This paper presents a calorimetric measurement of layer-specific inward-flowing fractions of absorbed solar energy for a number of geometric configurations common in fenestrations with shading. The inward-flowing fractions are found to be relatively insensitive to exterior conditions. Results for an interior venetian blind over double glazing agree with thermal model calculations in the literature, and are the first layer-specific verification of these calculations. It is argued that a data base of these inward-flowing fractions for a suitably broad class of geometries will make possible the determination of solar heat gain coefficient from non-calorimetric measurements of solar-optical properties of complex fenestration components, a procedure termed solar-thermal separation.

%B ASHRAE Transactions %V 102, Part 1 %G eng %L LBL-37038 %1Windows and Daylighting Group

%2 LBL-37038 %0 Conference Paper %B ASHRAE Transactions %D 1995 %T A Comparison Between Calculated and Measured SHGC For Complex Fenestration Systems %A Joseph H. Klems %A Jeffrey L. Warner %A Guy O. Kelley %XCalorimetric measurements of the dynamic net heat flow through a complex fenestration system consisting of a buff venetian blind inside clear double glazing are used to derive the direction-dependent beam SHGC of the fenestration. These measurements are compared with calculations according to a proposed general method for deriving complex fenestration system SHGCs from bidirectional layer optical properties and generic calorimetric properties. Previously published optical measurements of the same venetian blind and generic inward-flowing fraction measurements are used in the calculation. The authors find satisfactory agreement between the SHGC measurements and the calculation.

Significant dependence on incident angle was found in the measured SHGCs. Profile angle was not found to be a useful variable in characterizing the system performance. The predicted SHGC was found to be inherently dependent on two angles, although only the incident angle variations were observable under the test conditions.

%B ASHRAE Transactions %C Atlanta, GA %V 102, Part 1 %8 02/1996 %G eng %L LBL-37037 %1Windows and Daylighting Group

%2 LBL-37037 %0 Conference Paper %B Thermal Performance of the Exterior Envelopes of Buildings VI Conference %D 1995 %T Measured Performance of Selective Glazings %A Joseph H. Klems %A Mehry Yazdanian %A Guy O. Kelley %XMeasurements of the net heat flow through four selective glazings in comparison with clear double glazing under late summer outdoor conditions are presented. The solar heat gain coefficient (SHGC) for each glazing is extracted from the data and shown to be angle-dependent. Good agreement is found between measured properties and calculations with WINDOW 4.1.

%B Thermal Performance of the Exterior Envelopes of Buildings VI Conference %C Clearwater Beach, FL %8 12/1995 %G eng %L LBL-37747 %1Windows and Daylighting Group

%2 LBL-37747