@conference {11809, title = {Energy and Daylight Performance of Angular Selective Glazings}, booktitle = {ASHRAE/DOE/BTECC Conference, Thermal Performance of the Exterior Envelopes of Buildings VII}, year = {1998}, month = {12/1998}, address = {Clearwater Beach, FL}, abstract = {

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.

}, author = {Robert Sullivan and Liliana O. Beltran and Eleanor S. Lee and Michael D. Rubin and Stephen E. Selkowitz} } @article {11528, title = {Advanced Optical Daylighting Systems: Light Shelves and Light Pipes}, journal = {1996 IESNA Annual Conference}, volume = {26}, year = {1997}, note = {

Presented at the 1996 IESNA Annual Conference
Cleveland, OH,
August 4-7, 1996

}, pages = {91-106}, chapter = {91}, address = {Cleveland, OH}, abstract = {

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.

}, doi = {10.1080/00994480.1997.10748194}, author = {Liliana O. Beltran and Eleanor S. Lee and Stephen E. Selkowitz} } @conference {11703, title = {Demonstration of a Light-Redirecting Skylight System at the Palm Springs Chamber of Commerce}, booktitle = {1996 ACEEE Summer Study on Energy Efficiency in Buildings: Profiting from Energy Efficiency}, year = {1996}, month = {08/1996}, address = {Pacific Grove, CA}, abstract = {

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.

}, author = {Eleanor S. Lee and Liliana O. Beltran and Stephen E. Selkowitz} } @conference {11643, title = {A Comprehensive Approach to Integrated Envelope and Lighting Systems for New Commercial Buildings}, booktitle = {ACEEE 1994 Summer Study on Energy Efficiency in Buildings}, year = {1994}, month = {09/1994}, address = {Pacific Grove, CA}, abstract = {

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.

}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Francis M. Rubinstein and Joseph H. Klems and Liliana O. Beltran and Dennis L. DiBartolomeo} } @conference {11710, title = {The Design and Evaluation of Three Advanced Daylighting Systems: Light Shelves, Light Pipes and Skylights}, booktitle = {Solar 94, Golden Opportunities for Solar Prosperity}, year = {1994}, month = {06/1994}, address = {San Jose, CA}, abstract = {

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.

}, author = {Liliana O. Beltran and Eleanor S. Lee and Konstantinos M. Papamichael and Stephen E. Selkowitz} } @conference {1801, title = {Simulating the Energy Performance of Holographic Glazings}, booktitle = {13th SPIE International Symposium on Optical Materials Technology for Energy Efficiency and Solar Energy Conversion}, year = {1994}, month = {04/1994}, address = {Freiburg, Germany}, abstract = {

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.

}, author = {Konstantinos M. Papamichael and Liliana O. Beltran and Reto A. Furler and Eleanor S. Lee and Stephen E. Selkowitz and Michael D. Rubin} } @techreport {1379, title = {The Energy Performance of Prototype Holographic Glazings}, year = {1993}, month = {02/1993}, abstract = {

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{\textquoteleft}s perimeter, because the cooling penalties due to solar heat gain are greater than the electric lighting savings due to daylighting.

}, author = {Konstantinos M. Papamichael and Liliana O. Beltran and Reto A. Furler and Eleanor S. Lee and Stephen E. Selkowitz and Michael D. Rubin} } @conference {1800, title = {Simulating the Daylight Performance of Fenestration Systems and Spaces of Arbitrary Complexity: The IDC Method}, booktitle = {3rd International Conference of the International Building Performance Simulation Association, Building Simulation 93}, year = {1993}, address = {Adelaide, Australia}, abstract = {

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.

}, author = {Konstantinos M. Papamichael and Liliana O. Beltran} }