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At least 307 records · Page 17

All sources NASA NTRS DOE OSTI

DOE OSTI2015

Analysis of Environmentally Friendly Refrigerant Options for Window Air Conditioners

This paper presents a technical assessment of environmentally friendly refrigerants as alternatives to R410A for window air conditioners. The alternative refrigerants that are studied for its replacement include R32, a mixture of R32/R125 with 90%/10% molar concentration, R600a, R290, R1234yf, R1234ze and R134a. Baseline experiments were performed on a window unit charged with R410A. The heat pump design model (HPDM) was modified and calibrated with the baseline data and was used to evaluate the comparative performance of the WAC with alternative refrigerants. The paper discusses the advantages and disadvantages of each refrigerants and their suitability for window air conditioners. Among all the refrigerants studied, R32 offers the best efficiency and the lowest Global Warming Potential (GWP), and hence its use will result in the overall environmental friendliness.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2018

Effect of Window-Layer Materials on p-n Junction Location in Cu(In,Ga)Se 2 Solar Cells

We report on measurements of junction location in Cu(In,Ga)Se $_{2}$ (CIGS) solar cells with different window-layer materials by nm-resolution electrical potential/field profiling across the junction using Kelvin probe force microscopy imaging on cross-section of the devices. The results illustrate that the device with a CdS window layer (CdS/CIGS) has a buried homojunction located inside the CIGS absorber with ~40-nm junction depth, whereas the ZnOS/CIGS devices with and without partial electrolyte treatment prior to the window-layer deposition are similar, exhibiting a heterointerface junction. This junction location may contribute in part to the highest efficiency of the CdS/CIGS device among the three devices.

14 SOLAR ENERGY↗

DOE OSTI2016

Study of the integrity of pressurized LEH window assemblies at cryogenic temperatures for NIF targets

The National Ignition Facility (NIF) is a directorate of LLNL, a DOE Lab, and is home to the world’s largest laser. This laser shoots its 192 beams at a target about the size of a pencil eraser. Within the target are two main chambers; and depending on the type of shot, those chambers need to be pressurized to a certain point at a very low temperature (18 Kelvin). The component used for keeping the hohlraum at its designated pressure is a Laser Entrance Hole (LEH) window, made from a thin (0.5um) polyimide film and an aluminum washer attached with a miniscule amount of polymeric adhesive. One issue that has been known to happen is the chambers will leak, at very low rates (5.0E-7 mBar-liter/s and under). At higher pressures significantly larger leak rates have been observed.There are three proposed mechanisms by which the LEH windows are leaking. The first is that there is a small pinhole somewhere in the freestanding film. This is the most unlikely because before any film is shipped from Luxel, it must pass a 50-75 torr room temperature pressure test. The second is a tear in the film at the edge of the washer. This type of damage suggests that the film is under additional stress at this edge portion and/or the edge of the washer itself is what is doing the damage. Lastly, it has been hypothesized that there are small channels under the window that do not get completely filled by the glue and, if they connect to the edge of the freestanding portion of the film, then the pressure can escape through them. These channels were the mechanism being most directly tested over the course of the experiments.

42 ENGINEERING↗

DOE OSTI2016

Assessment of candidates for target window material in accelerator-driven molybdenum-99 production

NorthStar Medical Technologies is pursuing production of an important medical isotope, Mo-99, through a photo-nuclear reaction of a Mo-100 target using a high-power electron accelerator. The current target utilizes an Inconel 718 window. The purpose of this study was to evaluate other candidate materials for the target window, which separates the high-pressure helium gas inside the target from the vacuum inside the accelerator beamline and is subjected to significant stress. Our initial analysis assessed the properties (density, thermal conductivity, maximum stress, minimum window thickness, maximum temperature, and figure of merit) for a range of materials, from which the three most promising were chosen: Inconel 718, 250 maraging steel, and standard-grade beryllium. These materials were subjected to further analysis to determine the effects of thermal and mechanical strain versus beam power at varying thicknesses. Both beryllium and the maraging steel were calculated to withstand more than twice as high beam power than Inconel 718.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Demonstration and Evaluation of Lightweight High Performance Quad-Pane Windows

Ten high-performance quad-pane windows (five quad-pane with suspended film and five quad-pane with thin glass) were installed at Building 41 of the Denver Federal Center in Colorado as part of a demonstration project to assess their thermal performance, life cycle costs, and deployment potential for replacing older single-pane windows. The U.S. Department of Energy's National Renewable Energy Laboratory performed several different evaluations to assess the viability of the quad-pane windows for GSA applications. Some of these assessments were performed with models, while others required onsite evaluations including time series measurements.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2021

Advancing insulation retrofits from flexible inexpensive lucid materials (AIR FILMs) for single-pane windows

This project focused on Advancing Insulation Retrofits from Flexible Inexpensive Lucid Materials (AIR FILMs) for Single-Pane Windows. The team developed innovative porous materials that can improve the energy efficiency of existing single-pane windows in commercial and residential buildings in two technical product categories: (1) retrofits that can be applied onto existing windowpanes and (2) manufactured windowpanes that can be installed into the existing window sash.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2021

Demonstration and Evaluation of Lightweight High Performance Secondary Windows

Eight secondary windows (single-pane and double-pane) were installed at Building 53 of the Denver Federal Center in Colorado as part of a demonstration project to assess their thermal performance, life cycle costs, and deployment potential for use in conjunction with existing, older single-pane windows. The U.S. Department of Energy's National Renewable Energy Laboratory performed several different evaluations to assess the viability of the secondary windows for GSA applications. Some assessments were performed with models, while others required onsite evaluations including time series measurements.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2022

Extending Analysis of Asay Windows to High Areal Mass Range [Slides]

The accretion layer addition to Asay window analysis results in new equations of motion that depend on the location of collisions within the layer. Asay window equations of motion can be represented in terms of experiment observables. Balance of linear momentum for variable mass systems provides a framework for developing equations of motion for Asay window diagnostics under a variety of operating assumptions. The growth in the accretion layer thickness during an experiment substantially influences mass and density measurements when high accumulation of areal mass is present.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2023

Extending the Asay window measurement model to high areal mass ranges [Slides]

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2018

10% Loss of Incident Power through Solar Reactor Window: Myth or Good Rule of Thumb?

It is known that a solar beam crossing a window losses 10% of its incident power. Yet, this affirmation is not supported by many published scientific evidences. In this work, a heat flux mapping method was used to determine the heat flux distributions at the focal spot of a solar concentrating device without and with a window on the incident beams' trajectory. The presence of a window on the beams' trajectory induces a 12% loss of the total power and a 11% decrease of the peak heat flux density.

14 SOLAR ENERGY↗

DOE OSTI2014

Characterization of an explosively bonded aluminum proton beam window for the Spallation Neutron Source

An effort is underway at the Spallation Neutron Source (SNS) to change the design of the 1st Generation high-nickel alloy proton beam window (PBW) to one that utilizes aluminum for the window material. One of the key challenges to implementation of an aluminum PBW at the SNS was selection of an appropriate joining method to bond an aluminum window to the stainless steel bulk shielding of the PBW assembly. An explosively formed bond was selected as the most promising joining method for the aluminum PBW design. A testing campaign was conducted to evaluate the strength and efficacy of explosively formed bonds that were produced using two different interlayer materials: niobium and titanium. The characterization methods reported here include tensile testing, thermal-shock leak testing, optical microscopy, and advanced scanning electron microscopy. All tensile specimens examined failed in the aluminum interlayer and measured tensile strengths were all slightly greater than the native properties of the aluminum interlayer, while elongation values were all slightly lower. A leak developed in the test vessel with a niobium interlayer joint after repeated thermal-shock cycles, and was attributed to an extensive crack network that formed in a layer of niobium-rich intermetallics located on the bond interfaces of the niobium interlayer; the test vessel with a titanium interlayer did not develop a leak under the conditions tested. Due to the experience gained from these characterizations, the explosively formed bond with a titanium interlayer was selected for the aluminum PBW design at the SNS.

316L Stainless Steel↗

DOE OSTI2014

Assessment of Environmentally Friendly Refrigerants for Window Air Conditioners

This paper presents technical assessment of environmentally friendly refrigerants for window air conditioners that currently use refrigerant R410A for residential and commercial applications. The alternative refrigerants that are studied for its replacement include R32, R600a, R290, R1234yf, R1234ze and a mixture of R32 (90% molar concentration) and R125 (10% molar concentration). Baseline experiments were performed on a window unit charged with R410A. The ORNL Heat Pump Design Model was calibrated with the baseline data and was used to assess the comparative performance of the WAC with alternative refrigerants. The paper discusses the advantages and disadvantages of each refrigerants and their suitability for window air conditioners.

Alternative refrigerants↗

DOE OSTI2012

Measure Guideline: Window Repair, Rehabilitation, and Replacement

This measure guideline provides information and guidance on rehabilitating, retrofitting, and replacing existing window assemblies in residential construction. The intent is to provide information regarding means and methods to improve the energy and comfort performance of existing wood window assemblies in a way that takes into consideration component durability, in-service operation, and longterm performance of the strategies.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2014

Evaluation of Low-E Storm Windows in the PNNL Lab Homes

This study examines the performance of exterior and interior low-e storm panels with a controlled whole home experimental design using PNNL's Lab Homes. Summing the estimated annual average heating and cooling savings, the installation of low-e storm panels resulted in approximately 10% annual energy savings. The results of the experiment will be used to determine and validate performance of low-e storm windows over double pane clear glass windows in a whole home setting.

energy savings↗

DOE OSTI2012

Measure Guideline: Wood Window Repair, Rehabilitation, and Replacement

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2026

Side-Chain Nanophase Separation Broadens the Double-Gyroid Stability Window in PS–PODMA Diblock Copolymers

Expanding access to bicontinuous network phases in block copolymers remains an important challenge because the double gyroid (DG) phase is usually stable only within a narrow composition window in conventional diblock copolymers. Here, we show that poly(styrene-block-octadecyl methacrylate) (PS-b-PODMA) exhibits an unusually broad DG window. Small-angle X-ray scattering measurements across a wide composition range reveal lamellar and hexagonally packed cylindrical phases at higher polystyrene fractions. In contrast, the DG phase appears over 0.22 ≤ fPS ≤ 0.35, with DG/BCC and DG/HEX coexistence near fPS = 0.18 and 0.40, respectively. This broad DG window is much wider than those reported for neat diblock copolymers and is not readily explained by conformational asymmetry alone. Wide-angle X-ray scattering detects a characteristic signature of nanophase separation within the PODMA-rich domains, indicating that side-chain ordering introduces an additional internal length scale. These results suggest that hierarchical side-chain nanophase separation modifies packing frustration and curvature selection, thereby broadening DG stability and providing a new molecular design strategy for stabilizing complex network morphologies.

Seko, Tamio↗

DOE OSTI2019

One-Dimensional Metallo-Superconductor Photonic Crystals as a Smart Window

A new structure to control the electromagnetic waves has been successfully designed for smart windows applications. The present photonic crystals (PCs) smart window is designed from a unit cell of two different materials such as A (metal) and B (superconductor) of thicknesses that repeated for N periods. The numerical results are investigated based on the characteristic matrix method. It was found that the angle of incidence has a significant effect on the transmission values. At 10{sup o} angle of incidence, we found more than 80% of the visible light and a near IR is transmitted whereas at 60{sup o} angle of incidence, the photonic band gap (PBG) begins to appear at wavelengths greater than 800 nm and the visible light transmittance remains more than 80%. Also, the dependence of the transmittance values on the periodicity and thickness of the proposed design was investigated. The proposed structure could be of potential use as a smart window in low-temperature applications and space industry.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2026

Efficacy of Gadolinium Gallium Garnet (GGG) as a High-Impedance Optical Window for Shock Wave Experiments

We conducted a series of plate impact experiments to examine the efficacy of < 111>-oriented gadolinium gallium garnet (GGG) single crystals as high-impedance optical window for Photonic Doppler velocimetry (PDV) under shock and double-shock loading. At ~ 123 GPa, shocked GGG remains fully transparent to 1550 nm light for at least 250 ns without any signal degradation. Above 135 GPa, PDV data measured through GGG exhibit a gradual loss of fringe contrast following shock entrance, which eventually leads to transparency loss. The duration for which shocked GGG remains transparent decreases with increasing pressure, and at ~ 148 GPa, it becomes opaque within ~ 20–30 ns. This limits the use of GGG as an interferometry window between ~ 110–140 GPa under single shock loading. Within this pressure range, the refractive index of GGG increases linearly with density: n = 1.552 + 0.054ρ. In contrast to single shock loading, where GGG becomes opaque rapidly above ~ 140 GPa, double-shocked GGG remains optically transparent for over 100 ns when it is first shocked to ~ 123 GPa and then reshocked to significantly higher pressures (215–233 GPa). Our findings raise the exciting possibility of GGG being used as a high-impedance optical window in multi-shock and shock-ramp loading experiments.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗