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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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At least 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Atmospheric plume progression as a function of time and distance from the release point for radioactive isotopes

The International Monitoring System contains up to 80 stations around the world that have aerosol and xenon monitoring systems designed to detect releases of radioactive materials to the atmosphere from nuclear tests. A rule of thumb description of plume concentration and duration versus time and distance from the release point is useful when designing and deploying new sample collection systems. This paper uses plume development from atmospheric transport modeling to provide a power-law rule describing atmospheric dilution factors as a function of distance from the release point.

atmospheric plume progression↗
DOE OSTI2024

On the Existence of Steady-State Solutions to the Equations Governing Fluid Flow in Networks

The steady-state solution of fluid flow in pipeline infrastructure networks driven by junction/node potentials is a crucial ingredient in various decision-support tools for system design and operation. While the nonlinear system is known to have a unique solution (when one exists), the absence of a definite result on the existence of solutions hobbles the development of computational algorithms, for it is not possible to distinguish between algorithm failure and non-existence of a solution. In this letter, we show that for any fluid whose equation of state is a scaled monomial, a unique solution exists for such nonlinear systems if the term solution is interpreted in terms of potentials and flows rather than pressures and flows. However, for gases following the CNGA equation of state, while the question of existence remains open, we construct an alternative system that always has a unique solution and show that the solution to this system is a good approximant of the true solution. Further, the existence result for flow of natural gas in networks also applies to other fluid flow networks such as water distribution networks or networks that transport carbon dioxide in carbon capture and sequestration. Most importantly, our result enables correct diagnosis of algorithmic failure, problem stiffness, and non-convergence in computational algorithms.

42 ENGINEERING↗
DOE OSTI2026

ENPAX (ENergy Platform — Automated eXpenditures) [SWR-26-053]

ENPAX (ENergy Platform — Automated eXpenditures) is an open-source Python library that provides modular, bottom-up capital and operating expenditure (CAPEX/OPEX) models for energy technologies. Cost estimates are derived using system design characteristics, site specific details, power system considerations and infrastructure assumptions.

Mulas Hernando, Daniel [National Laboratory of the↗
DOE OSTI2024

Recent Advances of PyROS: A Pyomo Solver for Nonconvex Two-Stage Robust Optimization in Process Systems Engineering

This poster highlights uncertainty and technical risk reduction capabilities in CCSI2, with a focus on robust optimization. It presents recent advances of the two-stage robust optimization (RO) solver PyROS and applications to advanced energy systems optimization. To demonstrate the computational performance and reliability of PyROS, a benchmarking study on a library of over 8,500 small-scale RO problems is presented. Further, PyROS is used to obtain robust system designs of a MEA-based CO2 absorber under uncertainty in the thermodynamic property models for a variety of CO2 capture rate threshold requirements. Overall, the results demonstrate that the PyROS solver, including recent extensions to multi-stage RO settings, provides a reliable avenue to optimize the design and operation of advanced energy systems subject to various sources of parametric uncertainty.

Sherman, Jason↗
DOE OSTI2024

Recent Advances of PyROS: A Pyomo Solver for Nonconvex Two-Stage Robust Optimization in Process Systems Engineering

This poster highlights uncertainty and technical risk reduction capabilities in CCSI2, with a focus on robust optimization. It presents recent advances of the two-stage robust optimization (RO) solver PyROS and applications to advanced energy systems optimization. To demonstrate the computational performance and reliability of PyROS, a benchmarking study on a library of over 8,500 small-scale RO problems is presented. Further, PyROS is used to obtain robust system designs of a MEA-based CO2 absorber under uncertainty in the thermodynamic property models for a variety of CO2 capture rate threshold requirements. Overall, the results demonstrate that the PyROS solver, including recent extensions to multi-stage RO settings, provides a reliable avenue to optimize the design and operation of advanced energy systems subject to various sources of parametric uncertainty.

Sherman, Jason↗
DOE OSTI2013

Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system

Purpose: Using hybrid x-ray/MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C-arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x-ray and MR imaging fields of view. Existing rotating anode x-ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x-ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction. Methods: The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x-ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode-anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors' assembly were also evaluated to determine its stability during acceleration, and a pulse width modulation algorithm was implemented to control the rotation speed of the motor. Results: At a magnetic flux density of 41 mT orthogonal to the axis of rotation (on the lower end of the expected flux density in the MR suite) the maximum speed of the motor was found to be 5150 revolutions per minute (rpm). The acceleration time necessary to reach 3000 rpm was found to be approximately 10 s at 59 mT. The resonance frequency of the assembly with the anode attached was 1310 rpm (21.8 Hz) which is far below the desired operating speeds. Pulse width modulation provides an effective method to control the speed of the motor with a resolution of 100 rpm. Conclusions: The proposed design can serve as a direct replacement to the conventional induction motor used in rotating anode x-ray tubes. It does not suffer from a reduced rotation speed when operating in a MR environment. The presence of chromic steel bearings in the prototype prevented testing at the higher field strengths, and future iterations of the design could eliminate this shortcoming. The prototype assembly demonstrates proof of concept of the authors' design and overcomes one of the major obstacles for a MR compatible rotating anode x-ray tube.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Solid oxide electrolysis cell and stack testing best practices

Solid oxide electrolyzer (SOE) technology is an emerging method for hydrogen production, noted for its superior electrical efficiency. Despite the significant progress made in recent years, the broad development of SOE technology is often constrained by the necessary and extensive "skill of the craft" required to successfully test simple single cell test articles. This may be linked to the dearth of practical and pragmatic guidance within the literature for safe, reliable, and performant test equipment and test procedures. Researchers at the Idaho National Laboratory (INL) have been actively testing SOEs ranging from button cells to stacks up to 500 kW, in collaboration with industry and other national laboratories. Based on operational experience, INL has developed system design procedures that ensure safe and reliable operation of SOE systems with the level of support required for each test. This paper presents key aspects of SOE stack and system testing, including safe design procedures, balance of plant components design, and specific implementations at INL. Practical design details of reactants, heat, and power management are presented along with lessons learned from the SOE test facility operations at INL.

08 HYDROGEN↗
DOE OSTI2022

An Integrated Risk Assessment Process of Safety-Related Digital I&C Systems in Nuclear Power Plants

Upgrading the existing analog instrumentation and control (I&C) systems to state-of-the-art digital I&C (DI&C) systems will greatly benefit existing light water reactors. However, the issue of software common cause failure (CCF) remains an obstacle in terms of qualification for digital technologies. Existing analyses of CCFs in I&C systems mainly focus on hardware failures. With the application and upgrading of new DI&C systems, design flaws could cause software CCFs to become a potential threat to plant safety, considering that most redundancy designs use similar digital platforms or software in their operating and application systems. With complex multilayer redundancy designs to meet the single failure criterion, these I&C safety systems are of particular concern in U.S. Nuclear Regulatory Commission licensing procedures. In Fiscal Year 2019, the Risk-Informed Systems Analysis (RISA) Pathway of the U.S. Department of Energy’s Light Water Reactor Sustainability Program initiated a project to develop a risk assessment strategy for delivering a strong technical basis to support effective, licensable, and secure DI&C technologies for digital upgrades and designs. An integrated risk assessment for the DI&C process was proposed for this strategy to identify potential key digital-induced failures, implement reliability analyses of related digital safety I&C systems, and evaluate the unanalyzed sequences introduced by these failures (particularly software CCFs) at the plant level. Here this paper summarizes these RISA efforts in the risk analysis of safety-related DI&C systems at Idaho National Laboratory.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2017

Vapor Intrusion Mitigation Beneath an Occupied Industrial Building at the Young - Rainey Science, Technology, and Research Center Largo, Florida - 17463

Groundwater contamination, consisting of chlorinated solvents, was identified in the southeastern portion of the Pinellas Site in Largo, Florida. The contamination is beneath Building 100, an 11-acre building that housed manufacturing facilities during US Department of Energy (DOE) operations at the site. Because the building was constructed in phases over a period of decades, it is comprised of approximately 20 different buildings, each with a separate foundation, all of which are now connected under a single roof. Based on the results of a pilot test that indicated the presence of volatile organic compounds beneath the floor slab and, in the absence of state regulations or guidance, DOE elected to proactively address the potential for release of these compounds into the facility by designing and installing a vapor intrusion (VI) mitigation system. To ventilate vapors from beneath the building, piping was installed from beneath the concrete floor slab through the roof, and negative pressure was created using electric blowers. The system design was complicated by foundation walls supporting each of the various sections of Building 100 and by special requirements due to the sensitive nature of the tenant's manufacturing activities and the heightened need for security. This paper addresses significant aspects of the design and construction of a VI mitigation system beneath a large, occupied industrial production facility, including technical, logistical, and environmental challenges; community relations; and regulatory relations. (authors)

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

The SURE House (Solar Decathlon 2015)

Coastal towns and cities across the Northeastern US, with their high population density, aged utility infrastructure, and unique geography, are increasingly vulnerable to climate change related storm events. In October 2012 superstorm Sandy highlighted the fragility of our current coastal building types and made clear the need for a new model of design and construction which works to understand and mitigate these weaknesses. Dramatic changes in public policy, championed by both The Federal Emergency Management Agency (FEMA) and the National Flood Insurance Program (NFIP) are driving the rebuilding of these shore communities, often resulting in costly renovations, un-sustainable neighborhood configurations and in direct conflict with concurrent government policies such as The American with Disabilities Act (ADA). The SURE HOUSE demonstrates a series of new design solutions to these conflicting public policies and environmental imperatives. At Stevens Institute of Technology, the 2015 Solar Decathlon started with the challenge: Can we design a home for coastal New Jersey that dramatically reduces its energy use while protecting itself from the realities of a changing, more extreme climate? The SURE HOUSE merges the iconic 20th century shore home with 21st century building science. Utilizing innovative renewable energy technologies, a ‘Passive House’ level building envelope, and rugged glass-fiber-composite materials to flood-proof the home, the SURE HOUSE is a high-performance, net-zero-energy home, armored against extreme weather, designed for the contemporary lifestyle of the Jersey Shore and other vulnerable coastal communities. SUSTAINABLE At Stevens, we recognize that energy use in the home and workplace is directly connected to the growing problem of climate change. Reducing our energy consumption by designing higher performing, compact homes that are both functional, comfortable and desirable is the first critical step towards a modern, sustainable architecture for New Jersey and beyond. This is what informed the architectural design of the house. Configured about a compact form, thickly insulated and air-sealed walls eliminate thermal bridging and minimize energy losses while advanced glazing brings in free solar heat during the winter months. As a result of these passive design strategies, the SURE HOUSE has a greatly reduced carbon footprint requiring 91% less energy than a typical New Jersey home. Photovoltaic (PV) arrays on both the rooftop and operable shutters easily provide energy in excess of the home’s modest demands. The Stevens team considers a truly sustainable home in the era of climate change, one that prioritizes low energy use, and integrates right-sized renewable generation to supply the home’s needs. Low consumption, low production. RESILIENT In October of 2012, Hurricane Sandy wreaked havoc along the east coast of the US. In New Jersey alone there was an estimated 29.4 billion dollars in damages, 346,000 homes affected, and almost two and a half million people left without power, in some cases for over 10 days. Recovery from this storm and associated flooding is ongoing to this day, as many New Jersey homeowners grapple with the large costs of rebuilding and struggle to adapt to complicated new home building regulations. Damage from this storm to Hoboken, the home of the Stevens Institute of Technology’s campus, and to the New Jersey shore was extensive and many students on the SURE HOUSE team were directly affected by this historic event. The Stevens design team recognizes that in a world of more frequent and stronger storms, the ability to absorb and adapt to change is more important than ever. Successfully weathering the next storm and its aftermath is one of the primary goals in the design of the SURE HOUSE prototype. The SURE HOUSE introduces unique ‘dry flood-proofing’ methods to residential construction. Innovative wall and floor flood-proofing, utilizing durable composite sheathing materials adapted from the boating industry, were developed by the student team to render the SURE House’s building envelope flood proof up to the FEMA AE 6/7 Zone (+ 6/7 feet of water above sea-level). Designed and fabricated utilizing glass-fiber composite materials, the custom storm shutter system serves to protect the large glazed openings of the home from both air-borne debris impact and water infiltration during a storm event while also providing deterrence from the vandalism that often occurs in the aftermath of a calamitous event. During extended power outages, a ‘resilient’ solar array is capable of supplying critical amounts of energy and hot water to the home, without the use of battery storage or grid infrastructure. PV Description AC GRID-TIED PV SYSTEM The SURE HOUSE solar system consists of two distinct arrays, the grid-tied rooftop array which produces AC Powerand the shutter-mounted array which converts DC power generated by the modules directly into usable heat for the domestic hot water (DHW). The roof-mounted AC grid-tied array is comprised of three strings, two 11 module strings connected to an SMA SB 5000TL-US-223 inverter and a single 10 module string equipped and an SMA SB 3000TL-US-22 central inverter. All modules for the rooftop AC array are LG MonoX 2804 watt solar panels, chosen for their durability and efficiency. Inverter sizing and string size are optimized to the electrical characteristics of the chosen PV modules and the desired energy production, see Appendix 5B. The SURE HOUSE is projected to produce 12,353 kWh per year to meet 6,157 kWh per year of estimated consumption. Solar modules for the two AC grid-tied sub arrays are mounted on the main roof surface of the SURE HOUSE with a 10 degree tilt angle using a partially-ballasted polyethylene roof mounting system made by Renusol, which is particularly suited to the corrosive salt air of a coastal environment. This method was chosen for its installation simplicity and to limit detrimental roof penetrations. The 10 degree tilt optimizes the energy generated per roof area at a lower price, see Appendix 5A, and ensures that there is minimal wind uplift. DC SOLAR ELECTRIC DOMESTIC HOT WATER The SURE HOUSE’s approach to sustainable and resilient domestic hot water (DHW) consists of a unique, custom engineered DC solar electric hot water system. Employing the use of Advanced Energy’s DC electric PV heater (DCPVH)5 to heat domestic water well beyond the draw temperature, the SURE HOUSE is able to obtain a remarkably high solar fraction of 75% or more. The custom modified 80 gallon Vaughn DHW tank acts as a large solar ‘battery’ that stores heat energy in the form of hot water at almost 150 degrees, harvesting energy when the sun is out for use later in the day or overnight. The system, which uses electricity rather than heated fluid, is distinct from traditional ‘solar thermal’ systems by eliminating the dangers and associated maintenance issues of fluid based systems. By forgoing the use of external fluid loops, overheated solar collectors and pipes are not an issue for the SURE HOUSE system which never needs any yearly or seasonal flushing. In weather conditions where the integrated DCPVH unit cannot produce enough hot water via solar energy alone, the Vaughn hot water tank comes factory made with an AC powered 2.6 COP heat pump and a AC heating coil that serve as back-up heating elements. The DCPVH is powered by a DC array consisting of 10 custom-made Solbian by PVilion 180 watt, monocrystalline, flexible solar modules6. The Solbian modules are directly mounted to the top half of the operable storm shutters on the south façade of the SURE HOUSE. The SURE HOUSE team worked closely with PVillion, a PV system designer specializing in flexible architectural photovoltaics, to design an adhesive system that works with the glass-fiber storm shutter surface in a reliable manner over an extended period. Because this system operates in DC-only mode and never connects to the municipal power grid, the system can continue to create hot water safely and effectively even during grid disruption events. This hot water, and the energy stored within it, could be used for a range of activities including washing and cooking to more elaborate hydronic heating systems as desired. See Appendix 6 for system engineering, sizing and modeling.

14 SOLAR ENERGY↗
DOE OSTI2022

Selective Heating Through Y-Junction Waveguide Designed by Acoustic Shape Optimization

Unlike phononic crystals or systems designed by topology optimization, waveguides designed by shape optimization do not have voids or internal defects, making the fabrication process more suitable for additive manufacturing. By designing a Y-junction waveguide through shape optimization, an ultrasonic wave can be controlled so that it propagates to a predetermined location just by adjusting its frequency. These demultiplexed ultrasonic waves can be used to transport signals or stimulate nearby materials. As an example, the ultrasonic wave is converted to heat at different locations, which can be applied to mechanisms that can take advantage of heating. First, shape optimization is performed on a cylindrical structure to selectively propagate ultrasonic waves of a particular frequency while attenuating others, which is analyzed through a finite element model. The numerical study results are compared with experimental measurements from samples fabricated through additive manufacturing methods. After verifying the concept, the Y-junction waveguide is fabricated to demultiplex the wave and selectively heat different locations. Here the results show that the method of combining shape optimization with additive manufacturing is exceptionally simple and capable of demultiplexing ultrasonic waves, which can replace complex electrical components with single-material waveguides.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Control, Fault Management, and Grid Support Functionality of an MV AC-DC Solid State Transformer based EV Extreme Fast Charging Station

Electric vehicles (EVs) have become increasingly popular in recent times while revolutionizing the consumer and commercial transportation market. The development of charging infrastructure has become one of the priorities for increasing the adoption of EVs. Extreme fast charging (XFC) technology can reduce the so-called ’range anxiety’ of consumers as they significantly reduce the charging time. With the advent of wide band-gap (WBG) power devices and improvement in power electronic converters, medium voltage (MV) solid state transformer (SST) based XFC system has the potential to replace the traditional XFC stations because of the lower footprint, ease of installation, enhanced control feature, and better system efficiency. The control system design is one of the critical aspects of the SST development process. Careful consideration and detailed analysis are required to find out suitable control method for the SST based on its topology among different centralized and decentralized control architectures. Also, the control parameters selection and potential improvement to the transient response of the controller ought to be investigated. Another major concern of the SST is different types of internal fault which reduces the overall reliability of the XFC system. As a result, designing a robust protection system is essential. Among different fault modes, open circuit switch faults have received significant attention as an active research area because of their likelihood and severe effects on converters. Therefore, the power stages used in the XFC system require functional and accurate open circuit switch fault management methods. An equally significant aspect of this SST based XFC is its compatibility in a microgrid where there is no synchronous generator present. When the grid is not available, the XFC SSTs can provide grid forming capability and continue supplying the critical loads in islanded mode. The transition between grid connected and islanded mode, especially the grid resynchronization process has to be carefully performed for the safety of the microgrid components. The challenges posed by the aforementioned issues have inspired the work done in this dissertation. Here, a 13.2 kV, 1 MVA, AC/DC SST for the XFC system is examined and a comparative analysis is conducted to select the control architecture based on feasibility of implementation and performance. A detailed control parameter design process is demonstrated considering the sensor dynamics and delay. The selected decentralized control method is augmented by introducing a novel sensor-less load current feedforward method to provide better voltage regulation at the DC bus during a change of load. Next, in the fault management section, a hierarchical failure mode effect analysis (FMEA) is proposed to enable a systematic design of the internal fault protection of the XFC SST as there are limited examples in the literature regarding the analysis of the safety and design of the protection of a power electronic converter system. Novel open circuit switch fault management methods for the converters in the system are presented. Finally, XFC SST based MV microgrid operations in grid connected mode and islanded mode are explored. A secondary control method for grid resynchronization is presented and a design process of control parameters is shown to ensure the stability of the secondary voltage and frequency regulation.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2022

Co-Design of Marine Energy Converters for Autonomous Underwater Vehicle Docking and Recharging - Software and Data

Software and testing data from the OH Hinsdale Wave lab for DOE-funded project on Co-Design of Marine Energy Converters for Autonomous Underwater Vehicle Docking and Recharging. This project will perform foundational research and testing to accelerate the sector-wide development and deployment of marine energy converters to provide Power-At-Sea. Specifically, we seek to overcome known challenges and knowledge gaps for the successful co-design of coupled Wave Energy Converter (WEC)-Autonomous Underwater Vehicles (AUV) systems; systems designed and tested for WEC array system health and environmental monitoring applications. This project brings together an experienced, multi-institution, and multi-disciplinary team to focus on the co-design of marine energy (ME) technologies and AUV docking systems, including multi-body hydrodynamic modeling, active control, autonomy, and hardware interfaces necessary to enable new WEC-focused understanding, and allow for robust and ubiquitous AUV docking and recharging in real-world conditions.

16 TIDAL AND WAVE POWER↗
DOE OSTI2013

High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems

This report summarizes the progress made during the April 01, 2010 – December 30, 2013 period under Cooperative Agreement DE-EE0002752 for the U.S. Department of Energy entitled “High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems.” The overall objective of this program is to advance the technology for well fluids lifting systems to meet the foreseeable pressure, temperature, and longevity needs of the Enhanced Geothermal Systems (EGS) industry for the coming ten years. In this program, lifting system requirements for EGS wells were established via consultation with industry experts and site visits. A number of artificial lift technologies were evaluated with regard to their applicability to EGS applications; it was determined that a system based on electric submersible pump (ESP) technology was best suited to EGS. Technical barriers were identified and a component-level technology development program was undertaken to address each barrier, with the most challenging being the development of a power-dense, small diameter motor that can operate reliably in a 300°C environment for up to three years. Some of the targeted individual component technologies include permanent magnet motor construction, high-temperature insulation, dielectrics, bearings, seals, thrust washers, and pump impellers/diffusers. Advances were also made in thermal management of electric motors. In addition to the overall system design for a full-scale EGS application, a subscale prototype was designed and fabricated. Like the full-scale design, the subscale prototype features a novel “flow-through-the-bore” permanent magnet electric motor that combines the use of high temperature materials with an internal cooling scheme that limits peak internal temperatures to <330°C. While the full-scale high-volume multi-stage pump is designed to lift up to 80 kg/s of process water, the subscale prototype is based on a production design that can pump 20 kg/s and has been modified for high-temperature operation. In parallel with the design and fabrication of the subscale prototype ESP system, a subscale test facility consisting of a high-temperature-high-pressure flow loop was designed, fabricated, and installed at GE Global Research in Niskayuna, NY. A test plan for the prototype system was also established. The original plan of testing the prototype hardware in the flow loop was delayed until a future date.

15 GEOTHERMAL ENERGY↗
DOE OSTI2021

Conceptual monopile and tower sizing for the IEA Wind Task 37 Borssele reference wind farm

This paper explores the preliminary design of the support structures for the IEA Wind Task 37 reference wind farm at the Borssele site III and IV. The study looks at two different design methods that might be used within larger wind farm system design optimization (i.e. lay-out, electrical systems, etc.). The first consists of a scaling tool that scales a detailed design according to the rated power, water depth, hub height and rotor diameter. The second is a physics-based optimization approach that relies on the WISDEM® design tool. This research compares the results of these two methods for the design of both the tower and monopile of the IEA 10-MW and 15-MW reference wind turbines at a range of sea depths (25 m, 30 m, 35 m, 40 m). The two tools yield very similar results in terms of monopile base diameter, support structure natural frequency and mass. WISDEM is then used to also investigate the sensitivity of the design to the tower top forces, wave conditions and the soil conditions. It is shown that tower top forces dominate the design. In general, large diameter structures can carry additional costs associated with manufacturing and transportation requirements. Thus, the paper is concluded with a trade-off study between mass and diameter that quantifies the effect of the reduction in monopile diameter with the increase in structural mass.

WIND ENERGY↗
DOE OSTI2012

ASC Co-design Proxy App Strategy

The NNSA labs representing the ASC program are coordinating on the development and release of a portfolio of proxy applications to be used in co-design. While each lab will develop their own set of proxy apps that represent the applications and algorithms of interest to them, we propose a common set of criteria to describe and measure proxy apps, and a strategy aimed at minimizing duplication and maximizing impact across the entire ASC proxy app portfolio. Proxy application (or proxy apps for short) is a catchall term for the simplification of characteristics of real applications that are of interest to DOE. These proxy apps are used in the co-design process as concrete examples for component and system designers to understand our software requirements. The proxy apps are generally openly available to the co-design community and, unlike benchmarks, are intended to facilitate the two-way communication required by co-design to optimally evaluate trade-offs in the system hardware, and inform the developer community of programming best practices for emerging architectures.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

SU-E-T-514: Investigating the Dose Distributions of Equiangular Spaced Noncoplanar Beams

Purpose It has been demonstrated that the use of noncoplanar beams in radiation therapy may Result in dose distributions that are comparable or better than standard coplanar beams [Pugachev, 2001]. A radiation therapy system designed with a noncoplanar beam geometry could allow for a full ring diagnostic quality imaging system to be placed around the patient. Additionally, if the noncoplanar beams were fixed in number and in their angle with respect to the patient’s axial plane, then both treatment and imaging could be achieved concurrently without the need for moving parts, which could greatly reduce treatment times. For such a system to be designed, it is necessary to determine the appropriate number of beams and the beam angles to achieve optimal dose distributions. For simplicity, the beam angles are assumed to be equiangular in the patient’s axial plane, and only the beam angle with respect to the axial plane are varied. This study aims to investigate the dose distributions produced by equiangular noncoplanar beams for multiple beam numbers and beam angles, and to compare these dose distributions with distributions achieved in coplanar volumetric arc therapy (VMAT). Methods Dose distributions produced by noncoplanar beams were calculated using the Varian Eclipse treatment planning system by varying the gantry, collimator, and couch angles to simulate the noncoplanar delivery method. Noncoplanar intensity-modulated (NC-IMRT) beams using 8, 12, and 16 beams with angles varying from 45 degrees to 54 with respect to the patient’s axial plane were studied. Results The NC-IMRT beams produced dose distributions comparable to VMAT plans for a number of treatment sites, and were capable of meeting similar dose-volume histogram constraints. Conclusion This study has demonstrated that a noncoplanar beam delivery method with fixed beam numbers and beam angles is capable of delivering dose distributions comparable to VMAT plans currently in use.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Benchmarking Non-Hardware Balance-of-System (Soft) Costs for U.S. Photovoltaic Systems, Using a Bottom-Up Approach and Installer Survey – Second Edition

This report presents results from the second U.S. Department of Energy (DOE) sponsored, bottom-up data-collection and analysis of non-hardware balance-of-system costs -- often referred to as 'business process' or 'soft' costs -- for U.S. residential and commercial photovoltaic (PV) systems. In service to DOE's SunShot Initiative, annual expenditure and labor-hour-productivity data are analyzed to benchmark 2012 soft costs related to (1) customer acquisition and system design (2) permitting, inspection, and interconnection (PII). We also include an in-depth analysis of costs related to financing, overhead, and profit. Soft costs are both a major challenge and a major opportunity for reducing PV system prices and stimulating SunShot-level PV deployment in the United States. The data and analysis in this series of benchmarking reports are a step toward the more detailed understanding of PV soft costs required to track and accelerate these price reductions.

14 SOLAR ENERGY↗