02100nas a2200169 4500008004100000050001500041245008300056210006900139300001000208490001200218520153600230100002301766700001901789700002301808700002701831856007201858 1997 eng d aLBNL-4009600aAnalysis of Binary Electrochromic Tungsten Oxides with Effective Medium Theory0 aAnalysis of Binary Electrochromic Tungsten Oxides with Effective a50-550 v308-3093 a

Multicomponent oxides are of increasing interest for electrochromic electrodes. To reduce the large number of permutations in composition it would be useful to be able to predict the properties of the mixtures from the pure oxide components. WO3 mixed with V2O5 has been produced by a sol-gel technique in order to increase durability and color neutrality of conventional WO3 electrochromic coatings. Chemical composition was confirmed by Rutherford backscattering spectrometry (RBS). Surface morphology was analyzed by atomic force microscopy (AFM). Electrochromic performance of the films was tested by cyclic voltammetry with in-situ transmission control. Optical constants of vanadium tungsten oxides were determined over the whole solar spectrum. The measurements included variable angle spectroscopic ellipsometry and spectral transmittance and reflectance. An attempt is made to treat doped tungsten oxide as an effective medium consisting of a mixture of WO3 with V2O5. In the clear state, comparison of optical constants and thickness directly determined on the samples yields qualitative agreement with results from effective-medium analysis. The resulting component fraction also agrees as long as the film density does not deviate too much from the linearly interpolated value between the pure components. For the colored state, preferential trapping of electrons at one atom species hinders the application of effective medium theory.

1 avon Rottkay, Klaus1 aÖzer, Nilgün1 aRubin, Michael, D.1 aRichardson, Thomas, J. uhttps://facades.lbl.gov/publications/analysis-binary-electrochromic01836nas a2200169 4500008004100000050001500041245008800056210006900144260002700213520124400240100001701484700001901501700002301520700002401543700002301567856007601590 1996 eng d aLBNL-3963300aAnalysis of Durability in Lithium Nickel Oxide Electrochromic Materials and Devices0 aAnalysis of Durability in Lithium Nickel Oxide Electrochromic Ma aSan Diego, CAc10/19963 a

Thin films of lithium nickel oxide were deposited by sputtering and laser ablation from targets of pressed nickel oxide and lithium oxide powders. These films were assembled into electrochromic test devices with tungsten oxide as the opposite electrode and a polymer electrolyte. Analysis of the failure modes was carried out at several levels: The composition and structure of the films were examined before and after cycling using a variety of techniques, such as infrared spectroscopy, nuclear-reaction analysis, Rutherford backscattering spectrometry, x-ray diffraction and atomic force microscopy. Absorption of water vapor was found to be a major factor determining the cyclic stability of the films. A new technique is described for incorporating reference electrodes made from an electronically isolated corner into devices. This structure enabled identification of potential problems associated with a particular interface. Finally, some of the devices were disassembled and the components examined. For example, a small quantity of the polymer was extracted and studied by gas chromatography and mass spectroscopy. Small organic fragments were discovered which correspond to expected weak points in the polymer structures.

1 aWen, Shi-Jie1 aKerr, John, B.1 aRubin, Michael, D.1 aSlack, Jonathan, L.1 avon Rottkay, Klaus uhttps://facades.lbl.gov/publications/analysis-durability-lithium-nickel03749nas a2200193 4500008004100000245010100041210006900142260003400211520306200245100002903307700002503336700002303361700001803384700002103402700002203423700002403445700001603469856007003485 1995 eng d00aAdvances in Thermal and Optical Simulations of Fenestration Systems: The Development of WINDOW 50 aAdvances in Thermal and Optical Simulations of Fenestration Syst aClearwater Beach, FLc12/19953 a

WINDOW is a personal-computer-based computer program used by manufacturers, researchers, and consumers to evaluate the thermal performance properties (U-factors, solar heat gain and shading coefficients, and visible transmittances) of complete windows and other fenestration systems. While WINDOW is used by thousands of users in the United States and internationally and is at the foundation of the National Fenestration Rating Council's U-factor and solar heat gain property procedures, improvements to the program are still necessary for it to meet user needs. Version 5, intended for release in late 1995, is being developed to meet these needs for increased accuracy, a flexible and state-of-the-art user interface, and the capabilities to handle more product types.

WINDOW 5 includes the capabilities to define and model the thermal performance of frames/dividers and their associated edge effects. Currently, such an analysis must be performed outside of WINDOW and requires simplifications to be made to frame profiles or is based on the use of generic frame and edge correlations. WINDOW's two-dimensional thermal model is composed of four sections: a graphical input, automatic grid generation, an finite-element analysis (FEA) solution, and the display of results. In the graphical input section, users are able to directly import a computer-aided design (CAD) drawing or a scanned image of a window profile, replicate its exact geometry, and assign material types and boundary conditions. The automatic grid generation is transparent to the user, with the exception of the requirement that complex shapes (i.e., an aluminum extrusion) be broken down into simpler polyshapes. Inclusion of an automatic grid generation makes detailed "true geometry" frame-and-edge heat-transfer analysis accessible to users without extensive knowledge of numerical methods of heat-transfer analysis. After the cross section is meshed it is sent to the FEA engine for solution and the results are returned. A postprocessor allows for the visual display of temperature and heat flux plots. Note that while this two-dimensional heat-transfer tool is being developed specifically for fenestration products, it also can be used to analyze other building envelope components.

WINDOW 5 also will include a built-in version of a national laboratory's program that allows the user to estimate the orientation-dependent annual energy impacts of a given window in a typical residence in various U.S. climates. This program is based on regressions to a database of DOE2.1 runs. Future versions will include a similar feature for commercial buildings.

Other technical additions include an improved angular/ spectral model for coated and uncoated glazings, the ability to analyze the optical properties of nonhomogeneous layers, and the ability to model the effects of laminated glazing layers. A door module permits the user to compute the total U-factors of exterior doors based on component U-factors calculated using the two-dimensional FEA module.

1 aFinlayson, Elizabeth, U.1 aArasteh, Dariush, K.1 aRubin, Michael, D.1 aSadlier, John1 aSullivan, Robert1 aHuizenga, Charlie1 aCurcija, Dragan, C.1 aBeall, Mark uhttps://facades.lbl.gov/publications/advances-thermal-and-optical