01722nas a2200169 4500008004100000245006100041210006100102260003100163490001600194520115400210100002501364700002901389700002401418700001601442700002201458856007201480 1997 eng d00aGuidelines for Modeling Projecting Fenestration Products0 aGuidelines for Modeling Projecting Fenestration Products aSan Francisco, CAc01/19980 v104, Part 13 a
Heat transfer patterns in projecting fenestration products (greenhouse windows, skylights, etc.) are different than those with typical planar window products. The projecting surfaces often radiate to each other, thereby invalidating the commonly used assumption that fenestration product interior surfaces radiate to a uniform room air temperature. The convective portion of the surface heat transfer coefficient is also significantly different from the one used with planar geometries, and is even more dependent on geometry and location. Projecting fenestration product profiles must therefore be modeled in their entirety. This paper presents the results of complete cross section, variable film-coefficient, 2-D heat transfer modeling of two greenhouse windows using the next generation of window specific heat transfer modeling tools. The use of variable film-coefficient models is shown to increase the accuracy with which simulation tools can compute U-factors. Simulated U-factors are also determined using conventional constant film coefficient algorithms. The results from both sets of simulations are compared with measured values.
1 aArasteh, Dariush, K.1 aFinlayson, Elizabeth, U.1 aCurcija, Dragan, C.1 aBaker, Jeff1 aHuizenga, Charlie uhttps://facades.lbl.gov/publications/guidelines-modeling-projecting