Search NASA⌕ Search

SEARCH · Search NASA

Results for “eem”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Utilization of PARAFAC ‐Modeled Excitation‐Emission Matrix ( EEM ) Fluorescence Spectroscopy to Identify Biogeochemical Processing of Dissolved Organic Matter in a Northern Peatland

Abstract In this study, we contrast the fluorescent properties of dissolved organic matter ( DOM ) in fens and bogs in a Northern Minnesota peatland using excitation emission matrix fluorescence spectroscopy with parallel factor analysis ( EEM ‐ PARAFAC ). EEM ‐ PARAFAC identified four humic‐like components and one protein‐like component and the dynamics of each were evaluated based on their distribution with depth as well as across sites differing in hydrology and major biological species. The PARAFAC ‐ EEM experiments were supported by dissolved organic carbon measurements ( DOC ), optical spectroscopy ( UV ‐Vis), and compositional characterization by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectroscopy ( FT ‐ ICR MS ). The FT ‐ ICR MS data indicate that metabolism in peatlands reduces the molecular weights of individual components of DOM , and oxygen‐rich less aromatic molecules are selectively biodegraded. Our data suggest that different hydrologic and biological conditions within the larger peat ecosystem drive molecular changes in DOM , resulting in distinctly different chemical compositions and unique fluorescent fingerprints. PARAFAC modeling of EEM data coupled with ultrahigh resolution FT ‐ ICR MS has the potential to provide significant molecular‐based information on DOM composition that will support efforts to better understand the composition, sources, and diagenetic status of DOM from different terrestrial and aquatic systems.

Tfaily, Malak M.↗
DOE OSTI2025

New Community Center Integrated Energy Efficiency Measures (EEMs) and Solar Photovoltaic Generation System in the Forest County Potawatomi Community

The Forest County Potawatomi Community (“FCPC” or “the Tribe”), is a federally recognized Indian Tribe located in Wisconsin. With the support of the United States Department of Energy, Office of Indian Energy (DOE IE) grant funding, the Tribe implemented their New Community Center Integrated EEMs and Solar Photovoltaic System in the Forest County Potawatomi Community project (the “Project”). The Project was developed and executed with the goal of partially energizing the Community Center while concurrently pursuing Tribal energy sovereignty through cost effective energy efficiency and generation measure.

14 SOLAR ENERGY↗
DOE OSTI2019

Livewire Data Platform - A Solution for EEMS Data Sharing

To bring about fundamental changes in our transportation system, data sharing must be endemic. The Livewire Data Platform is a user-friendly, searchable platform allowing easy and secure data sharing and discovery for DOE's Energy Efficient Mobility Systems (EEMS) researchers. The platform was funded by the DOE Vehicle Technologies Office (VTO) to enable a research community that builds partnerships and collaboration around data in order to find answers to today's biggest mobility challenges.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2020

Livewire Data Platform - A Solution for Energy Efficient Mobility Systems (EEMS) Data Sharing

The Livewire Data Platform is a data storage and exchange platform. It provides: a platform, allowing data sharing and discovery by linking disparate data sources to a single website via application programming interfaces (APIs); a community, building partnerships and collaboration rather than competition; a system, allowing shared data to increase in size and complexity as EEMS evolves.

47 OTHER INSTRUMENTATION↗
DOE OSTI2014

Development of EEM based silicon–water and silica–water wall potentials for non-reactive molecular dynamics simulations

Molecular dynamics simulations of heat transfer in gases are computationally expensive when the wall molecules are explicitly modeled. To save computational time, an implicit boundary function is often used. Steele's potential has been used in studies of fluid–solid interface for a long time. In this work, the conceptual idea of Steele's potential was extended in order to simulate water–silicon and water–silica interfaces. A new wall potential model is developed by using the electronegativity-equalization method (EEM), a ReaxFF empirical force field and a non-reactive molecular dynamics package PumMa. Contact angle simulations were performed in order to validate the wall potential model. Contact angle simulations with the resulting tabulated wall potentials gave a silicon–water contact angle of 129°, a quartz–water contact angle of 0°, and a cristobalite–water contact angle of 40°, which are in reasonable agreement with experimental values.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

A Drop in the Bucket or a Pebble in a Pond: Commercial Building Partners’ Replication of EEMs Across Their Portfolios

This study presents findings from questionnaire and interview data investigating replication efforts of Commercial Building Partnership (CBP) partners that worked directly with the Pacific Northwest National Laboratory (PNNL). PNNL partnered with 12 organizations on new and retrofit construction projects as part of the U.S. Department of Energy (DOE) CBP program. PNNL and other national laboratories collaborate with industry leaders that own large portfolios of buildings to develop high performance projects for new construction and renovation. This project accelerates market adoption of commercially available energy saving technologies into the design process for new and upgraded commercial buildings. The labs provide assistance to the partners’ design teams and make a business case for energy investments. From the owner’s perspective, a sound investment results in energy savings based on corporate objectives and design. Through a feedback questionnaire, along with personal interviews, PNNL gathered qualitative and quantitative information relating to replication efforts by each organization. Data through this process were analyzed to provide insight into two primary research areas: 1) CBP partners’ replication efforts of technologies and approaches used in the CBP project to the rest of the organization’s building portfolio (including replication verification), and, 2) the market potential for technology diffusion into the total U.S. commercial building stock, as a direct result of the CBP entire program.

Commercial Building Partnerships↗
DOE OSTI2022

Livewire Data Platform-A Solution for Energy Efficient Mobility Systems (EEMS) Data Sharing

This presentation is an overview of progress made on the Livewire Data Platform since June 2021. Livewire is a publicly accessible platform for sharing energy efficiency and mobility research data funded by DOE's Vehicle Technologies Office. Core services and platform capabilities of Livewire include: Free, secure data storage; Access management that allows data owners to control who sees their data; Data collection and preservation; Quality characterization; Detailed access and download metrics; and Increased visibility of projects and data.

energy efficiency mobility↗
DOE OSTI2023

Livewire Data Platform-A Solution for Energy Efficient Mobility Systems (EEMS) Data Sharing

This presentation is an overview of progress made on the Livewire Data Platform since June 2022. Livewire is a publicly accessible platform for sharing energy efficiency and mobility research data funded by DOE's Vehicle Technologies Office. Core services and platform capabilities of Livewire include: Free, secure data storage; Access management that allows data owners to control who sees their data; Data collection and preservation; Quality characterization; Detailed access and download metrics; and Increased visibility of projects and data. Anyone can create an account and access data at https://livewire.energy.gov/.

energy efficiency↗
DOE OSTI2017

Solidification and Re-melting Phenomena During Slurry Preparation Using the RheoMetal™ Process

The melting sequence of the enthalpy exchange material (EEM) and formation of a slurry in the RheoMetal™ process was investigated. The EEM was extracted and quenched, together with a portion of the slurry at different processing times before complete melting. The EEM initially increased in size/diameter due to melt freezing onto its surface, forming a freeze-on layer. The initial growth of this layer was followed by a period of a constant diameter of the EEM with subsequent melting and decrease of diameter. Microstructural characterization of the size and morphology of different phases in the EEM and in the freeze-on layer was made. Dendritic equiaxed grains and eutectic regions containing Si particles and Cu-bearing particles and Fe-rich particles were observed in the as-cast EEM. The freeze-on layer consisted of dendritic aluminum tilted by about 30 deg in the upstream direction, caused by the rotation of the EEM. Energy dispersion spectroscopy analysis showed that the freeze-on layer had a composition corresponding to an alloy with higher melting point than the EEM and thus shielding the EEM from the surrounding melt. Microstructural changes in the EEM showed that temperature rapidly increased to 768 K (495 °C), indicated by incipient melting of the lowest temperature melting eutectic in triple junction grain boundary regions with Al{sub 2}Cu and Al{sub 5}Mg{sub 8}Si{sub 6}Cu{sub 2} phases present. As the EEM temperature increased further the binary Al-Si eutectic started to melt to form a region of a fully developed coherent mushy state. Experimental results and a thermal model indicated that as the dendrites spheroidized near to the interface at the EEM/freeze-on layer reached a mushy state with 25 pct solid fraction, coherency was lost and disintegration of the freeze-on layer took place. Subsequently, in the absence of the shielding effect from the freeze-on Layer, the EEM continued to disintegrate with a coherency limit of a solid fraction estimated to be 50 pct.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Evaluating the energy impact potential of energy efficiency measures for retrofit applications: A case study with U.S. medium office buildings

Quantifying the energy savings of various energy efficiency measures (EEMs) for an energy retrofit project often necessitates an energy audit and detailed whole building energy modeling to evaluate the EEMs; however, this is often cost-prohibitive for small and medium buildings. In order to provide a defined guideline for projects with assumed common baseline characteristics, this paper applies a sensitivity analysis method to evaluate the impact of individual EEMs and groups these into packages to produce deep energy savings for a sample prototype medium office building across 15 climate zones in the United States. We start with one baseline model for each climate zone and nine candidate EEMs with a range of efficiency levels for each EEM. Three energy performance indicators (EPIs) are defined, which are annual electricity use intensity, annual natural gas use intensity, and annual energy cost. Then, a Standard Regression Coefficient (SRC) sensitivity analysis method is applied to determine the sensitivity of each EEM with respect to the three EPIs, and the relative sensitivity of all EEMs are calculated to evaluate their energy impacts. For the selected range of efficiency levels, the results indicate that the EEMs with higher energy impacts (i.e., higher sensitivity) in most climate zones are high-performance windows, reduced interior lighting power, and reduced interior plug and process loads. However, the sensitivity of the EEMs also vary by climate zone and EPI; for example, improved opaque envelope insulation and efficiency of cooling and heating systems are found to have a high energy impact in cold and hot climates.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

How Do Electricity Pricing Programs Impact the Selection of Energy Efficiency Measures? - A Case Study with U.S. Medium Office Buildings

Building owners usually select energy efficiency measures (EEMs) by referring to return on investment (ROI). Current studies tend to apply static energy price to estimate ROI. However, more and more buildings are adopting dynamic electricity pricing programs. To understand how electricity pricing programs impact the selection of EEMs, this paper presents an analysis of the ROIs of EEMs under different pricing programs using U.S. medium office buildings as an example. Eight EEMs in four typical cities are selected as case studies. Considering five electricity pricing programs scenarios (one static program and four dynamic programs), EEMs are selected based on their ROIs. The main findings are: (1) The ROIs of EEMs change under different pricing programs. (2) In Honolulu, Buffalo, and Denver, replacing interior fixtures with higher-efficiency fixtures has a significantly higher ROI than the rest EEMs under all five pricing programs. However, the ROI of this EEM in Honolulu ranges from 28% to 47% for different pricing programs. (3) Similarly, in Fairbanks, replace heating coil with higher-efficiency coil produce higher ROI than the rest under all five pricing programs. (4) For other EEMs, their ROI rankings vary according to electricity pricing programs.

demand response↗
DOE OSTI2025

A Comparison Between Industrial Energy Efficiency Measures in Guatemala and the United States

Energy auditing has been cited as a key tool in closing the gap between the actual energy consumption in industrial facilities and what should be at an environmentally sustainable level. Several factors affect the likelihood that energy audits will be effective in closing that gap, and more analysis is needed to understand these factors, especially for developing nations. This study compares three energy efficiency measures (EEMs) frequently recommended in both the United States and Guatemala, namely, installing solar panels to generate electricity, installing higher-efficiency lighting, and upgrading to premium efficiency motors. The implementation of each of these EEMs contributes to more sustainable energy consumption, and each of these EEM’s payback periods is affected by capital costs, energy costs, and other local factors analyzed in this study. Projected payback periods for each EEM based on Guatemalan and U.S. capital cost and energy cost ranges are assessed via EEM-specific payback period calculations and compared to the energy audit data from each country. While lower capital costs incentivize EEM implementation and reduce payback periods, there is an interplay between energy cost and capital cost that impacts the trends in the U.S. and Guatemala. As in the case of the solar panel installation EEM, though Guatemalan companies pay ~110% more for electricity than U.S. companies, when Guatemalan capital costs are lower, payback periods are lower than in the U.S. Conversely, in cases where Guatemalan capital costs are higher—as for higher-efficiency lighting and motor installation—Guatemalan payback periods are roughly the same as those in the U.S. because of the higher Guatemalan energy costs.

Khosla, Radhika↗
NASA NTRS2007

Improved Underwater Excitation-Emission Matrix Fluorometer

A compact, high-resolution, two-dimensional excitation-emission matrix fluorometer (EEMF) has been designed and built specifically for use in identifying and measuring the concentrations of organic compounds, including polluting hydrocarbons, in natural underwater settings. Heretofore, most EEMFs have been designed and built for installation in laboratories, where they are used to analyze the contents of samples collected in the field and brought to the laboratories. Because the present EEMF can be operated in the field, it is better suited to measurement of spatially and temporally varying concentrations of substances of interest. In excitation-emission matrix (EEM) fluorometry, fluorescence is excited by irradiating a sample at one or more wavelengths, and the fluorescent emission from the sample is measured at multiple wavelengths. When excitation is provided at only one wavelength, the technique is termed one-dimensional (1D) EEM fluorometry because the resulting matrix of fluorescence emission data (the EEM) contains only one row or column. When excitation is provided at multiple wavelengths, the technique is termed two-dimensional (2D) EEM fluorometry because the resulting EEM contains multiple rows and columns. EEM fluorometry - especially the 2D variety - is well established as a means of simultaneously detecting numerous dissolved and particulate compounds in water. Each compound or pool of compounds has a unique spectral fluorescence signature, and each EEM is rich in information content, in that it can contain multiple fluorescence signatures. By use of deconvolution and/or other mixture-analyses techniques, it is often possible to isolate the spectral signature of compounds of interest, even when their fluorescence spectra overlap. What distinguishes the present 2D EEMF over prior laboratory-type 2D EEMFs are several improvements in packaging (including a sealed housing) and other aspects of design that render it suitable for use in natural underwater settings. In addition, the design of the present 2D EEMF incorporates improvements over the one prior commercial underwater 2D EEMF, developed in 1994 by the same company that developed the present one. Notable advanced features of the present EEMF include the following: 1) High sensitivity and spectral resolution are achieved by use of an off-the-shelf grating spectrometer equipped with a sensor in the form of a commercial astronomical- grade 256 532-pixel charge-coupled-device (CCD) array. 2) All of the power supply, timing, control, and readout circuits for the illumination source and the CCD, ancillary environmental monitoring sensors, and circuitry for controlling a shutter or filter motor are custom-designed and mounted compactly on three circuit boards below a fourth circuit board that holds the CCD (see figure). 3) The compactness of the grating spectrometer, CCD, and circuit assembly makes it possible to fit the entire instrument into a compact package that is intended to be maneuverable underwater by one person. 4) In mass production, the cost of the complete instrument would be relatively low - estimated at approximately $30,000 at 2005 prices.

Moore, Casey↗
DOE OSTI2019

Evaluation of High Rotor Pole Switched Reluctance Motors to Control Condenser Fans in a Commercial Refrigeration System

A high rotor pole switched reluctance motor (HRSRM) designed by Software Motor Corporation was evaluated for use as a condenser fan motor due to its reported high motor efficiency over a broad range of speeds and added advanced control potential. The project was split into two phases; the first of which was to determine the direct energy savings due to the increased motor efficiency, the second was to leverage the additional benefits of the energy efficiency measure (EEM) to create additional energy savings. This report only discusses results from the first phase of the project. Nine 1.5hp HRSRMs were installed parallel to the same number of legacy induction motors of a supermarket commercial refrigeration system located in Lakeside, Colorado. At this site, the 1.5 hp legacy motors had historically adjusted condenser fan speed from 200-870 rpm based on outdoor air temperature and compressor discharge pressure. This type of control is known as variable head pressure control (VHPC). These nine new motors were given a signal from the legacy variable frequency drive (VFD) to match the motor speed of the legacy motors. Determination of the energy savings of the EEM was performed over a two-month period, at which time a correlation between legacy and EEM power consumption was developed based on motor speed. Annual data that had been collected from 2016-2017 (before the two-month test period) was then leveraged to predict the annual energy savings of the EEM for a complete retrofit using both VHPC and constant fan speed control. Table 1 displays the quantitative results. The EEM saved 27% of total energy consumption of the condenser fan motors for constant fan speed control, while the energy savings increased to 32% when using VHPC. This was due to the improved motor efficiency of the HRSR motor at low speeds. While the constant speed fan control kept the motors running at 870 rpm, VHPC adjusted fan speed between 200-870rpm based on the outdoor air temperature and the compressor discharge pressure. These savings are assuming a direct replacement with no additional controls. Retrofitting a constant speed fan control system with HRSRMs and switching to VHPC would provide significant energy savings looking at the condenser alone. Additional considerations of the EEM were noted during the project as well. The HRSRM system made it possible to identify and remotely shutdown an individual motor when a piece of foam locked the fan and thereby the motor. With the traditional system, a locked rotor could have caused motor damage unless a breaker or fuse was activated. Furthermore, due to vibration complaints from the installation technicians, the ramp-up time of the HRSRM had to be increased to a minute. After implementing this change no complaints for excessive vibration were recorded.

15 GEOTHERMAL ENERGY↗