%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 Applied Physics Letters %D 2013 %T Drifting potential humps in ionization zones: The “propeller blades” of high power impulse magnetron sputtering %A André Anders %A Matjaž Panjan %A Robert Franz %A Joakim Andersson %A Pavel A. Ni %K Electric fields %K ionization %K plasma ionization %K sputter deposition %K sputtering %X

Ion energy distribution functions measured for high power impulse magnetron sputtering show features, such as a broad peak at several 10 eV with an extended tail, as well as asymmetry with respect to E × B, where E and B are the local electric and magnetic field vectors, respectively. Here it is proposed that those features are due to the formation of a potential hump of several 10 V in each of the traveling ionization zones. Potential hump formation is associated with a negative-positive-negative space charge that naturally forms in ionization zones driven by energetic drifting electrons.

%B Applied Physics Letters %V 103 %P 144103 %8 10/2013 %N 14 %! Appl. Phys. Lett. %R 10.1063/1.4823827 %0 Journal Article %J Solar Energy Materials and Solar Cells %D 2013 %T An empirical study of a full-scale polymer thermochromic window and its implications on material science development objectives %A Eleanor S. Lee %A Xiufeng Pang %A Sabine Hoffmann %A Howdy Goudey %A Anothai Thanachareonkit %K buildings energy efficiency %K Solar control %K Thermochromic %K windows %X

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

%B Solar Energy Materials and Solar Cells %V 116 %P 14-26 %8 09/2013 %2 LBNL-6376E %& 14 %R 10.1016/j.solmat.2013.03.043 %0 Report %D 2013 %T A Pilot Demonstration of Electrochromic and Thermochromic Windows in the Denver Federal Center, Building 41, Denver, Colorado %A Eleanor S. Lee %A Luis L. Fernandes %A Howdy Goudey %A Jacob C. Jonsson %A Dragan C. Curcija %A Xiufeng Pang %A Dennis L. DiBartolomeo %A Sabine Hoffmann %K building controls %K daylighting %K Demand Side Management %K electrochromic %K energy-efficiency %K Smart windows %K switchable windows %K Thermochromic %K Window %X

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.

%8 07/2013 %U http://gsa.gov/portal/content/187967 %2 LBNL-1005095 %0 Journal Article %J Building and Environment %D 2011 %T Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems %A Byoung-Chul Park %A An-Seop Choi %A Jae-Weon Jeong %A Eleanor S. Lee %K automated roller shade systems %K daylight responsive dimming systems %K daylighting %K Integrated systems %K photoelectric controls %X

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.

%B Building and Environment %V 46 %P 747-757 %8 03/2011 %G eng %N 3 %1

Windows and Daylighting Group

%2 LBNL-4418E %& 747 %R 10.1016/j.buildenv.2010.10.007 %0 Journal Article %J ASHRAE Transactions %D 2009 %T Field Measurements of Innovative Indoor Shading Systems in a Full-Scale Office Testbed %A Eleanor S. Lee %A Dennis L. DiBartolomeo %A Joseph H. Klems %A Robert D. Clear %A Kyle S. Konis %A Mehry Yazdanian %A Byoung-Chul Park %X

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 façade 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.

%B ASHRAE Transactions %V 115 %P 706-728 %8 10/2009 %N 2 %& 706 %0 Manuscript %D 2009 %T Innovative Façade Systems for Low-energy Commercial Buildings %A Eleanor S. Lee %A Stephen E. Selkowitz %A Dennis L. DiBartolomeo %A Joseph H. Klems %A Robert D. Clear %A Kyle S. Konis %A Maria Konstantoglou %A Mark Perepelitza %X

Glazing and façade 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.

Façade designs that deliberately recognize the fundamental synergistic relationships between the façade, lighting, and mechanical systems have the potential to deliver high performance over the life of the building. These "integrated" façade 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 — technology concepts, measured data, case study information, simulation tools, etc. — can enable architects and engineers to define integrated façade 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.

%I Lawrence Berkeley National Laboratory %C Berkeley %8 11/2009 %0 Journal Article %J Applied Surface Science %D 2008 %T Functionalization of Hydrogen-free Diamond-like Carbon Films using Open-air Dielectric Barrier Discharge Atmospheric Plasma Treatments %A Jose L. Endrino %A Jose F. Marco %A Phitsanu Poolcharuansin %A Ayalasomayajula R. Phani %A Matthew Allen %A José M. Albella %A André Anders %K Cell viability %K DLC %K Ion implantation and deposition %K wettability %K XPS %X

A dielectric barrier discharge (DBD) technique has been employed to produce uniform atmospheric plasmas of He and N2 gas mixtures in open air in order to functionalize the surface of filtered-arc deposited hydrogen-free diamond-like carbon (DLC) films. XPS measurements were carried out on both untreated and He/N2 DBD plasma-treated DLC surfaces. Chemical states of the C 1s and N 1s peaks were collected and used to characterize the surface bonds. Contact angle measurements were also used to record the short- and long-term variations in wettability of treated and untreated DLC. In addition, cell viability tests were performed to determine the influence of various He/N2 atmospheric plasma treatments on the attachment of osteoblast MC3T3 cells. Current evidence shows the feasibility of atmospheric plasmas in producing long-lasting variations in the surface bonding and surface energy of hydrogen-free DLC and consequently the potential for this technique in the functionalization of DLC-coated devices.

%B Applied Surface Science %C Boulder, CO %V 254 %8 08/2008 %G eng %N 17 %1

Windows and Daylighting Group

%2 LBNL-265E %& 5323 %R 10.1016/j.apsusc.2008.02.065 %0 Report %D 2007 %T Daylighting the New York Times Headquarters Building: Final Report: Commissioning Daylighting Systems and Estimation of Demand Response %A Eleanor S. Lee %A Glenn D. Hughes %A Robert D. Clear %A Luis L. Fernandes %A Sila Kiliccote %A Mary Ann Piette %A Francis M. Rubinstein %A Stephen E. Selkowitz %K automated daylighting controls %K automated window shades %K daylighting %K demand response %K energy-efficiency %K visual comfort %X

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

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

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

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

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

%C Berkeley %8 08/2007 %0 Conference Paper %B 2006 ACEEE Summer Study on Energy Efficiency in Buildings %D 2006 %T Dynamic Controls for Energy Efficiency and Demand Response: Framework Concepts and a New Construction Case Study in New York %A Sila Kiliccote %A Mary Ann Piette %A David S. Watson %A Glenn D. Hughes %X

Many of today's advanced building control systems are designed to improve granularity of control for energy efficiency. Examples include direct digital controls for building heating, ventilation, and cooling systems (HVAC), and dimmable ballasts for continuous dimming for daylighting applications. This paper discusses recent research on the use of new and existing controls in commercial buildings for integrated energy efficiency and demand response (DR). The paper discusses the use of DR controls strategies in commercial buildings and provides specific details on DR control strategy design concepts for a new building in New York. We present preliminary results from EnergyPlus simulations of the DR strategies at the New York Times Headquarters building currently under construction. The DR strategies at the Times building involve unique state of the art systems with dimmable ballasts, movable shades on the glass facade, and underfloor air HVAC. The simulation efforts at this building are novel, with an innovative building owner considering DR and future DR program participation strategies during the design phase. This paper also discusses commissioning plans for the DR strategies. The trends in integration of various systems through the EMCS, master versus supervisory controls and dynamic operational modes concepts are presented and future research directions are outlined.

%B 2006 ACEEE Summer Study on Energy Efficiency in Buildings %C Pacific Grove, CA %8 06/2006 %G eng %2 LBNL-60615 %4

August 13-18, 2006

%#

demand response

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Commercial Building Systems Group

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y

%0 Journal Article %J Review of Scientific Instruments %D 2006 %T Filtered cathodic arc deposition with ion-species-selective bias %A André Anders %A Nitisak Pasaja %A Sakon Sansongsiri %A Sunnie H.N. Lim %X

A dual-cathode arc plasma source was combined with a computer-controlled bias amplifier such as to synchronize substrate bias with the pulsed production of plasma. In this way, bias can be applied in a material-selective way. The principle has been applied to the synthesis metal-doped diamond-like carbon films, where the bias was applied and adjusted when the carbon plasma was condensing, and the substrate was at ground when the metal was incorporated. In doing so, excessive sputtering by too-energetic metal ions can be avoided while the sp3/sp2 ratio can be adjusted. It is shown that the resistivity of the film can be tuned by this species-selective bias. The principle can be extended to multiple-material plasma sources and complex materials.

%B Review of Scientific Instruments %G eng %L LBNL-61733 %1

Windows and Daylighting Group

%2 LBNL-61733 %0 Journal Article %J Surface and Coatings Technology %D 2006 %T Plasma biasing to control the growth conditions of diamond-like carbon %A André Anders %A Nitisak Pasaja %A Sunnie H.N. Lim %A Tim C. Petersen %A Vicki J. Keast %K Diamond-like carbon films %K Electron energy loss spectroscopy %K Plasma bias %K Substrate bias %K transmission electron microscopy %X

It is well known that the structure and properties of diamond-like carbon, and in particular the sp3/sp2 ratio, can be controlled by the energy of the condensing carbon ions or atoms. In many practical cases, the energy of ions arriving at the surface of the growing film is determined by the bias applied to the substrate. The bias causes a sheath to form between substrate and plasma in which the potential difference between plasma potential and surface potential drops. In this contribution, we demonstrate that the same results can be obtained with grounded substrates by shifting the plasma potential. This plasma biasing (as opposed to substrate biasing) is shown to work well with pulsed cathodic carbon arcs, resulting in tetrahedral amorphous carbon (ta-C) films that are comparable to the films obtained with the conventional substrate bias. To verify the plasma bias approach, ta-C films were deposited by both conventional and plasma bias and characterized by transmission electron microscopy (TEM) and electron energy loss spectrometry (EELS). Detailed data for comparison of these films are provided.

%B Surface and Coatings Technology %V 201 %P 4628-4632 %8 01/2007 %G eng %N 8 %1

Windows and Daylighting Group

%2 LBNL-59023 %& 4628 %R 10.1016/j.surfcoat.2006.09.313 %0 Journal Article %J Solar Energy %D 2005 %T Bi-Directional Transmission Properties of Venetian Blinds: Experimental Assessment Compared to Ray-Tracing Calculations %A Marilyn Andersen %A Michael D. Rubin %A Rebecca Powles %A Jean-Louis Scartezzini %X

An accurate evaluation of daylight distribution through advanced fenestration systems (complex glazing, solar shading systems) requires the knowledge of their Bidirectional light Transmission (Reflection) Distribution Function BT(R)DF. An innovative equipment for the experimental assessment of these bi-directional functions has been developed, based on a digital imaging detection system. An extensive set of BTDF measurements was performed with this goniophotometer on Venetian blinds presenting curved slats with a mirror coating on the upper side. In this paper, the measured data are compared with ray-tracing results achieved with a virtual copy of the device, that was constructed with a commercial ray-tracing software. The model of the blind was created by implementing the measured reflection properties of the slats coatings in the ray-tracing calculations. These comparisons represent an original and objective validation methodology for detailed bi-directional properties for a complex system; the good agreement between the two methods, yet presenting very different parameters and assessment methodologies, places reliance both on the digital-imaging detection system and calibration, and on the potentiality of a flexible calculation method combining ray-tracing simulations with simple components measurements.

%B Solar Energy %V 78 %P 187-198 %G eng %L LBNL-58818 %1

Windows and Daylighting Group

%2 LBNL-58818 %0 Journal Article %J IEEE Transactions on Plasma Science %D 2005 %T Plasma-Based Ion Implantation and Deposition: A Review of Physics, Technology, and Applications %A Jacques Pelletier %A André Anders %X

After pioneering work in the 1980s, plasma-based ion implantation (PBII) and plasma-based ion implantation and deposition (PBIID) can now be considered mature technologies for surface modification and thin film deposition. This review starts by looking at the historical development and recalling the basic ideas of PBII. Advantages and disadvantages are compared to conventional ion beam implantation and physical vapor deposition for PBII and PBIID, respectively, followed by a summary of the physics of sheath dynamics, plasma and pulse specifications, plasma diagnostics, and process modelling. The review moves on to technology considerations for plasma sources and process reactors. PBII surface modification and PBIID coatings are applied in a wide range of situations. They include the by-now traditional tribological applications of reducing wear and corrosion through the formation of hard, tough, smooth, low-friction and chemically inert phases and coatings, e.g. for engine components. PBII has become viable for the formation of shallow junctions and other applications in microelectronics. More recently, the rapidly growing field of biomaterial synthesis makes used of PBII&D to produce surgical implants, bio- and blood-compatible surfaces and coatings, etc. With limitations, also non-conducting materials such as plastic sheets can be treated. The major interest in PBII processing originates from its flexibility in ion energy (from a few eV up to about 100 keV), and the capability to efficiently treat, or deposit on, large areas, and (within limits) to process non-flat, three-dimensional workpieces, including forming and modifying metastable phases and nanostructures. We use the acronym PBII&D when referring to both implantation and deposition, while PBIID implies that deposition is part of the process.

%B IEEE Transactions on Plasma Science %V 33 %P 1944-1959 %G eng %L LBNL-57610 %1

Windows and Daylighting Group

%2 LBNL-57610 %0 Conference Paper %B 2002 ACEEE Summer Study on Energy Efficiency in Buildings %D 2002 %T Energy Efficient Windows in the Southern Residential Windows Market %A Alison Tribble %A Kate Offringa %A Bill Prindle %A Dariush K. Arasteh %A Jay Zarnikau %A Arlene Stewart %A Ken Nittler %X

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

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

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

%B 2002 ACEEE Summer Study on Energy Efficiency in Buildings %C Pacific Grove, CA %8 08/2002 %G eng %L LBNL-51425 %1

Windows and Daylighting Group

%2 LBNL-51425 %0 Report %D 2002 %T Energy Savings and Pollution Prevention Benefits of Solar Heat Gain Standards in the International Energy Conservation Code %A Bill Prindle %A Dariush K. Arasteh %X

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

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

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

%G eng %L LBNL-51426 %1

Windows and Daylighting Group

%2 LBNL-51426 %0 Journal Article %J Physical Review B %D 2002 %T In Situ X-Ray Absorption Spectroscopy Study of Hydrogen Absorption by Nickel-Magnesium Thin Films %A Baker Farangis %A Ponnusamy Nachimuthu %A Thomas J. Richardson %A Jonathan L. Slack %A Rupert C.C. Perera %A Eric M. Gullikson %A Dennis W. Lindle %A Michael D. Rubin %X

Structural and electronic properties of co-sputtered Ni-Mg thin films with varying Ni to Mg ratio were studied by in situ x-ray absorption spectroscopy in the Ni L-edge and Mg K-edge regions. Codeposition of the metals led to increased disorder and decreased coordination around Ni and Mg compared to pure metal films. Exposure of the metallic films to hydrogen resulted in formation of hydrides and increased disorder. The presence of hydrogen as a near neighbor around Mg caused a drastic reduction in the intensities of multiple scattering resonances at higher energies. The optical switching behavior and changes in the x-ray spectra varied with Ni to Mg atomic ratio. Pure Mg films with Pd overlayers were converted to MgH2: The H atoms occupy regular sites as in bulk MgH2. Although optical switching was slow in the absence of Ni, the amount of H2 absorption was large. Incorporation of Ni in Mg films led to an increase in the speed of optical switching but decreased maximum transparency. Significant shifts in the Ni L3 and L2 peaks are consistent with strong interaction with hydrogen in the mixed films.

%B Physical Review B %V 67 %8 02/2003 %G eng %N 8 %1

Windows and Daylighting Group

%2 LBNL-51067 %! Phys. Rev. B %R 10.1103/PhysRevB.67.085106 %0 Report %D 2002 %T Optics Version 5.1.01 %A Richard Versluis %A Rebecca Powles %A Michael D. Rubin %I Regents of the University of California %C Berkeley, CA %8 11/2002 %G eng %L LBNL-52148 %1

Windows and Daylighting Group

%2 LBNL-52148 %0 Conference Paper %B Fifth International Meeting on Electrochromism %D 2002 %T Structural and Electronic Properties of Magnesium-3D Transition Metal Switchable Mirrors %A Baker Farangis %A Ponnusamy Nachimuthu %A Thomas J. Richardson %A Jonathan L. Slack %A Bruno K. Meyer %A Rupert C.C. Perera %A Michael D. Rubin %K EXAFS %K Hydrogen storage materials %K NEXAFS %K thin films %K x-ray diffraction %X

We have observed reversible mirror-to-transparent state switching in a variety of mixed metal thin films containing magnesium and first-row transition elements including Ni, Fe, Co, Mn, and Ti. The very large changes in both reflectance and transmittance on loading these films with hydrogen are accompanied by significant structural and electronic transformations. The valence states and coordination of metal atoms during hydrogen loading were followed using dynamic in situ transmissionmode X-ray absorption spectroscopy. Time-resolved Mg K-edge and Ni, Co, Mn, and Ti L-edge spectra reflect both reversible and irreversible changes in the metal environments. These spectra are compared to those of reference materials and to predictions from calculations.

%B Fifth International Meeting on Electrochromism %C Golden, CO %8 12/2002 %G eng %1

Windows and Daylighting Group

%2 LBNL-51415 %R 10.1016/j.ssi.2003.08.041 %0 Journal Article %J Journal of Alloys and Compounds %D 2002 %T X-Ray Absorption Spectroscopy of Transition Metal-Magnesium Hydride Thin Films %A Thomas J. Richardson %A Baker Farangis %A Jonathan L. Slack %A Ponnusamy Nachimuthu %A Rupert C.C. Perera %A Nobumichi Tamura %A Michael D. Rubin %K EXAFS %K Hydrogen storage materials %K NEXAFS %K thin films %K x-ray diffraction %X

Mixed metal thin films containing magnesium and a first-row transition element exhibit very large changes in both reflectance and transmittance on exposure to hydrogen gas. Changes in electronic structure and coordination of the magnesium and transition metal atoms during hydrogen absorption were studied using dynamic in situ transmission mode X-ray absorption spectroscopy. Mg K-edge and Ni, Co, and Ti L-edge spectra reflect both reversible and irreversible changes in the metal environments. A significant shift in the nickel L absorption edge shows it to be an active participant in hydride formation. The effect on cobalt and titanium is much less dramatic, suggesting that these metals act primarily as catalysts for formation of magnesium hydride.

%B Journal of Alloys and Compounds %V 356-357 %P 204-207 %8 08/2003 %G eng %1

Windows and Daylighting Group

%2 LBNL-50574 %& 204 %R 10.1016/S0925-8388(02)01237-9 %0 Journal Article %J Energy and Buildings %D 2001 %T A Method for Simulating the Performance of Photosensor-Based Lighting Controls %A Charles K. Ehrlich %A Konstantinos M. Papamichael %A Judy Lai %A Kenneth L. Revzan %X

The unreliability of photosensor-based lighting controls continues to be a significant market barrier that prevents widespread acceptance of daylight dimming controls in commercial buildings. Energy savings from the use of daylighting in commercial buildings is best realized through the installation of reliable photoelectric lighting controls that dim electric lights when sufficient daylight is available to provide adequate background and/or task illumination. In prior work, the authors discussed the limitations of current simulation approaches and presented a robust method to simulate the performance of photosensor-based controls using an enhanced version of the radiance lighting simulation package. The method is based on the concept of multiplying two fisheye images: one generated from the angular sensitivity of the photosensor and the other from a 180 or 360 deg. fisheye image of the space as seen by the photosensor. This paper includes a description of the method, its validation and possible applications for designing, placing, calibrating and commissioning photosensor-based lighting controls.

%B Energy and Buildings %V 34 %P 883-889 %G eng %L LBNL-49018 %1

Windows and Daylighting Group

%2 LBNL-49018 %0 Conference Paper %B 2001 Building Simulation 7th International Building Performance Simulation Association Conference %D 2001 %T Simulating the Operation of Photosensor-Based Lighting Controls %A Charles K. Ehrlich %A Konstantinos M. Papamichael %A Judy Lai %A Kenneth L. Revzan %X

Energy savings from the use of daylighting in commercial buildings are realized through implementation of photoelectric lighting controls that dim electric lights when sufficient daylight is available to provide adequate workplane illumination. The dimming level of electric lighting is based on the signal of a photosensor. Current simulation approaches for such systems are based on the questionable assumption that the signal of the photosensor is proportional to the task illuminance. This paper presents a method that simulates the performance of photosensor controls considering the acceptance angle, angular sensitivity, placement of the photosensor within a space, and color correction filter. The method is based on the multiplication of two fisheye images: one generated from the angular sensitivity of the photosensor and the other from a 180- or 360-degree fisheye image of the space as seen by the photosensor. The paper includes a detailed description of the method and its implementation, example applications, and validation results based on comparison with measurements in an actual office space.

%B 2001 Building Simulation 7th International Building Performance Simulation Association Conference %C Rio de Janeiro, Brazil %8 08/2001 %G eng %L LBNL-47544 %1

Windows and Daylighting Group

%2 LBNL-47544 %0 Conference Paper %B Revista della Statzione Sperimentale del Vetro %D 2000 %T Optical Properties of Glazing Materials at Normal Incidence %A Michael D. Rubin %A Rebecca Powles %X

Measurements of spectral transmittance T and reflectance R at normal incidence continue to be the most common and accurate source of energy performance data for glazing materials. Prediction of these radiometric properties from more fundamental materials data is often confounded by the complexity and uncertainty of coating structures. Angle-dependent radiometric properties of coated glazing will probably be predicted from normal-incidence data rather than being measured at many angles. The general error level demonstrated in round-robin tests is on the order 1-2%; it is often necessary to achieve better levels of performance. Based on results obtained following the round-robin tests, it is expected that accuracy of better than 0.5% can be generally achieved. A new type of absolute standard reference is described and tested with promising results.

%B Revista della Statzione Sperimentale del Vetro %C Paris, France %P 13-16 %8 10/2000 %G eng %L LBNL-48322 %1

Windows and Daylighting Group

%2 LBNL-48322 %0 Report %D 1999 %T RESFEN 3.1: A PC Program for Calculating the Heating and Cooling Energy Use of Windows in Residential Buildings %A Robin Mitchell %A Yu Joe Huang %A Dariush K. Arasteh %A Robert Sullivan %A Santosh Phillip %X

A computer tool such as RESFEN can help consumers and builders pick the most energy-efficient and cost-effective window for a given application, whether it is a new home, an addition, or a window replacement. It calculates heating and cooling energy use and associated costs as well as peak heating and cooling demand for specific window products. Users define a specific scenario by specifying house type (single-story or two-story), geographic location, orientation, electricity and gas cost, and building configuration details (such as wall, floor, and HVAC system type). Users also specify size, shading, and thermal properties of the window they wish to investigate. The thermal properties that RESFEN requires are: U-factor, Solar Heat Gain Coefficient, and air leakage rate. RESFEN calculates the energy and cost implications of the window compared to an insulated wall. The relative energy and cost impacts of two different windows can be compared.

RESFEN 3.0 was a major improvement over previous versions because it performs hourly calculations using a version of the DOE 2.1E (LBL 1980, Winkelmann et al. 1993) energy analysis simulation program. RESFEN 3.1 incorporates additional improvements including input assumptions for the base case buildings taken from the National Fenestration Rating Council (NFRC) Annual Energy Subcommittee's efforts.

%I Lawrence Berkeley National Laboratory %C Berkeley %8 08/1999 %G eng %1

Windows and Daylighting Group

%2 LBNL-40682 Rev. %0 Report %D 1999 %T Toward a Virtual Building Laboratory %A Joseph H. Klems %A Elizabeth U. Finlayson %A Thomas H. Olsen %A David W Banks %A Jani M. Pallis %X

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

%8 03/1999 %G eng %1

Windows and Daylighting Group

%2 LBNL-43006 %0 Journal Article %J Automation in Construction %D 1997 %T Building Design Advisor: Automated Integration of Multiple Simulation Tools %A Konstantinos M. Papamichael %A John LaPorta %A Hannah L. Chauvet %X

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®-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.

%B Automation in Construction %I Elsevier %V 6 %P 341-352 %8 08/1997 %G eng %N 4 %L LBNL-40591 %2 LBNL-40591 %3

479901

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%& 341 %R 10.1016/S0926-5805(97)00043-5 %0 Journal Article %J Solar Energy %D 1997 %T Window Optics %A Michael D. Rubin %A Klaus von Rottkay %A Rebecca Powles %X

Optical and radiative properties of glazing materials are primary inputs for determination of energy performance in buildings. This paper revisits the problem and reformulates the calculations to encompass a variety of solutions to practical problems in window optics. Properties of composite systems such as flexible films applied to rigid glazing and laminated glazing can be predicted from measurements on isolated components in air or other gases. Properties of a series of structures can be generated from those of a base structure. For example, the measured properties of a coated or uncoated substrate can be extended to a range of available substrate thicknesses without the need to measure each thickness. Similarly, a coating type could be transferred by calculation to any other substrate. A simple monolithic model for extrapolating from normal properties to oblique properties is shown to have sufficient accuracy for the purpose of annual energy performance calculations. A process is initiated to develop a reliable method for determination of effective indices suitable for more detailed spectral and directional optical calculations.

%B Solar Energy %V 62 %P 149-161 %G eng %L LBNL-39911 %1

Windows and Daylighting Group

%2 LBNL-39911 %0 Conference Paper %B ACADIA 1996 Conference %D 1996 %T The Building Design Advisor %A Konstantinos M. Papamichael %A John LaPorta %A Hannah L. Chauvet %A Deirdre Collins %A Thomas Trzcinski %A Jack A. Thorpe %A Stephen E. Selkowitz %X

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™-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.

%B ACADIA 1996 Conference %C Tucson, AZ %8 03/1996 %G eng %2 LBL-38584 %3

827301

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October 31 - November 1, 1996

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%0 Report %D 1996 %T Design and Evaluation of Daylighting Applications of Holographic Glazings %A Konstantinos M. Papamichael %A Charles K. Ehrlich %A Gregory J. Ward %X

When combined with appropriate electric lighting dimming controls, the use of daylight for ambient and task illumination can significantly reduce energy requirements in commercial buildings. While skylights can effectively illuminate any part of one-story buildings, conventional side windows can illuminate only a 15 ft - 20 ft (4.6 m - 6.1 m) depth of the building perimeter. Even so, the overall efficacy of daylight is limited, because side windows produce uneven distributions of daylight. Achieving adequate illumination at distances further away from the window results in excessive illumination near the window, which increases cooling loads from the associated solar heat gain. As a result, the use of larger apertures and/or higher transmittance glazings, to introduce daylight deeper than 15 ft - 20 ft (4.6 m - 6.1 m), may prove ineffective with respect to saving energy, because cooling load penalties may exceed the electric lighting savings.

The need for more uniform distribution of daylight admitted through side windows has stimulated significant research and development efforts in new fenestration designs and glazing technologies. Many of these approaches, including holographic glazings, rely on the common strategy of redirecting sunlight and reflecting it off the ceiling towards the back of the room. Prior studies on the daylight and energy performance of holographic glazings have been disappointing, however inconclusive because of poor hologram quality, low diffraction efficiency and inadequate hologram design and building application considerations [Papamichael et al 1994].

%G eng %L LBNL-44167 %1

Windows and Daylighting Group

%2 LBNL-44167 %0 Conference Paper %B Solar 94, Golden Opportunities for Solar Prosperity %D 1994 %T The Design and Evaluation of Three Advanced Daylighting Systems: Light Shelves, Light Pipes and Skylights %A Liliana O. Beltran %A Eleanor S. Lee %A Konstantinos M. Papamichael %A Stephen E. Selkowitz %X

We present results from the design and evaluation of three advanced daylighting systems: a light shelf, a light pipe, and a skylight. These systems use optical films and an optimizedsgeometry to passively intercept and redirect sunlight further into the building. The objectives of these designs are to increase daylighting illuminance levels at distances of 4.6-9.1 m (15-30 ft) from the window, and to improve the uniformity of the daylight distribution and the luminance gradient across the room under variable sun and sky conditions throughout the year. The designs were developed through a series of computer-assisted ray-tracing studies, photometric measurements, and observations using physical scale models. Comprehensive sets of laboratory measurements in combination with analytical routines were then used to simulate daylight performance for any solar position. Results show increased daylight levels and an improved luminance gradient throughout the year - indicating that lighting energy consumption and cooling energy due to lighting can be substantially reduced with improvements to visual comfort. Future development of the designs may further improve the daylighting performance of these systems.

%B Solar 94, Golden Opportunities for Solar Prosperity %C San Jose, CA %8 06/1994 %G eng %L LBL-34458 %1

Windows and Daylighting Group

%2 LBL-34458 %0 Conference Paper %B SPIE International Symposium on Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIII, April 18-22, 1994 %D 1994 %T Effect of Switching Control Strategies on the Energy Performance of Electrochromic Windows %A Robert Sullivan %A Eleanor S. Lee %A Konstantinos M. Papamichael %A Michael D. Rubin %A Stephen E. Selkowitz %X

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

%B SPIE International Symposium on Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIII, April 18-22, 1994 %C Freiburg, Germany %8 04/1994 %G eng %1

Windows and Daylighting Group

%2 LBNL-35453 %0 Conference Paper %B 13th SPIE International Symposium on Optical Materials Technology for Energy Efficiency and Solar Energy Conversion %D 1994 %T Simulating the Energy Performance of Holographic Glazings %A Konstantinos M. Papamichael %A Liliana O. Beltran %A Reto A. Furler %A Eleanor S. Lee %A Stephen E. Selkowitz %A Michael D. Rubin %X

The light diffraction properties of holographic diffractive structures present an opportunity to improve the daylight performance in side-lit office spaces by redirecting and reflecting sunlight off the ceiling, providing adequate daylight illumination up to 30 ft (9.14 m) from the window wall. Prior studies of prototypical holographic glazings, installed above conventional view windows, have shown increased daylight levels over a deeper perimeter area than clear glass, for selected sun positions. In this study, we report on the simulation of the energy performance of prototypical holographic glazings assuming a commercial office building in the inland Los Angeles climate.

The simulation of the energy performance involved determination of both luminous and thermal performance. Since the optical complexity of holographic glazings prevented the use of conventional algorithms for the simulation of their luminous performance, we used a newly developed method that combines experimentally determined directional workplane illuminance coefficients with computer-based analytical routines to determine a comprehensive set of daylight factors for many sun positions. These daylight factors were then used within the DOE-2.1D energy simulation program to determine hourly daylight and energy performance over the course of an entire year for four window orientations.

Since the prototypical holographic diffractive structures considered in this study were applied on single pane clear glass, we also simulated the performance of hypothetical glazings, assuming the daylight performance of the prototype holographic glazings and the thermal performance of double-pane and low-e glazings. The results of our analyses show that these prototypical holographic glazings did not save significant electric energy or reduce peak electricity demand compared to conventional energy-efficient window systems in inland Los Angeles office buildings, mainly because of their low diffraction efficiency. Finally, we address various design and implementation issues towards potential performance improvement.

%B 13th SPIE International Symposium on Optical Materials Technology for Energy Efficiency and Solar Energy Conversion %C Freiburg, Germany %8 04/1994 %G eng %L LBL-35382 Rev. %1

Windows and Daylighting Group

%2 LBL-35382R %0 Report %D 1993 %T The Energy Performance of Prototype Holographic Glazings %A Konstantinos M. Papamichael %A Liliana O. Beltran %A Reto A. Furler %A Eleanor S. Lee %A Stephen E. Selkowitz %A Michael D. Rubin %X

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

%8 02/1993 %G eng %1

Windows and Daylighting Group

%2 LBL-34367 %0 Conference Paper %B 3rd International Conference of the International Building Performance Simulation Association, Building Simulation 93 %D 1993 %T Simulating the Daylight Performance of Fenestration Systems and Spaces of Arbitrary Complexity: The IDC Method %A Konstantinos M. Papamichael %A Liliana O. Beltran %X

A new method to simulate the daylight performance of fenestration systems and spaces is presented. This new method, named IDC (Integration of Directional Coefficients), allows the simulation of the daylight performance of fenestration systems and spaces of arbitrary complexity, under any sun, sky and ground conditions. The IDC method is based on the combination of scale model photometry and computer-based simulation. Physical scale models are used to experimentally determine a comprehensive set of directional illuminance coefficients at reference points of interest, which are then used in analytical, computer-based routines, to determine daylight factors or actual daylight illuminance values under any sun, sky and ground conditions.

The main advantage of the IDC method is its applicability to any optically complex environment. Moreover, the computer-based analytical routines are fast enough to allow for hourly simulation of the daylight performance over the course of an entire year. However, the method requires appropriate experimental facilities for the determination of the Directional Coefficients. The IDC method has been implemented and used successfully in inter-validation procedures with various daylight simulation computer programs. Currently, it is used to simulate the daylight performance of fenestration systems that incorporate optically complex components, such as Venetian blinds, optically treated light shelves and light pipes.

%B 3rd International Conference of the International Building Performance Simulation Association, Building Simulation 93 %C Adelaide, Australia %G eng %L LBL-33945 %1

Windows and Daylighting Group

%2 LBL-33945 %0 Conference Paper %B International Daylighting Conference Proceedings %D 1986 %T The Integration of Operable Shading Systems and Lighting Controls %A Konstantinos M. Papamichael %A Francis M. Rubinstein %A Stephen E. Selkowitz %A Gregory J. Ward %X

Using daylighting in commercial buildings may significantly reduce electric lighting requirements if appropriatesphotoelectric controls are used to adjust the electric lighting output according to the available daylight. Prior analysis andsresults from monitored buildings and scale-model measurements suggest that the selection, placement, and installation ofsthe control photosensor is a difficult task, even with simple non-operable fenestration systems, since the daylightscontributions from sun, sky, and ground change continuously. The problem becomes even more complex forsfenestration systems that incorporate operable shading devices, because every adjustment changes the systems opticalsproperties. This paper presents results from measurements in a scale model under real skies, designed to bettersunderstand the problem of integrating fenestration and lighting controls. The scale model represented a typical officesspace and was equipped with motorized venetian blinds. Three control photosensors mounted on the ceiling weresconsidered for the operation of the electric lighting system, and two control strategies were considered for the operation ofsthe venetian blinds. Two ground-plane reflectances and two window orientations were examined. Results indicate thatsthe signal from a ceiling-mounted control photosensor shielded from direct light from the window shows the bestscorrelation with daylight work-plane illuminance, regardless of ground plane reflectance or venetian blind slat angle for allsslat angles that do not allow penetration of direct solar radiation. Results also indicate that the control strategies of thesvenetian blinds that were considered for the purposes of this study may result in significantly different slat angles, andsthus different daylighting work-plane illuminances and electric lighting requirements, especially when the ground-planesreflectance is high.

%B International Daylighting Conference Proceedings %C Long Beach, CA %8 11/1986 %G eng %L LBL-20536 %1

Windows and Daylighting Group

%2 LBL-20536