A new method for predicting the solar heat gain of complex fenestration systems
A new method of predicting the solar heat gain through complex fenestration systems involving nonspecular layers such as shades or blinds has been examined in a project jointly sponsored by ASHRAE and DOE. In this method, a scanning radiometer is used to measure the bidirectional radiative transmittance and reflectance of each layer of a fenestration system. The properties of systems containing these layers are then built up computationally from the measured layer properties using a transmission/multiple-reflection calculation. The calculation produces the total directional-hemispherical transmittance of the fenestration system and the layer-by-layer absorptances. These properties are in turn combined with layer-specific measurements of the inward-flowing fractions of absorbed solar energy to produce the overall solar heat gain coefficient. This method has been used to determine the solar heat gain coefficient of a double-glazed window with an interior white shade. The resulting solar heat gain coefficient was compared to a direct measurement of the same system using the Mobile Window Thermal Test (MoWiTT) Facility for measuring window energy performance, and the two results agreed. This represents the first in a series of planned validations and applications of the new method.
- Research Organization:
- Lawrence Berkeley Lab., CA (United States)
- Sponsoring Organization:
- USDOE; ASHRAE; USDOE, Washington, DC (United States); American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6928587
- Report Number(s):
- LBL-32198; CONF-921239-1; ON: DE93004770; CNN: Agreement BG87-127
- Resource Relation:
- Conference: American Society of Heating and Refrigerating, and Air Conditioning Engineers/Department of Energy (ASHRAE/DOE/BTECC) thermal performance of the exterior envelopes of buildings 5 conference, Clearwater Beach, FL (United States), 7-10 Dec 1992
- Country of Publication:
- United States
- Language:
- English
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