scholarly journals In-situ air temperature and humidity measurements over diverse landcovers in Greenbelt, MD Nov. 2013–Nov. 2015

2016 ◽  
Author(s):  
Mark L. Carroll ◽  
Molly E. Brown ◽  
Margaret R. Wooten ◽  
Joel E. Donham ◽  
Alfred B. Hubbard ◽  
...  
Keyword(s):  
Urban Areas ◽  
Climate Adaptation ◽  
National Laboratory ◽  
Mitigation Strategies ◽  
Building Roof ◽  
Oak Ridge ◽  
Average Value ◽  
Temperature And Humidity ◽  
The Difference ◽  
Major Surface

Abstract. As our climate changes through time there is an ever increasing need to quantify how and where it is changing so that mitigation strategies can be implemented. Urban areas have a disproportionate amount of warming due, in part, to the conductive properties of concrete and asphalt surfaces that make up an urban environment. The NASA Climate Adaptation Science Investigation working group at Goddard Space Flight Center in Greenbelt MD conducted a study to collect temperature and humidity data at 15 minute intervals from 12 sites on center. These sites represented the major surface types on center: asphalt, building roof, grass field, forest, and rain garden. The data show a strong distinction in the thermal properties of these surfaces on the center and the difference between the average value for the center compared to a local meteorological station. The data have been submitted to Oak Ridge National Laboratory Distributed Active Archive Center (ORNL-DAAC) for archival in comma separated value (csv) file format http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1319.

scholarly journals In situ air temperature and humidity measurements over diverse land covers in Greenbelt, Maryland, November 2013–November 2015

2016 ◽  
Vol 8 (2) ◽  
pp. 415-423 ◽  
Author(s):  
Mark L. Carroll ◽  
Molly E. Brown ◽  
Margaret R. Wooten ◽  
Joel E. Donham ◽  
Alfred B. Hubbard ◽  
...  
Keyword(s):  
Urban Areas ◽  
Climate Adaptation ◽  
National Laboratory ◽  
Mitigation Strategies ◽  
Building Roof ◽  
Oak Ridge ◽  
Temperature And Humidity ◽  
Humidity Measurements ◽  
The Difference ◽  
Major Surface

Abstract. As our climate changes through time there is an ever-increasing need to quantify how and where it is changing so that mitigation strategies can be implemented. Urban areas have a disproportionate amount of warming due, in part, to the conductive properties of concrete and asphalt surfaces, surface albedo, heat capacity, lack of water, etc. that make up an urban environment. The NASA Climate Adaptation Science Investigation working group at Goddard Space Flight Center in Greenbelt, MD, conducted a study to collect temperature and humidity data at 15 min intervals from 12 sites at the center. These sites represent the major surface types at the center: asphalt, building roof, grass field, forest, and rain garden. The data show a strong distinction in the thermal properties of these surfaces at the center and the difference between the average values for the center compared to a local meteorological station. The data have been submitted to Oak Ridge National Laboratory Distributed Active Archive Center (ORNL-DAAC) for archival in comma separated value (csv) file format (Carroll et al., 2016) and can be found by following this link: http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1319.

The LAJ Cycle: A New Combined-Cycle Fossil Fuel Power System

2002 ◽  
Author(s):  
Roddie R. Judkins ◽  
Timothy R. Armstrong ◽  
Solomon D. Labinov
Keyword(s):  
Fuel Cells ◽  
Natural Gas ◽  
Power System ◽  
Fossil Fuel ◽  
High Efficiency ◽  
National Laboratory ◽  
Combined Cycle ◽  
Mitigation Strategies ◽  
Model Calculations ◽  
Oak Ridge

Oak Ridge National Laboratory (ORNL) has developed a novel system for combined-cycle power generation, called the LAJ cycle. This system could serve as a basis for the development of a new generation of high-efficiency combined cycles. In one of several possible configurations of the new combined-cycle fossil fuel power system, natural gas enters the system at 4.0 MPa and about 300 K, is heated and reformed, and is transferred to a turbine at 4.0 MPa and 1200 K. The gas expands in the turbine to 0.6 MPa and 800 K, and then flows successively to heat exchangers and a condenser-separator, after which it is separated into two gas streams, one containing principally CO with some CH4 and water vapor and the other containing pure H2. The CO and H2 flow to separate fuel cells and undergo electrochemical oxidation with the concomitant production of electricity. Separate streams of water and carbon dioxide (CO2) are produced, making this cycle compatible with carbon mitigation strategies based on sequestration. Model calculations indicate combined-cycle efficiencies greater than 70% based on the lower heating value of natural gas. The high efficiencies realized result from a combination of the high-pressure natural gas reformate expansion and the highly efficient CO and H2 fuel cells. Most of the power derives from the fuel cells in the system.

scholarly journals Analysis of urban heat island characteristics and mitigation strategies for eight arid and semi-arid gulf region cities

2021 ◽  
Vol 80 (7) ◽  
Author(s):  
Ammar Abulibdeh
Keyword(s):  
Land Cover ◽  
Urban Areas ◽  
Arid Regions ◽  
Mitigation Strategies ◽  
Heat Island ◽  
Gulf Region ◽  
Green Areas ◽  
Urban Heat ◽  
The Difference ◽  
Semi Arid

AbstractThe aim of the study is, therefore, to analyze the formation of the UHIs in eight different cities in arid and semi-arid regions. The analysis is based on land cover (LC) classification (urban, green, and bare areas). The study found that bare areas had the highest mean LST values compared to the urban and green areas. The results show that the difference in temperatures between the bare areas and the urban areas ranges between 1 and 2 °C, between the bare areas and green areas ranges between 1 and 7 °C, and between the urban areas and green areas ranges between 1 and 5 °C. Furthermore, the LST values varied for each of the LULC categories, and hence some areas in the three categories had lower or higher LST values than in other categories. Hence, one category may not always have the highest LST value compared to other categories. The outcomes of this study may, therefore, have critical implications for urban planners who seek to mitigate UHI effects in arid and semi-arid urban areas.

scholarly journals Heat and dry islands observed over Jakarta, Indonesia, in 2012

2014 ◽  
Vol 364 ◽  
pp. 140-144
Author(s):  
H. Widyasamratri ◽  
K. Souma ◽  
T. Suetsugi ◽  
H. Ishidaira ◽  
Y. Ichikawa ◽  
...  
Keyword(s):  
Urban Areas ◽  
Thermal Environment ◽  
Monsoon Season ◽  
Sea Breeze ◽  
Early Morning ◽  
Specific Humidity ◽  
Air Temperatures ◽  
Temperature And Humidity ◽  
Urbanized Areas ◽  
The Difference

Abstract. Recent population increases in urban areas of Asian countries have extended artificial land cover, increased energy consumption, and caused various problems. Higher air temperatures over urban areas (heat islands) degrade residential environments and affect human health. In Jakarta, the largest city in Indonesia and the second largest city in Asia, previous studies have relied on only a few observation points and physically-based models. To study the thermal environment in Jakarta in more detail, we performed seven fixed-point temperature and humidity observations from the dry to the pre-monsoon season (from 16 September to 18 October) in 2012. Over densely urbanized areas, higher temperatures and lower humidity were observed around noon compared with the sparsely urbanized areas. The maximum differences in temperature and specific humidity were found to be around 3 °C and 0.005 kg/kg, respectively. The differences in temperature and humidity became smaller in the afternoon because of the penetration of sea breezes. At night, the differences became larger again because the sea breeze weakened. Then, a difference of around 3°C was observed, except in the early morning. Although the difference in daytime temperature was smaller between densely urbanized areas and suburban areas, similar tendency was also confirmed in the daily time series averaged for sunny days in dry season.

Evaluation of Different Efficiency Concepts of an Integrated Energy System (IES)

2004 ◽  
Author(s):  
Andrei Yu. Petrov ◽  
Abdolreza Zaltash ◽  
Solomon D. Labinov ◽  
D. Tom Rizy ◽  
Xiaohong Liao ◽  
...  
Keyword(s):  
National Laboratory ◽  
Performance Testing ◽  
Energy System ◽  
The United States ◽  
Hot Water ◽  
Actual Performance ◽  
Heating Value ◽  
Oak Ridge ◽  
Integrated Energy System ◽  
The Difference

The Integrated Energy System (IES) market in the United States (US) and worldwide has been increasingly expanding over the last few years. But there is still a lot of disagreement in interpretation of one of the most important IES performance parameters — efficiency. Some organizations, for example, use higher heating value (HHV) of fuel in efficiency calculations while some use lower heating value (LHV). Some accounts for auxiliary and parasitic losses while others do not. Some adhere to the “first-law” of efficiency while some use other methods, i.e., calculations recommended by the Federal Energy Regulatory Commission or the US Combined Heat & Power Association. Different efficiency concepts based on actual performance testing from the IES Laboratory at Oak Ridge National Laboratory (ORNL) are evaluated in this paper. The equipment studied included: a 30-kW microturbine, an air-to-water heat recovery unit (HRU), a 10-ton (35 kW) hot water-fired (indirect-fired) single-effect absorption chiller, and a direct-fired desiccant dehumidification unit. Efficiencies of different configurations of the above-mentioned equipment based on various approaches are compared. In addition, IES efficiency gains due to the replacement of a 1st generation HRU (effectiveness of approximately 75%) with a 2nd generation HRU (effectiveness of approximately 92%) for the same IES arrangement are discussed. The results showed that the difference in HHV- and LHV-based efficiencies for different IES arrangements could reach 5–8%, and that the difference in efficiency values calculated with different methods for the same arrangement could reach 27%. Therefore, it is very important to develop standard guidelines for efficiency calculations that would be acceptable and used by the majority of IES manufacturers and end-users. At the very least, every manufacturer or user should clearly indicate the basis for their efficiency calculations.

scholarly journals Urban Energy Systems: Research at Oak Ridge National Laboratory

2021 ◽  
pp. 281-308
Author(s):  
Budhendra Bhaduri ◽  
Ryan McManamay ◽  
Olufemi Omitaomu ◽  
Jibo Sanyal ◽  
Amy Rose
Keyword(s):  
Traffic Congestion ◽  
Urban Areas ◽  
National Laboratory ◽  
Human Dimensions ◽  
Critical Infrastructures ◽  
Laboratory System ◽  
Sustainable Mobility ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory ◽  
Urban Energy

AbstractIn the coming decades, our planet will witness unprecedented urban population growth in both established and emerging communities. The development and maintenance of urban infrastructures are highly energy-intensive. Urban areas are dictated by complex intersections among physical, engineered, and human dimensions that have significant implications for traffic congestion, emissions, and energy usage. In this chapter, we highlight recent research and development efforts at Oak Ridge National Laboratory (ORNL), the largest multipurpose science laboratory within the U.S. Department of Energy’s (DOE) national laboratory system, that characterizes the interactions between the human dynamics and critical infrastructures in conjunction with the integration of four distinct components: data, critical infrastructure models, and scalable computation and visualization, all within the context of physical and social systems. Discussions focus on four key topical themes: population and land use, sustainable mobility, the energy-water nexus, and urban resiliency, that are mutually aligned with DOE’s mission and ORNL’s signature science and technology capabilities. Using scalable computing, data visualization, and unique datasets from a variety of sources, the institute fosters innovative interdisciplinary research that integrates ORNL expertise in critical infrastructures including energy, water, transportation, and cyber, and their interactions with the human population.

scholarly journals Facility scale inventory of dairy methane emissions in California: Implications for mitigation

2020 ◽  
Author(s):  
Alison R. Marklein ◽  
Deanne Meyer ◽  
Marc L. Fischer ◽  
Seongeun Jeong ◽  
Talha Rafiq ◽  
...  
Keyword(s):  
Spatial Scales ◽  
National Laboratory ◽  
State Level ◽  
Mitigation Strategies ◽  
Manure Management ◽  
Enteric Fermentation ◽  
Specific Calculation ◽  
Oak Ridge ◽  
Ch4 Emissions ◽  
Total State

Abstract. Dairies emit roughly half of total methane (CH4) emissions in California, generating CH4 from both enteric fermentation by ruminant gut microbes and anaerobic decomposition of manure. Representation of these emission processes is essential for management and mitigation of CH4 emissions, and is typically done using standardized emission factors applied at large spatial scales (e.g., state level). However, CH4-emitting activities and management decisions vary across facilities, and current inventories do not have sufficiently high spatial resolution to capture changes at this scale. Here, we develop a spatially-explicit database of dairies in California, with information from operating permits and California-specific reports detailing herd demographics and manure management at the facility scale. We calculated manure management and enteric fermentation CH4 emissions using two previously published bottom-up approaches and a new farm-specific calculation developed in this work. We also estimate the effect of mitigation strategies – the use of mechanical separators and installation of anaerobic digesters – on CH4 emissions. We predict that implementation of digesters at the 109 dairies that are existing or planned in California will reduce manure CH4 emissions from those facilities by an average of 35 %, and total state CH4 emissions by 6 % (or ~ 47.3 Gg CH4/yr). In addition to serving as a planning tool for mitigation, this database is useful as a prior for atmospheric observation-based emissions estimates, attribution of emissions to a specific facility, and to validate CH4 emissions reductions from management changes. Raster files of the datasets and associated metadata are available from the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics (ORNL DAAC; Marklein et al., 2020; https://doi.org/10.3334/ORNLDAAC/1814).

scholarly journals Vista-LA: Mapping methane-emitting infrastructure in the Los Angeles megacity

2018 ◽  
Vol 10 (1) ◽  
pp. 653-676 ◽  
Author(s):  
Valerie Carranza ◽  
Talha Rafiq ◽  
Isis Frausto-Vicencio ◽  
Francesca M. Hopkins ◽  
Kristal R. Verhulst ◽  
...  
Keyword(s):  
Los Angeles ◽  
Urban Areas ◽  
National Laboratory ◽  
Complex Mixture ◽  
Methane Emissions ◽  
Point Sources ◽  
Climate Mitigation ◽  
Analysis Tool ◽  
Oak Ridge ◽  
Methane Source

Abstract. Methane (CH4) is a potent greenhouse gas (GHG) and a critical target of climate mitigation efforts. However, actionable emission reduction efforts are complicated by large uncertainties in the methane budget on relevant scales. Here, we present Vista, a Geographic Information System (GIS)-based approach to map potential methane emissions sources in the South Coast Air Basin (SoCAB) that encompasses Los Angeles, an area with a dense, complex mixture of methane sources. The goal of this work is to provide a database that, together with atmospheric observations, improves methane emissions estimates in urban areas with complex infrastructure. We aggregated methane source location information into three sectors (energy, agriculture, and waste) following the frameworks used by the State of California GHG Inventory and the Intergovernmental Panel on Climate Change (IPCC) Guidelines for GHG Reporting. Geospatial modeling was applied to publicly available datasets to precisely geolocate facilities and infrastructure comprising major anthropogenic methane source sectors. The final database, Vista-Los Angeles (Vista-LA), is presented as maps of infrastructure known or expected to emit CH4. Vista-LA contains over 33 000 features concentrated on  <  1 % of land area in the region. Currently, Vista-LA is used as a planning and analysis tool for atmospheric measurement surveys of methane sources, particularly for airborne remote sensing, and methane hotspot detection using regional observations. This study represents a first step towards developing an accurate, spatially resolved methane flux estimate for point sources in SoCAB, with the potential to address discrepancies between bottom–up and top–down methane emissions accounting in this region. The Vista-LA datasets and associated metadata are available from the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics (ORNL DAAC; https://doi.org/10.3334/ORNLDAAC/1525).

Polarized neutron diffraction at a spallation source for magnetic studies

2012 ◽  
Vol 45 (5) ◽  
pp. 1024-1029 ◽  
Author(s):  
A. Pramanick ◽  
V. Lauter ◽  
X.-L. Wang ◽  
K. An ◽  
H. Ambaye ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
National Laboratory ◽  
Time Of Flight ◽  
Magnetic Form Factor ◽  
Magnetic Studies ◽  
Polarized Neutrons ◽  
Oak Ridge ◽  
Spallation Source ◽  
Polarized Neutron ◽  
The Difference

The availability of high-power spallation neutron sources, along with advances in the development of coupled moderators and neutron polarizers, has made it possible to use polarized neutrons on time-of-flight diffractometers forin situstudies of phenomena contributing to field-induced magnetization of a material. Different electronic and structural phenomena that contribute to the overall magnetization of a material can be studied and clearly identified with polarized neutron diffraction measurements. This article reports the first results from polarized neutron diffraction experiments on a time-of-flight instrument at a spallation source. Magnetic field-induced rotation of electron spins in an Ni–Mn–Ga single crystal was measured with polarized neutron diffraction at the MAGICS reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. The difference in intensities measured with spin-up and spin-down polarized neutrons is proportional to the field-induced magnetization of the crystal. The polarized neutron measurements indicate that the magnetic form factor for the 3delectrons of Mn in Ni–Mn–Ga is lower than the value reported earlier for an ideal spherical symmetry of electronic distribution. Future experiments for studying field-induced magnetization in materials following the current methodology are outlined.

scholarly journals Facility-scale inventory of dairy methane emissions in California: implications for mitigation

2021 ◽  
Vol 13 (3) ◽  
pp. 1151-1166
Author(s):  
Alison R. Marklein ◽  
Deanne Meyer ◽  
Marc L. Fischer ◽  
Seongeun Jeong ◽  
Talha Rafiq ◽  
...  
Keyword(s):  
Spatial Scales ◽  
National Laboratory ◽  
State Level ◽  
Mitigation Strategies ◽  
Manure Management ◽  
Enteric Fermentation ◽  
Specific Calculation ◽  
Oak Ridge ◽  
Ch4 Emissions ◽  
Total State

Abstract. Dairies emit roughly half of total methane (CH4) emissions in California, generating CH4 from both enteric fermentation by ruminant gut microbes and anaerobic decomposition of manure. Representation of these emission processes is essential for management and mitigation of CH4 emissions and is typically done using standardized emission factors applied at large spatial scales (e.g., state level). However, CH4-emitting activities and management decisions vary across facilities, and current inventories do not have sufficiently high spatial resolution to capture changes at this scale. Here, we develop a spatially explicit database of dairies in California, with information from operating permits and California-specific reports detailing herd demographics and manure management at the facility scale. We calculated manure management and enteric fermentation CH4 emissions using two previously published bottom-up approaches and a new farm-specific calculation developed in this work. We also estimate the effect of mitigation strategies – the use of mechanical separators and installation of anaerobic digesters – on CH4 emissions. We predict that implementation of digesters at the 106 dairies that are existing or planned in California will reduce manure CH4 emissions from those facilities by an average of 26 % and total state CH4 emissions by 5 % (or ∼36.5 Gg CH4/yr). In addition to serving as a planning tool for mitigation, this database is useful as a prior for atmospheric observation-based emissions estimates, attribution of emissions to a specific facility, and validation of CH4 emissions reductions from management changes. Raster files of the datasets and associated metadata are available from the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics (ORNL DAAC; Marklein and Hopkins, 2020; https://doi.org/10.3334/ORNLDAAC/1814).

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