02126nas a2200169 4500008004100000050001500041245006600056210006600122260003400188520154400222100002101766700002501787700002101812700002301833700002701856856007301883 1998 eng d aLBNL-4169400aEnergy and Daylight Performance of Angular Selective Glazings0 aEnergy and Daylight Performance of Angular Selective Glazings aClearwater Beach, FLc12/19983 a

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

1 aSullivan, Robert1 aBeltran, Liliana, O.1 aLee, Eleanor, S.1 aRubin, Michael, D.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/energy-and-daylight-performance01627nas a2200157 4500008004100000245007200041210006900113260001800182300001100200490000700211520110000218100002501318700002101343700002701364856007801391 1997 eng d00aAdvanced Optical Daylighting Systems: Light Shelves and Light Pipes0 aAdvanced Optical Daylighting Systems Light Shelves and Light Pip aCleveland, OH a91-1060 v263 a

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.

1 aBeltran, Liliana, O.1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/advanced-optical-daylighting-systems01361nas a2200145 4500008004100000050001400041245009700055210006900152260003100221520081700252100002101069700002501090700002701115856007301142 1996 eng d aLBL-3813100aDemonstration of a Light-Redirecting Skylight System at the Palm Springs Chamber of Commerce0 aDemonstration of a LightRedirecting Skylight System at the Palm  aPacific Grove, CAc08/19963 a

As part of a demonstration project to provide a comprehensive energy upgrade to a 294 m2 (3168 ft2) commercial building, an advanced skylight design was developed using optical light control materials and geometry to provide daylight to two adjoining offices. The skylight system was developed using outdoor physical model tests and simulation tools Limited on-site measurements and occupant polls were conducted. Market issues were addressed. The skylight systems were found to improve lighting quality and to control excessive daylight illuminance levels compared to a conventional diffusing bubble skylight. Daylighting principles developed in earlier work for vertical glazing systems (light shelves and light pipes) were shown to be applicable in skylight designs at full-scale.

1 aLee, Eleanor, S.1 aBeltran, Liliana, O.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/demonstration-light-redirecting02537nas a2200181 4500008004100000050001400041245010200055210006900157260003100226520187100257100002102128700002702149700002802176700002202204700002502226700002902251856007502280 1994 eng d aLBL-3573200aA Comprehensive Approach to Integrated Envelope and Lighting Systems for New Commercial Buildings0 aComprehensive Approach to Integrated Envelope and Lighting Syste aPacific Grove, CAc09/19943 a

We define a comprehensive approach to integrated envelope and lighting systems design as one that balances energy efficiency with anequal regard to the resultant environmental quality. By integrating envelope components (glazing, shading, and daylighting), lighting components (fixtures and controls) and building HVAC/ energy management control systems, we create building systems that have the potential to achieve significant decreases in electricity consumption and peak demand while satisfying occupant physiological and psychological concerns.

This paper presents results on the development, implementation, and demonstration of two specific integrated envelope and lighting systems:

  1. A system emphasizing dynamicsenvelope components and responsive electric lighting systems, that offer the potential to achieve energy efficiency goals and a near optimum comfort environment throughout the year by adapting to meteorological conditions and occupant preferences in real time, and
  2. perimeter daylighting systems that increase the depth of daylight penetration from sidelight windows and improves visual comfort with the use of a small inlet aperture.

The energy performance of the systems was estimated using the DOE-2 building energy simulation program. Field tests with reduced scale models were conducted to determine daylighting and thermal performance in real time under actual weather conditions. Demonstrations of these integrated systems are being planned or are in progress in collaboration with utility programs to resolve real-world implementation issues under complex site, building, and cost constraints. Results indicate that integrated systems offer solutions that not only achieve significant peak demand reductions but also realize consistent energy savings with added occupant comfort and satisfaction.

1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E.1 aRubinstein, Francis, M.1 aKlems, Joseph, H.1 aBeltran, Liliana, O.1 aDiBartolomeo, Dennis, L. uhttps://facades.lbl.gov/publications/comprehensive-approach-integrated01829nas a2200157 4500008004100000050001400041245011000055210006900165260002600234520122600260100002501486700002101511700003401532700002701566856007801593 1994 eng d aLBL-3445800aThe Design and Evaluation of Three Advanced Daylighting Systems: Light Shelves, Light Pipes and Skylights0 aDesign and Evaluation of Three Advanced Daylighting Systems Ligh aSan Jose, CAc06/19943 a

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.

1 aBeltran, Liliana, O.1 aLee, Eleanor, S.1 aPapamichael, Konstantinos, M.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/design-and-evaluation-three-advanced02740nas a2200181 4500008004100000050001900041245006200060210006200122260003100184520212100215100003402336700002502370700002102395700002102416700002702437700002302464856007102487 1994 eng d aLBL-35382 Rev.00aSimulating the Energy Performance of Holographic Glazings0 aSimulating the Energy Performance of Holographic Glazings aFreiburg, Germanyc04/19943 a

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.

1 aPapamichael, Konstantinos, M.1 aBeltran, Liliana, O.1 aFurler, Reto, A.1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/simulating-energy-performance02087nas a2200181 4500008004100000024001100041245006100052210005700113260001200170520150200182100003401684700002501718700002101743700002101764700002701785700002301812856007001835 1993 eng d aDA-30200aThe Energy Performance of Prototype Holographic Glazings0 aEnergy Performance of Prototype Holographic Glazings c02/19933 a

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

1 aPapamichael, Konstantinos, M.1 aBeltran, Liliana, O.1 aFurler, Reto, A.1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/energy-performance-prototype02011nas a2200133 4500008004100000050001400041245011500055210006900170260002400239520148000263100003401743700002501777856007501802 1993 eng d aLBL-3394500aSimulating the Daylight Performance of Fenestration Systems and Spaces of Arbitrary Complexity: The IDC Method0 aSimulating the Daylight Performance of Fenestration Systems and  aAdelaide, Australia3 a

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.

1 aPapamichael, Konstantinos, M.1 aBeltran, Liliana, O. uhttps://facades.lbl.gov/publications/simulating-daylight-performance-0