%0 Report %D 2014 %T Angular selective window systems: Assessment of technical potential for energy saving %A Luis L. Fernandes %A Eleanor S. Lee %A Andrew McNeil %A Jacob C. Jonsson %A Thierry Stephane Nouidui %A Xiufeng Pang %A Sabine Hoffmann %K angular selective systems %K Building energy-efficiency %K daylighting %K Shading Systems %K windows %X

Static angular selective shading systems block or filter direct sunlight and admit daylight within a specific range of incident solar angles. They can potentially deliver energy efficient performance within the typical 4.6-m (15-ft) deep perimeter zone of buildings when tailored to a specific façade orientation and latitude. The objective of this study is to quantify the technical potential of these systems to reduce energy use and peak demand in commercial buildings, specifically: a) achieve 30-50% reductions in perimeter zone energy use vs. ASHRAE 90.1-2004, b) constrain peak window loads to less than 43 W/m2-floor (4 W/ft2-floor), and c) to the extent possible, admit useful daylight in the perimeter zone without exceeding the peak solar load constraint. Three distinctly different commercial shading systems were evaluated: a micro-perforated screen, a tubular shading structure (double- and triple-paned configurations), and an expanded metal mesh. This evaluation was performed mainly through computer simulation for a multitude of scenarios, including multiple climates (Chicago, Illinois and Houston, Texas), window-to-wall ratios (0.15-0.60), building codes (ASHRAE 90.1-2004 and 2010) and lighting control configurations (with and without daylighting controls). Angular selective shading systems are optically complex and cannot be modeled accurately using conventional simulation tools, prompting the development of unique versions of the EnergyPlus, Radiance and Window simulation tools. Results show significant potential reductions in perimeter zone energy use, with the best commercially-available system reaching 28% and 47% savings, relative to ASHRAE 90.1- 2004 and respectively without and with daylighting controls, on south facades in Chicago with WWR=0.45, while constraining peak window heat gains to under 43 W/m2-floor, and enabling significant savings from daylighting controls. Results suggest that it is possible that existing systems can be improved to more consistently achieve 30-50% energy savings. Level of angular selectivity, spectral selectivity of low-e coatings and thermal conductance of the angle-selective layer were identified as critical factors for the performance of angular selective systems. Static, angular selective shading systems offer a potentially low-cost option to significantly reduce window heat gains and control glare from visibility of the sun orb, while permitting the admission of useful daylight and access to views to the outdoors. This type of system shows significant potential to contribute towards net-zero energy goals in both new and retrofit construction.

%P 36 %8 01/2014 %9 DOE / CEC PIER Technical Report %2 LBNL-187060 %0 Journal Article %J Plasma Sources Science and Technology %D 2014 %T Asymmetric particle fluxes from drifting ionization zones in sputtering magnetrons %A Matjaž Panjan %A Robert Franz %A André Anders %K Instrumentation and measurement %K Plasma physics %K Surfaces, interfaces and thin films %X

Electron and ion fluxes from direct current and high-power impulse magnetron sputtering (dcMS and HiPIMS) plasmas were measured in the plane of the target surface. Biased collector probes and a particle energy and mass analyzer showed asymmetric emission of electrons and of singly and doubly charged ions. For both HiPIMS and dcMS discharges, higher fluxes of all types of particles were observed in the direction of the electrons' E x B drift. These results are put in the context with ionization zones that drift over the magnetron's racetrack. The measured currents of time-resolving collector probes suggest that a large fraction of the ion flux originates from drifting ionization zones, while energy-resolving mass spectrometry indicates that a large fraction of the ion energy is due to acceleration by an electric field. This supports the recently proposed hypothesis that each ionization zone is associated with a negative–positive–negative space charge structure, thereby producing an electric field that accelerates ions from the location where they were formed.

%B Plasma Sources Science and Technology %V 23 %P 025007 %8 04/2014 %N 2 %! Plasma Sources Sci. Technol. %R 10.1088/0963-0252/23/2/025007 %0 Web Page %D 2014 %T Award of Excellence Winner Selkowitz Drives the Nation Toward Better Performing Buildings %A Nadine M. Post %B Engineering News-Record %I ENR.com %P Acceptance speech for the Engineering News-Record, Award of Excellence, April 3, 2014 %8 04/07/2014 %G eng %U http://enr.construction.com/people/awards/2014/0407-Award-of-Excellence-Winner-Selkowitz-Drives-the-Nation-Toward-Better-Performing-Buildings.asp %0 Journal Article %J Journal of Building Performance Simulation %D 2013 %T Acceleration of the matrix multiplication of Radiance three phase daylighting simulations with parallel computing on heterogeneous hardware of personal computer %A Wangda Zuo %A Andrew McNeil %A Michael Wetter %A Eleanor S. Lee %K daylighting simulation %K graphics processing unit %K multicore central processing unit %K OpenCL %K parallel computing %X

Building designers are increasingly relying on complex fenestration systems to reduce energy consumed for lighting and HVAC in low energy buildings. Radiance, a lighting simulation program, has been used to conduct daylighting simulations for complex fenestration systems. Depending on the configurations, the simulation can take hours or even days using a personal computer. This paper describes how to accelerate the matrix multiplication portion of a Radiance three-phase daylight simulation by conducting parallel computing on heterogeneous hardware of a personal computer. The algorithm was optimized and the computational part was implemented in parallel using OpenCL. The speed of new approach was evaluated using various daylighting simulation cases on a multicore central processing unit and a graphics processing unit. Based on the measurements and analysis of the time usage for the Radiance daylighting simulation, further speedups can be achieved by using fast I/O devices and storing the data in a binary format.

%B Journal of Building Performance Simulation %2 LBNL-6461E %R 10.1080/19401493.2013.795193 %0 Report %D 2013 %T Annual daylighting performance of a passive optical light shelf in sidelit perimeter zones of commercial buildings %A Andrew McNeil %A Eleanor S. Lee %K bidirectional scattering distribution functions %K buildings energy efficiency %K daylighting %K Radiance simulations %X

Sunlight redirecting systems have the potential to significantly offset electric lighting energy use in deep perimeter zones of buildings where the windows are subject to high daylight availability. New Radiance modeling tools have recently been developed and validated, enabling accurate and timely simulation analysis of the annual energy and comfort performance of these optically-complex, anisotropic systems. A parametric study was conducted using these tools to evaluate the performance of a commercially-available passive optical light shelf (OLS) in a 17.4 m deep (57 ft), south-facing open plan office zone in three climates. Daylighting efficiency, discomfort glare, and lighting energy savings with continuous dimming and bi-level switching controls were determined at varying depths within the zone. The OLS decreased lighting energy use significantly throughout the depth of the space and achieved these savings with minimal discomfort glare in the area near the window. Annual lighting energy use intensity was reduced to 1.71-1.82 kWh/ft2-yr (22-27%) over the full depth of the perimeter zone across the three climates modeled (Phoenix, Washington DC, and Minneapolis) compared to a non-daylit zone at 2.34 kWh/ft2-yr. There was a greater occurrence of discomfort glare (3-7% during daytime work hours) if the occupant was in a seated view position looking at the window from the back of the room. The system is passive, needing no adjustment during the day and over the seasons and can be used as a retrofit measure in existing buildings. These results are encouraging and demonstrate how the primary daylit sidelit area can be extended well beyond the defined limits provided by the newly adopted ASHRAE 90.1-2010 code (i.e., 1.0 times the head height of the window).

%0 Report %D 2013 %T Automated Production of Optimization-Based Control Logics for Dynamic Façade Systems, with Experimental Application to Two-Zone External Venetian Blinds %A Brian E. Coffey %A Andrew McNeil %A Thierry Stephane Nouidui %A Eleanor S. Lee %8 09/2013 %9 CEC PIER Technical Report %0 Conference Paper %B SimBuild 2012, 5th National Conference of IBPSA-USA, August 1-3, 2012 %D 2012 %T Application of a stochastic window use model in EnergyPlus %A Spencer M. Dutton %A Hui Zhang %A Yongchao Zhai %A Edward A. Arens %A Youness Bennani Smires %A Samuel L. Brunswick %A Kyle S. Konis %A Philip Haves %X

Natural ventilation, used appropriately, has the potential to provide both significant HVAC energy savings, and improvements in occupant satisfaction.

Central to the development of natural ventilation models is the need to accurately represent the behavior of building occupants. The work covered in this paper describes a method of implementing a stochastic window model in EnergyPlus. Simulated window use data from three stochastic window opening models was then compared to measured window opening behavior, collected in a naturally-ventilated office in California. Recommendations regarding the selection of stochastic window use models, and their implementation in EnergyPlus, are presented.

%B SimBuild 2012, 5th National Conference of IBPSA-USA, August 1-3, 2012 %C Madison, WI %8 08/2012 %U https://escholarship.org/uc/item/2gm7r783 %0 Conference Paper %B 12th International Conference of the International Building Performance Simulation Association (Building Simulation 2011) %D 2011 %T Acceleration of Radiance for Lighting Simulation by using Parallel Computing with OpenCL %A Wangda Zuo %A Andrew McNeil %A Michael Wetter %A Eleanor S. Lee %X

This study attempted to accelerate annual daylighting simulations for fenestration systems in Radiance ray-tracing program. The algorithm was optimized to reduce both the redundant data input/output operations and floating-point operations. To further accelerate the simulation speed, calculation for matrices multiplications was implemented in parallel on a graphics processing unit using OpenCL, a cross-platform parallel programming language. Numerical experiments show that combination of above measures can speed up the annual daylighting simulations 101.7 times or 28.6 times when sky vector has 146 or 2306 elements, respectively.

%B 12th International Conference of the International Building Performance Simulation Association (Building Simulation 2011) %C Sydney, Australia %P p. 110-117 %8 11/2011 %G eng %1

Windows and Daylighting Group

%2 LBNL-5049E %0 Journal Article %J Journal of Physics D: Applied Physics %D 2011 %T Achieving high mobility ZnO:Al at very high growth rates by dc filtered cathodic arc deposition %A Rueben J. Mendelsberg %A Sunnie H.N. Lim %A Yuankun Zhu %A Joe Wallig %A Delia J. Milliron %A André Anders %X

Achieving a high growth rate is paramount for making large-area transparent conducting oxide coatings at a low cost. Unfortunately, the quality of thin films grown by most techniques degrades as the growth rate increases. Filtered dc cathodic arc is a lesser known technique which produces a stream of highly ionized plasma, in stark contrast to the neutral atoms produced by standard sputter sources. Ions bring a large amount of potential energy to the growing surface which is in the form of heat, not momentum. By minimizing the distance from cathode to substrate, the high ion flux gives a very high effective growth temperature near the film surface without causing damage from bombardment. The high surface temperature is a direct consequence of the high growth rate and allows for high-quality crystal growth. Using this technique, 500–1300 nm thick and highly transparent ZnO : Al films were grown on glass at rates exceeding 250 nm min−1 while maintaining resistivity below 5 × 10−4 Ω cm with electron mobility as high as 60 cm2 V−1 s−1.

%B Journal of Physics D: Applied Physics %V 44 %P 232003-232007 %N 23 %2 LBNL-5585E %! J. Phys. D: Appl. Phys. %& 232003 %R 10.1088/0022-3727/44/23/232003 %0 Report %D 2006 %T Advancement of Electrochromic Windows %A Eleanor S. Lee %A Stephen E. Selkowitz %A Robert D. Clear %A Dennis L. DiBartolomeo %A Joseph H. Klems %A Luis L. Fernandes %A Gregory J. Ward %A Vorapat Inkarojrit %A Mehry Yazdanian %K commercial buildings %K daylight %K daylighting controls %K Electrochromic windows %K energy efficiency %K human factors %K peak demand %K switchable windows %K visual comfort %X

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

%8 04/2006 %G eng %1

Windows and Daylighting Group

%2 LBNL-59821 %0 Generic %D 2004 %T Analysis of visual comfort using high-dynamic-range luminance images %A Vorapat Inkarojrit %G eng %0 Conference Paper %B GreenBuild, the annual USGBC International Conference and Expo %D 2003 %T Advanced Interactive Façades — Critical Elements for Future Green Buildings? %A Stephen E. Selkowitz %A Øyvind Aschehoug %A Eleanor S. Lee %X

Building designers and owners have always been fascinated with the extensive use of glass in building envelopes. Today the highly glazed façade has almost become an iconic element for a "green building" that provides daylighting and a visual connection with the natural environment. Even before the current interest in green buildings there was no shortage of highly glazed building designs. But many of these buildings either rejected sunlight, and some associated daylight and view with highly reflective glazings or used highly transmissive glass and encountered serious internal comfort problems that could only be overcome with large HVAC systems, resulting in significant energy, cost and environmental penalties.

%B GreenBuild, the annual USGBC International Conference and Expo %8 11/2013 %2 LBNL-53876 %0 Conference Paper %B ACEEE 2002 Summer Study on Energy Efficiency in Buildings: Teaming for Efficency %D 2002 %T Active Load Management with Advanced Window Wall Systems: Research and Industry Perspectives %A Eleanor S. Lee %A Stephen E. Selkowitz %A Mark S. Levi %A Steven L. Blanc %A Erin McConahey %A Maurya McClintock %A Pekka Hakkarainen %A Neil L. Sbar %A Michael P. Myser %X

Advanced window wall systems have the potential to provide demand response by reducing peak electric loads by 20-30% in many commercial buildings through the active control of motorized shading systems, switchable window coatings, operable windows, and ventilated double-skin facade systems. These window strategies involve balancing daylighting and solar heat gains, heat rejection through ventilation, and night-time natural ventilation to achieve space-conditioning and lighting energy use reductions without the negative impacts on occupants associated with other demand responsive (DR) strategies.

This paper explores conceptually how advanced window systems fit into the context of active load management programs, which cause customers to directly experience the time-varying costs of their consumption decisions. Technological options are suggested. We present pragmatic criteria that building owners use to determine whether to deploy such strategies. A utility's perspective is given. Industry also provides their perspectives on where the technology is today and what needs to happen to implement such strategies more broadly in the US.

While there is significant potential for these advanced window concepts, widespread deployment is unlikely to occur with business-as-usual practice. Technologically, integrated window-lighting-HVAC products are underdeveloped. Implementation is hindered by fragmented labor practices, non-standard communication protocols, and lack of technical expertise. Design tools and information products that quantify energy performance, occupant impacts, reliability, and other pragmatic concerns are not available. Interest within the building industry in sustainability, energy-efficiency, and increased occupant amenity, comfort, and productivity will be the driving factors for these advanced facades in the near term — at least until the dust settles on the deregulated electricity market.

%B ACEEE 2002 Summer Study on Energy Efficiency in Buildings: Teaming for Efficency %C Pacific Grove, CA %8 08/2002 %G eng %L LBNL-50855 %1

Windows and Daylighting Group

%2 LBNL-50855 %0 Journal Article %J Solar Energy Materials and Solar Cells %D 2002 %T Application issues for large-area electrochromic windows in commercial buildings %A Eleanor S. Lee %A Dennis L. DiBartolomeo %X

Projections of performance from small-area devices to large-area windows and enterprise marketing have created high expectations for electrochromic glazings. As a result, this paper seeks to precipitate an objective dialog between material scientists and building-application scientists to determine whether actual large-area electrochromic devices will result in significant performance benefits and what material improvements are needed, if any, to make electrochromics more practical for commercial building applications. Few in situ tests have been conducted with large-area electrochromic windows applied in buildings. This study presents monitored results from a full-scale field test of large-area electrochromic windows to illustrate how this technology will perform in commercial buildings. The visible transmittance (T v ) of the installed electrochromic ranged from 0.11 to 0.38. The data are limited to the winter period for a south-east-facing window. The effect of actual device performance on lighting energy use, direct sun control, discomfort glare, and interior illumination is discussed. No mechanical system loads were monitored. These data demonstrate the use of electrochromics in a moderate climate and focus on the most restrictive visual task: computer use in offices. Through this small demonstration, we were able to determine that electrochromic windows can indeed provide unmitigated transparent views and a level of dynamic illumination control never before seen in architectural glazing materials. Daily lighting energy use was 6-24% less compared to the 11%-glazing, with improved interior brightness levels. Daily lighting energy use was 3% less to 13% more compared to the 38%-glazing, with improved window brightness control. The electrochromic window may not be able to fulfill both energy-efficiency and visual comfort objectives when low winter direct sun is present, particularly for computer tasks using cathode-ray tube (CRT) displays. However, window and architectural design as well as electrochromic control options are suggested as methods to broaden the applicability of electrochromics for commercial buildings. Without further modification, its applicability is expected to be limited during cold winter periods due to its slow switching speed. © 2002 Elsevier Science B.V. All rights reserved.

%B Solar Energy Materials and Solar Cells %V 71 %P 465–491 %8 03/2002 %G eng %N 4 %2 LBNL-45841 %R 10.1016/S0927-0248(01)00101-5 %0 Conference Paper %B Daylighting 98 Conference %D 1998 %T Advanced Fenestration Systems for Improved Daylight Performance %A Stephen E. Selkowitz %A Eleanor S. Lee %X

The use of daylight to replace or supplement electric lighting in commercial buildings can result in significant energy and demand savings. High performance fenestration systems are a necessary, but not sufficient, element of any successful daylighting design that reduces lighting energy use. However, these savings may be reduced if the fenestration systems impose adverse thermal loads. New fenestration technologies have been developed over the last twenty years, aiming at controlling the intensity of the incoming solar radiation, its interior distribution and its spectral composition, as well as thermal losses and gains. Some of these have proven successful for specific or general building applications, while others are still under development and testing to understand limitations and potential benefits.

In this paper we review the state of the art of several advanced fenestration systems which, are designed to maximize the energy-saving potential of daylighting while improving comfort and visual performance, at an affordable cost. We first review the key performance issues that successful fenestration systems must address, and then review several classes of fenestration systems intended to meet those performance needs. The systems are reviewed in two categories: static and dynamic. Static systems include not only glazings, such as spectrally selective and holographic glazings, but specialized designs of light-shelves and light-pipes, while dynamic systems cover automatically operated blinds and electrochromic glazings.

We include a discussion of the research directions in this area, and how these efforts might lead to static and dynamic hardware and system solutions that fulfill the multiple roles that these systems must play in terms of energy efficiency, comfort, visual performance, health, and amenity in future buildings.

%B Daylighting 98 Conference %C Ottawa, Canada %8 05/1998 %G eng %L LBNL-41461 %1

Windows and Daylighting Group

%2 LBNL-41461 %0 Journal Article %J 1996 IESNA Annual Conference %D 1997 %T Advanced Optical Daylighting Systems: Light Shelves and Light Pipes %A Liliana O. Beltran %A Eleanor S. Lee %A Stephen E. Selkowitz %X

We present two perimeter daylighting systems that passively redirect beam sunlight further from the window wall using special optical films, an optimized geometry, and a small glazing aperture. The objectives of these systems are (1) to increase daylight illuminance levels at 4.6-9.1 m (15-30 ft) from the window aperture with minimum solar heat gains and (2) to improve the uniformity of the daylighting luminance gradient across the room under variable solar conditions throughout the year. The designs were developed through a series of computer-assisted ray-tracing studies, laser visualization techniques, and photometric measurements and observations using physical scale models. Bi-directional illuminance measurements in combination with analytical routines were then used to simulate daylight performance for any solar position, and were incorporated into the DOE-2.1E building energy analysis computer program to evaluate energy savings. Results show increased daylight levels and an improved luminance gradient throughout the year compared to conventional daylighting systems.

%B 1996 IESNA Annual Conference %C Cleveland, OH %V 26 %P 91-106 %G eng %N 2 %1

Windows and Daylighting Group

%2 LBL-38133 %& 91 %R 10.1080/00994480.1997.10748194 %0 Journal Article %J Thin Solid Films %D 1997 %T Analysis of Binary Electrochromic Tungsten Oxides with Effective Medium Theory %A Klaus von Rottkay %A Nilgün Özer %A Michael D. Rubin %A Thomas J. Richardson %X

Multicomponent oxides are of increasing interest for electrochromic electrodes. To reduce the large number of permutations in composition it would be useful to be able to predict the properties of the mixtures from the pure oxide components. WO3 mixed with V2O5 has been produced by a sol-gel technique in order to increase durability and color neutrality of conventional WO3 electrochromic coatings. Chemical composition was confirmed by Rutherford backscattering spectrometry (RBS). Surface morphology was analyzed by atomic force microscopy (AFM). Electrochromic performance of the films was tested by cyclic voltammetry with in-situ transmission control. Optical constants of vanadium tungsten oxides were determined over the whole solar spectrum. The measurements included variable angle spectroscopic ellipsometry and spectral transmittance and reflectance. An attempt is made to treat doped tungsten oxide as an effective medium consisting of a mixture of WO3 with V2O5. In the clear state, comparison of optical constants and thickness directly determined on the samples yields qualitative agreement with results from effective-medium analysis. The resulting component fraction also agrees as long as the film density does not deviate too much from the linearly interpolated value between the pure components. For the colored state, preferential trapping of electrons at one atom species hinders the application of effective medium theory.

%B Thin Solid Films %V 308-309 %P 50-55 %G eng %L LBNL-40096 %1

Windows and Daylighting Group

%2 LBNL-40096 %0 Conference Paper %B 2nd International Meeting on Electrochromism %D 1996 %T Analysis of Durability in Lithium Nickel Oxide Electrochromic Materials and Devices %A Shi-Jie Wen %A John B. Kerr %A Michael D. Rubin %A Jonathan L. Slack %A Klaus von Rottkay %X

Thin films of lithium nickel oxide were deposited by sputtering and laser ablation from targets of pressed nickel oxide and lithium oxide powders. These films were assembled into electrochromic test devices with tungsten oxide as the opposite electrode and a polymer electrolyte. Analysis of the failure modes was carried out at several levels: The composition and structure of the films were examined before and after cycling using a variety of techniques, such as infrared spectroscopy, nuclear-reaction analysis, Rutherford backscattering spectrometry, x-ray diffraction and atomic force microscopy. Absorption of water vapor was found to be a major factor determining the cyclic stability of the films. A new technique is described for incorporating reference electrodes made from an electronically isolated corner into devices. This structure enabled identification of potential problems associated with a particular interface. Finally, some of the devices were disassembled and the components examined. For example, a small quantity of the polymer was extracted and studied by gas chromatography and mass spectroscopy. Small organic fragments were discovered which correspond to expected weak points in the polymer structures.

%B 2nd International Meeting on Electrochromism %C San Diego, CA %8 10/1996 %G eng %L LBNL-39633 %1

Windows and Daylighting Group

%2 LBNL-39633 %0 Conference Paper %B Thermal Performance of the Exterior Envelopes of Buildings VI Conference %D 1995 %T Advances in Thermal and Optical Simulations of Fenestration Systems: The Development of WINDOW 5 %A Elizabeth U. Finlayson %A Dariush K. Arasteh %A Michael D. Rubin %A John Sadlier %A Robert Sullivan %A Charlie Huizenga %A Dragan C. Curcija %A Mark Beall %X

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

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

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

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

%B Thermal Performance of the Exterior Envelopes of Buildings VI Conference %C Clearwater Beach, FL %8 12/1995 %G eng %1

Windows and Daylighting Group

%2 LBL-37283 %0 Book Section %B Advances in Solar Energy, An Annual Review of Research and Development %D 1995 %T Advances in Window Technology: 1973-1993 %A Dariush K. Arasteh %X

Until the 1970s, the thermal performance of windows and other fenestration technologies was rarely of interest to manufacturers, designers, and scientists. Since then, however, a significant research and industry effort has focused on better understanding window thermal and optical behavior, how windows influence building energy patterns, and on the development of advanced products. This chapter explains how fenestration technologies can make a positive impact on building energy flows, what physical phenomena govern window heat and light transfer, what new products have been developed, and what new products are currently the subject of international research efforts.

%B Advances in Solar Energy, An Annual Review of Research and Development %P 339-382 %G eng %L LBL-36891 %1

Windows and Daylighting Group

%2 LBL-36891 %0 Conference Paper %B International Building Performance Simulation Association Fourth International Conference %D 1995 %T Advancing Lighting and Daylighting Simulation: The Transition from Analysis to Design Aid Tools %A Robert J. Hitchcock %X

This paper explores three significant software development requirements for making the transition from standalone lighting simulation/analysis tools to simulation-based design aid tools. These requirements include specialized lighting simulation engines, facilitated methods for creating detailed simulatable building descriptions, and automated techniques for providing lighting design guidance. Initial computer implementations meant to address each of these requirements are discussed to further elaborate these requirements and to illustrate work-in-progress toward fulfilling them.

%B International Building Performance Simulation Association Fourth International Conference %C Madison, WI %8 08/1995 %G eng %2 LBL-37285