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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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A system for combined heat and electric power generation, preferably including a heat reservoir and one or more electric generators, each preferably including a heat source and an energy converter. A method for combined heat and electric power generation, preferably including activating an electric generator, deactivating the electric generator, and/or providing heat from a heat reservoir.
The integration of new energy technologies into electric power systems requires methods which recognize the full range of dynamic events in both the new generating unit and the power system. Since new energy technologies are initially perceived as small contributors to large systems, little attention is generally paid to system integration, i.e. dynamic events in the power system are ignored. As a result, most new energy sources are only capable of base-load operation, i.e. they have no load following or cycling capability. Wind turbines are no exception. Greater awareness of this implicit (and often unnecessary) limitation is needed. Analysis methods are recommended which include very low penetration (infinite bus) as well as very high penetration (stand-alone) scenarios.
Recently, there have been several proposals submitted to funding agencies for long-lived high altitude (about 70,000 feet) airships for communications, surveillance, etc. In order for these airships to remain at altitude, high power, high efficiency, lightweight solar arrays must be used, and high efficiency power management and distribution systems must be employed. The needs for high power and high efficiency imply high voltage systems. However, the air pressure at these extreme altitudes is such that electrical power systems will be near the Paschen discharge minimum over a wide range of electrode separations. In this paper, preliminary calculations are made for acceptable high voltage design practices under ambient, hydrogen and helium gas atmospheres.
A microgrid can enhance a site’s electrical power system during normal operations, as well as provide reliable backup power to critical loads when electric utility power is interrupted. When components of a microgrid (and potentially the entire system) can be justified economically and paid for out of energy savings or avoided costs, implementation by one of several privately financed federal procurement mechanisms is possible. However, it is typically difficult to achieve enough savings and avoided costs to cover the design, equipment, and installation of certain microgrid components that are required to integrate the system. This presentation explores procurement options and agreements that may be useful to federal agencies interested in implementing microgrids at their sites. This information will be most useful to agencies when they are exploring electric energy system resilience options and/or considering different procurement options to meet their needs.
Electrified Aircraft Propulsion (EAP) systems hold potential for the reduction of aircraft fuel burn and emissions. To realize this potential for single-aisle aircraft, control technology challenges associated with EAP designs are increasing the demand for Hardware-In-the-Loop (HIL) studies that address the tightly coupled electrical powertrain and turbofan propulsion systems. Reconfigurable HIL testbeds enable the study of integrated supervisory control and control approaches that augment engine shaft torques to improve performance. This paper presents an overview of conceptual EAP controls architecture testing in two HIL testbeds. The NASA Electric Aircraft Testbed provides the ability for megawatt class electric powertrain testing for technology maturation. A 100 kilowatt testbed, the Hybrid Propulsion Emulation Rig, allows for rapid controls technology trade studies. In both testbeds, controls testing is performed by implementing the electrical power system in hardware while turbomachinery is emulated via electric machines that are commanded by a real-time model and controls. A novel scaling algorithm is applied to emulate the inertial loads of the turbomachinery that causes the electric machines to respond in a fashion similar to that of the full-scale propulsion system they represent. Results demonstrate desired control performance at both testbed scales for the conceptual EAP architecture.
Electrified Aircraft Propulsion (EAP) systems hold potential for the reduction of aircraft fuel burn and emissions. To realize this potential for single-aisle aircraft, control technology challenges associated with EAP designs are increasing the demand for Hardware-In-the-Loop (HIL) studies that address the tightly coupled electrical powertrain and turbofan propulsion systems. Reconfigurable HIL testbeds enable the study of integrated supervisory control and control approaches that augment engine shaft torques to improve performance. This paper presents an overview of conceptual EAP controls architecture testing in two HIL testbeds. The NASA Electric Aircraft Testbed provides the ability for megawatt class electric powertrain testing for technology maturation. A 100 kilowatt testbed, the Hybrid Propulsion Emulation Rig, allows for rapid controls technology trade studies. In both testbeds, controls testing is performed by implementing the electrical power system in hardware while turbomachinery is emulated via electric machines that are commanded by a real-time model and controls. A novel scaling algorithm is applied to emulate the inertial loads of the turbomachinery that causes the electric machines to respond in a fashion similar to that of the full-scale propulsion system they represent. Results demonstrate desired control performance at both testbed scales for the conceptual EAP architecture.
The power generation capability of the International Space Station (ISS) is being augmented with the installation of new solar arrays. The new solar arrays, named iROSA (ISS Roll Out Solar Array), are installed in front of original main truss solar arrays and integrate into the existing structure and electrical power system of the ISS. However, iROSA represents significant changes in technology for solar arrays compared to the original solar arrays on the ISS main truss. Knowing the power capabilities of the augmented solar arrays is critical for near-term and long-term mission planning and utilization. This new iROSA installation thus requires updates to be made to the prior-day methods of calculating power generation capability for the ISS. New types of solar cells and array designs, both electrically and structurally, present challenges for concurrent computational modeling of both the original solar arrays and the newer iROSA. This presentation will detail the development and integration of the computational models to calculate the power for the augmented arrays on ISS and the evaluation of the model to ensure that it functions with and without iROSA and returns accurate predictions of power generation in nominal and off-nominal conditions.
Simultaneous increase of power generation through renewable systems and load due owing to the rapid growth in electrified road transportation systems, leads to new challenges in the design, operation, and protection of distribution-level electrical power systems. This paper addresses challenges related to the integration of new sources or loads to a distribution grid through long alternating current lines. The International Council on Large Electric Systems medium-voltage benchmark model developed for North America was used for simulation studies. Use cases were developed to illuminate the issues related to long alternating current lines and the usefulness of medium-voltage direct current lines in a distribution network.
Glint occurs when light reflects off a specular (mirror-like) surface. In the context of spacecraft, glinted light can land in places that may cause unintended negative effects. During the Artemis I mission in November and December of 2022, the Orion vehicle was configured intentionally to cause glint to occur to study its effect on the Orion electrical power system (EPS). With the vehicle in a nose-to-sun attitude, light was reflected off the crew module’s reflective skin and onto forward-pointed solar array wings (SAWs), producing more current than would result from direct solar flux alone. Along with this flight test, glint was unexpectedly observed several other times during the mission, primarily due to light reflecting from one SAW to another. The planned glint events helped to anchor the models previously used to study this phenomenon and to understand what parameters have the most significant impact on glinted current generation. With refined models, the SAW-to-SAW glint occurrences were studied with the goal of characterizing its potential impact on vehicle operation.
NASA’s Artemis exploration campaign includes multiple elements that utilize photovoltaic power generation. Artemis mission profiles feature a variety of events that can limit solar array generation and stress electrical power system (EPS) performance, including eclipses, propulsive or navigational maneuvers which constrain the positioning of the solar arrays, and spiral trajectories with significant radiation degradation. These features make predicting the performance of the power system particularly important and requires accurate modeling of power generation by the solar arrays under a variety of conditions. One of the tools used to predict spacecraft EPS performance is the System Power Analysis for Capability Evaluation (SPACE) model developed at NASA Glenn Research Center. SPACE is used by NASA to model EPS performance for the Orion crew transport vehicle and the Power and Propulsion Element (PPE) of the Gateway space station. This presentation will provide an overview of how SPACE calculates solar array performance, including degradation factors considered and environmental conditions that drive the solar array designs. Additionally, Orion array performance predictions generated by SPACE will be compared to flight data collected during the Artemis I mission.
Glint occurs when light reflects off a specular (mirror-like) surface. In the context of spacecraft, glinted light can land in places that may cause unintended, negative effects. During the Artemis I mission in November and December of 2022, glint was forced to occur in order to study its effect on the Orion electrical power system (EPS). With the vehicle in a nose-to-sun attitude, light was reflected off the crew module’s reflective skin and onto forward pointed solar array wings (SAWs), producing more current than would result from direct solar flux alone. The goal of this in-flight test was to anchor the models previously used to study this phenomenon and to understand what parameters have the most significant impact on glinted current generation. In this presentation, the two models used for estimating optical properties for glint analysis will be discussed, as well as a worst-case study that was performed before the Artemis I mission. In-flight telemetry data will be compared to values of SAW section current produced by the models. Each of the optical properties and parameters studied will be outlined and their significance on the impact of glint will be discussed.
In March 2019, Pacific Northwest National Laboratory (PNNL) and National Renewable Energy Laboratory (NREL) held a workshop to discuss the characterization of hydropower resources within electric power system models. The workshop took place at the Western Electricity Coordinating Council in Salt Lake City, Utah, and was sponsored by the Water Power Technologies Office of the US Department of Energy. The intention of the workshop is to support the federal energy research initiative HydroWIRES. The Initiative has a specific technical objective to advance the representation of hydropower resources in relevant water and power models and to address the seams between the two. This report describes the workshop, contributions from attendees, a summary of the findings of the event and proposed next steps. The themes and recommendations from this workshop have provided foundational guidance for future research and program strategy.
The electric power sector is expected to grow in size, importance, and complexity around the world as economies expand and electric supply technologies and demand patterns evolve in significant ways. At the same time the electric power sector may see substantial increases in VRE generating technologies which can add variability and uncertainty to the diurnal and seasonal profile of electric supply. With these forces in play, the emergence of modular, flexible electricity storage technologies may have profound impacts on the operation of electric power systems. Here we reduce a storage modeling gap in MSD models by incorporating grid-based electricity storage into the electric sector dynamics of the Global Change Analysis Model-USA (GCAM-USA) with improved power sector representation. We find a potentially significant role for storage technologies in the future of the U.S. power system, with storage capacity ranging from 7.7 to 14.7 GW in 2050 and 13.9 to 31.6 GW in 2100 across several techno-economic scenarios. We also find that storage can help to smooth variability in residual load arising from evolving electricity demands and the introduction of high shares of VRE to the electric grid. This reduces reliance on high-cost peaking generators, improves system-wide capacity factors, and limits curtailment of VRE.
Program simulates power circuits and systems. Small Signal A.C. Analysis program (SSAC) valuable tool for design and analysis of electrical-power-system circuits. By combining "black box" power-system components operating in specified manner, user characterizes system modeled. Menu-driven program proved simple and cost effective in development and modification of arbitrary power-system configurations. Package includes sample data from Dynamic Explorer satellite family. Results compared favorable to calculations from such general circuit-analysis programs as SPICE. Written in FORTRAN 77.
To replicate a hyper-velocity fragmentation event using modern-day spacecraft materials and construction techniques to better improve the existing DoD and NASA breakup models: DebriSat is intended to be representative of modern LEO satellites. Major design decisions were reviewed and approved by Aerospace subject matter experts from different disciplines. DebriSat includes 7 major subsystems. Attitude determination and control system (ADCS), command and data handling (C&DH), electrical power system (EPS), payload, propulsion, telemetry tracking and command (TT&C), and thermal management. To reduce cost, most components are emulated based on existing design of flight hardware and fabricated with the same materials. center dotA key laboratory-based test, Satellite Orbital debris Characterization Impact Test (SOCIT), supporting the development of the DoD and NASA satellite breakup models was conducted at AEDC in 1992. Breakup models based on SOCIT have supported many applications and matched on-orbit events reasonably well over the years.
Existing DoD and NASA satellite breakup models are based on a key laboratory-based test, Satellite Orbital debris Characterization Impact Test (SOCIT), which has supported many applications and matched on-orbit events involving older satellite designs reasonably well over the years. In order to update and improve the break-up models and the NASA Size Estimation Model (SEM) for events involving more modern satellite designs, the NASA Orbital Debris Program Office has worked in collaboration with the University of Florida to replicate a hypervelocity impact using a satellite built with modern-day spacecraft materials and construction techniques. The spacecraft, called DebriSat, was intended to be a representative of modern LEO satellites and all major designs decisions were reviewed and approved by subject matter experts at Aerospace Corporation. DebriSat is composed of 7 major subsystems including attitude determination and control system (ADCS), command and data handling (C&DH), electrical power system (EPS), payload, propulsion, telemetry tracking and command (TT&C), and thermal management. To reduce cost, most components are emulated based on existing design of flight hardware and fabricated with the same materials. All fragments down to 2 mm is size will be characterized via material, size, shape, bulk density, and the associated data will be stored in a database for multiple users to access. Laboratory radar and optical measurements will be performed on a subset of fragments to provide a better understanding of the data products from orbital debris acquired from ground-based radars and telescopes. The resulting data analysis from DebriSat will be used to update break-up models and develop the first optical SEM in conjunction with updates into the current NASA SEM. The characterization of the fragmentation will be discussed in the subsequent presentation.
To replicate a hyper-velocity fragmentation event using modern-day spacecraft materials and construction techniques to better improve the existing DoD and NASA breakup models. DebriSat is intended to be representative of modern LEO satellites.Major design decisions were reviewed and approved by Aerospace subject matter experts from different disciplines. DebriSat includes 7 major subsystems. Attitude determination and control system (ADCS), command and data handling (C&DH), electrical power system (EPS), payload, propulsion, telemetry tracking and command (TT&C), and thermal management. To reduce cost, most components are emulated based on existing design of flight hardware and fabricated with the same materials. A key laboratory-based test, Satellite Orbital debris Characterization Impact Test (SOCIT), supporting the development of the DoD and NASA satellite breakup models was conducted at AEDC in 1992 .Breakup models based on SOCIT have supported many applications and matched on-orbit events reasonably well over the years.
Many space missions proposed for the time period from 1985 to 2000 will require large spacecraft to support the onboard loads. In some cases, large electrical power systems will be needed to supply the electrical/electronic equipment loads. These electronic systems will be used for communications, radar, and experimental equipment for aid to earth's overcrowded communication systems, exploration of new energy resources, space exploration, and eventually to supplement terrestrial electric power utilities. For the near term (1985-1990), some of these systems have power levels to 50 kW. The long-term programs, 1990 to post-2000, could possibly have demands in the order of multimegawatts. The problems which have to be solved to construct the required high-voltage power supply systems are considered. Data and conceptual designs generated are found to indicate that grounding and bonding for high power systems can be accomplished in spacecraft by using either manual or automatic joining of the structural members.