A New Method for Predicting the Solar Heat Gain of Complex Fenestration Systems II. Detailed Description of the Matrix Layer Calculation

TitleA New Method for Predicting the Solar Heat Gain of Complex Fenestration Systems II. Detailed Description of the Matrix Layer Calculation
Publication TypeJournal Article
Year of Publication1993
AuthorsJoseph H. Klems
JournalASHRAE Transactions
Volume100
Issue1
Other NumbersDA-321
Abstract

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 bi-directional 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.

A preceding paper outlined the method and provided the physical derivation of the calculation. In this second of a series of related papers the detailed development of the matrix layer calculation is presented.

LBNL Report Number

LBL-34716