02515nas a2200145 4500008004100000245008900041210006900130260003000199490001600229520198000245100002102225700002402246700002502270856007402295 2000 eng d00aNatural Convection Effects in Three-Dimensional Window Frames with Internal Cavities0 aNatural Convection Effects in ThreeDimensional Window Frames wit aCincinnati, Ohioc06/20010 v107, Part 23 a

This paper studies three-dimensional natural convection effects in window frames with internal cavities. Infrared (IR) thermography experiments, computational fluid dynamics (CFD) simulations, and calculations with traditional software for simulating two-dimensional heat conduction were conducted. The IR thermography experiments mapped surface temperatures during steady-state thermal tests between ambi-ent thermal chambers set at 0 deg. C and 20 deg. C. Using anon-contact infrared scanning radiometer and an external referencing technique, we were able to obtain surface temperature maps with a resolution of 0.1 deg. C and 3 mm and an estimated uncertainty of 0.5 deg. C and +/-3 mm. The conjugate CFD simulations modeled the enclosed air cavities, frame section walls, and foam board surround panel. With the two-dimensional heat conduction simulation software, weusedcorrelations to model heat transfer in the air cavities. For both the CFD simulations and the conduction simulation software, boundary conditions at the external air/solid interface were modeled using constant surface heat-transfer coefficients with fixed ambient air temperatures.

Different cases were studied, including simple, four-sided frame sections (with one open internal cavity), simple vertical sections with a single internal cavity, and horizontal sections with a single internal cavity. The sections tested in the Infrared Thermography Laboratory (IR lab) were made of PVC. Both PVC and thermally broken aluminum sections were modeled. Based on the current investigations, it appears that the thermal transmittance or U-factor of a four-sided section can be found by calculating the average of the thermal transmittance of the respective single horizontal and vertical sections. In addition, we conclude that two-dimensional heat transfer simulation software agrees well with CFD simulations if the natural convection correlations used for the internal cavities are correct.

1 aGustavsen, Arlid1 aGriffith, Brent, T.1 aArasteh, Dariush, K. uhttps://facades.lbl.gov/publications/natural-convection-effects-three01437nas a2200157 4500008004100000050001500041245009200056210006900148260003100217520085700248100002001105700002001125700002501145700002101170856008801191 1996 eng d aLBNL-3969200aThe National Energy Requirements of Residential Windows in the U.S.: Today and Tomorrow0 aNational Energy Requirements of Residential Windows in the US To aPacific Grove, CAc08/19963 a

This paper describes an end-use analysis of the national energy requirements of U.S. residential window technologies. We estimate that the current U.S. stock of 19 billion square feet of residential windows is responsible for 1.7 quadrillion BTUs (or quads) per year of energy use - 1.3 quads of heating and 0.4 quads of cooling energy - which represents about 2% of total U.S. energy consumption. We show that national energy use due to windows could be reduced by 25% by the year 2010 through accelerated adoption of currently available, advanced window technologies such as low-e and solar control low-e coatings, vinyl and wood frames, and superwindows. We evaluate the economics of the technologies regionally, considering both climatic and energy price variations, and find that the technologies would be cost effective for most consumers.

1 aFrost, Karl, J.1 aEto, Joseph, H.1 aArasteh, Dariush, K.1 aYazdanian, Mehry uhttp://aceee.org/files/proceedings/1996/data/papers/SS96_Panel10_Paper07.pdf#page=101245nas a2200169 4500008004100000024001100041245008800052210006900140260002900209520065400238100001800892700001800910700002100928700002500949700002700974856007401001 1995 eng d aBS-33100aNFRC Efforts to Develop a Residential Fenestration Annual Energy Rating Methodology0 aNFRC Efforts to Develop a Residential Fenestration Annual Energy aToronto, Canadac06/19953 a

This paper documents efforts currently being undertaken by the National Fenestration Rating Councils Annual Energy Rating Subcommittee to develop procedures to quantify the energy impacts of fenestration products in typical residential buildings throughout the United States. Parallel paths focus on (1) the development of simplified heating and cooling indices and (2) the development of a more detailed methodology to calculate the cost and energy impacts of specific products in a variety of housing types. These procedures are currently under discussion by NFRCs Technical Committee; future efforts will also address commercial buildings.

1 aCrooks, Brian1 aLarsen, James1 aSullivan, Robert1 aArasteh, Dariush, K.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/nfrc-efforts-develop-residential