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.

1 aKlems, Joseph, H. uhttps://facades.lbl.gov/publications/solar-heat-gain-through-skylight01152nas a2200109 4500008004100000050001500041245011700056210006900173520069900242100002200941856007900963 2000 eng d aLBNL-4668200aSolar Heat Gain Through Fenestrations Containing Shading: Procedures for Estimating Performace from Minimal Data0 aSolar Heat Gain Through Fenestrations Containing Shading Procedu3 aThe 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.

1 aKlems, Joseph, H. uhttps://facades.lbl.gov/publications/solar-heat-gain-through-fenestrations01177nas a2200145 4500008004100000050001500041245011000056210006900166260003000235490001600265520062700281100002200908700002400930856007700954 1996 eng d aLBNL-3924800aSolar Heat Gain Coefficient of Complex Fenestrations with a Venetian Blind for Differing Slat Tilt Angles0 aSolar Heat Gain Coefficient of Complex Fenestrations with a Vene aPhiladelphia, PAc01/19970 v103, Part 13 aMeasured 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.

1 aKlems, Joseph, H.1 aWarner, Jeffrey, L. uhttps://facades.lbl.gov/publications/solar-heat-gain-coefficient-complex