Simulating the energy performance of holographic glazings
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 9 m from the window wall. Prior studies of prototypical holographic glazings, installed above conventional 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 new 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 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. 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, mainly because of their low diffraction efficiency. Finally, we address design and implementation issues towards potential performance improvement.
- Research Organization:
- Lawrence Berkeley Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 10166493
- Report Number(s):
- LBL-35382-Rev.; CONF-9404167-1-Rev.; ON: DE94014969; IN: DA-316
- Resource Relation:
- Conference: SPIE 13: international symposium on optical materials technology for energy efficiency and solar energy conversion,Freiburg (Germany),18-22 Apr 1994; Other Information: PBD: May 1994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
WINDOWS
GLAZING
OFFICE BUILDINGS
DAYLIGHTING
HOLOGRAPHY
ENERGY CONSERVATION
COMPUTERIZED SIMULATION
RADIOMETERS
DIFFRACTION
320105
990200
BUILDING SERVICES
MATHEMATICS AND COMPUTERS