://facades.lbl.gov/publications/effect-underlayer-coalescence-silver02647nas a2200193 4500008004100000050001500041245007200056210006900128260003100197520201300228100002002241700001902261700001802280700002502298700001802323700002002341700001702361856007502378 2002 eng d aLBNL-5142500aEnergy Efficient Windows in the Southern Residential Windows Market0 aEnergy Efficient Windows in the Southern Residential Windows Mar aPacific Grove, CAc08/20023 a

The greatest potential in the U.S. for cost-effective energy savings from currently available energy efficient residential windows and skylights exists in the southern market. Prindle and Arasteh recently reported that ten southern states could save over 400 million kwh and 233 MW of peak electricity generating capacity annually by adopting the International Energy Conservation Code (IECC) standard of 0.40 (or less) solar heat gain coefficient (SHGC) for new construction (Prindle & Arasteh 2001). In 2000, Anello et al. demonstrated savings of 14.7 percent in reduced cooling load with high-performance windows (Anello et al. 2000). In 2002, Wilcox demonstrated savings of 20 percent while simulation analysis estimates cooling energy savings in the 30 percent range (Wilcox 2002).

In the southern market, there is significant opportunity for reducing cooling energy use with low solar gain low-E windows. Yet, the southern market has been slow to embrace this new technology. Market research shows that while low-E products have achieved up to 70 percent of the market share in some colder climates (Jennings, Degens & Curtis 2002), they have gained less than 10 percent of the southern windows market (Prindle & Arasteh 2001).

This paper will explore the residential windows market by considering the following: market barriers unique to the southern market; distribution channels in the South; the roles of utilities, codes officials, and other organizations; and other indirect factors that influence this market. This paper will profile current market transformation efforts with case studies of the Florida Windows Initiative, sponsored by the Efficient Windows Collaborative at the Alliance to Save Energy, and the Texas Windows Initiative, sponsored by the American Electric Power Company. Finally, this paper will identify the next steps that will be critical to transforming the southern residential windows market to more efficient window and skylight products.

1 aTribble, Alison1 aOffringa, Kate1 aPrindle, Bill1 aArasteh, Dariush, K.1 aZarnikau, Jay1 aStewart, Arlene1 aNittler, Ken uhttps://facades.lbl.gov/publications/energy-efficient-windows-southern02249nas a2200181 4500008004100000245009800041210006900139260001200208520162500220100002101845700001301866700002101879700002401900700002401924700002301948700002701971856006901998 2002 eng d00aEnergy Performance Analysis of Electrochromic Windows in New York Commercial Office Buildings0 aEnergy Performance Analysis of Electrochromic Windows in New Yor c11/20023 a

A DOE-2.1E energy simulation analysis of a switchable electrochromic (EC) glazing with daylighting controls has been conducted for prototypical office buildings in New York (NY). The modeling included four types of office buildings: "old" and "new" vintages and large (10,405 m2, 112,000 ft2) and small (502m2, 5400 ft2) buildings. Five commercially available, base case windows with and without interior shades were modeled. Window area varied from 0 to 60% of the exterior floor-to-floor wall area. The electric lighting had either no controls or continuous daylighting controls. The prototypes were modeled in New York City or Buffalo.

Energy performance ata are given for each of the four perimeter zones. Data are presented as a function of window-to-wall ratio in order to better understand the interactions between 1) electric lighting energy use and daylight admission and 2) solar heat gains and space-conditioning energy use. Maximum and minimum reductions in energy use between the EC glazing and all other base case conditions are also presented. Projected energy use reductions relative to typical specified NY office buildings are presented as an indication of the potential impacts EC glazings might have in retrofit and new construction.

The energy and demand reductions provided by EC glazings with daylighting controls relative to what is typically specified in office buildings in NY are quite substantial. EC glazings will also dampen fluctuations in interior daylight levels and window brightness, potentially increasing visual comfort.

1 aLee, Eleanor, S.1 aZhou, L.1 aYazdanian, Mehry1 aInkarojrit, Vorapat1 aSlack, Jonathan, L.1 aRubin, Michael, D.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/energy-performance-analysis02885nas a2200121 4500008004100000050001500041245012800056210006900184520239700253100001802650700002502668856007002693 2002 eng d aLBNL-5142600aEnergy Savings and Pollution Prevention Benefits of Solar Heat Gain Standards in the International Energy Conservation Code0 aEnergy Savings and Pollution Prevention Benefits of Solar Heat G3 a

The International Energy Conservation Code (IECC), published by the International Code Council, the code development orgalization of building code officials, contains new provisions that save energy and reduce air pollution emissions. Its most significant new provision is a prescriptive standard for solar heat gain control in windows in wanner climate zones. Because solar heat gain through windows is one of the largest components of residential cooling loads, this standard reduces cooling loads dramatically, which in turn reduces electricity consumption, utility bills, and powerplant pollution emissions. It can also reduce the size of cooling equipment, a capital cost saving that can offset increased costs for the higher performance windows needed to meet the standard.

This paper documents the potential energy efficiency, dollar, and pollution reduction benefits of the IECCs solar heat gain standard. Using the RESFEN model developed at Lawrence Berkeley National Laboratory, we simulated a typical new home in ten southern states that would be affected the new IECC solar heat gain standard. Our analysis found that in these ten states, adoption of the IECC in its first year could save 400 million kWh, $38 million in electric bills, and 233 MW of peak electricity generating capacity. The cumulative savings from these homes in year 20 would rise to 80 billion kwh, $7.6 billion in electricity bills, and 4,660 Megawatts of generating capacity. In year twenty, the electric energy savings would also prevent the emission of 20,000 tons of NOx and over 1.5 million tons of carbon equivalent.

Extrapolating the calculations in this paper to include other states with significant cooling load reduction from the IECC leads us to believe peak savings from new construction will total 300MW annually. Given that the window replacement and remodeling market is slightly larger than the new construction market (and here the baseline is poorer performing single glazing), leads to the conclusion that savings which include the remodeling and replacement market should exceed 600MW annually. This would eliminate the need to build two average sized 300MW power plants every year. Additional, similar savings could also be expected from applying this technology to windows in commercial buildings, although we have not accounted for these savings in these estimates.

1 aPrindle, Bill1 aArasteh, Dariush, K. uhttps://facades.lbl.gov/publications/energy-savings-and-pollution02215nas a2200121 4500008004100000245007700041210006900118260001200187520177800199100001601977700002501993856007502018 2002 eng d00aAn Evaluation of Alternative Qualifying Criteria for Energy Star Windows0 aEvaluation of Alternative Qualifying Criteria for Energy Star Wi c05/20023 a

Energy Star is a voluntaly partnership between the U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), and industry. Energy Star, at both DOE andsEPA, is based on legislative mandates to implement voluntary, non-regulatory programs to promote products that are substantially more efficient than required by Federal standards (the DOE Energy Star program originated with Section 127 of the Energy Policy Act of 1992 (EPACT), and the EPA Energy Star program originated with Section 103 of the CleansAir Act amendments of 1990). The base criteria under EPACT requires DOE to establish voluntary energy efficiency product programs that serve to increase the technical energy performance potential of products, are cost-effective for the consumer, save energy and thus reduce green house gas emissions. Criteria used by EPA under the Clean Air Act are similar but reflect a greater emphasis on reducing green house gas emissions.

The primary objective of the partnership is to expand the market for energy-efficient products. EPA and DOE use the Energy Star label to recognize and promlote the most energy-efficient subset of the market. The label is a simple mechanism that allows consumers to easily identify the most energy-efficient products in the marketplace. In developing specifications for the Energy Star label, EPA and DOE consider several key factors, including:

1 aBarbour, Ed1 aArasteh, Dariush, K. uhttps://facades.lbl.gov/publications/evaluation-alternative-qualifying02487nas a2200145 4500008004100000024001100041245009700052210006900149260003100218520194000249100002102189700002902210700002702239856007502266 2000 eng d aDA-41400aElectrochromic Windows for Commercial Buildings: Monitored Results from a Full-Scale Testbed0 aElectrochromic Windows for Commercial Buildings Monitored Result aPacific Grove, CAc04/20003 a

Electrochromic glazings promise to be the next major advance in energy-efficient window technology, helping to transform windows and skylights from an energy liability to an energy source for the nations building stock. Monitored results from a full-scale demonstration of large-area electrochromic windows are given. The test consisted of two side-by-side, 3.7x4.6 m, office-like rooms. In each room, five 62x173-cm lower electrochromic windows and five 62x43-cm upper electrochromic windows formed a large window wall. The window-to-exterior wall ratio (WWR) was 0.40. The southeast-facing electrochromic windows had an overall visible transmittance (Tv) range of Tv =0.11-0.38 and were integrated with a dimmable electric lighting system to provide constant work plane illuminance and to control direct sun.

Daily lighting use from the automated electrochromic window system decreased by 6 to 24% compared to energy use with static, low-transmission (Tv =0.11), unshaded windows in overcast to clear sky winter conditions in Oakland, California. Daily lighting energy use increased as much as 13% compared to lighting energy use with static windows that had Tv =0.38. Even when lighting energy savings were not obtainable, the visual environment produced by the electrochromic windows, indicated by well-controlled window and room luminance levels, was significantly improved for computer-type tasks throughout the day compared to the visual environment with unshaded 38%-glazing. Cooling loads were not measured, but previous building energy simulations indicate that additional savings could be achieved. To ensure visual and thermal comfort, electrochromics require occasional use of interior or exterior shading systems when direct sun is present. Other recommendations to improve electrochromic materials and controls are noted along with some architectural constraints.

1 aLee, Eleanor, S.1 aDiBartolomeo, Dennis, L.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/electrochromic-windows-commercial01729nas a2200145 4500008004100000050001500041245004700056210004700103260002900150520125500179100002701434700002401461700002301485856007501508 2000 eng d aLBNL-4651000aElectrochromism in Copper Oxide Thin Films0 aElectrochromism in Copper Oxide Thin Films aUppsala, Swedenc08/20003 a

Transparent thin films of copper(I) oxide prepared on conductive SnO2:F glass substrates by anodic oxidation of sputtered copper films or by direct electrodeposition of Cu2O transformed reversibly to opaque metallic copper films when reduced in alkaline electrolyte. In addition, the same Cu2O films transform reversibly to black copper(II) oxide when cycled at more anodic potentials. Copper oxide-to-copper switching covered a large dynamic range, from 85% and 10% photopic transmittance, with a coloration efficiency of about 32 cm2/C. Gradual deterioration of the switching range occurred over 20 to 100 cycles. This is tentatively ascribed to coarsening of the film and contact degradation caused by the 65% volume change on conversion of Cu to Cu2O. Switching between the two copper oxides (which have similar volumes) was more stable and more efficient (CE = 60 cm2/C), but covered a smaller transmittance range (60% to 44% T). Due to their large electrochemical storage capacity and tolerance for alkaline electrolytes, these cathodically coloring films may be useful as counter electrodes for anodically coloring electrode films such as nickel oxide or metal hydrides.

1 aRichardson, Thomas, J.1 aSlack, Jonathan, L.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/electrochromism-copper-oxide-thin01139nas a2200133 4500008004100000050001500041245004800056210004800104260002200152520070500174100002100879700002700900856007800927 1999 eng d aLBNL-4276100aEstablishing the Value of Advanced Glazings0 aEstablishing the Value of Advanced Glazings aBath, UKc04/19993 a

Numerous glazing technologies are under development worldwide to improve the performance of building facades. High-performance glazings can provide substantial energy and related environmental benefits, but often at greatly increased first cost when compared to conventional design solutions. To increase market viability, we discuss strategies to reduce the actual and owner-perceived costs associated with developing and producing advanced window systems, specifically switchable electrochromic glazings, and we also suggest marketing strategies designed to appeal to early adopter and mainstream purchasers. These strategies may be applicable to a broad range of advanced glazing materials.

1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/establishing-value-advanced-glazings01128nas 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 a

The 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-quasi01659nas 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 a

Metallic 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-optical02650nas a2200145 4500008004100000050001500041245008000056210006900136490000700205520214200212100002102354700002902375700002702404856007302431 1998 eng d aLBNL-4086700aThe Effect of Venetian Blinds on Daylight Photoelectric Control Performance0 aEffect of Venetian Blinds on Daylight Photoelectric Control Perf0 v283 a

We investigate how a venetian blind, a common but optically complex fenestration system, contributes to the unreliable performance of daylighting control systems. Using a fully instrumented, full-scale testbed facility, we monitored the daylighting performance of a modified closed-loop proportional photoelectric control system in a private office over the course of a year. The ratio of workplane illuminance from daylight to photosensor signal is characterized in terms of solar condition and venetian blind angle. Variations in this ratio causes actual illuminance levels to be periodically insufficient. This type of characterization can be used by the installer to determine whether the initial control adjustments made during commissioning will lead to reliable performance under most daylight conditions. Commissioning guidelines are given with caution, based on our observations from this specific case study.

We quantified the effect of variability in this ratio on control performance. With a middle-of-the-road gain constant, monitored workplane illuminance levels did not fall below 90% of the design setpoint for 91% of the year. When discrepancies occurred, differences between the daylight correlation and measured conditions were the primary cause of insufficient illuminance at the workplane. This performance is not applicable to commercially-available closed-loop proportional systems because 1) typical systems are rarely commissioned properly upon installation, and 2) off-the-shelf systems combine the photosensor's response to daylight and electric light into one gain parameter. Even though the prototype system was subject to the same discrepancies in the daylight correlation fit as commercially-available systems, performance was substantially improved because the prototype was able to separate the electric lighting contribution to workplane illuminance from the daylighting contribution, at no added cost. Commissioning should accommodate the effect of the fenestration system, since variations in luminance distributions produced by the window are the primary cause of unreliable performance.

1 aLee, Eleanor, S.1 aDiBartolomeo, Dennis, L.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/effect-venetian-blinds-daylight02282nas a2200229 4500008004100000245008200041210006900123260001200192300001000204490000700214520155300221653002501774653002801799653001501827100002301842700001701865700002701882700001901909700002301928700002401951856007701975 1998 eng d00aElectrochromic lithium nickel oxide by pulsed laser deposition and sputtering0 aElectrochromic lithium nickel oxide by pulsed laser deposition a c07/1998 a59-660 v543 a

Thin films of lithium nickel oxide were deposited by sputtering and pulsed laser deposition (PLD) from targets of pressed LiNiO2 powder. The composition and structure of these films were analyzed using a variety of techniques, such as nuclear-reaction analysis, Rutherford backscattering spectrometry (RBS), X-ray diffraction, infrared spectroscopy, and atomic-force microscopy. Crystalline structure, surface morphology and chemical composition of LixNi1−xO thin films depend strongly on deposition oxygen pressure, temperature as well as substrate–target distance. The films produced at temperatures lower than 600°C spontaneously absorb CO2 and H2O at their surface once they are exposed to the air. The films deposited at 600°C proved to be stable in air over a long period. Even at room temperature the PLD films are denser and more stable than sputtered films. RBS determined the composition of the best films to be Li0.5Ni0.5O deposited by PLD at 60 mTorr O2 pressure. Electrochemical tests show that the films exhibit excellent reversibility in the range 1.0–3.4 V versus lithium. Electrochemical formatting which is used to develop electrochromism in other films is not needed for the stoichiometric films. The optical transmission range is almost 70% at 550 nm for 150 nm-thick films. Devices made from these films were analyzed using novel reference electrodes and by disassembling after cycling.

10aLithium nickel oxide10apulsed laser deposition10asputtering1 aRubin, Michael, D.1 aWen, Shi-Jie1 aRichardson, Thomas, J.1 aKerr, John, B.1 avon Rottkay, Klaus1 aSlack, Jonathan, L. uhttps://facades.lbl.gov/publications/electrochromic-lithium-nickel-oxide01510nas 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 a

Thin 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-101800nas a2200169 4500008004100000050001500041245016500056210006900221300001400290490000700304520115200311100002001463700002501483700002301508700002301531856007601554 1998 eng d aLBNL-4182000aEllipsometry on Sputter Deposited Tin Oxide Films: Optical Constants Versus Stoichiometry Hydrogen Content, and Amount of Electrochemically Intercalated Lithium0 aEllipsometry on Sputter Deposited Tin Oxide Films Optical Consta a7734-77410 v373 a

Tin oxide thin films were deposited by reactive radio-frequency magnetron sputtering onto In2O3:Sn coated and bare glass substrates. Optical constants in the 300-2500 nm wavelength range were determined by a combination of variable-angle spectroscopic ellipsometry and spectrophotometric transmittance measurements. Surface roughness was modeled from optical measurements and compared with atomic-force microscopy. The two techniques gave consistent results. The fit between experimental optical data and model results could be significantly improved when it was assumed that the refractive index of the Sn oxide varied across the film thickness. Varying the oxygen partial pressure during deposition made it possible to obtain films whose complex refractive index changed at the transition from SnO to SnO2. An addition of hydrogen gas during sputtering led to lower optical constants in the full spectral range in connection with a blue shift of the band gap. Electrochemical intercalation of lithium ions into the Sn oxide films raised their refractive index and enhanced their refractive-index gradient.

1 aIsidorsson, Jan1 aGranqvist, Claes, G.1 avon Rottkay, Klaus1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/ellipsometry-sputter-deposited-tin01148nas a2200121 4500008004100000050001500041245006500056210006100121260003700182520071000219100002700929856007000956 1998 eng d aLBNL-4141400aThe Elusive Challenge of Daylighted Buildings 25 Years Later0 aElusive Challenge of Daylighted Buildings 25 Years Later aOttawa, Ontario, Canadac05/19983 a

As we approach the end of the decade of the 1990s, daylighting is increasingly promoted as a design strategy and building solution that can save energy and improve human performance and satisfaction in indoor spaces. Similar claims were made in the 1970s in the aftermath of the oil embargo. Twenty-five years later, in a world newly concerned about carbon emissions, global warming, and sustainable design, daylighted buildings are again proposed as a solution. While it is possible to find some examples of well daylighted buildings that have been built in the last 25 years, the fact that there are so few suggests that the optimistic outlook for daylighting needs to be critically (re)examined.

1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/elusive-challenge-daylighted02126nas a2200169 4500008004100000050001500041245006600056210006600122260003400188520154400222100002101766700002501787700002101812700002301833700002701856856007301883 1998 eng d aLBNL-4169400aEnergy and Daylight Performance of Angular Selective Glazings0 aEnergy and Daylight Performance of Angular Selective Glazings aClearwater Beach, FLc12/19983 a

This paper presents the results of a study investigating the energy and daylight performance of anisotropic angular selective glazings. The DOE-2.1E energy simulation program was used to determine the annual cooling, lighting and total electricity use, and peak electric demand. RADIANCE, a lighting simulation program, was used to determine daylight illuminance levels and distribution. We simulated a prototypical commercial office building module located in Blythe, California. We chose three hypothetical conventional windows for comparison: a single-pane tinted window, a double-pane low-E window, and a double-pane spectrally selective window. Daylighting controls were used. No interior shades were modeled in order to isolate the energy effects of the angular selective glazing. Our results show that the energy performance of the prototype angular selective windows is about the same as conventional windows for a 9.14 m (30 ft) deep south-facing perimeter zone with a large-area window in the hot, sunny climate of Blythe. It is theoretically possible to tune the angular selectivity of the glazing to achieve annual cooling energy reductions of 18%, total electricity use reductions of 15%, and peak electric demand reductions of 11% when compared to a conventional glazing with the same solar-optical properties at normal incidence. Angular selective glazings can provide more uniformly distributed daylight, particularly in the area next to the window, which will result in a more visually comfortable work environment.

1 aSullivan, Robert1 aBeltran, Liliana, O.1 aLee, Eleanor, S.1 aRubin, Michael, D.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/energy-and-daylight-performance02449nas a2200157 4500008004100000050001500041245014100056210006900197260003400266520183000300100002402130700001902154700001802173700002502191856007502216 1998 eng d aLBNL-4177200aExperimental Techniques for Measuring Temperature and Velocity Fields to Improve the Use and Validation of Building Heat Transfer Models0 aExperimental Techniques for Measuring Temperature and Velocity F aClearwater Beach, FLc12/19983 a

When modeling thermal performance of building components and envelopes, researchers have traditionally relied on average surface heat-transfer coefficients that often do not accurately represent surface heat-transfer phenomena at any specific point on the component being evaluated. The authors have developed new experimental techniques that measure localized surface heat-flow phenomena resulting from convection. The data gathered using these new experimental procedures can be used to calculate local film coefficients and validate complex models of room and building envelope heat flows. These new techniques use a computer controlled traversing system to measure both temperatures and air velocities in the boundary layer near the surface of a building component, in conjunction with current methods that rely on infrared (IR) thermography to measure surface temperatures. Measured data gathered using these new experimental procedures are presented here for two specimens: (1) a Calibrated Transfer Standard (CTS) that approximates a constant-heat-flux, flat plate; and (2) a dual-glazed, low-emittance (low-e), wood-frame window. The specimens were tested under steady-state heat flow conditions in laboratory thermal chambers. Air temperature and mean velocity data are presented with high spatial resolution (0.25- to 25-mm density). Local surface heat-transfer film coefficients are derived from the experimental data by means of a method that calculates heat flux using a linear equation for air temperature in the inner region of the boundary layer. Local values for convection surface heat-transfer rate vary from 1 to 4.5 W/m2K. Data for air velocity show that convection in the warm-side thermal chamber is mixed forced/natural, but local velocity maximums occur from 4 to 8 mm from the window glazing.

1 aGriffith, Brent, T.1 aTurler, Daniel1 aGoudey, Howdy1 aArasteh, Dariush, K. uhttps://facades.lbl.gov/publications/experimental-techniques-measuring02057nas a2200229 4500008004100000050001500041245011100056210006900167260002700236300001100263490000900274520128000283653002601563653002801589653001901617653002201636100002301658700002701681700002301708700002401731856007201755 1997 eng d aLBNL-4066800aEffective Medium Approximation of the Optical properties of electrochromic cerium-titanium oxide compounds0 aEffective Medium Approximation of the Optical properties of elec aSan Diego, CAc07/1997 a19-Sep0 v31383 a

Cerium titanium oxide samples derived from a solution have been compared against sputtered films over a wide range of different compositions. X-ray diffraction was used to investigate the structural properties of the compound material existing in a two-phase mixture MAO2-MBO2. The optical properties were evaluated over the whole solar spectrum by variable angle spectroscopic ellipsometry combined with spectrophutometry. The spectral complex refractive index was determined for CeO2 and TiO2, as well as for their compounds. To reduce the large number of permutations in composition of multi-component oxides it would be useful to be able to predict the properties of the mixtures from the pure oxide components. Therefore these results were compared to those obtained by effective medium theory utilizing the optical constants of CeO2 and TiO2. In order to investigate the performance as passive counter-electrode in Li+ based electrochromic devices the films were tested by cyclic voltammetry with in-situ transmission control. Chemical composition was measured by Rutherford backscattering spectrometry. Surface morphology was analyzed by atomic force microscopy.

10acerium titanium oxide10aeffective medium theory10aelectrochromic10aoptical constants1 avon Rottkay, Klaus1 aRichardson, Thomas, J.1 aRubin, Michael, D.1 aSlack, Jonathan, L. uhttps://facades.lbl.gov/publications/effective-medium-approximation02253nas a2200169 4500008004100000050001500041245007700056210006900133260002900202300001000231490001000241520169000251100001701941700002301958700002301981856007902004 1996 eng d aLBNL-3959300aElectrochromic Lithium Nickel Oxide Thin Film by Pulsed Laser Deposition0 aElectrochromic Lithium Nickel Oxide Thin Film by Pulsed Laser De aSan Antonio, TXc10/1996 a54-630 v96-243 a

Thin films of lithium nickel oxide were deposited by pulsed laser deposition (PLD) from targets of pressed LiNiO2 powder with layered structure. The composition, structure and surface air sensitivity of these films were analyzed using a variety of techniques, such as nuclear reaction analysis, Rutherford backscattering spectrometry (RBS), x-ray diffraction, infrared spectroscopy, and atomic force microscopy. Optical properties were measured using a combination of variable angle spectroscopic ellipsometry and spectroradiometry. Crystalline structure, surface morphology and chemical composition of LixNi1-xO thin films depend strongly on deposition oxygen pressure, temperature as well as substrate target distance. The films produced at temperatures lower than 600 °C spontaneously absorb CO2 and H2O at their surface once they are exposed to the air. The films deposited at 600 °C proved to be stable in air over a long period. Even when deposited at room temperature the PLD films are denser and more stable than sputtered films. RBS determined that the best electrochromic films had the stoichiometric composition Li0.5Ni0.5O when deposited at 60 mTorr O2 pressure. Electrochemical tests show that the films exhibit excellent reversibility in the range 1.0 V to 3.4 V versus lithium and long cyclic life stability in a liquid electrolyte half cell. Electrochemical formatting which is used to develop electrochromism in other films and nickel oxide films is not needed for these stoichiometric films. The optical transmission range is almost 70% at 550 nm for 120 nm thick films.

1 aWen, Shi-Jie1 avon Rottkay, Klaus1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/electrochromic-lithium-nickel-oxide-003351nas a2200169 4500008004100000050001500041245006800056210006800124260002400192300001200216490001600228520278700244100002103031700002303052700002703075856007903102 1996 eng d aLBNL-3990500aEnergy Performance Analysis of Prototype Electrochromic Windows0 aEnergy Performance Analysis of Prototype Electrochromic Windows aBoston, MAc07/1997 a149-1560 v103, Part 23 a

This paper presents the results of a study investigating the energy performance of three newly developed prototype electrochromic devices. The DOE-2.1E energy simulation program was used to analyze the annual cooling, lighting, and total electric energy use and peak demand as a function of window type and size. We simulated a prototypical commercial office building module located in the cooling-dominated locations of Phoenix, AZ and Miami, FL. Heating energy use was also studied in the heating-dominated location of Madison, WI. Daylight illuminance was used to control electrochromic state-switching. Two types of window systems were analyzed; i.e., the outer pane electrochromic glazing was combined with either a conventional low-E or a spectrally selective inner pane. The properties of the electrochromic glazings are based on measured data of new prototypes developed as part of a cooperative DOE-industry program.

Our results show the largest difference in annual electric energy performance between the different window types occurs in Phoenix and is about 6.5 kWh/m2 floor area (0.60 kWh/ft2) which can represent a cost of about $.52/m2 ($.05/ft2) using electricity costing $.08/kWh. Much larger differences exist when electrochromic windows are compared to conventional glazings in use today. At large window sizes, such energy savings can be as large as 90 kWh/m2 (8.4 kWh/ft2). Specific electrochromic performance varies with window-to-wall area ratio; i.e., at low ratios, one type electrochromic performs best, while at large ratios, another type performs best. In general, an electrochromic glazing combined with a spectrally selective glazings is better than one combined with a low-E glazing; however, at low-window-to-wall area ratios, this situation reverses slightly. There is almost no difference in peak electric demand for the different electrochromic windows analyzed.

In heating-dominated locations, the electrochromic should be maintained in its bleached state during the heating season to take advantage of beneficial solar heat gain which would reduce the amount of required heating. This also means that the electrochromic window with the largest solar heat gain coefficient is best. The largest heating energy performance difference in Madison for the various window types is 43 MJ/m2 floor area (4.0 kBtu/ft2). This represents a cost of about $.26/m2 floor area ($.024/ft2) using gas costing $0.60/therm ($5.69/GJ, $6.00/MBtu). However, a non-switching electrochromic will not provide desired glare control so that a control strategy that minimizes winter heating use may not be routinely desirable in many buildings.

1 aSullivan, Robert1 aRubin, Michael, D.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/energy-performance-analysis-prototype01784nas a2200157 4500008004100000050001400041245009500055210006900150260003100219520120900250100002101459700002101480700002301501700002701524856007501551 1996 eng d aLBL-3825200aThe Energy Performance of Electrochromic Windows in Heating-Dominated Geographic Locations0 aEnergy Performance of Electrochromic Windows in HeatingDominated aFreiburg, Germanyc09/19963 a

This paper presents the results of a study investigating the energy performance of electrochromic windows in heating-dominated geographic locations under a variety of state-switching control strategies. We used the DOE-2.1E energy simulation program to analyze the annual heating, cooling and lighting energy use and performance as a function of glazing type, size, and electrochromic control strategy. We simulated a prototypical commercial office building module located in Madison, Wisconsin. Control strategies analyzed were based on daylight illuminance, incident total solar radiation, and space cooling load. Our results show that overall energy performance is best if the electrochromic is left in its clear or bleached state during the heating season, but controlled during the cooling season using daylight illuminance as a control strategy. Even in such heating dominated locations as Madison, there is still a well-defined cooling season when electrochromic switching will be beneficial. However, having the electrochromic remain in its bleached state during the winter season may result in glare and visual comfort problems for occupants much in the same way as conventional glazings.

1 aSullivan, Robert1 aLee, Eleanor, S.1 aRubin, Michael, D.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/energy-performance-electrochromic02188nas a2200169 4500008004100000024001200041245007000053210006900123260002900192490001600221520160700237100002101844700002201865700002501887700002701912856007901939 1996 eng d aUC-160000aEnergy Performance of Evacuated Glazings in Residential Buildings0 aEnergy Performance of Evacuated Glazings in Residential Building aSan Antonio, TXc06/19960 v102, Part 23 a

This paper presents the results of a study investigating the energy performance of evacuated glazings or glazings which maintain a vacuum between two panes of glass. Their performance is measured by comparing results to prototype highly insulated superwindows as well as a more conventional insulating glass unit with a low-E coating and argon gas fill. We used the DOE-2.1E energy analysis simulation program to analyze the annual and hourly heating energy use due to the windows of a prototypical single-story house located in Madison, Wisconsin. Cooling energy performance was also investigated. Our results show that for highly insulating windows, the solar heat gain coefficient is as important as the windows U-factor in determining heating performance for window orientations facing west-south-east. For other orientations in which there is not much direct solar radiation, the windows U-factor primarily governs performance. The vacuum glazings had lower heating requirements than the superwindows for most window orientations. The conventional low-E window outperformed the superwindows for southwest-south-southeast orientations. These performance differences are directly related to the solar heat gain coefficients of the various windows analyzed. The cooling performance of the windows was inversely related to the heating performance. The low solar heat gain coefficients of the superwindows resulted in the best cooling performance. However, we were able to mitigate the cooling differences of the windows by using an interior shading device that reduced the amount of solar gain.

1 aSullivan, Robert1 aBeck, Fredric, A.1 aArasteh, Dariush, K.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/energy-performance-evacuated-glazings01938nas a2200157 4500008004100000024001100041245003800052210003800090260003400128520145500162100001901617700002501636700002201661700002501683856007201708 1995 eng d aTA-34200aEdge Conduction in Vacuum Glazing0 aEdge Conduction in Vacuum Glazing aClearwater Beach, FLc03/19953 a

Vacuum glazing is a form of low-conductance double glazing using an internal vacuum between the two glass sheets to eliminate heat transport by gas conduction and convection. An array of small support pillars separates the sheets; fused solder glass forms the edge seal. Heat transfer through the glazing occurs by radiation across the vacuum gap, conduction through the support pillars, and conduction through the bonded edge seal. Edge conduction is problematic because it affects stresses in the edge region, leading to possible failure of the glazing; in addition, excessive heat transfer because of thermal bridging in the edge region can lower overall window thermal performance and decrease resistance to condensation.

Infrared thermography was used to analyze the thermal performance of prototype vacuum glazings, and, for comparison, atmospheric pressure superwindows. Research focused on mitigating the edge effects of vacuum glazings through the use of insulating trim, recessed edges, and framing materials. Experimentally validated finite-element and finite-difference modeling tools were used for thermal analysis of prototype vacuum glazing units and complete windows. Experimental measurements of edge conduction using infrared imaging were found to be in good agreement with finite-element modeling results for a given set of conditions. Finite-element modeling validates an analytic model developed for edge conduction.

1 aSimko, Tom, M.1 aCollins, Richard, E.1 aBeck, Fredric, A.1 aArasteh, Dariush, K. uhttps://facades.lbl.gov/publications/edge-conduction-vacuum-glazing01364nas a2200145 4500008004100000245008300041210006900124260001200193300001200205490000700217520087500224100001901099700002101118856007901139 1995 eng d00aElectrochemical Lithium Insertion in Sol-gel Deposited LiNbO3 Films0 aElectrochemical Lithium Insertion in Solgel Deposited LiNbOsub3s c12/1995 a367-3750 v393 a

Inorganic LiNbO3 ion conducting films were prepared by sol-gel process involving two alkoxides, lithium ethoxide and niobium ethoxide. The films were analyzed by ellipsometry, X-ray diffractometry, scanning electron microscopy and impedance spectroscopy. Impedance spectroscopy indicated that the Li+ conductivity values were in the range of 6-8 x 10-7 S cm-1. The morphology and thickness of these films played an important role in the insertion of lithium ions. Spectrophotometric investigation showed that LiNbO3 films exhibit very weak cathodic coloration from 350 to 900 nm spectral region. The previous termelectrochemical and opticalnext term properties clearly indicate that sol-gel deposited LiNbO3 films can be used as lithium ion conducting layers for electrochromic device application.

1 aÖzer, Nilgün1 aLampert, Carl, M uhttps://facades.lbl.gov/publications/electrochemical-lithium-insertion-sol02425nas a2200169 4500008004100000024001100041245009500052210006900147260003100216520180500247100002102052700002102073700003402094700002302128700002702151856007702178 1994 eng d aUC-35000aEffect of Switching Control Strategies on the Energy Performance of Electrochromic Windows0 aEffect of Switching Control Strategies on the Energy Performance aFreiburg, Germanyc04/19943 a

This paper presents the results of a study investigating the energy performance of electrochromic windows under a variety of state-switching control strategies. We used the DOE-2.1E energy simulation program to analyze the annual cooling, lighting, and total electricity use and peak demand as a function of glazing type, size, and electrochromic control strategy. We simulated a prototypical commercial office building module located in the cooling-dominated location of Blythe, California. Control strategies analyzed were based on daylight illuminance, incident total solar radiation, and space cooling load. Our results show that when a daylighting strategy is used to reduce electric lighting requirements, control algorithms based on daylight illuminance results in the best overall annual energy performance. If daylighting is not an design option, controls based on space cooling load yield the best performance through solar heat gain reduction. The performance of incident total solar radiation control strategies varies as a function of the switching setpoints; for small to moderate window sizes which result in small to moderate solar gains, a large setpoint-range was best since it provides increased illuminance for daylighting without much cooling penalty; for larger window sizes, which provide adequate daylight, a smaller setpoint-range was best to reduce unwanted solar heat gains and the consequential increased cooling requirement. Of particular importance is the fact that reduction in peak electric demand was found to be independent of the type of control strategy used for electrochromic switching. This is because the electrochromics are generally in their most colored state under peak conditions, and the mechanism used for achieving such a state is not important.

1 aSullivan, Robert1 aLee, Eleanor, S.1 aPapamichael, Konstantinos, M.1 aRubin, Michael, D.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/effect-switching-control-strategies02087nas a2200181 4500008004100000024001100041245006100052210005700113260001200170520150200182100003401684700002501718700002101743700002101764700002701785700002301812856007001835 1993 eng d aDA-30200aThe Energy Performance of Prototype Holographic Glazings0 aEnergy Performance of Prototype Holographic Glazings c02/19933 a

We report on the simulation of the energy performance of prototype holographic glazings in commercial office buildings in a California climate. These prototype glazings, installed above conventional side windows, are designed to diffract the transmitted solar radiation and reflect it off the ceiling, providing adequate daylight illumination for typical office tasks up to 10m from the window. In this study, we experimentally determined a comprehensive set of solar-optical properties and characterized the contribution of the prototype holographic glazings to workplane illuminance in a scale model of a typical office space. We then used the scale model measurements to simulate the energy performance of the holographic glazings over the course of an entire year for four window orientations (North, East, South and West) for the inland Los Angeles climate, using the DOE-2.lD building energy analysis computer program. The results of our experimental analyses indicate that these prototype holographic glazings diffract only a small fraction of the incident light. The results of this study indicate that these prototype holographic glazings will not save energy in commercial office buildings. Their performance is very similar to that of clear glass, which, through side windows, cannot efficiently illuminate more than a 4m - 6m depth of a building`s perimeter, because the cooling penalties due to solar heat gain are greater than the electric lighting savings due to daylighting.

1 aPapamichael, Konstantinos, M.1 aBeltran, Liliana, O.1 aFurler, Reto, A.1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/energy-performance-prototype01040nas a2200133 4500008004100000050001400041245006900055210006500124520057500189100002500764700002100789700002700810856006900837 1985 eng d aLBL-1745600aThe Effects of Skylight Parameters on Daylighting Energy Savings0 aEffects of Skylight Parameters on Daylighting Energy Savings3 a

Skylight parameters that affect lighting, cooling, heating, fan, and total energy use in office buildings are examined using the state-of-the-art building energy analysis computer code, DOE-2.1B. The lighting effects of skylight spatial distribution, skylight area, skylight visible transmission, well factor, illumination setpoint, interior partitions, ceiling height, and glazing characteristics are discussed. This study serves as the foundation for the creation of a DOE-2.1B database and design tools for estimating daylighting energy savings from skylights.

1 aArasteh, Dariush, K.1 aJohnson, Russell1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/effects-skylight-parameters01779nas a2200169 4500008004100000050001400041245006100055210006100116300001200177490000700189520124700196100002501443700002101468700002701489700002101516856007201537 1985 eng d aLBL-1745700aEnergy Performance and Savings Potentials with Skylights0 aEnergy Performance and Savings Potentials with Skylights a154-1790 v913 a

This study systematically explores the energy effects of skylight systems in a prototypical office building module and examines the savings from daylighting. For specific climates, roof/skylight characteristics are identified that minimize total energy or peak electrical demand. Simplified techniques for energy performance calculation are also presented based on a multiple regression analysis of our data base so that one may easily evaluate daylightings effects on total and component energy loads and electrical peaks. This provides additional insights into the influence of skylight parameters on energy consumption and electrical peaks. We use the DOE-2.15 energy analysis program with newly incorporated daylighting algorithms to determine hourly, monthly, and annual impacts of daylighting strategies on electrical lighting consumption, cooling, heating, fan power, peak electrical demands, and total energy use. A database of more than 2000 parametric simulations for 14 U.S. climates has been generated. Parameters varied include skylight-to-roof ratio, shading coefficient, visible transmittance, skylight well light loss, electric lighting power density, roof heat transfer coefficient, and electric lighting control type.

1 aArasteh, Dariush, K.1 aJohnson, Russell1 aSelkowitz, Stephen, E.1 aSullivan, Robert uhttps://facades.lbl.gov/publications/energy-performance-and-savings