Using the open source CFD code Nalu to simulate complex geometries relevant to wind energy simulations.
Abstract not provided.
Barone, Matthew F.↗
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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.
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Production of Neutrons by Transport of a GCR Solar Minimum Spectrum through Shielding - Paper 112
The requirements for radiation instrumentation in space can be quite different from those used for terrestrial applications. For example, most neutron instruments used for dosimetry applications used on Earth are sensitive to fission neutron energies and lower, and as such are only useful for neutron energies below 20 to 50 MeV. In space, neutrons are created by galactic cosmic ray (GCR) and solar energetic particle (SEP) interactions in materials, and as such can attain TeV energies and higher. The purpose of this study is to determine the significance of the flux of high energy neutrons in space, and to what degree neutron instruments in space must be sensitive to those high energy neutrons. PHITS transport code calculations of secondary neutron production through various thicknesses of aluminum and water shielding indicate that a significant fraction of the neutron flux and neutron effective dose comes from neutrons above 20 MeV. Measurement of high energy neutrons in space is a difficult task, especially given that the measurement will take place in a mixed radiation field where any signal from an incident neutron must be separated from signals generated by gamma rays, electrons and charged hadrons. Conventional neutron detection methodology dictates that the ability to detect high energy neutrons with a sufficient efficiency depends on the mass of the neutron detector, to first order. The more mass a neutron detector has, the higher the probability of detecting a high energy neutron. However, adding mass comes at a premium in space, often adding costs that prohibit the implementation of a new design with more mass. Thus, to accurately measure the effective dose to humans in space from secondary neutron irradiation, it requires novel methodologies that can stretch the limits of low-mass neutrons detectors, such as developing versatile response functions that are well characterized and can function over a wide range of very different neutron energy spectra. (authors)
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Meteorological Observations for Renewable Energy Applications at Site 300
In early October 2010, two Laser and Detection Ranging (LIDAR) units (LIDAR-96 and LIDAR-97), a 3 m tall flux tower, and a 3 m tall meteorological tower were installed in the northern section of Site 300 (Figure 1) as a first step in development of a renewable energy testbed facility. This section of the SMS project is aimed at supporting that effort with continuous maintenance of atmospheric monitoring instruments capable of measuring vertical profiles of wind speed and wind direction at heights encountered by future wind power turbines. In addition, fluxes of energy are monitored to estimate atmospheric mixing and its effects on wind flow properties at turbine rotor disk heights. Together, these measurements are critical for providing an accurate wind resource characterization and for validating LLNL atmospheric prediction codes for future renewable energy projects at Site 300. Accurate, high-resolution meteorological measurements of wind flow in the planetary boundary layer (PBL) and surface-atmosphere energy exchange are required for understanding the properties and quality of available wind power at Site 300. Wind speeds at heights found in a typical wind turbine rotor disk (~ 40-140 m) are driven by the synergistic impacts of atmospheric stability, orography, and land-surface characteristics on the mean wind flow in the PBL and related turbulence structures. This section of the report details the maintenance and labor required in FY11 to optimize the meteorological instruments and ensure high accuracy of their measurements. A detailed look at the observations from FY11 is also presented. This portion of the project met the following milestones: Milestone 1: successful maintenance and data collection of LIDAR and flux tower instruments; Milestone 2: successful installation of solar power for the LIDAR units; and Milestone 3: successful implementation of remote data transmission for the LIDAR units.
17 WIND ENERGY↗
Application of the BINS superheated drop detector spectrometer to the {sup 9}Be(p,xn) neutron energy spectrum determination
In the framework of TRASCO-BNCT project, a Bubble Interactive Neutron Spectrometer (BINS) device was applied to the characterization of the angle-and energy-differential neutron spectra generated by the {sup 9}Be(p,xn)reaction. The BINS spectrometer uses two superheated emulsion detectors, sequentially operated at different temperatures and thus provides a series of six sharp threshold responses, covering the 0.1-10 MeV neutron energy range. Spectrum unfolding of the data was performed by means of MAXED code. The obtained angle, energy-differential spectra were compared with those measured with a Bonner sphere spectrometer, a silicon telescope spectrometer and literature data.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Analytic derivative couplings for spin-flip configuration interaction singles and spin-flip time-dependent density functional theory
We revisit the calculation of analytic derivative couplings for configuration interaction singles (CIS), and derive and implement these couplings for its spin-flip variant for the first time. Our algorithm is closely related to the CIS analytic energy gradient algorithm and should be straightforward to implement in any quantum chemistry code that has CIS analytic energy gradients. The additional cost of evaluating the derivative couplings is small in comparison to the cost of evaluating the gradients for the two electronic states in question. Incorporation of an exchange-correlation term provides an ad hoc extension of this formalism to time-dependent density functional theory within the Tamm-Dancoff approximation, without the need to invoke quadratic response theory or evaluate third derivatives of the exchange-correlation functional. Application to several different conical intersections in ethylene demonstrates that minimum-energy crossing points along conical seams can be located at substantially reduced cost when analytic derivative couplings are employed, as compared to use of a branching-plane updating algorithm that does not require these couplings. Application to H{sub 3} near its D{sub 3h} geometry demonstrates that correct topology is obtained in the vicinity of a conical intersection involving a degenerate ground state.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OE Energy Storage Systems Safety Roadmap Focus on Proposed Changes to the ICC International Codes Special Briefing Paper — Unofficial Hearing Results April 2018
The goal of the DOE OE ESS Safety Roadmap1 is to foster confidence in the safety and reliability of energy storage systems (ESSs). Three interrelated objectives support the realization of that goal: research, codes and standards, and communication/coordination. The objective focused on codes and standards is - To apply research and development (R&D) to support efforts that are focused on ensuring that codes and standards are available to enable the safe implementation of ESSs in a comprehensive, non-discriminatory and science-based manner. The purpose of this special briefing paper is to support the above objective by providing information about current and upcoming efforts being conducted by U.S. standards developing organizations, specifically code changes associated with the 2018 Group A International Codes (I-Codes) of the International Code Council (ICC) that are relevant to ESSs.
25 ENERGY STORAGE↗
Reported Energy and Cost Savings from the DOE ESPC IDIQ Program: FY 2024
Energy Savings Performance Contracts (ESPCs) are a contractual mechanism that allow a federal agency to procure energy savings and facility improvements without upfront capital costs to reduce costs and enhance mission resiliency. ESPCs are covered under FAR Part 23.2, and 42 USC § 8287. Section 8287(a)(2)(A) of Title 42 of the U.S. Code requires that each energy savings performance contract (ESPC) undergo an annual energy audit, resulting in a separate audit report for every project. The objective of the present report is to compile and analyze all annual ESPC audit reports issued between October 1, 2023, and September 30, 2024, for projects awarded under Generations 1, 2, and 3 of DOE’s ESPC IDIQ contracts. During this period, 205 measurement and verification (M&V) reports were produced for 200 projects; the total number of reports exceeds the number of projects because some projects generated more than one report (for example, a few projects measure savings twice per year and produce two audit reports annually, each covering a different six-month period). By aggregating the results from these individual audits, the report determines the portfolio-wide realization rate of energy and cost savings for all active ESPC projects awarded under DOE’s IDIQ program.
29 ENERGY PLANNING, POLICY, AND ECONOMY↗
A simplified Reynolds stress model for unsteady turbulent boundary layers
A simplified Reynolds stress model has been developed for the prediction of unsteady turbulent boundary layers. By assuming that the net transport of Reynolds stresses is locally proportional to the net transport of the turbulent kinetic energy, the time dependent full Reynolds stress model is reduced to a set of ordinary differential equations. These equations contain only time derivatives and can be readily integrated in a time dependent boundary layer or Navier-Stokes code. The turbulent kinetic energy and dissipation rate needed for the model are obtained by solving the k-epsilon equations. This simplified Reynolds stress turbulence model (SRSM) does not use the eddy viscosity assumption, which may not be valid for unsteady turbulent flows. The anisotropy of both the steady and the unsteady turbulent normal stresses can be captured by the SRSM model. Through proper damping of the shear stresses, the present model can be used in the near wall region of turbulent boundary layers. This model has been validated against data for steady and unsteady turbulent boundary layers, including periodic turbulent boundary layers subjected to a mean adverse pressure gradient. For the cases tested, the predicted unsteady velocity and turbulent stress components agree well with the experimental data. Comparison between the predictions from the SRSM model and a k-epsilon model is also presented.
Fan, Sixin↗
CPMC-Lab: A Matlab package for Constrained Path Monte Carlo calculations
We describe CPMC-Lab, a Matlab program for the constrained-path and phaseless auxiliary-field Monte Carlo methods. These methods have allowed applications ranging from the study of strongly correlated models, such as the Hubbard model, to ab initio calculations in molecules and solids. The present package implements the full ground-state constrained-path Monte Carlo (CPMC) method in Matlab with a graphical interface, using the Hubbard model as an example. The package can perform calculations in finite supercells in any dimensions, under periodic or twist boundary conditions. Importance sampling and all other algorithmic details of a total energy calculation are included and illustrated. This open-source tool allows users to experiment with various model and run parameters and visualize the results. It provides a direct and interactive environment to learn the method and study the code with minimal overhead for setup. Furthermore, the package can be easily generalized for auxiliary-field quantum Monte Carlo (AFQMC) calculations in many other models for correlated electron systems, and can serve as a template for developing a production code for AFQMC total energy calculations in real materials. Several illustrative studies are carried out in one- and two-dimensional lattices on total energy, kinetic energy, potential energy, and charge- and spin-gaps.
Computer Science↗
Monte Carlo Analyses of the FOEHN Experiment
The FOEHN critical experiment, which has been carried out at Cadarache (France) in the reactor EOLE in the early 70s, was designed to verify RHF design analyses. This study focuses on the impact of the FOEHN experiment uncertainties on the calculation of the energy deposition. The latter has been obtained by the Monte Carlo codes Serpent and MCNP. In the calculation of the energy deposition, the first code relies on KERMA factors whereas the latter code relies on Q-values. The two Monte Carlo codes share the same geometry and material specifications. In addition to the design and experiment parameters uncertainties, nuclear data also impacts the calculation of the energy deposition. In this study, the MCNP simulations use three different nuclear data library sets: ENDF/B versions VII.0, VII.1, and VIII.0. Finally, the ksens card of MCNP, using perturbation theory, has been used to identify the cross sections and isotopes with largest impact on the effective multiplication factor. By showing that the use of different software and computational methodologies and design parameters uncertainties do not significantly impact the core power distribution, this work demonstrate the appropriateness of the tools and methods employed for the conversion of involute-plate reactors.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Fusion Neutron Generator
The proposed code, named FROG (Fusion neutron Generator) is built upon the open-source particle transport Monte Carlo toolkit Geant4. Geant4 provides C++ classes that can be leveraged to build application-specific codes dealing with the transport of particles through matter. Geant4-based codes are applied in high-energy particle physics experiments, medical applications, shielding, and space applications for example. The FROG code allows the user to define the geometry of a neutron converter device shaped as a hollow cylinder, where a neutron breeding material such as lithium deuteride (LiD) is cladded by two concentric cylinders. Such neutron converter is then placed inside a regular nuclear fission reactor, where thermal neutrons will react with the neutron breeder material (typically, Lithium 6), and through a series of reactions, will generate high-energy neutrons – neutrons whose kinetic energy are around 14 MeV. The hollowed central portion can hold a specimen that will be bombarded by high-energy neutrons created inside the neutron breeding material. Figuratively speaking, this type of device transforms neutrons from thermal (~0.625 eV) to fusion (~14 MeV) energies and is sometimes termed “fusion-to-thermal neutron converters” in the literature. The code consists of C++ source file compiled and linked to generate an executable. The user can select the dimensions of the converter (radius, length, and thickness of the breeder material), the breeder material type, the cladding material, and the specimen material that will be activated or irradiated. As input, the neutron flux for a specific location inside a reactor, for instance, positions in ATR, is required. As output, the code predicts the number of high-energy neutrons produced, the total neutron flux and fluence as well as its detailed spectrum. The physics involved in such device is very complex, as it requires modeling neutron transport, light-ion (tritons) transport, as well as fusion reactions. The Geant4 toolkit provides the required physical models.
Martin, NicholasP. [Idaho National Laboratory (INL↗
L- and M-shell absorption measurements of radiatively heated Fe plasma
Measurements of iron-plasma absorption spectrum over 150-1200 eV photon energy range were reported at temperature T = (72 {+-} 4) eV. The electron temperature was diagnosed with the absorption spectrum of aluminum mixed with iron. The density was not diagnosed directly but obtained from a radiative hydrodynamic simulation with the Multi-1D code. The broad photon energy range enables simultaneous observation of the L-shell and M-shell transitions that dominate the radiation transport at this temperature. The spectrally resolved transmission data were compared to the detailed-configuration-accounting model calculations and reasonable agreement was found.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Measuring Impact of U.S. DOE Geothermal Technologies Office Funding: Considerations for Development of a Geothermal Resource Reporting Metric
This paper reviews existing methodologies and reporting codes used to describe extracted energy resources such as coal and oil and describes a comparable proposed methodology to describe geothermal resources. The goal is to provide the U.S. Department of Energy's (DOE) Geothermal Technologies Office (GTO) with a consistent and comprehensible means of assessing the impacts of its funding programs. This framework will allow for GTO to assess the effectiveness of research, development, and deployment (RD&D) funding, prioritize funding requests, and demonstrate the value of RD&D programs to the U.S. Congress. Standards and reporting codes used in other countries and energy sectors provide guidance to inform development of a geothermal methodology, but industry feedback and our analysis suggest that the existing models have drawbacks that should be addressed. In order to formulate a comprehensive metric for use by GTO, we analyzed existing resource assessments and reporting methodologies for the geothermal, mining, and oil and gas industries, and we sought input from industry, investors, academia, national labs, and other government agencies. Using this background research as a guide, we describe a methodology for assessing and reporting on GTO funding according to resource knowledge and resource grade (or quality). This methodology would allow GTO to target funding or measure impact by progression of projects or geological potential for development.
15 GEOTHERMAL ENERGY↗
Lessons Learned and Scalability Achieved When Porting Uintah to DOE Exascale Systems
A key challenge faced when preparing codes for Department of Energy (DOE) exascale systems was designing scalable applications for systems featuring hardware and software not yet available at leadership-class scale. With such systems now available, it is important to evaluate scalability of the resulting software solutions on these target systems. One such code designed with the exascale DOE Aurora and DOE Frontier systems in mind is the Uintah Computational Framework, an open-source asynchronous many-task (AMT) runtime system. To prepare for exascale, Uintah adopted a portable MPI+X hybrid parallelism approach using the Kokkos performance portability library (i.e., MPI+Kokkos). This paper complements recent work with additional details and an evaluation of the resulting approach on Aurora and Frontier. Results are shown for a challenging benchmark demonstrating interoperability of 3 portable codes essential to Uintah-related combustion research. These results demonstrate single-source portability across Aurora and Frontier with scaling characteristics shown to 3,072 Aurora nodes and 9,216 Frontier nodes. In addition to showing results run to new scales on new systems, this paper also discusses lessons learned through efforts preparing Uintah for exascale systems.
Holmen, John [ORNL] (ORCID:0000000259342641)↗
The Continual Intercomparison of Radiation Codes: Results from Phase I
The computer codes that calculate the energy budget of solar and thermal radiation in Global Climate Models (GCMs), our most advanced tools for predicting climate change, have to be computationally efficient in order to not impose undue computational burden to climate simulations. By using approximations to gain execution speed, these codes sacrifice accuracy compared to more accurate, but also much slower, alternatives. International efforts to evaluate the approximate schemes have taken place in the past, but they have suffered from the drawback that the accurate standards were not validated themselves for performance. The manuscript summarizes the main results of the first phase of an effort called "Continual Intercomparison of Radiation Codes" (CIRC) where the cases chosen to evaluate the approximate models are based on observations and where we have ensured that the accurate models perform well when compared to solar and thermal radiation measurements. The effort is endorsed by international organizations such as the GEWEX Radiation Panel and the International Radiation Commission and has a dedicated website (i.e., http://circ.gsfc.nasa.gov) where interested scientists can freely download data and obtain more information about the effort's modus operandi and objectives. In a paper published in the March 2010 issue of the Bulletin of the American Meteorological Society only a brief overview of CIRC was provided with some sample results. In this paper the analysis of submissions of 11 solar and 13 thermal infrared codes relative to accurate reference calculations obtained by so-called "line-by-line" radiation codes is much more detailed. We demonstrate that, while performance of the approximate codes continues to improve, significant issues still remain to be addressed for satisfactory performance within GCMs. We hope that by identifying and quantifying shortcomings, the paper will help establish performance standards to objectively assess radiation code quality, and will guide the development of future phases of CIRC
Oreopoulos, Lazaros↗
How Can Cities Use Urban-Scale Building Energy Modeling?
Whole-building energy modeling (BEM) is a multi-purpose tool for building energy efficiency, supporting design, code development and compliance, green labeling, incentive programs, and even building operations. A new buzz-prefix making its way around the BEM community is 'urban-scale'. But what is urban-scale BEM (UBEM)? And can it help cities--or other entities--save energy? We describe a taxonomy of UBEM based on the interactions that are modeled between buildings and between buildings and other systems. Each type of UBEM supports different analyses and applications. We describe each UBEM type and, using a survey of sustainability managers in major U.S. cities, give examples of how it is currently used in practice or could be used in the future. The four types of UBEM are 'Portfolio', 'District', 'Weather', and 'System' BEM. Portfolio BEM considers no interactions between buildings and no other systems. It is conventional BEM repeated on multiple buildings. It is also by far the most commonly used UBEM with applications to retrofit screening and targeting.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
The Demonstration of Power over Ethernet (PoE) Technologies in Commercial and Institutional Buildings
PoE technologies are currently ubiquitous in offices in the form of phones, access points, and IP security cameras and managed by on-site IT staff. As low voltage DC-power capabilities have increased with network switches, PoE devices are now being integrated across additional building systems, including lighting, computers, and HVAC controls. Since PoE devices are connected to network switches, energy monitoring and management can be performed through the IT network management software. Data and results from technology validations are still very limited for PoE equipment. This lack of information hinders higher adoption as its benefits and challenges have been insufficiently quantified in real-world scenarios. The use of IT network switches to power and control lighting, plug loads, and HVAC were demonstrated at a variety of sites including offices, schools, and a hotel. This paper presents the findings of a three-year DOE-/State of Minnesota-funded project that demonstrated and assessed the energy and non-energy benefits of Power over Ethernet (PoE) technologies at four commercial/institutional sites. The goals of the demonstrations were to: (1) assess the receptiveness of commercial and institutional markets to these new technologies, (2) demonstrate the feasibility of PoE technologies within standard design/construction practices and commercial codes, (3) assess the energy and cost savings opportunities of these technologies, (4) provide energy management opportunities where they typically are not available, and (5) formulate approaches to spur adoption of these technologies in the marketplace.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
The Demonstration of Power over Ethernet (PoE) Technologies in Commercial and Institutional Buildings
PoE technologies are currently ubiquitous in offices in the form of phones, access points, and IP security cameras and managed by on-site IT staff. As low voltage DC-power capabilities have increased with network switches, PoE devices are now being integrated across additional building systems, including lighting, computers, and HVAC controls. Since PoE devices are connected to network switches, energy monitoring and management can be performed through the IT network management software. Data and results from technology validations are still very limited for PoE equipment. This lack of information hinders higher adoption as its benefits and challenges have been insufficiently quantified in real-world scenarios. The use of IT network switches to power and control lighting, plug loads, and HVAC were demonstrated at a variety of sites including offices, schools, and a hotel. This paper presents the findings of a three-year DOE-/State of Minnesota-funded project that demonstrated and assessed the energy and non-energy benefits of Power over Ethernet (PoE) technologies at four commercial/institutional sites. The goals of the demonstrations were to: (1) assess the receptiveness of commercial and institutional markets to these new technologies, (2) demonstrate the feasibility of PoE technologies within standard design/construction practices and commercial codes, (3) assess the energy and cost savings opportunities of these technologies, (4) provide energy management opportunities where they typically are not available, and (5) formulate approaches to spur adoption of these technologies in the marketplace.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗