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DESIGN AND ANALYSIS OF AN INTEGRATED PULSE MODULATED S-BAND POWER AMPLIFIER IN GALLIUM NITRIDE PROCESS

Description: The design of power amplifiers in any semi-conductor process is not a trivia exercise and it is often encountered that the simulated solution is qualitatively different than the results obtained. Phenomena such as oscillation occurring either in-band or out of band and sometimes at subharmonic intervals, continuous spectrum noticed in some frequency bands, often referred to as chaos, and jumps and hysteresis effects can all be encountered and render a design useless. All of these problems might have been identified through a more rigorous approach to stability analysis. Designing for stability is probably the one area of amplifier design that receives the least amount of attention but incurs the most catastrophic of effects if it is not performed properly. Other parameters such as gain, power output, frequency response and even matching may suitable mitigation paths. But the lack of stability in an amplifier has no mitigating path. In addition to of loss of the design completely there are the increased production cycle costs, costs involved with investigating and resolving the problem and the costs involved with schedule slips or delays resulting from it. The Linville or Rollett stability criteria that many microwave engineers follow and rely exclusively on is not sufficient by itself to ensure a stable and robust design. It will be shown that the universal belief that unconditional stability is obtained through an analysis of the scattering matrix S to determine if 1 and |{Delta}{sub S}| < 1 is only part of the procedure and other tools must be used to validate the criteria. The research shown contributes to the state of the art by developing a more thorough stability design technique for designing amplifiers of any class, whether that be current mode or switch mode, than is currently undertaken with the goal of obtaining first pass design ...
Date: April 4, 2012
Creator: SEDLOCK, STEVE
Partner: UNT Libraries Government Documents Department

Low-Enriched Uranium Fuel Conversion Activities for the High Flux Isotope Reactor, Annual Report for FY 2011

Description: This report describes progress made during FY11 in ORNL activities to support converting the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum (UMo) alloy. With both radial and axial contouring of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in performance to users from the current levels achieved with HEU fuel. Studies are continuing to demonstrate that the fuel thermal safety margins can be preserved following conversion. Studies are also continuing to update other aspects of the reactor steady state operation and accident response for the effects of fuel conversion. Technical input has been provided to Oregon State University in support of their hydraulic testing program. The HFIR conversion schedule was revised and provided to the GTRI program. In addition to HFIR conversion activities, technical support was provided directly to the Fuel Fabrication Capability program manager.
Date: March 1, 2012
Creator: Renfro, David G; Cook, David Howard; Freels, James D; Griffin, Frederick P; Ilas, Germina; Sease, John D et al.
Partner: UNT Libraries Government Documents Department

National Energy Audit Tool for Multifamily Buildings Development Plan

Description: The U.S. Department of Energy's (DOE's) Weatherization Assistance Program (WAP) enables low-income families to reduce their energy costs by providing funds to make their homes more energy efficient. In addition, the program funds Weatherization Training and Technical Assistance (T and TA) activities to support a range of program operations. These activities include measuring and documenting performance, monitoring programs, promoting advanced techniques and collaborations to further improve program effectiveness, and training, including developing tools and information resources. The T and TA plan outlines the tasks, activities, and milestones to support the weatherization network with the program implementation ramp up efforts. Weatherization of multifamily buildings has been recognized as an effective way to ramp up weatherization efforts. To support this effort, the 2009 National Weatherization T and TA plan includes the task of expanding the functionality of the Weatherization Assistant, a DOE-sponsored family of energy audit computer programs, to perform audits for large and small multifamily buildings This report describes the planning effort for a new multifamily energy audit tool for DOE's WAP. The functionality of the Weatherization Assistant is being expanded to also perform energy audits of small multifamily and large multifamily buildings. The process covers an assessment of needs that includes input from national experts during two national Web conferences. The assessment of needs is then translated into capability and performance descriptions for the proposed new multifamily energy audit, with some description of what might or should be provided in the new tool. The assessment of needs is combined with our best judgment to lay out a strategy for development of the multifamily tool that proceeds in stages, with features of an initial tool (version 1) and a more capable version 2 handled with currently available resources. Additional development in the future is expected to be needed if more capabilities ...
Date: March 1, 2012
Creator: Malhotra, Mini; MacDonald, Michael; Accawi, Gina K; New, Joshua Ryan & Im, Piljae
Partner: UNT Libraries Government Documents Department

Performance of Variable Capacity Heat Pumps in a Mixed Humid Climate

Description: Variable capacity heat pumps represent the next wave of technology for heat pumps. In this report, the performance of two variable capacity heat pumps (HPs) is compared to that of a single or two stage baseline system. The units were installed in two existing research houses located in Knoxville, TN. These houses were instrumented to collect energy use and temperature data while both the baseline systems and variable capacity systems were installed. The homes had computer controlled simulated occupancy, which provided consistent schedules for hot water use and lighting. The temperature control and energy use of the systems were compared during both the heating and cooling seasons. Multiple linear regression models were used along with TMY3 data for Knoxville, TN in order to normalize the effect that the outdoor air temperature has on energy use. This enables a prediction of each system's energy use over a year with the same weather. The first system was a multi-split system consisting of 8 indoor units and a single outdoor unit. This system replaced a 16 SEER single stage HP with a zoning system, which served as the baseline. Data was collected on the baseline system from August 2009 to December 2010 and on the multi-split system from January 2011 to January 2012. Soon after the installation of the multi-split system, some of the smaller rooms began over-conditioning. This was determined to be caused by a small amount of continuous refrigerant flow to all of the indoor units when the outdoor unit was running regardless of whether they were calling for heat. This, coupled with the fact that the indoor fans run continuously, was providing enough heat in some rooms to exceed the set point. In order to address this, the indoor fans were disabled when not actively heating per the manufacturer's recommendation. ...
Date: April 1, 2012
Creator: Munk, Jeffrey D; Gehl, Anthony C & Jackson, Roderick K
Partner: UNT Libraries Government Documents Department

Potential Energy Savings Due to Phase Change Material in a Building Wall Assembly: An Examination of Two Climates

Description: Phase change material (PCM), placed in an exterior wall, alters the temperature profile within the wall and thus influences the heat transport through the wall. This may reduce the net energy transport through the wall via interactions with diurnal temperature swings in the external environment or reduce the electricity needed to meet the net load through the wall by shifting the time of the peak load to a time when the cooling system operates more efficiently. This study covers a broad range of parameters that can influence the effectiveness of such a merged thermal storage-thermal insulation system. These parameters included climate, PCM location within the wall, amount of PCM, midpoint of the PCM melting and freezing range relative to the indoor setpoint temperature, temperature range over which phase change occurs, and the wall orientation. Two climates are investigated using finite difference and optimization analyses: Phoenix and Baltimore, with two utility rate schedules. Although potential savings for a PCM with optimized properties were greater when the PCM was concentrated near the inside wall surface, other considerations described here lead to a recommendation for a full-thickness application. An examination of the temperature distribution within the walls also revealed the potential for this system to reduce the amount of energy transported through the wall framing. Finally, economic benefits can exceed energy savings when time-of-day utility rates are in effect, reflecting the value of peak load reductions for the utility grid.
Date: March 1, 2012
Creator: Childs, Kenneth W & Stovall, Therese K
Partner: UNT Libraries Government Documents Department

Godiva IV and Juliet Diagnostics CED-1, Rev. 1 (IER-176)

Description: The Juliet experiment is currently in preliminary design (IER-128). This experiment will utilize a suite of diagnostics to measure the physical state of the device (temperature, surface motion, stress, etc.) and the total and time rate of change of neutron and gamma fluxes. A variety of potential diagnostics has been proposed in this CED-1 report. Based on schedule and funding, a subset of diagnostics will be selected for testing using the Godiva IV pulsed reactor as a source of neutrons and gammas. The diagnostics development and testing will occur over a two year period (FY12-13) culminating in a final set of diagnostics to be fielded for he Juliet experiment currently proposed for execution in FY15.
Date: April 11, 2012
Creator: Scorby, J C & Myers, W L
Partner: UNT Libraries Government Documents Department

Inverted Metamorphic Multijunction (IMM) Cell Processing Instructions

Description: This technical report details the processing schedule used to fabricate Inverted Metamorphic Multijunction (IMM) concentrator solar cells at The National Renewable Energy Laboratory (NREL). These devices are used as experimental test structures to support the research at NREL that is focused on increasing the efficiency of photovoltaic power conversion. They are not intended to be devices suitable for deployment in working concentrator systems primarily because of heat sinking issues. The process schedule was developed to be compatible with small sample sizes and to afford relatively rapid turn-around times, in support of research efforts. The report describes the use of electro deposition of gold for both the back and front contacts. Electro-deposition is used because of its rapid turn around time and because it is a benign metallization technique that is seldom responsible for damage to the semiconductors. The layer transfer technique is detailed including the use of a commercially available adhesive and the etching away of the parent gallium arsenide substrate. Photolithography is used to define front contact grids as well as the mesa area of the cell. Finally, the selective wet chemical etchant system is introduced and its use to reveal the back contact is described.
Date: February 1, 2012
Creator: Duda, A.; Ward, S. & Young, M.
Partner: UNT Libraries Government Documents Department

Dynamometer Testing of a NW2200 Drivetrain: Cooperative Research and Development Final Report, CRADA Number CRD-10-394

Description: Northern Power Systems specializes in direct drive wind turbine designs. CRADA CRD-10-394 involved testing the NW2200 wind turbine power train. Power train testing is important because it allows validation of the generator design and some control algorithms prior to installation on a tower, where this data would be more difficult and time consuming to collect. In an effort to keep the commercial product schedule on time, Northern Power requested testing support from the National Renewable Energy Laboratory for this testing. The test program was performed using NREL's 2.5 MW dynamometer test bed at the National Wind Technology Center near Boulder, CO.
Date: April 1, 2012
Creator: Wallen, R.
Partner: UNT Libraries Government Documents Department

Reactive power interconnection requirements for PV and wind plants : recommendations to NERC.

Description: Voltage on the North American bulk system is normally regulated by synchronous generators, which typically are provided with voltage schedules by transmission system operators. In the past, variable generation plants were considered very small relative to conventional generating units, and were characteristically either induction generator (wind) or line-commutated inverters (photovoltaic) that have no inherent voltage regulation capability. However, the growing level of penetration of non-traditional renewable generation - especially wind and solar - has led to the need for renewable generation to contribute more significantly to power system voltage control and reactive power capacity. Modern wind-turbine generators, and increasingly PV inverters as well, have considerable dynamic reactive power capability, which can be further enhanced with other reactive support equipment at the plant level to meet interconnection requirements. This report contains a set of recommendations to the North-America Electricity Reliability Corporation (NERC) as part of Task 1-3 (interconnection requirements) of the Integration of Variable Generation Task Force (IVGTF) work plan. The report discusses reactive capability of different generator technologies, reviews existing reactive power standards, and provides specific recommendations to improve existing interconnection standards.
Date: February 1, 2012
Creator: McDowell, Jason (General Electric, Schenectady, NY); Walling, Reigh (General Electric, Schenectady, NY); Peter, William (SunPower, Richmond, CA); Von Engeln, Edi (NV Energy, Reno, NV); Seymour, Eric (AEI, Fort Collins, CO); Nelson, Robert (Siemens Wind Turbines, Orlando, FL) et al.
Partner: UNT Libraries Government Documents Department

THERMOGRAVIMETRIC CHARACTERIZATION OF GLOVEBOX GLOVES

Description: An experimental project was initiated to characterize mass loss when heating different polymer glovebox glove material samples to three elevated temperatures, 90, 120, and 150 C. Samples from ten different polymeric gloves that are being considered for use in the tritium gloveboxes were tested. The intent of the study was to determine the amount of material lost. These data will be used in a subsequent study to characterize the composition of the material lost. One goal of the study was to determine which glove composition would least affect the glovebox atmosphere stripper system. Samples lost most of the mass in the initial 60 minutes of thermal exposure and as expected increasing the temperature increased the mass loss and shortened the time to achieve a steady state loss. The most mass loss was experienced by Jung butyl-Hypalon{reg_sign} at 146 C with 12.9% mass loss followed by Piercan Hypalon{reg_sign} at 144 C with 11.4 % mass loss and Jung butyl-Viton{reg_sign} at 140 C with 5.2% mass loss. The least mass loss was experienced by the Jung Viton{reg_sign} and the Piercan polyurethane. Unlike the permeation testing (1) the vendor and fabrication route influences the amount of gaseous species that is evolved. Additional testing to characterize these products is recommended. Savannah River Site (SRS) has many gloveboxes deployed in the Tritium Facility. These gloveboxes are used to protect the workers and to ensure a suitable environment in which to handle tritium gas products. The gas atmosphere in the gloveboxes is purified using a stripper system. The process gas strippers collect molecules that may have hydrogen or its isotopes attached, e.g., waters of hydration, acids, etc. Recently, sulfur containing compounds were detected in the stripper system and the presence of these compounds accelerates the stripper system's aging process. This accelerated aging requires the strippers to ...
Date: February 29, 2012
Creator: Korinko, P.
Partner: UNT Libraries Government Documents Department

Wind energy Computerized Maintenance Management System (CMMS) : data collection recommendations for reliability analysis.

Description: This report addresses the general data requirements for reliability analysis of fielded wind turbines and other wind plant equipment. The report provides a rationale for why this data should be collected, a list of the data needed to support reliability and availability analysis, and specific data recommendations for a Computerized Maintenance Management System (CMMS) to support automated analysis. This data collection recommendations report was written by Sandia National Laboratories to address the general data requirements for reliability analysis of operating wind turbines. This report is intended to help develop a basic understanding of the data needed for reliability analysis from a Computerized Maintenance Management System (CMMS) and other data systems. The report provides a rationale for why this data should be collected, a list of the data needed to support reliability and availability analysis, and specific recommendations for a CMMS to support automated analysis. Though written for reliability analysis of wind turbines, much of the information is applicable to a wider variety of equipment and analysis and reporting needs. The 'Motivation' section of this report provides a rationale for collecting and analyzing field data for reliability analysis. The benefits of this type of effort can include increased energy delivered, decreased operating costs, enhanced preventive maintenance schedules, solutions to issues with the largest payback, and identification of early failure indicators.
Date: January 1, 2012
Creator: Peters, Valerie A. & Ogilvie, Alistair B.
Partner: UNT Libraries Government Documents Department

NEAMS Software Licensing, Release, and Distribution: Implications for FY2013 Work Package Planning

Description: The vision of the NEAMS program is to bring truly predictive modeling and simulation (M&S) capabilities to the nuclear engineering community in order to enable a new approach to the analysis of nuclear systems. NEAMS anticipates issuing in FY 2018 a full release of its computational 'Fermi Toolkit' aimed at advanced reactor and fuel cycles. The NEAMS toolkit involves extensive software development activities, some of which have already been underway for several years, however, the Advanced Modeling and Simulation Office (AMSO), which sponsors the NEAMS program, has not yet issued any official guidance regarding software licensing, release, and distribution policies. This motivated an FY12 task in the Capability Transfer work package to develop and recommend an appropriate set of policies. The current preliminary report is intended to provide awareness of issues with implications for work package planning for FY13. We anticipate a small amount of effort associated with putting into place formal licenses and contributor agreements for NEAMS software which doesn't already have them. We do not anticipate any additional effort or costs associated with software release procedures or schedules beyond those dictated by the quality expectations for the software. The largest potential costs we anticipate would be associated with the setup and maintenance of shared code repositories for development and early access to NEAMS software products. We also anticipate an opportunity, with modest associated costs, to work with the Radiation Safety Information Computational Center (RSICC) to clarify export control assessment policies for software under development.
Date: June 1, 2012
Creator: Bernholdt, David E
Partner: UNT Libraries Government Documents Department

The First ASME Code Stamped Cryomodule at SNS

Description: The first spare cryomodule for the Spallation Neutron Source (SNS) has been designed, fabricated, and tested by SNS personnel. The approach to design for this cryomodule was to hold critical design features identical to the original design such as bayonet positions, coupler positions, cold mass assembly, and overall footprint. However, this is the first SNS cryomodule that meets the pressure requirements put forth in the 10 CFR 851: Worker Safety and Health Program. The most significant difference is that Section VIII of the ASME Boiler and Pressure Vessel Code was applied to the vacuum vessel of this cryomodule. Applying the pressure code to the helium vessels within the cryomodule was considered. However, it was determined to be schedule prohibitive because it required a code case for materials that are not currently covered by the code. Good engineering practice was applied to the internal components to verify the quality and integrity of the entire cryomodule. The design of the cryomodule, fabrication effort, and cryogenic test results will be reported in this paper.
Date: July 1, 2012
Creator: Howell, M. P.; Crofford, M. T.; Douglas, D. L.; Kim, S.-H.; Steward, S. T.; Strong, W. H. et al.
Partner: UNT Libraries Government Documents Department

Energy Savings Modeling of Standard Commercial Building Re-tuning Measures: Large Office Buildings

Description: Today, many large commercial buildings use sophisticated building automation systems (BASs) to manage a wide range of building equipment. While the capabilities of BASs have increased over time, many buildings still do not fully use the BAS's capabilities and are not properly commissioned, operated or maintained, which leads to inefficient operation, increased energy use, and reduced lifetimes of the equipment. This report investigates the energy savings potential of several common HVAC system retuning measures on a typical large office building prototype model, using the Department of Energy's building energy modeling software, EnergyPlus. The baseline prototype model uses roughly as much energy as an average large office building in existing building stock, but does not utilize any re-tuning measures. Individual re-tuning measures simulated against this baseline include automatic schedule adjustments, damper minimum flow adjustments, thermostat adjustments, as well as dynamic resets (set points that change continuously with building and/or outdoor conditions) to static pressure, supply air temperature, condenser water temperature, chilled and hot water temperature, and chilled and hot water differential pressure set points. Six combinations of these individual measures have been formulated - each designed to conform to limitations to implementation of certain individual measures that might exist in typical buildings. All of these measures and combinations were simulated in 16 cities representative of specific U.S. climate zones. The modeling results suggest that the most effective energy savings measures are those that affect the demand-side of the building (air-systems and schedules). Many of the demand-side individual measures were capable of reducing annual HVAC system energy consumption by over 20% in most cities that were modeled. Supply side measures affecting HVAC plant conditions were only modestly successful (less than 5% annual HVAC energy savings for most cities for all measures). Combining many of the retuning measures revealed deep savings potential. Some ...
Date: June 1, 2012
Creator: Fernandez, Nicholas; Katipamula, Srinivas; Wang, Weimin; Huang, Yunzhi & Liu, Guopeng
Partner: UNT Libraries Government Documents Department

National Green Building Standard Analysis

Description: DOE's Building America Program is a research and development program to improve the energy performance of new and existing homes. The ultimate goal of the Building America Program is to achieve examples of cost-effective, energy efficient solutions for all U.S. climate zones. Periodic maintenance of an ANSI standard by review of the entire document and action to revise or reaffirm it on a schedule not to exceed five years is required by ANSI. In compliance, a consensus group has once again been formed and the National Green Building Standard is currently being reviewed to comply with the periodic maintenance requirement of an ANSI standard.
Date: July 1, 2012
Creator: NAHB Research Center, Upper Marlboro, Maryland
Partner: UNT Libraries Government Documents Department

U.S. Virgin Islands Petroleum Price-Spike Preparation

Description: This NREL technical report details a plan for the U.S. Virgin Islands (USVI) to minimize the economic damage caused by major petroleum price increases. The assumptions for this plan are that the USVI will have very little time and money to implement it and that the population will be highly motivated to follow it because of high fuel prices. The plan's success, therefore, is highly dependent on behavior change. This plan was derived largely from a review of the actions taken and behavior changes made by companies and commuters throughout the United States in response to the oil price spike of 2008. Many of these solutions were coordinated by or reported through the 88 local representatives of the U.S. Department of Energy's Clean Cities program. The National Renewable Energy Laboratory provides technical and communications support for the Clean Cities program and therefore serves as a de facto repository of these solutions. This plan is the first publication that has tapped this repository.
Date: June 1, 2012
Creator: Johnson, C.
Partner: UNT Libraries Government Documents Department