@techreport {60771, title = {High Performance Building Fa{\c c}ade Solutions-Phase II}, year = {2014}, month = {03/2014}, abstract = {

The High Performance Building Fa{\c c}ade Solutions{\textendash}Phase II project was initiated through the California Energy Commission{\textquoteright}s Public Interest Energy Research (PIER) program in July 2010 to support industry{\textquoteright}s development and deployment of both incremental and breakthrough fa{\c c}ade 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 fa{\c c}ade 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 fa{\c c}ade 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{\textquoteright}s long-term goal of achieving zero net energy use in the next decade.

}, keywords = {automated shading, between-pane shading, bidirectional scattering distribution functions, building energy simulation tools, Complex fenestration systems, daylighting, daylighting simulation tools, electrochromics, exterior shading, goniophotometer, light shelves, microprismatic films, model predictive controls, motorized shading, shading, solar-optical properties, switchable windows, thermochromics, virtual prototyping, window heat transfer}, author = {Eleanor S. Lee and Brian E. Coffey and Luis L. Fernandes and Sabine Hoffmann and Andrew McNeil and Anothai Thanachareonkit and Gregory J. Ward} } @techreport {58288, title = {Automated Production of Optimization-Based Control Logics for Dynamic Fa{\c c}ade Systems, with Experimental Application to Two-Zone External Venetian Blinds}, year = {2013}, month = {09/2013}, type = {CEC PIER Technical Report}, author = {Brian E. Coffey and Andrew McNeil and Thierry Stephane Nouidui and Eleanor S. Lee} } @techreport {60935, title = {A Pilot Demonstration of Electrochromic and Thermochromic Windows in the Denver Federal Center, Building 41, Denver, Colorado}, year = {2013}, note = {

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

}, month = {07/2013}, abstract = {

Chromogenic glazing materials are emerging technologies that tint reversibly from a clear to dark tinted state either passively in response to environmental conditions or actively in response to a command from a switch or building automation system. Switchable coatings on glass manage solar radiation and visible light while enabling unobstructed views to the outdoors. Building energy simulations estimate that actively controlled, near-term chromogenic glazings can reduce perimeter zone heating, ventilation, and air- conditioning (HVAC) and lighting energy use by 10-20\% and reduce peak electricity demand by 20-30\%, achieving energy use levels that are lower than an opaque, insulated wall.

This project demonstrates the use of two types of chromogenic windows: thermochromic and electrochromic windows. By 2013, these windows will begin production in the U.S. by multiple vendors at high-volume manufacturing plants, enabling lower cost and larger area window products to be specified. Both technologies are in the late R\&D stage of development, where cost reductions and performance improvements are underway. Electrochromic windows have been installed in numerous buildings over the past four years, but monitored energy-efficiency performance has been independently evaluated in very limited applications. Thermochromic windows have been installed in one other building with an independent evaluation, but results have not yet been made public.

}, keywords = {building controls, daylighting, Demand Side Management, electrochromic, energy-efficiency, Smart windows, switchable windows, Thermochromic, Window}, url = {http://gsa.gov/portal/content/187967}, author = {Eleanor S. Lee and Luis L. Fernandes and Howdy Goudey and Jacob C. Jonsson and Dragan C. Curcija and Xiufeng Pang and Dennis L. DiBartolomeo and Sabine Hoffmann} } @techreport {3441, title = {A Post-Occupancy Monitored Evaluation of the Dimmable Lighting, Automated Shading, and Underfloor Air Distribution System in The New York Times Building}, year = {2013}, month = {01/2013}, institution = {Lawrence Berkeley National Laboratory}, address = {Berkeley, CA}, abstract = {

With aggressive goals to reduce national energy use and carbon emissions, the US Department of Energy will be looking to exemplary buildings that have already invested in new approaches to achieving the energy performance goals now needed at a national level. The New York Times Building, in New York, New York, incorporates a number of innovative technologies, systems and processes and could become a model for widespread replication in new and existing buildings. Post-occupancy data are invaluable in establishing confidence in innovation. A year-long monitored study was conducted to verify energy performance, assess occupant comfort and satisfaction with the indoor environment, and evaluate impacts on maintenance and operations. Lessons learned were derived from the analysis; these lessons could help identify and shape policy, financial, or supporting strategies to accelerate diffusion in the commercial building market.

}, author = {Eleanor S. Lee and Luis L. Fernandes and Brian E. Coffey and Andrew McNeil and Robert D. Clear and Thomas L. Webster and Fred S. Bauman and Darryl J. Dickerhoff and David Heinzerling and Tyler Hoyt} } @article {3185, title = {Discomfort Glare: What Do We Actually Know?}, journal = {Lighting Research and Technology}, volume = {April 2012}, year = {2012}, month = {05/2012}, abstract = {

Glare models were reviewed with an eye for missing conditions or inconsistencies. We found ambiguities as to when to use small source versus large source models, and as to what constitutes a glare source in a complex scene. We also found surprisingly little information validating the assumed independence of the factors driving glare.

A barrier to progress in glare research is the lack of a standardized dependent measure of glare. We inverted the glare models to predict luminance, and compared model predictions against the 1949 Luckiesh \& Guth data that form the basis of many of them. The models perform surprisingly poorly, particularly with regards to the luminance-size relationship and additivity. Evaluating glare in complex scenes may require fundamental changes to form of the glare models.

}, doi = {10.1177/1477153512444527}, author = {Robert D. Clear} } @booklet {1213, title = {Electro-Responsive Polymer Glazings For Smart Windows With Dynamic Daylighting Control}, year = {2012}, month = {02/2012}, abstract = {

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.

}, author = {Georgeta Masson and Rueben Mendlesberg and Irene Fernandez-Cuesta and Stefano Cabrini and Delia J. Milliron and Brett A. Helms and Eleanor S. Lee and Andrew McNeil and Stephen E. Selkowitz} } @article {55431, title = {End User Impacts of Automated Electrochromic Windows in a Pilot Retrofit Application}, journal = {Energy and Buildings}, volume = {47}, year = {2012}, month = {04/2012}, pages = {267-284}, chapter = {267}, abstract = {

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\%.

}, keywords = {buildings energy efficiency, control systems, daylighting, Electrochromic windows, Integrated systems, Intelligent buildings}, doi = {10.1016/j.enbuild.2011.12.003}, author = {Eleanor S. Lee and Erin S. Claybaugh and Marc LaFrance} } @techreport {58289, title = {Integrated control of operable fenestration systems and thermally massive HVAC systems: Methods and simulation studies of energy savings potential}, year = {2012}, month = {10/2012}, type = {DOE/ CEC PIER Technical Report}, abstract = {

The future design of high performance buildings is expected to involve more active facade technologies, acting in intelligent collaboration with the HVAC and lighting systems to produce comfortable indoor environments with reduced energy consumption. Integrated control of active facade systems and HVAC is challenging, particularly with thermally-massive HVAC systems such as radiant floors and ceilings. This paper describes methods for devising near-optimal controllers for such integrated systems, allowing for any arbitrary level of complexity in the facade system. An offline-optimization approximation to model predictive control is used with a model consisting of a reduced- order approximation of the zone and HVAC thermal properties and an interpolation grid of the daylight and solar gains attributes of the facade in its various possible states. The optimization over the 24-hour prediction horizon is split into two levels, with GenOpt used at the top level to deal with the complexity of the facade, alongside a linear programming solution to the chilled slab control. The model can be calibrated to match monitored data, or some combination of whole-building energy modeling and Radiance outputs. To test the methods and to estimate energy savings potential, case studies were performed with a calibrated model based on an EnergyPlus ASHRAE 90.1-2010 office building, modi ed to use radiant slabs and operable Venetian blinds (either internal or external) or electochromic glazing. Results are shown for four US climates. Further research is discussed.

}, author = {Brian E. Coffey} } @article {58922, title = {The {\textquoteleft}recycling trap{\textquoteright}: a generalized explanation of discharge runaway in high-power impulse magnetron sputtering}, journal = {Journal of Physics D: Applied Physics}, volume = {45}, year = {2012}, month = {01/2012}, pages = {012003}, abstract = {

Contrary 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.

}, issn = {0022-3727}, doi = {10.1088/0022-3727/45/1/012003}, author = {Andr{\'e} Anders and Ji{\v r}{\'\i} {\v C}apek and Mat{\^e}j H{\'a}la and Ludvik Martinu} } @techreport {58299, title = {Model-based controls for integrated shading and UFAD control: Report on initial studies}, year = {2011}, month = {10/2011}, type = {DOE/ CEC PIER Technical Report}, abstract = {

Methods and initial results are described for model-based controls with offline optimization for integrated shading and UFAD control for an office building in New York. Two cases are studied through lookup-table calculation and annual simulation of the resulting controllers: one case with interior blinds, the other case with exterior blinds. The interior blind case was found to reduce HVAC energy by 5\% over a simple baseline control, and the exterior blind case produced a 5.6\% HVAC energy savings over the baseline. Further investigations and case studies are planned.

}, keywords = {cloud computing, integrated controls, Model predictive control (MPC), offline optimization, shading and HVAC controls}, author = {Brian E. Coffey and Eleanor S. Lee} } @techreport {58281, title = {Modeling solar heat gains of complex fenestration systems using bidirectional scattering distribution functions}, year = {2011}, month = {09/2011}, type = {DOE/ CEC PIER Technical Report}, author = {Thierry Stephane Nouidui and Andrew McNeil and Christian Kohler and Brian E. Coffey and Eleanor S. Lee} } @article {12172, title = {Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems}, journal = {Building and Environment}, volume = {46}, year = {2011}, month = {03/2011}, pages = {747-757}, chapter = {747}, abstract = {

Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90\% of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems as a single system.

}, keywords = {automated roller shade systems, daylight responsive dimming systems, daylighting, Integrated systems, photoelectric controls}, doi = {10.1016/j.buildenv.2010.10.007}, author = {Byoung-Chul Park and An-Seop Choi and Jae-Weon Jeong and Eleanor S. Lee} } @article {1957, title = {Visual Comfort Analysis of Innovative Interior and Exterior Shading Systems for Commercial Buildings using High Resolution Luminance Images}, journal = {LEUKOS The Journal of the Illuminating Engineering Society of North America}, volume = {7}, year = {2011}, month = {1/2011}, abstract = {

The objective of this study was to explore how calibrated high dynamic range (HDR) images (luminance maps) acquired in real world daylit environments can be used to characterize, evaluate, and compare visual comfort conditions of innovative facade shading and light-redirecting systems. Detailed (1536 x 1536 pixel) luminance maps were time-lapse acquired from two view positions in an unoccupied full scale testbed facility. These maps were analyzed using existing visual comfort metrics to quantify how innovative interior and exterior shading systems compare to conventional systems under real sun and sky conditions over a solstice-to-solstice test interval. The results provide a case study in the challenges and potential of methods of visualizing, evaluating and summarizing daily and seasonal variation of visual comfort conditions computed from large sets of image data.

}, doi = {10.1582/LEUKOS.2011.07.03003}, author = {Kyle S. Konis and Eleanor S. Lee and Robert D. Clear} } @techreport {58235, title = {Post-Occupancy Evaluation of The New York Times Headquarters Building: an Examination of Causes for Occupant Satisfaction and Dissatisfaction with the Energy-Efficiency Measures}, year = {2010}, month = {10/2010}, type = {DOE/LBNL Technical report}, address = {Berkeley}, abstract = {

A post-occupancy evaluation (POE) survey was issued by The New York Times (NYT) to their employees with the assistance of Sustainable Energy Partnerships (SEP). SEP conducted a detailed analysis of the survey data (September 29, 2010 draft) and found that a significant fraction of the building occupants were satisfied to very satisfied with the overall building. Compared to other buildings, the overall level of satisfaction was greater than the norm of surveyed buildings.

This additional analysis was conducted to identify potential causes of the occupants{\textquoteright} satisfaction or dissatisfaction with the innovative lighting, shading, and space- conditioning systems themselves and/or the resultant indoor environment produced by these systems. The analysis used various methods to identify statistically significant factors, where the factors were those given in the survey questionnaire. Additional factors or causes of satisfaction and dissatisfaction were identified through analysis of the detailed comments: this was done for the questions related to the lighting section of the survey.

}, author = {Robert D. Clear} } @article {58228, title = {Field Measurements of Innovative Indoor Shading Systems in a Full-Scale Office Testbed}, journal = {ASHRAE Transactions}, volume = {115}, year = {2009}, month = {10/2009}, pages = {706-728}, chapter = {706}, abstract = {

The development of spectrally selective low-e glass with its superior solar control and high daylight admission has led to widespread use of large-area, "transparent" or visually clear glass windows in commercial building facades. This type of fa{\c c}ade can provide significant inherent daylighting potential (ability to offset lighting energy use) and move us closer to the goal of achieving zero energy buildings, if not for the unmitigated glare that results from the unshaded glazing. Conventional shading systems result in a significant loss of daylight and view. Can innovative shading solutions successfully balance the tradeoffs between daylight, solar heat gains, discomfort glare, and view?

To investigate this issue, a six-month solstice-to-solstice field study was conducted in a sunny climate to measure the thermal and daylighting performance of a south-facing, full- scale, office testbed with large-area windows and a variety of innovative indoor shading systems. Indoor shading systems included manually-operated and automated roller shades, Venetian blinds, daylight-redirecting blinds, and a static translucent diffusing panel placed inboard of the window glazing. These innovative systems were compared to a reference shade lowered to block direct sun.

With continuous dimming controls, all shading systems yielded lighting energy savings between 43-69\% compared to a non-dimming case, but only the automated systems were able to meet visual comfort criteria throughout the entire monitored period. Cooling loads due to solar and thermal loads from the window were increased by 2-10\% while peak cooling loads were decreased by up to 14\%. The results from this experiment illustrate that some indoor shading systems can preserve daylight potential while meeting comfort requirements. Trends will differ significantly depending on application.

}, author = {Eleanor S. Lee and Dennis L. DiBartolomeo and Joseph H. Klems and Robert D. Clear and Kyle S. Konis and Mehry Yazdanian and Byoung-Chul Park} } @techreport {1458, title = {High Performance Building Facade Solutions: PIER Final Project Report}, year = {2009}, month = {12/2009}, abstract = {

Building fa{\c c}ades 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. fa{\c c}ades 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, fa{\c c}ade 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 fa{\c c}ades industry to develop, evaluate, and accelerate market deployment of emerging, high-performance, integrated fa{\c c}ade 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 fa{\c c}ade-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 fa{\c c}ade 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 fa{\c c}ade 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.

}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Dennis L. DiBartolomeo and Joseph H. Klems and Robert D. Clear and Kyle S. Konis and Robert J. Hitchcock and Mehry Yazdanian and Robin Mitchell and Maria Konstantoglou} } @article {58915, title = {Innovative Fa{\c c}ade Systems for Low-energy Commercial Buildings}, year = {2009}, month = {11/2009}, publisher = {Lawrence Berkeley National Laboratory}, address = {Berkeley}, abstract = {

Glazing and fa{\c c}ade systems have very large impacts on all aspects of commercial building performance. They directly influence peak heating and cooling loads, and indirectly influence lighting loads when daylighting is considered. In addition to being a major determinant of annual energy use, they can have significant impacts on peak cooling system sizing, electric load shape, and peak electric demand. Because they are prominent architectural and design elements and because they influence occupant preference, satisfaction and comfort, the design optimization challenge is more complex than with many other building systems.

Fa{\c c}ade designs that deliberately recognize the fundamental synergistic relationships between the fa{\c c}ade, lighting, and mechanical systems have the potential to deliver high performance over the life of the building. These "integrated" fa{\c c}ade systems represent a key opportunity for commercial buildings to significantly reduce energy and demand, helping to move us toward our goal of net zero energy buildings by 2030.

Provision of information {\textemdash} technology concepts, measured data, case study information, simulation tools, etc. {\textemdash} can enable architects and engineers to define integrated fa{\c c}ade solutions and draw from a wide variety of innovative technologies to achieve ambitious energy efficiency goals.

This research is directed toward providing such information and is the result of an on-going collaborative research and development (R\&D) program, supported by the U.S. Department of Energy and the California Energy Commission Public Interest Energy Research (PIER) program.

}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Dennis L. DiBartolomeo and Joseph H. Klems and Robert D. Clear and Kyle S. Konis and Maria Konstantoglou and Mark Perepelitza} } @article {11733, title = {Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools}, journal = {Journal of Building Physics}, volume = {32}, number = {2}, year = {2008}, pages = {131-153}, abstract = {

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. Based on a literature review and an evaluation of current methods of modeling heat transfer through window frames, we conclude that current procedures specified in ISO standards are not sufficiently adequate for accurately evaluating heat transfer through the low-conductance frames.

We conclude that the near-term priorities for improving the modeling of heat transfer through low-conductance frames are:

  1. Add 2-D view-factor radiation to standard modeling and examine the current practice of averaging surface emissivity based on area weighting and the process of making an equivalent rectangular frame cavity.
  2. Assess 3-D radiation effects in frame cavities and develop recommendation for inclusion into the design fenestration tools.
  3. Assess existing correlations for convection in vertical cavities using CFD.
  4. Study 2-D and 3-D natural convection heat transfer in frame cavities for cavities that are proven to be deficient from item 3 above. Recommend improved correlations or full CFD modeling into ISO standards and design fenestration tools, if appropriate.
  5. Study 3 D hardware short-circuits and propose methods to ensure that these effects are incorporated into ratings.
  6. Study the heat transfer effects of ventilated frame cavities and propose updated correlations.
}, author = {Arlid Gustavsen and Dariush K. Arasteh and Bj{\o}rn Petter Jelle and Dragan C. Curcija and Christian Kohler} } @techreport {1972, title = {WINDOW 6.2/THERM 6.2 Research Version User Manual}, year = {2008}, month = {01/2008}, pages = {1-126}, institution = {Lawrence Berkeley National Laboratory}, address = {Berkeley}, abstract = {

WINDOW 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{\textquoteright}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.

}, author = {Robin Mitchell and Christian Kohler and Joseph H. Klems and Michael D. Rubin and Dariush K. Arasteh and Charlie Huizenga and Tiefeng Yu and Dragan C. Curcija} } @techreport {58305, title = {Commissioning and verification procedures for the automated roller shade system at The New York Times Headquarters}, year = {2007}, month = {05/2007}, address = {Berkeley}, abstract = {

This document describes the procedures for verification testing of a newly installed automated roller shade system. The automated roller shade system has been designed to control direct sun and window glare while admitting daylight and permitting view out. Procedures in this document focus on verifying that the glare control aspect of this commercially-available system works prior to building occupancy. A high dynamic range luminance measurement tool, developed for this project, is used to verify that the average window luminance is within acceptable limits. Additional spreadsheet and visualization tools are described. The commissioning agent (CxA) and The New York Times will use these procedures during the commissioning phase of the building to verify that the automated control system is operating as intended.

}, author = {Eleanor S. Lee and Robert D. Clear and Gregory J. Ward and Luis L. Fernandes} } @techreport {58303, title = {Daylighting the New York Times Headquarters Building: Final Report: Commissioning Daylighting Systems and Estimation of Demand Response}, year = {2007}, month = {08/2007}, address = {Berkeley}, abstract = {

The technical energy-savings potential for smart integrated window-daylighting systems is excellent and can yield significant reductions in US commercial building energy use if adopted by a significant percentage of the market. However, conventional automated shades and daylighting controls have been commercially available for over two decades with less than 1-2\% market penetration in the US. As with many innovations, the problem with accelerating market adoption is one of demonstrating real performance and decreasing risk and cost. The New York Times considered use of such daylighting systems for their new 139,426 m2 (1.5 Mft2) headquarters building in downtown Manhattan.

In the initial phase of work, The New York Times employed a unique approach to create a competitive marketplace for daylighting systems and to address their concerns about risk by building a full-scale daylighting mockup and evaluating commercially-available products. This field test formed the strategic cornerstone for accelerating an industry response to the building owners{\textquoteright} challenge to a sleepy market. A procurement specification was produced and bids were received that met The Times cost-effective criteria. The Times decided to proceed with using these innovative systems in their new building.

This next phase of work consisted of two distinct tasks: 1) to develop and use commissioning tools and procedures to insure that the automated shade and daylighting control systems operate as intended prior to occupancy; and 2) to estimate the peak demand savings resulting from different levels of demand response (DR) control strategies (from moderate to severe load curtailment) and then determine the financial implications given various DR programs offered by the local utility and New York Independent System Operator in the area.

Commissioning daylighting control systems is mandatory to insure that design intent is met, that the systems are tuned to optimal performance, and to eliminate problems and errors before occupants move in. Commissioning tools were developed and procedures were defined and then used to verify that the daylighting systems operated according to the technical specifications. For both lighting control and shading systems, the Times and the manufacturers were able to resolve most of the bugs and fine-tune the systems prior to occupancy.

The demand response (DR) strategies at the New York Times building involve unique state-of-the-art systems with dimmable ballasts, movable shades on the glass facade, and underfloor air HVAC. The process to develop the demand response strategies, the results of the EnergyPlus model, the activities to implement the DR strategies in the controls design at the New York Times Headquarters building and the evaluation of economics of participating in DR programs are presented and discussed. The DR simulation iv efforts for this building design are novel, with an innovative building owner evaluating DR and future DR program participation strategies during the design and construction phase using advanced simulation tools.

}, keywords = {automated daylighting controls, automated window shades, daylighting, demand response, energy-efficiency, visual comfort}, author = {Eleanor S. Lee and Glenn D. Hughes and Robert D. Clear and Luis L. Fernandes and Sila Kiliccote and Mary Ann Piette and Francis M. Rubinstein and Stephen E. Selkowitz} } @techreport {58306, title = {Quick Start Guide: Commissioning and verification procedures for the automated roller shade system at The New York Times Headquarters}, year = {2007}, month = {05/2007}, address = {Berkeley}, abstract = {

This quick start guide summarizes the steps required to verify the performance of a newly installed automated roller shade system. The automated roller shade system at The New York Times Headquarters has been designed to control direct sun and window glare while admitting daylight and permitting view out. Procedures in this guide focus on verifying that the glare control aspect of this commerciallyavailable system works prior to building occupancy. A high dynamic range luminance measurement tool, developed for this project, is used to verify that the average window luminance is within acceptable limits. The commissioning agent (CxA) and The New York Times will use these procedures during the commissioning phase of the building to verify that the automated control system is operating as intended.

}, author = {Eleanor S. Lee and Robert D. Clear and Gregory J. Ward and Luis L. Fernandes} } @techreport {1077, title = {Advancement of Electrochromic Windows}, year = {2006}, month = {04/2006}, abstract = {

This guide provides consumer-oriented information about switchable electrochromic (EC) windows. Electrochromic windows change tint with a small applied voltage, providing building owners and occupants with the option to have clear or tinted windows at any time, irrespective of whether it{\textquoteright}s sunny or cloudy. EC windows can be manually or automatically controlled based on daylight, solar heat gain, glare, view, energy-efficiency, peak electricity demand response, or other criteria. Window controls can be integrated with other building systems, such as lighting and heating/cooling mechanical systems, to optimize interior environmental conditions, occupant comfort, and energy-efficiency.

}, keywords = {commercial buildings, daylight, daylighting controls, Electrochromic windows, energy efficiency, human factors, peak demand, switchable windows, visual comfort}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Robert D. Clear and Dennis L. DiBartolomeo and Joseph H. Klems and Luis L. Fernandes and Gregory J. Ward and Vorapat Inkarojrit and Mehry Yazdanian} } @techreport {1264, title = {A Design Guide for Early-Market Electrochromic Windows}, year = {2006}, abstract = {

Switchable variable-tint electrochromic windows preserve the view out while modulating transmitted light, glare, and solar heat gains and can reduce energy use and peak demand. To provide designers objective information on the risks and benefits of this technology, this study offers data from simulations, laboratory tests, and a 2.5-year field test of prototype large-area electrochromic windows evaluated under outdoor sun and sky conditions. The study characterized the prototypes in terms of transmittance range, coloring uniformity, switching speed, and control accuracy. It also integrated the windows with a daylighting control system and then used sensors and algorithms to balance energy efficiency and visual comfort, demonstrating the importance of intelligent design and control strategies to provide the best performance. Compared to an efficient low-e window with the same daylighting control system, the electrochromic window showed annual peak cooling load reductions from control of solar heat gains of 19-26\% and lighting energy use savings of 48-67\% when controlled for visual comfort. Subjects strongly preferred the electrochromic window over the reference window, with preferences related to perceived reductions in glare, reflections on the computer monitor, and window luminance. The EC windows provide provided the benefit of greater access to view year-round. Though not definitive, findings can be of great value to building professionals.

}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Robert D. Clear and Dennis L. DiBartolomeo and Joseph H. Klems and Luis L. Fernandes and Gregory J. Ward and Vorapat Inkarojrit and Mehry Yazdanian} } @conference {11848, title = {Evaluating Fenestration Products for Zero-Energy Buildings: Issues for Discussion}, booktitle = {SimBuild 2006: Building Sustainability and Performance Through Simulation}, year = {2006}, month = {08/2006}, address = {Cambridge, MA}, abstract = {

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?

}, author = {Dariush K. Arasteh and Dragan C. Curcija and Yu Joe Huang and Charlie Huizenga and Christian Kohler} } @techreport {58258, title = {Experimental Validation of Daylighting Simulation Methods for Complex Fenestration Systems}, year = {2006}, month = {05/2006}, abstract = {

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{\textquoteright} 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.

}, author = {Fawaz Maamari and Marilyn Andersen and Jan de Boer and William L. Carroll and Dominique Dumortier and Phillip Greenup} } @article {1861, title = {Subject Response to Electrochromic Windows}, journal = {Energy and Buildings}, volume = {38}, number = {7}, year = {2006}, month = {07/2006}, pages = {758-779}, chapter = {758}, abstract = {

Forty-three subjects worked in a private office with switchable electrochromic windows, manually-operated Venetian blinds, and dimmable fluorescent lights. The electrochromic window had a visible transmittance range of approximately 3-60\%. Analysis of subject responses and physical data collected during the work sessions showed that the electrochromic windows reduced the incidence of glare compared to working under a fixed transmittance (60\%) condition. Subjects used the Venetian blinds less often and preferred the variable transmittance condition, but used slightly more electric lighting with it than they did when window transmittance was fixed.

}, keywords = {Electrochromic windows, energy use, Subjective response, Venetian blind use}, doi = {10.1016/j.enbuild.2006.03.011}, author = {Robert D. Clear and Vorapat Inkarojrit and Eleanor S. Lee} } @techreport {58563, title = {Summary results of visual comfort measurements at the electrochromic windows testbed}, year = {2006}, note = {

Included as an attachment to the Advancement of Electrochromic Windows final report.

}, month = {03/2006}, address = {Berkeley}, abstract = {

The study was performed at the Lawrence Berkeley National Laboratory (LBNL) windows testbed in Berkeley California. The location is 37.4{\textdegree}N latitude. The maximum solar altitude ranges from approximately 29{\textdegree} to 76{\textdegree}, with a yearly average of about 53{\textdegree}. The testbed rooms have their windows mounted due south. The azimuthal angle at sunrise varies from approximately 60{\textdegree} from due south in the winter to 120{\textdegree} in summer. The analysis was restricted to the period from 6:00-18:00 standard time. Sunrise ranges from 4:42 to 7:17 (solar time), so the sun was not visible during part of the winter study periods.

}, author = {Robert D. Clear} } @techreport {58284, title = {Daylighting the New York Times Headquarters Building: Final Report}, year = {2005}, month = {06/2005}, abstract = {

The technical energy-savings potential for smart integrated window-daylighting systems is excellent and can yield significant reductions in US commercial building energy use if adopted by a significant percentage of the market. However, conventional automated shades and daylighting controls have been commercially available for over two decades with less than 1-2\% market penetration in the US. As with 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{\textquoteright} 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.

}, keywords = {automated daylighting controls, automated window shades, daylighting, energy-efficiency, visual comfort}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Glenn D. Hughes and Robert D. Clear and Gregory J. Ward and John Mardaljevic and Judy Lai and Mehlika Inanici and Vorapat Inkarojrit} } @conference {11697, title = {DElight2 Daylighting Analysis in Energy Plus: Integration and Preliminary User Results}, booktitle = {Building Simulation 2005}, year = {2005}, month = {08/2005}, address = {Montreal, Canada}, abstract = {

DElight is a simulation engine for daylight and electric lighting system analysis in buildings. DElight calculates interior illuminance levels from daylight, and the subsequent contribution required from electric lighting to meet a desired interior illuminance. DElight has been specifically designed to integrate with building thermal simulation tools. This paper updates the DElight capability set, the status of integration into the simulation tool EnergyPlus, and describes a sample analysis of a simple model from the user perspective.

}, author = {William L. Carroll and Robert J. Hitchcock} } @conference {1934, title = {Two-Dimension Conduction and CFD Simulations for Heat Transfer in Horizontal Window Frame Cavities}, booktitle = {2005 ASHRAE Winter Meeting}, volume = {111}, year = {2005}, month = {02/2005}, address = {Orlando, FL}, abstract = {

Accurately analyzing heat transfer in window frames and glazings is important for developing and characterizing the performance of highly insulating window products. This paper uses computational fluid dynamics (CFD) modeling to assess the accuracy of the simplified frame cavity conduction/convection models presented in ISO 15099 and used in software for rating and labeling window products. Three representative complex cavity cross-section profiles with varying dimensions and aspect ratios are examined. The results presented support the ISO 15099 rule that complex cavities with small throats should be subdivided; however, our data suggest that cavities with throats smaller than 7 mm should be subdivided, in contrast to the ISO 15099 rule, which places the break point at 5 mm. The agreement between CFD modeling results and the results of the simplified models is moderate for the heat transfer rates through the cavities. The differences may be a result of the underlying ISO 15099 Nusselt number correlations being based on studies where cavity height/length aspect ratios were smaller than 0.5 and greater than 5 (with linear interpolation assumed in between). The results presented here are for horizontal frame members because convection in vertical jambs involves very different aspect ratios that require three-dimensional CFD simulations.

}, author = {Arlid Gustavsen and Dariush K. Arasteh and Christian Kohler and Dragan C. Curcija} } @conference {11745, title = {Development of Trade-Off Equations for EnergyStar Windows}, booktitle = {SimBuild 2004}, year = {2004}, month = {08/2004}, address = {Boulder, CO}, abstract = {

The authors explore the feasibility of adding a performance option to DOE{\textquoteright}s EnergyStar{\textcopyright} 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{\textcopyright} 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.

}, author = {Yu Joe Huang and Robin Mitchell and Stephen E. Selkowitz and Dariush K. Arasteh and Robert D. Clear} } @book {58586, title = {Window Systems for High-Performance Buildings}, year = {2004}, month = {04/2004}, pages = {400}, publisher = {W. W. Norton \& Company, Inc.,}, organization = {W. W. Norton \& Company, Inc.,}, address = {New York, NY}, abstract = {

A guide to essential window design issues, technologies, and applications for designers, specifiers, and builders.

The challenge in designing facades and selecting windows in commercial buildings is balancing many issues and criteria. This fact-packed guide outlines the basics of glazing selection and provides critical information and performance data on the energy efficiency, interior environment, technical, and life-cycle-cost considerations that drive window design decisions in commercial buildings.

}, isbn = {978-0-393-73121-7}, issn = {0198711956}, author = {John Carmody and Stephen E. Selkowitz and Eleanor S. Lee and Dariush K. Arasteh} } @techreport {1894, title = {THERM 5/WINDOW 5 NFRC Simulation Manual}, year = {2003}, abstract = {

This 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.

}, author = {Robin Mitchell and Christian Kohler and Dariush K. Arasteh and John Carmody and Charlie Huizenga and Dragan C. Curcija} } @conference {1936, title = {Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer in Window Frames with Internal Cavities - Part 1: Cavities Only}, booktitle = {ASHRAE Winter Meeting}, year = {2003}, month = {02/2005}, address = {Orlando, FL}, abstract = {

Accurately analyzing heat transfer in window frame cavities is essential for developing and characterizing the performance of highly insulating window products. Window frame thermal performance strongly influences overall product thermal performance because framing materials generally perform much more poorly than glazing materials. This paper uses Computational Fluid Dynamics (CFD) modeling to assess the accuracy of the simplified frame cavity conduction/convection models presented in ISO 15099 and used in software for rating and labeling window products. (We do not address radiation heat-transfer effects.) We examine three representative complex cavity cross-section profiles with varying dimensions and aspect ratios. Our results support the ISO 15099 rule that complex cavities with small throats should be subdivided; however, our data suggest that cavities with throats smaller than seven millimeters (mm) should be subdivided, in contrast to the ISO 15099 rule, which places the break point at five mm. The agreement between CFD modeling results and the results of the simplified models is moderate. The differences in results may be a result of the underlying ISO correlations being based on studies where cavity height/length (H/L) aspect ratios were smaller than 0.5 and greater than five (with linear interpolation assumed in between). The results presented here are for horizontal frame members because convection in vertical jambs involves very different aspect ratios that require three-dimensional CFD simulations. Ongoing work focuses on quantifying the exact effect on window thermal performance indicators of using the ISO 15099 approximations in typical real window frames.

}, author = {Arlid Gustavsen and Christian Kohler and Dariush K. Arasteh and Dragan C. Curcija} } @book {11676, title = {Daylight in Buildings. A Source Book on Daylighting Systems and Components}, year = {2001}, note = {

Download: Daylight in Buildings
A hard copy of the book may be obtained by sending a request to Ellen Thomas at\ EllenThomas@lbl.gov.\ Only one copy per individual, U.S. or Canadians only.\  If you reside elsewhere, go to\ http://task21.iea-shc.org/to find out how to obtain a copy in your country.\ 

}, url = {https://facades.lbl.gov/daylight-buildings-source-book-daylighting-systems}, author = {Nancy Ruck and {\O}yvind Aschehoug and Sirri Aydinli and Jens Christoffersen and Gilles Courret and Ian Edmonds and Roman Jakobiak and Martin Kischkoweit-Lopin and Martin Klinger and Eleanor S. Lee and Laurent Michel and Jean-Louis Scartezzini and Stephen E. Selkowitz} } @conference {11950, title = {Improving Information Technology to Maximize Fenestration Energy Efficiency}, booktitle = {Performance of Exterior Envelopes of Whole Buildings VIII}, year = {2001}, month = {12/2001}, address = {Clearwater Beach, FL}, abstract = {

Annual 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.

}, author = {Dariush K. Arasteh and Robin Mitchell and Christian Kohler and Charlie Huizenga and Dragan C. Curcija} } @techreport {1527, title = {The Integrated Energy-Efficiency Window-Wall System}, year = {2001}, author = {Michael Arney and James Fairman and John Carmody and Dariush K. Arasteh} } @techreport {1971, title = {WINDOW 5.0 User Manual for Analyzing Window Thermal Performance}, year = {2001}, author = {Robin Mitchell and Christian Kohler and Dariush K. Arasteh and Charlie Huizenga and Dragan C. Curcija} } @techreport {1892, title = {THERM 2.1 NFRC Simulation Manual}, year = {2000}, month = {07/2000}, pages = {260}, abstract = {

This document, the THERM 2.1 NFRC Simulation Manual, discusses how to use THERM to model products for NFRC certified simulations and assumes that the user is already familiar with the THERM program. In order to learn how to use THERM, it is necessary to become familiar with the material in the THERM User{\textquoteright}s Manual.

In general, this manual references the THERM User{\textquoteright}s Manual rather than repeating the information.

If there is a conflict between the THERM User{\textquoteright}s Manual and the THERM 2.1 NFRC Simulation Manual, the THERM 2.1 NFRC Simulation Manual takes precedence.

}, author = {Robin Mitchell and Christian Kohler and Dariush K. Arasteh and Elizabeth U. Finlayson and Charlie Huizenga and Dragan C. Curcija and John Carmody} } @conference {11671, title = {A Database of Window Annual Energy Use in Typical North American Residences}, booktitle = {2000 ASHRAE Winter Meeting}, year = {1999}, month = {02/2000}, address = {Dallas, Texas}, abstract = {

This 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.

}, author = {Dariush K. Arasteh and Yu Joe Huang and Robin Mitchell and Robert D. Clear and Christian Kohler} } @techreport {1235, title = {Daylighting Simulation: Methods, Algorithms, and Resources}, year = {1999}, abstract = {

The search for and collection of daylighting analysis methods and algorithms led to two important observations. First, there is a wide range of needs for different types of methods to produce a complete analysis tool. These include:

Second, very advantageously, there have been rapid advances in many basic methods in these areas, due to other forces. They are in part driven by:

This has led to a very rich set of information resources that have direct applicability to the small daylighting analysis community. Furthermore, much of this information is in fact available online.

}, author = {William L. Carroll} } @article {1828, title = {Solid State Gadolinium-Magnesium Hydride Optical Switch}, journal = {Applied Physics Letters}, volume = {75}, number = {13}, year = {1999}, month = {09/1999}, pages = {1863-1865}, chapter = {1863}, abstract = {

The optical switching properties of gadolinium-magnesium hydride have been demonstrated in a solid-state electrochromic device. With positive polarization of the hydride electrode, the visible reflectance approaches 35\% with virtually zero transmission, while with negative polarization, the visible transmission exceeds 25\% at 650 nm. The switching is reversible, with intermediate optical properties between the transparent and reflecting states.

}, url = {http://dx.doi.org/10.1063/1.124853}, author = {Robert D. Armitage and Michael D. Rubin and Thomas J. Richardson and Nada O{\textquoteright}Brien and Yong Chen} } @conference {1890, title = {THERM 2.0: A Building Component Model for Steady-State Two-Dimensional Heat Transfer}, booktitle = {Building Simulation 99, International Building Performance Simulation Association (IBPSA)}, year = {1999}, month = {09/1999}, address = {Kyoto, Japan}, abstract = {

THERM 2.0 is a state-of-the-art software program, available without cost, that uses the finite-element method to model steady-state, two-dimensional heat-transfer problems. It includes a powerful simulation engine combined with a simple, interactive interface and graphic results. Although it was developed primarily to model thermal properties of windows, it is appropriate for other building components such as walls, doors, roofs, and foundations, and is useful for modeling thermal bridges in many other contexts, such as the design of equipment.

}, author = {Charlie Huizenga and Dariush K. Arasteh and Elizabeth U. Finlayson and Robin Mitchell and Brent T. Griffith and Dragan C. Curcija} } @article {1675, title = {Office Worker Response to an Automated Venetian Blind and Electric Lighting System: A Pilot Study}, journal = {Energy and Buildings}, volume = {28}, year = {1998}, month = {10/1998}, pages = {205-218}, chapter = {205}, abstract = {

A prototype integrated, dynamic building envelope and lighting system designed to optimize daylight admission and solar heat gain rejection on a real-time basis in a commercial office building is evaluated. Office worker response to the system and occupant-based modifications to the control system are investigated to determine if the design and operation of the prototype system can be improved. Key findings from the study are: (1) the prototype integrated envelope and lighting system is ready for field testing, (2) most office workers (N=14) were satisfied with the system, and (3) there were few complaints. Additional studies are needed to explain how illuminance distribution, lighting quality, and room design can affect workplane illuminance preferences.

}, keywords = {behavior, Comfort, commercial buildings, daylighting, envelope}, doi = {10.1016/S0378-7788(98)00023-1}, author = {Edward L. Vine and Eleanor S. Lee and Robert D. Clear and Dennis L. DiBartolomeo and Stephen E. Selkowitz} } @techreport {1891, title = {THERM 2.0: a PC Program for Analyzing Two-Dimensional Heat Transfer through Building products}, year = {1998}, abstract = {

THERM is a state-of-the-art, Microsoft Windows?-based computer program developed at Lawrence Berkeley National Laboratory (LBNL) for use by building component manufacturers, engineers, educators, students, architects, and others interested in heat transfer. Using THERM, you can model two-dimensional heat-transfer effects in building components such as windows, walls, foundations, roofs, and doors; appliances; and other products where thermal bridges are of concern. THERM{\textquoteright}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.

}, author = {Elizabeth U. Finlayson and Robin Mitchell and Dariush K. Arasteh and Charlie Huizenga and Dragan C. Curcija} } @article {2882, title = {Building Design Advisor: Automated Integration of Multiple Simulation Tools}, journal = {Automation in Construction}, volume = {6}, number = {4}, year = {1997}, month = {08/1997}, pages = {341-352}, publisher = {Elsevier}, chapter = {341}, abstract = {

The Building Design Advisor (BDA) is a software environment that supports the integrated use of multiple analysis and visualization tools throughout the building design process, from the initial, conceptual and schematic phases to the detailed specification of building components and systems. Based on a comprehensive design theory, the BDA uses an object-oriented representation of the building and its context, and acts as a data manager and process controller to allow building designers to benefit from the capabilities of multiple tools.

The BDA provides a graphical user interface that consists of two main elements: the Building Browser and the Decision Desktop. The Browser allows building designers to quickly navigate through the multitude of descriptive and performance parameters addressed by the analysis and visualization tools linked to the BDA. Through the Browser the user can edit the values of input parameters and select any number of input and/or output parameters for display in the Decision Desktop. The Desktop allows building designers to compare multiple design alternatives with respect to multiple descriptive and performance parameters addressed by the tools linked to the BDA.

The BDA is implemented as a Windows{\textregistered}-based application for personal computers. Its initial version is linked to a Schematic Graphic Editor (SGE), which allows designers to quickly and easily specify the geometric characteristics of building components and systems. For every object created in the SGE, the BDA activates a Default Value Selector (DVS) mechanism that selects "smart" default values from a Prototypes Database for all non-geometric parameters required as input to the analysis and visualization tools linked to the BDA. In addition to the SGE that is an integral part of its user interface, the initial version of the BDA is linked to a daylight analysis tool, an energy analysis tool, and a multimedia, Web-based Case Studies Database (CSD). The next version of the BDA will be linked to additional analysis tools, such as the DOE-2 (thermal, energy and energy cost) and RADIANCE (day/lighting and rendering) computer programs. Plans for the future include the development of links to cost estimating and environmental impact modules, building rating systems, CAD software and electronic product catalogs.

}, doi = {10.1016/S0926-5805(97)00043-5}, author = {Konstantinos M. Papamichael and John LaPorta and Hannah L. Chauvet} } @article {11906, title = {Guidelines for Modeling Projecting Fenestration Products}, journal = {ASHRAE Transactions}, volume = {104, Part 1}, year = {1997}, month = {01/1998}, address = {San Francisco, CA}, abstract = {

Heat transfer patterns in projecting fenestration products (greenhouse windows, skylights, etc.) are different than those with typical planar window products. The projecting surfaces often radiate to each other, thereby invalidating the commonly used assumption that fenestration product interior surfaces radiate to a uniform room air temperature. The convective portion of the surface heat transfer coefficient is also significantly different from the one used with planar geometries, and is even more dependent on geometry and location. Projecting fenestration product profiles must therefore be modeled in their entirety. This paper presents the results of complete cross section, variable film-coefficient, 2-D heat transfer modeling of two greenhouse windows using the next generation of window specific heat transfer modeling tools. The use of variable film-coefficient models is shown to increase the accuracy with which simulation tools can compute U-factors. Simulated U-factors are also determined using conventional constant film coefficient algorithms. The results from both sets of simulations are compared with measured values.

}, author = {Dariush K. Arasteh and Elizabeth U. Finlayson and Dragan C. Curcija and Jeff Baker and Charlie Huizenga} } @article {11949, title = {Improving Computer Simulations of Heat Transfer for Projecting Fenestration products: Using Radiation View-Factor Models}, journal = {ASHRAE Transactions}, volume = {104, Part 1}, number = {Part 1}, year = {1997}, abstract = {

The window well formed by the concave surface on the warm side of skylights and garden windows can cause surface heat-flow rates to be different for these projecting types of fenestration products than for normal planar windows. Current methods of simulating fenestration thermal conductance (U-value) use constant boundary condition values for overall surface heat transfer. Simulations that account for local variations in surface heat transfer rates (radiation and convection) may be more accurate for rating and labeling window products whose surfaces project outside a building envelope. This paper, which presents simulation and experimental results for one projecting geometry, is the first step in documenting the importance of these local effects.

A generic specimen, called the foam garden window, was used in simulations and experiments to investigate heat transfer of projecting surfaces. Experiments focused on a vertical cross section (measurement plane) located at the middle of the window well on the warm side of the specimen. The specimen was placed between laboratory thermal chambers that were operated at American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) winter heating design conditions. Infrared thermography was used to map surface temperatures. Air temperature and velocity were mapped throughout the measurement plane using a mechanical traversing system. Finite-element computer simulations that directly modeled element-to-element radiation were better able to match experimental data than simulations that used fixed coefficients for total surface heat transfer. Air conditions observed in the window well suggest that localized convective effects were the reason for the difference between actual and modeled surface temperatures. U-value simulation results were 5 to 10\% lower when radiation was modeled directly.

}, author = {Brent T. Griffith and Dragan C. Curcija and Daniel Turler and Dariush K. Arasteh} } @conference {2884, title = {The Building Design Advisor}, booktitle = {ACADIA 1996 Conference}, year = {1996}, month = {03/1996}, address = {Tucson, AZ}, abstract = {

The Building Design Advisor (BDA) is a software environment that supports the integrated use of multiple analysis and visualization tools throughout the building design process, from the initial, schematic design phases to the detailed specification of building components and systems. Based on a comprehensive design theory, the BDA uses an object-oriented representation of the building and its context, and acts as a data manager and process controller to allow building designers to benefit from the capabilities of multiple tools. The BDA provides a graphical user interface that consists of two main elements: the Building Browser and the Decision Desktop. The Browser allows building designers to quickly navigate through the multitude of descriptive and performance parameters addressed by the analysis and visualization tools linked to the BDA. Through the Browser the user can edit the values of input parameters and select any number of input and/or output parameters for display in the Decision Desktop. The Desktop allows building designers to compare multiple design alternatives with respect to any number of parameters addressed by the tools linked to the BDA. The BDA is implemented as a Windows{\texttrademark}-based application for personal computers. Its initial version is linked to a Schematic Graphic Editor (SGE), which allows designers to quickly and easily specify the geometric characteristics of building components and systems. For every object created in the SGE, the BDA supplies モsmartヤ default values from a Prototypical Values Database (PVD) for all non-geometric parameters required as input to the analysis and visualization tools linked to the BDA. In addition to the SGE and the PVD, the initial version of the BDA is linked to a daylight analysis tool, an energy analysis tool, and a multimedia Case Studies Database (CSD). The next version of the BDA will be linked to additional tools, such as a photo-accurate rendering program and a cost analysis program. Future versions will address the whole building life-cycle and will be linked to construction, commissioning and building monitoring tools.

}, author = {Konstantinos M. Papamichael and John LaPorta and Hannah L. Chauvet and Deirdre Collins and Thomas Trzcinski and Jack A. Thorpe and Stephen E. Selkowitz} } @conference {11532, title = {Advances in Thermal and Optical Simulations of Fenestration Systems: The Development of WINDOW 5}, booktitle = {Thermal Performance of the Exterior Envelopes of Buildings VI Conference }, year = {1995}, month = {12/1995}, address = {Clearwater Beach, FL}, abstract = {

WINDOW is a personal-computer-based computer program used by manufacturers, researchers, and consumers to evaluate the thermal performance properties (U-factors, solar heat gain and shading coefficients, and visible transmittances) of complete windows and other fenestration systems. While WINDOW is used by thousands of users in the United States and internationally and is at the foundation of the National Fenestration Rating Council{\textquoteright}s U-factor and solar heat gain property procedures, improvements to the program are still necessary for it to meet user needs. Version 5, intended for release in late 1995, is being developed to meet these needs for increased accuracy, a flexible and state-of-the-art user interface, and the capabilities to handle more product types.

WINDOW 5 includes the capabilities to define and model the thermal performance of frames/dividers and their associated edge effects. Currently, such an analysis must be performed outside of WINDOW and requires simplifications to be made to frame profiles or is based on the use of generic frame and edge correlations. WINDOW{\textquoteright}s two-dimensional thermal model is composed of four sections: a graphical input, automatic grid generation, an finite-element analysis (FEA) solution, and the display of results. In the graphical input section, users are able to directly import a computer-aided design (CAD) drawing or a scanned image of a window profile, replicate its exact geometry, and assign material types and boundary conditions. The automatic grid generation is transparent to the user, with the exception of the requirement that complex shapes (i.e., an aluminum extrusion) be broken down into simpler polyshapes. Inclusion of an automatic grid generation makes detailed "true geometry" frame-and-edge heat-transfer analysis accessible to users without extensive knowledge of numerical methods of heat-transfer analysis. After the cross section is meshed it is sent to the FEA engine for solution and the results are returned. A postprocessor allows for the visual display of temperature and heat flux plots. Note that while this two-dimensional heat-transfer tool is being developed specifically for fenestration products, it also can be used to analyze other building envelope components.

WINDOW 5 also will include a built-in version of a national laboratory{\textquoteright}s program that allows the user to estimate the orientation-dependent annual energy impacts of a given window in a typical residence in various U.S. climates. This program is based on regressions to a database of DOE2.1 runs. Future versions will include a similar feature for commercial buildings.

Other technical additions include an improved angular/ spectral model for coated and uncoated glazings, the ability to analyze the optical properties of nonhomogeneous layers, and the ability to model the effects of laminated glazing layers. A door module permits the user to compute the total U-factors of exterior doors based on component U-factors calculated using the two-dimensional FEA module.

}, author = {Elizabeth U. Finlayson and Dariush K. Arasteh and Michael D. Rubin and John Sadlier and Robert Sullivan and Charlie Huizenga and Dragan C. Curcija and Mark Beall} } @conference {11761, title = {Edge Conduction in Vacuum Glazing}, booktitle = {Thermal Performance of the Exterior Envelopes of Buildings VI Conference }, year = {1995}, month = {03/1995}, address = {Clearwater Beach, FL}, abstract = {

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.

}, author = {Tom M. Simko and Richard E. Collins and Fredric A. Beck and Dariush K. Arasteh} } @article {11964, title = {The Influence of Nitrogen Ion Energy on the Quality of GaN Films Grown with Molecular Beam Epitaxy}, journal = {Journal of Electronic Materials}, volume = {24}, number = {4}, year = {1995}, month = {04/1995}, pages = {249-255}, chapter = {249}, abstract = {

Since the growth of GaN using molecular beam epitaxy (MBE) occurs under metastable growth conditions, activated nitrogen is required to drive the forward synthesis reaction. In the process of exciting the nitrogen using a plasma or ion-beam source, species with large kinetic energies are generated. Impingement on the growth surface by these species can result in subsurface damage to the growing film, as well as an enhancement of the reverse decomposition reaction rate. In this study, we investigate the effect of the kinetic energy of the impinging nitrogen ions during growth on the resulting optical and structural properties of GaN films. Strong band-edge photoluminescence and cathodoluminescence are found when a kinetic energy of ~10 eV are used, while luminescence is not detectable when the kinetic energies exceeds 18 eV. Also, we find that the use of conductive SiC substrates results in more homogeneous luminescence than the use of insulating sapphire substrates. This is attributed to sample surface charging in the case of sapphire substrates and subsequent variation in the incident ion flux and kinetic energy across the growth surface.This study clearly shows that the quality of GaN films grown by MBE are presently limited by damage from the impingement of high energy species on the growth surface.

}, keywords = {Activated nitrogen, GaN, molecular beam epitaxy (MBE), nitrogen ion energy}, issn = {0361-5235}, doi = {10.1007/BF02659683}, author = {T.C. Fu and Nathan Newman and Erin C. Jones and James S. Chan and Xiaohong Liu and Michael D. Rubin and Nathan W. Cheung and Eicke R. Weber} } @conference {12115, title = {NFRC Efforts to Develop a Residential Fenestration Annual Energy Rating Methodology}, booktitle = {Window Innovations Conference 1995}, year = {1995}, month = {06/1995}, address = {Toronto, Canada}, abstract = {

This paper documents efforts currently being undertaken by the National Fenestration Rating Councils Annual Energy Rating Subcommittee to develop procedures to quantify the energy impacts of fenestration products in typical residential buildings throughout the United States. Parallel paths focus on (1) the development of simplified heating and cooling indices and (2) the development of a more detailed methodology to calculate the cost and energy impacts of specific products in a variety of housing types. These procedures are currently under discussion by NFRCs Technical Committee; future efforts will also address commercial buildings.

}, author = {Brian Crooks and James Larsen and Robert Sullivan and Dariush K. Arasteh and Stephen E. Selkowitz} } @article {12195, title = {Preparation and Properties of Spin-Coated Nb2O5 Films by the Sol-Gel Process for Electrochemical Applications}, journal = {Thin Solid Films}, volume = {277}, number = {2-Jan}, year = {1995}, month = {05/1996}, pages = {162-168}, chapter = {162}, abstract = {

The preparation and properties of Nb2O5 coatings made by the sol-gel process were investigated. The films were deposited by spin coating on In2O3:Sn/glass and quartz substrates from a polymeric solutions of niobia derived from niobium ethoxide. The films were characterized by investigation of the stoichiometry, refractive index, optical transmission, electrochemical behavior, and the microstructure. X-ray diffraction studies showed the films to be amorphous for heat treatments below 450 {\textdegree}C. X-ray photoelectron spectroscopy (XPS) measurement revealed the O:Nb atomic stoichiometry to be 5:2. Cyclic voltammetric measurements showed that the Nb2O5/1 M LiClO4-propylene carbonate system exhibits electrochemical reversibility beyond 1200 cycles without change in performance. In situ UV-Vis-NIR spectroelectrochemical measurement revealed that Nb2O5 films exhibit an electrochromic effect in the spectral range 300\<λ\<2100 nm and remain unchanged in the infrared spectral range. The change in visible transmittance was 40\% for a 250 nm thick electrode. XPS spectra indicate that Nb(V) is reduced to a lower valence state Nb(IV) in a colored state with injected Li+. The bronze coloration is due to a simultaneous injection of electrons and Li+ ions into Nb2O5. The sol-gel-deposited\ Nb2O5 films are useful for cathodically coloring electrochromic electrodes in electrochromic devices.

}, keywords = {Electrochemistry, Niobium oxide, optical properties, X-ray photoelectron spectroscopy}, url = {http://dx.doi.org/10.1016/0040-6090(95)08011-2}, author = {Nilg{\"u}n {\"O}zer and Din-Guo Chen and Carl M Lampert} } @article {1900, title = {Thermal Annealing Characteristics of Si and Mg-implanted GaN Thin Films}, journal = {Applied Physics Letters}, volume = {68}, number = {19}, year = {1995}, month = {03/1996}, pages = {2702-2704}, chapter = {2702}, abstract = {

In this letter, we report the results of ion implantation of GaN using 28Si and 23Mg species. Structural and electrical characterizations of the GaN thin films after thermal annealing show that native defects in the GaN films dominate over implant doping effects. The formation energies of the annealing induced defects are estimated to range from 1.4 to 3.6 eV. A 30 keV10^14 cm-2 Mg implant results in the decrease of the free-carrier concentration by three orders of magnitude compared to unimplanted GaN up to an annealing temperature of 690 {\textdegree}C. Furthermore, we have observed the correlation between these annealing-induced defects to both improved optical and electrical properties.

}, keywords = {annealing, crystal doping, defect states, electrical properties, gallium nitrides, ion implantation, magnesium additions, microstructure, silicon additions}, issn = {0003-6951}, doi = {10.1063/1.116314}, author = {James S. Chan and Nathan W. Cheung and Lawrence F. Schloss and Erin C. Jones and William S. Wong and Nathan Newman and Xiaohong Liu and Eicke R. Weber and A. Gassman and Michael D. Rubin} } @conference {11890, title = {Fundamental Materials-Issues Involved in the Growth of GaN by Molecular Beam Epitaxy}, year = {1994}, abstract = {

Gallium nitride is one of the most promising materials for ultraviolet and blue light-emitting diodes and lasers. Both Molecular Beam Epitaxy (MBE) and Metal-Organic Chemical Vapor Deposition (MOCVD) have recently made strong progress in fabricating high-quality epitaxial GaN thin films. In this paper, we review materials-related issues involved in MBE growth. We show that a strong understanding of the unique meta-stable growth process allows us to correctly predict the optimum conditions for epitaxial GaN growth. The resulting structural, electronic and optical properties of the GaN films are described in detail.

}, author = {Nathan Newman and T.C. Fu and Z. Liu and Zuzanna Liliental-Weber and Michael D. Rubin and James S. Chan and Erin C. Jones and Jennifer T. Ross and Ian M. Tidswell and Kin Man Yu and Nathan W. Cheung and Eicke R. Weber} } @conference {12084, title = {Modeling Windows in DOE 2.1E}, booktitle = {Thermal Performance of the Exterior Envelopes of Buildings V Conference}, year = {1994}, month = {12/1992}, address = {Clearwater Beach, FL}, abstract = {

The most recent version of the DOE-2 building energy simulation program, DOE-2.1E, provides for more detailed modeling of the thermal and optical properties of windows. The window calculations account for the temperature effects on U-value, and update the incident angle correlations for the solar heat gain properties and visible transmittance. Initial studies show up to a 30\% difference in calculating peak solar heat gain between the detailed approach and a constant shading-coefficient approach. The modeling approach is adapted from Lawrence Berkeley Laboratorys WINDOW 4 computer program, which is used in the National Fenestration Rating Council (NFRC) U-value rating procedure 100-91. This gives DOE-2.1E the capability to assess the annual and peak energy performance of windows consistent with the NFRC procedure. The program has an extensive window library and algorithms for simulating switchable glazings. The program also accounts for the influence of framing elements on the heat transfer and solar heat gain through the window.

}, author = {M. Susan Reilly and Frederick C. Winkelmann and Dariush K. Arasteh and William L. Carroll} } @conference {11636, title = {Comparison of AIN Films Grown by RF at Magnetron Sputtering and Ion-Assisted Molecular Beam Epitaxy}, booktitle = {Materials Research Society}, volume = {300}, year = {1993}, month = {04/1993}, address = {San Francisco, CA}, abstract = {

Crystalline aluminum nitride (AlN) thin films were formed on various substrates by using RF magnetron sputtering of an A1 target in a nitrogen plasma and also by ion-assisted molecular beam epitaxy (IAMBE). Basal-oriented AlN/(111) Si showed a degradation of crystallinity with increased substrate temperature from 550 to 770 {\textdegree}C, while the crystallinity of AlN/(0001) Al2O3 samples improved from 700 to 850 {\textdegree}C. The optical absorption characteristics of the AlN/(0001) Al2O3 films as grown by both deposition methods revealed a decrease in sub-band gap absorption with increased substrate temperature.

}, author = {James S. Chan and T.C. Fu and Nathan W. Cheung and Jennifer T. Ross and Nathan Newman and Michael D. Rubin} } @article {12159, title = {P-Type Gallium Nitride by Reactive Ion-Beam Molecular Beam Epitaxy with Ion Implantation, Diffusion or Coevaporation of Mg}, journal = {Applied Physics Letters}, volume = {64}, number = {1}, year = {1993}, pages = {64-66}, chapter = {64}, abstract = {

Gallium nitride is one of the most promising materials for ultraviolet and blue light-emitting diodes and lasers. The principal technical problem that limits device applications has been achieving controllable p-type doping. Molecular beam epitaxy assisted by a nitrogen ion beam produced p-type GaN when doped via ion implantation, diffusion, or coevaporation of Mg. Nearly intrinsic p-type material was also produced without intentional doping, exhibiting hole carrier concentrations of 5{\texttimes}1011 cm-3 and hole mobilities of over 400 cm2/V/s at 250 K. This value for the hole mobility is an order of magnitude greater than previously reported.

}, keywords = {carrier density, carrier mobility, crystal doping, diffusion, evaporation, gallium nitrides, ion implantation, magnesium additions, molecular beam epitaxy, p-type conductors}, issn = {0003-6951}, doi = {10.1063/1.110870}, author = {Michael D. Rubin and Nathan Newman and James S. Chan and T.C. Fu and Jennifer T. Ross} }