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Mixing Appropriations and Private Financing to Meet Federal Energy Management Goals

Description: This report compares several strategies for mixing appropriations and private financing in a typical federal agency that has identified $100 million in required energy conservation measures (ECMs) at its facilities. The analysis shows that in order to maximize savings and minimize overall life-cycle cost, the best strategy for the agency is to use private financing to fund as many of the ECMs as possible within the statutory maximum 25-year project term, beginning with the ECMs with the shortest paybacks. Available appropriations should either be applied to a privately financed project as a one-time payment from savings (i.e., as a buydown ) or used to directly fund longer-payback ECMs that cannot be included in the privately financed project.
Date: June 1, 2012
Creator: Shonder, John A
Partner: UNT Libraries Government Documents Department

The Life-cycle of Operons

Description: Operons are a major feature of all prokaryotic genomes, but how and why operon structures vary is not well understood. To elucidate the life-cycle of operons, we compared gene order between Escherichia coli K12 and its relatives and identified the recently formed and destroyed operons in E. coli. This allowed us to determine how operons form, how they become closely spaced, and how they die. Our findings suggest that operon evolution is driven by selection on gene expression patterns. First, both operon creation and operon destruction lead to large changes in gene expression patterns. For example, the removal of lysA and ruvA from ancestral operons that contained essential genes allowed their expression to respond to lysine levels and DNA damage, respectively. Second, some operons have undergone accelerated evolution, with multiple new genes being added during a brief period. Third, although most operons are closely spaced because of a neutral bias towards deletion and because of selection against large overlaps, highly expressed operons tend to be widely spaced because of regulatory fine-tuning by intervening sequences. Although operon evolution seems to be adaptive, it need not be optimal: new operons often comprise functionally unrelated genes that were already in proximity before the operon formed.
Date: November 18, 2005
Creator: Price, Morgan N.; Arkin, Adam P. & Alm, Eric J.
Partner: UNT Libraries Government Documents Department

Evaluating indoor exposure modeling alternatives for LCA: A case study in the vehicle repair industry

Description: We evaluated three exposure models with data obtained from measurements among workers who use"aerosol" solvent products in the vehicle repair industry and with field experiments using these products to simulate the same exposure conditions. The three exposure models were the: 1) homogeneously-mixed-one-box model, 2) multi-zone model, and 3) eddy-diffusion model. Temporally differentiated real-time breathing zone volatile organic compound (VOC) concentration measurements, integrated far-field area samples, and simulated experiments were used in estimating parameters, such as emission rates, diffusivity, and near-field dimensions. We assessed differences in model input requirements and their efficacy for predictive modeling. The One-box model was not able to resemble the temporal profile of exposure concentrations, but it performed well concerning time-weighted exposure over extended time periods. However, this model required an adjustment for spatial concentration gradients. Multi-zone models and diffusion-models may solve this problem. However, we found that the reliable use of both these models requires extensive field data to appropriately define pivotal parameters such as diffusivity or near-field dimensions. We conclude that it is difficult to apply these models for predicting VOC exposures in the workplace. However, for comparative exposure scenarios in life-cycle assessment they may be useful.
Date: May 1, 2009
Creator: Demou, Evangelia; Hellweg, Stefanie; Wilson, Michael P.; Hammond, S. Katharine & McKone, Thomas E.
Partner: UNT Libraries Government Documents Department

Life Cycle Assessment of Hydrogen Production via Natural Gas Steam Reforming

Description: A life cycle assessment of hydrogen production via natural gas steam reforming was performed to examine the net emissions of greenhouse gases as well as other major environmental consequences. LCA is a systematic analytical method that helps identify and evaluate the environmental impacts of a specific process or competing processes.
Date: September 28, 2000
Creator: Spath, P. L. & Mann, M. K.
Partner: UNT Libraries Government Documents Department

The role of Life Cycle Assessment in identifying and reducing environmental impacts of CCS

Description: Life Cycle Assessment (LCA) should be used to assist carbon capture and sequestration (CCS) planners to reduce greenhouse gas (GHG) emissions and avoid unintended environmental trade-offs. LCA is an analytical framework for determining environmental impacts resulting from processes, products, and services. All life cycle stages are evaluated including raw material sourcing, processing, operation, maintenance, and component end-of-life, as well as intermediate stages such as transportation. In recent years a growing number of LCA studies have analyzed CCS systems. We reviewed 50+ LCA studies, and selected 11 studies that compared the environmental performance of 23 electric power plants with and without CCS. Here we summarize and interpret the findings of these studies. Regarding overall climatemitigation effectiveness of CCS, we distinguish between the capture percentage of carbon in the fuels, the net carbon dioxide (CO2) emission reduction, and the net GHG emission reduction. We also identify trade-offs between the climate benefits and the potential increased non-climate impacts of CCS. Emissions of non-CO2 flue gases such as NOx may increase due to the greater throughput of fuel, and toxicity issues may arise due to the use of monoethanolamine (MEA) capture solvent, resulting in ecological and human health impacts. We discuss areas where improvements in LCA data or methods are needed. The decision to implement CCS should be based on knowledge of the overall environmental impacts of the technologies, not just their carbon capture effectiveness. LCA will be an important tool in providing that knowledge.
Date: April 20, 2011
Creator: Sathre, Roger; Masanet, Eric; Cain, Jennifer & Chester, Mikhail
Partner: UNT Libraries Government Documents Department

Comparison of Life Cycle Costs for LLRW Management in Texas

Description: This report documents a comparison of life-cycle costs of an assured isolation facility in Texas versus the life-cycle costs for a traditional belowground low-level radioactive waste disposal facility designed for the proposed site near Sierra Blanca, Texas.
Date: August 1, 1999
Creator: Baird, R. D.; Rogers, B. C.; Chau, N. & Kerr, Thomas A
Partner: UNT Libraries Government Documents Department

Systematic Review and Harmonization of Life Cycle GHG Emission Estimates for Electricity Generation Technologies (Presentation)

Description: This powerpoint presentation to be presented at the World Renewable Energy Forum on May 14, 2012, in Denver, CO, discusses systematic review and harmonization of life cycle GHG emission estimates for electricity generation technologies.
Date: June 1, 2012
Creator: Heath, G.
Partner: UNT Libraries Government Documents Department

Dose-Response Modeling for Life Cycle Impact Assessment: Findingsof the Portland Review Workshop

Description: The United Nations Environment Program (UNEP)/SETAC Life Cycle Initiative aims at putting life cycle thinking into practice and at improving the supporting tools for this process through better data and indicators. The initiative has thus launched three programs with associated working groups (see http://www.uneptie.org/pc/sustain/lcinitiative/). The Task Force on Toxic Impacts was established under the Life Cycle Impact Assessment (LCIA) program to establish recommended practice and guidance for use in human toxicity, ecosystem toxicity, and related categories with direct effects on human health and ecosystem health. The workshop consisted of three elements. (A) presentations summarizing (1) the goals of the LCIA Task Force (2) historical approaches to exposure and toxic impacts in LCIA (3) current alternative proposals for addressing human health impacts. Viewgraphs from two of these presentations are provided in Appendix B to this report. (B) Discussion among a panel of experts about the scientific defensibility of these historical and proposed approaches in the context of the goals of the LCIA Task Force 3 on toxicity impacts. (C) Development of the recommendations to the LCIA program and working group for optimum short- and long-term strategies for addressing human health impacts in LCA.
Date: June 1, 2006
Creator: McKone, Thomas E.; Kyle, Amy D.; Jolliet, Olivier; Olsen, StigIrving & Hauschild, Michael
Partner: UNT Libraries Government Documents Department

An Optimizing Algorithm for Automating Lifecycle Assembly Processes

Description: Designing products for ~ assembly and disassembly during its entire Iifecycle for purposes including service, field repair, upgrade, and disposal is a process that involves many disciplines. In additiou finding the best solution often involves considering the design as a whole and by considering its intended Iifecycle. DifFerent goals and cortstmints (compared to initial assembly) require us to re-visit the significant fi,mdamental assumptions and methods that underlie current assembly planning techniques. Previous work in this area has been limited to either academic studies of assembly planning or applied studies of lifecycle assembly processes, which give no attention to automatic planning. It is believed that merging these two areas will result in a much greater ability to design for, analyze, and optimize the disassembly and assembly processes.
Date: December 9, 1998
Creator: Brown, R.G. & Calton, T.L.
Partner: UNT Libraries Government Documents Department

Photovoltaic system reliability

Description: This paper discusses the reliability of several photovoltaic projects including SMUD`s PV Pioneer project, various projects monitored by Ascension Technology, and the Colorado Parks project. System times-to-failure range from 1 to 16 years, and maintenance costs range from 1 to 16 cents per kilowatt-hour. Factors contributing to the reliability of these systems are discussed, and practices are recommended that can be applied to future projects. This paper also discusses the methodology used to collect and analyze PV system reliability data.
Date: October 1, 1997
Creator: Maish, A.B.; Atcitty, C. & Greenberg, D.
Partner: UNT Libraries Government Documents Department

Passive measurement of nitrogen oxides to assess traffic-related pollutant exposure for the East Bay Children's Respiratory Health Study

Description: This paper provides an overview of software interoperability as it relates to the energy simulation of buildings. The paper begins with a discussion of the difficulties in using sophisticated analysis tools like energy simulation at various stages in the building life cycle, and the potential for interoperability to help overcome these difficulties. An overview of the Industry Foundation Classes (IFC), a common data model for supporting interoperability under continuing development by the International Alliance for Interoperability (IAI) is then given. The process of creating interoperable software is described next, followed by specific details for energy simulation tools. The paper closes with the current status of, and future plans for, the ongoing efforts to achieve software interoperability.
Date: September 1, 2003
Creator: Singer, Brett C.; Hodgson, Alfred T.; Hotchi, Toshifumi & Kim, Janice J.
Partner: UNT Libraries Government Documents Department

Software interoperability for energy simulation

Description: This paper provides an overview of software interoperability as it relates to the energy simulation of buildings. The paper begins with a discussion of the difficulties in using sophisticated analysis tools like energy simulation at various stages in the building life cycle, and the potential for interoperability to help overcome these difficulties. An overview of the Industry Foundation Classes (IFC), a common data model for supporting interoperability under continuing development by the International Alliance for Interoperability (IAI) is then given. The process of creating interoperable software is described next, followed by specific details for energy simulation tools. The paper closes with the current status of, and future plans for, the ongoing efforts to achieve software interoperability.
Date: July 31, 2002
Creator: Hitchcock, Robert J.
Partner: UNT Libraries Government Documents Department

An Analysis of Scientific Learning in Growing Silkworms

Description: The purpose of this study is to give the results of a science experiment in an elementary grade in raising silkworms. The purpose of the experiment was not to learn the laws and principles of science, but to determine whether the life cycle of the silkworm would create a greater interest in the field of science.
Date: 1947
Creator: Roberts, Odessa Hensley
Partner: UNT Libraries

Life Cycle Greenhouse Gas Emissions from Concentrating Solar Power (Fact Sheet)

Description: The National Renewable Energy Laboratory (NREL) recently led the Life Cycle Assessment (LCA) Harmonization Project, a study that makes great strides in clarifying inconsistent and conflicting GHG emission estimates in the published literature while providing more precise estimates of GHG emissions from utility-scale CSP systems.
Date: November 1, 2012
Partner: UNT Libraries Government Documents Department

Life Cycle GHG Emissions from Conventional Natural Gas Power Generation: Systematic Review and Harmonization (Presentation)

Description: This research provides a systematic review and harmonization of the life cycle assessment (LCA) literature of electricity generated from conventionally produced natural gas. We focus on estimates of greenhouse gases (GHGs) emitted in the life cycle of electricity generation from conventionally produced natural gas in combustion turbines (NGCT) and combined-cycle (NGCC) systems. A process we term "harmonization" was employed to align several common system performance parameters and assumptions to better allow for cross-study comparisons, with the goal of clarifying central tendency and reducing variability in estimates of life cycle GHG emissions. This presentation summarizes preliminary results.
Date: December 1, 2012
Creator: Heath, G.; O'Donoughue, P. & Whitaker, M.
Partner: UNT Libraries Government Documents Department

Life Cycle Assessment of Pavements: A Critical Review of Existing Literature and Research

Description: This report provides a critical review of existing literature and modeling tools related to life-cycle assessment (LCA) applied to pavements. The review finds that pavement LCA is an expanding but still limited research topic in the literature, and that the existing body of work exhibits methodological deficiencies and incompatibilities that serve as barriers to the widespread utilization of LCA by pavement engineers and policy makers. This review identifies five key issues in the current body of work: inconsistent functional units, improper system boundaries, imbalanced data for asphalt and cement, use of limited inventory and impact assessment categories, and poor overall utility. This review also identifies common data and modeling gaps in pavement LCAs that should be addressed in future work. These gaps include: the use phase (rolling resistance, albedo, carbonation, lighting, leachate, and tire wear and emissions), asphalt fumes, feedstock energy of bitumen, traffic delay, the maintenance phase, and the end-of-life phase. This review concludes with a comprehensive list of recommendations for future research, which shed light on where improvements in knowledge can be made that will benefit the accuracy and comprehensiveness of pavement LCAs moving forward.
Date: April 20, 2010
Creator: Santero, Nicholas; Masanet, Eric & Horvath, Arpad
Partner: UNT Libraries Government Documents Department

Development of the household sample for furnace and boilerlife-cycle cost analysis

Description: Residential household space heating energy use comprises close to half of all residential energy consumption. Currently, average space heating use by household is 43.9 Mbtu for a year. An average, however, does not reflect regional variation in heating practices, energy costs, or fuel type. Indeed, a national average does not capture regional or consumer group cost impacts from changing efficiency levels of heating equipment. The US Department of Energy sets energy standards for residential appliances in, what is called, a rulemaking process. The residential furnace and boiler efficiency rulemaking process investigates the costs and benefits of possible updates to the current minimum efficiency regulations. Lawrence Berkeley National Laboratory (LBNL) selected the sample used in the residential furnace and boiler efficiency rulemaking from publically available data representing United States residences. The sample represents 107 million households in the country. The data sample provides the household energy consumption and energy price inputs to the life-cycle cost analysis segment of the furnace and boiler rulemaking. This paper describes the choice of criteria to select the sample of houses used in the rulemaking process. The process of data extraction is detailed in the appendices and is easily duplicated. The life-cycle cost is calculated in two ways with a household marginal energy price and a national average energy price. The LCC results show that using an national average energy price produces higher LCC savings but does not reflect regional differences in energy price.
Date: May 31, 2005
Creator: Whitehead, Camilla Dunham; Franco, Victor; Lekov, Alex & Lutz, Jim
Partner: UNT Libraries Government Documents Department

Life-Cycle Assessment of Energy and Environmental Impacts of LED Lighting Products Part 2: LED Manufacturing and Performance

Description: Part 2 of the project (this report) uses the conclusions from Part 1 as a point of departure to focus on two objectives: producing a more detailed and conservative assessment of the manufacturing process and providing a comparative LCA with other lighting products based on the improved manufacturing analysis and taking into consideration a wider range of environmental impacts. In this study, we first analyzed the manufacturing process for a white-light LED (based on a sapphire-substrate, blue-light, gallium-nitride LED pumping a yellow phosphor), to understand the impacts of the manufacturing process. We then conducted a comparative LCA, looking at the impacts associated with the Philips Master LEDbulb and comparing those to a CFL and an incandescent lamp. The comparison took into account the Philips Master LEDbulb as it is now in 2012 and then projected forward what it might be in 2017, accounting for some of the anticipated improvements in LED manufacturing, performance and driver electronics.
Date: May 1, 2012
Creator: Scholand, Michael & Dillon, Heather E.
Partner: UNT Libraries Government Documents Department