Detailed heat flow measurements on a skylight mounted on a light well of significant depth are presented. It is shown that during the day much of the solar energy that strikes the walls of the well does not reach the space below. Instead, this energy is trapped in the stratified air of the light well and eventually either conducted through the walls of the well or back out through the skylight. The standard model for predicting fenestration heat transfer does not agree with the measurements when it is applied to the skylight/well combination as a whole (the usual practice), but does agree reasonably well when it is applied to the skylight alone, using the well air temperature near the skylight. A more detailed model gives good agreement. Design implications and future research directions are discussed.

%B ASHRAE Chicago %C Chicago, IL %V 108, Part 1 %P 512-524 %8 01/2003 %G eng %L LBNL-48835 %1Windows and Daylighting Group

%2 LBNL-48835 %0 Conference Paper %D 2001 %T Solar Heat Gain through Fenestration Systems Containing Shading: Summary of Procedures for Estimating Performance from Minimal Data %A Joseph H. Klems %XThe computational methods for calculating the properties of glazing systems containing shading from the properties of their components have been developed, but the measurement standards and property data bases necessary to apply them have not. It is shown that with a drastic simplifying assumption these methods can be used to calculate system solar-optical properties and solar heat gain coefficients for arbitrary glazing systems, while requiring limited data about the shading. Detailed formulas are presented, and performance multipliers are defined for the approximate treatment of simple glazings with shading. As higher accuracy is demanded, the formulas become very complicated.

%V 108, Part 1 %P 512-524 %G eng %L LBNL-48672 %1Windows and Daylighting Group

%2 LBNL-48672 %0 Report %D 2000 %T Solar Heat Gain Through Fenestrations Containing Shading: Procedures for Estimating Performace from Minimal Data %A Joseph H. Klems %XThe computational methods for calculating the properties of glazing systems containing shading from the properties of their components have been developed, but the measurement standards and property data bases necessary to apply them have not. It is shown that with a drastic simplifying assumption these methods can be used to calculate system solar-optical properties and solar heat gain coefficients for arbitrary glazing systems, while requiring limited data about the shading. Detailed formulas are presented, and performance multipliers are defined for the approximate treatment of simple glazings with shading. As higher accuracy is demanded, the formulas become very complicated.

%G eng %L LBNL-46682 %1Windows and Daylighting Group

%2 LBNL-46682 %0 Conference Paper %B ASHRAE Symposium %D 1996 %T Solar Heat Gain Coefficient of Complex Fenestrations with a Venetian Blind for Differing Slat Tilt Angles %A Joseph H. Klems %A Jeffrey L. Warner %XMeasured bidirectional transmittances and reflectances of a buff-colored venetian blind together with a layer calculation scheme developed in previous publications are utilized to produce directional-hemispherical properties for the venetian blind layer and solar heat gain coefficients for the blind in combination with clear double glazing. Results are presented for three blind slat tilt angles and for the blind mounted either interior to the double glazing or between the glass panes. Implications of the results for solar heat gain calculations are discussed in the context of sun positions for St. Louis, MO.

%B ASHRAE Symposium %C Philadelphia, PA %V 103, Part 1 %8 01/1997 %G eng %L LBNL-39248 %1Windows and Daylighting Group

%2 LBNL-39248 %0 Journal Article %J Review of Scientific Instruments %D 1985 %T Simple Phase-Sensitive Detector for Wheatstone Bridge Resistance Measurements %A Dennis L. DiBartolomeo %A Joseph H. Klems %XA simple and economical phase-sensitive detector circuit is described. The circuit, which was developed for use with large-area heat-flow sensors that employ resistance temperature detection, uses a synchronous rectifier driven by a square wave. It is shown that the circuit has good linearity, resolution, and immunity to external and internal noise.

%B Review of Scientific Instruments %V 56 %P 755-757 %G eng %L LBL-18002 %1Windows and Daylighting Group

%2 LBL-18002