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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Control of new energy sources in an electric utility system

The addition of generators based on renewable resources to the electric power system brings new problems of control and communication if the generators are to be controlled as an integrated part of the power system. Since many of these generators are small, it will require a large number of them, connected to the distribution system, to represent an appreciable fraction of the total generation. This situation contrasts with present day generation control which typically involves only the control of a small number of large generators. This paper examines the system requirements for integrated control, and proposes a control arrangement in which the incremental cost of power is an important parameter.

Kirkham, H.↗
NASA NTRS1976

Design study of wind turbines 50 kW to 3000 kW for electric utility applications. Volume 1: Summary report

Wind turbine configurations that would lead to generation of electrical power in a cost effective manner were considered. All possible overall system configurationss, operating modes, and sybsystem concepts were evaluated for both technical feasibility and compatibility with utility networks, as well as for economic attractiveness. A design optimization computer code was developed to determine the cost sensitivity of the various design features, and thus establish the configuration and design conditions that would minimize the generated energy costs. The preliminary designs of both a 500 kW unit and a 1500 kW unit operating in a 12 mph and 18 mph median wind speed respectively, were developed. The rationale employed and the key findings are summarized.

Source record↗
NASA NTRSDate not supplied

Utilizing Electrical Power Extraction for Stability Bleed Reduction within Gas Turbine Engines

This paper studies the role of power extraction in gas turbine stability and how an engine may be designed to utilize this extraction to replace engine stability bleed requirements with electrical system requirements. The considered engine architecture contains two engine spools and a power turbine spool. In the baseline, low-pressure compressor stall margin is maintained by bleed air from the back of the low-pressure compressor, which is then dumped to the bypass. Power extraction from the high-pressure and low-pressure shafts are then utilized as a replacement for this bleed. This study considers component performance, sizing, efficiency, and operability, but does not consider weight or cost. Analysis within this paper is general and the concepts could be applied to other dual spool engine types, including a turbofan. Results show it is possible to completely remove the stability bleed between the low pressure and high-pressure compressor by utilizing a 35% power extraction from the high-pressure shaft or a 1.5% power extraction from the low-pressure turbine.

Gas Turbine↗
NASA NTRSDate not supplied

Utilizing Electrical Power Extraction for Stability Bleed Reduction within Gas Turbine Engines

This paper studies the role of power extraction in gas turbine stability and how an engine may be designed to utilize this extraction to replace engine stability bleed requirements with electrical system requirements. The considered engine architecture contains two engine spools and a power turbine spool. In the baseline, low-pressure compressor stall margin is maintained by bleed air from the back of the low-pressure compressor, which is then dumped to the bypass. Power extraction from the high-pressure and low-pressure shafts are then utilized as a replacement for this bleed. This study considers component performance, sizing, efficiency, and operability, but does not consider weight or cost. Analysis within this paper is general and the concepts could be applied to other dual spool engine types, including a turbofan. Results show it is possible to completely remove the stability bleed between the low pressure and high-pressure compressor by utilizing a 35% power extraction from the high-pressure shaft or a 1.5% power extraction from the low-pressure turbine.

Gas Turbine↗
NASA NTRS1976

Design study of wind turbines 50 kW to 3000 kW for electric utility applications. Volume 2: Analysis and design

All possible overall system configurations, operating modes, and subsystem concepts for a wind turbine configuration for cost effective generation of electrical power were evaluated for both technical feasibility and compatibility with utility networks, as well as for economic attractiveness. A design optimization computer code was developed to determine the cost sensitivity of the various design features, and thus establish the configuration and design conditions that would minimize the generated energy costs. The preliminary designs of both a 500 kW unit and a 1500 kW unit operating in a 12 mph and 18 mph median wind speed respectively, were developed. The various design features and components evaluated are described, and the rationale employed to select the final design configuration is given. All pertinent technical performance data and component cost data is included. The costs of all major subassemblies are estimated and the resultant energy costs for both the 500 kW and 1500 kW units are calculated.

Source record↗
NASA NTRS1989

Central electrical utility power for a satellite ring city in low earth orbit space

Information is given in viewgraph form on central electrical power for a satellite ring city, defined as a group of large free flyers of 10 to 20 units with perhaps 100 people in each unit, and organized in a circle so that power can be fed from a central location. The free flyers would be located at 300 to 700 miles in altitude, and spaced about a kilometer apart. Potential activities of a ring city are listed as well as the electrical power needs. Information is given on costs and individual and centralized solar arrays and nuclear reactor systems.

Myers, Ira T.↗
NASA NTRS1977

Thermal storage for electric utilities

Applications of the thermal energy storage (TES) principle (storage of sensible heat or latent heat, or heat storage in reversible chemical reactions) in power systems are evaluated. Load leveling behind the meter, load following at conventional thermal power plants, solar thermal power generation, and waste heat utilization are the principal TES applications considered. Specific TES examples discussed include: storage heaters for electric-resistance space heating, air conditioning TES in the form of chilled water or eutectic salt baths, hot water TES, and trans-seasonal storage in heated water in confined aquifers.

Swet, C. J.↗
NASA NTRS2017

Synergistic Use of Nighttime Satellite Data, Electric Utility Infrastructure, and Ambient Population to Improve Power Outage Detections in Urban Areas

Natural and anthropogenic hazards are frequently responsible for disaster events, leading to damaged physical infrastructure, which can result in loss of electrical power for affected locations. Remotely-sensed, nighttime satellite imagery from the Suomi National Polar-orbiting Partnership (Suomi-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) can monitor power outages in disaster-affected areas through the identification of missing city lights. When combined with locally-relevant geospatial information, these observations can be used to estimate power outages, defined as geographic locations requiring manual intervention to restore power. In this study, we produced a power outage product based on Suomi-NPP VIIRS DNB observations to estimate power outages following Hurricane Sandy in 2012. This product, combined with known power outage data and ambient population estimates, was then used to predict power outages in a layered, feedforward neural network model. We believe this is the first attempt to synergistically combine such data sources to quantitatively estimate power outages. The VIIRS DNB power outage product was able to identify initial loss of light following Hurricane Sandy, as well as the gradual restoration of electrical power. The neural network model predicted power outages with reasonable spatial accuracy, achieving Pearson coefficients (r) between 0.48 and 0.58 across all folds. Our results show promise for producing a continental United States (CONUS)- or global-scale power outage monitoring network using satellite imagery and locally-relevant geospatial data.

da/night band↗
NASA NTRS1976

Design study of wind turbines 50 kW to 3000 kW for electric utility applications. Volume 3: Supplementary design and analysis tasks

Additional design and analysis data are provided to supplement the results of the two parallel design study efforts. The key results of the three supplemental tasks investigated are: (1) The velocity duration profile has a significant effect in determining the optimum wind turbine design parameters and the energy generation cost. (2) Modest increases in capacity factor can be achieved with small increases in energy generation costs and capital costs. (3) Reinforced concrete towers that are esthetically attractive can be designed and built at a cost comparable to those for steel truss towers. The approach used, method of analysis, assumptions made, design requirements, and the results for each task are discussed in detail.

Source record↗
NASA NTRS1977

Performance potential of combined cycles integrated with low-Btu gasifiers for future electric utility applications

A comparison and an assessment of 10 advanced utility power systems on a consistent basis and to a common level of detail were analyzed. Substantial emphasis was given to a combined cycle systems integrated with low-Btu gasifiers. Performance and cost results from that study were presented for these combined cycle systems, together with a comparative evaluation. The effect of the gasifier type and performance and the interface between the gasifier and the power system were discussed.

Nainiger, J. J.↗
NASA NTRS1976

Design study of wind turbines 50 kW to 3000 kW for electric utility applications: Analysis and design

In the conceptual design task, several feasible wind generator systems (WGS) configurations were evaluated, and the concept offering the lowest energy cost potential and minimum technical risk for utility applications was selected. In the optimization task, the selected concept was optimized utilizing a parametric computer program prepared for this purpose. In the preliminary design task, the optimized selected concept was designed and analyzed in detail. The utility requirements evaluation task examined the economic, operational, and institutional factors affecting the WGS in a utility environment, and provided additional guidance for the preliminary design effort. Results of the conceptual design task indicated that a rotor operating at constant speed, driving an AC generator through a gear transmission is the most cost effective WGS configuration. The optimization task results led to the selection of a 500 kW rating for the low power WGS and a 1500 kW rating for the high power WGS.

Source record↗
NASA NTRS1977

Impacts and Benefits of a Satellite Power System on the Electric Utility Industry

The purpose of this limited study was to investigate six specific issues associated with interfacing a Satellite Power System (5 GW) with large (by present standards) terrestrial power pools to a depth sufficient to determine if certain interface problems and/or benefits exist and what future studies of these problems are required. The issues investigated are as follows: (1) Stability of Power Pools Containing a 5 GWe SPS; (2) Extra Reserve Margin Required to Maintain the Reliability of Power Pools Containing a 5 GWe SPS; (3) Use of the SPS in Load Following Service (i.e. in two independent pools whose times of peak demand differ by three hours); (4) Ownership of the SPS and its effect on SPS Usage and Utility Costs; (5) Utility Sharing of SPS related RD and D Costs; (6) Utility Liability for SPS Related Hazards.

Winer, B. M.↗
NASA NTRS1980

Upper stages utilizing electric propulsion

The payload capabilities of upper stages using electric propulsion for a LEO to GEO orbit transfer mission are discussed. Payloads are calculated using an established methodology which employs assumptions concerning state-of-the-art electric propulsion technology. The effects on payloads are examined for variations of total mass in LEO (MLEO), thrusting (trip) times, propellant type, specific impulse, and power source specific mass. It is found that the ratios of payload masses to total mass in LEO are insensitive to MLEO, which allows a highly condensed presentation of the overall payload capability. Electric stages are shown capable of delivering payloads in thrusting times less than 50 days with the payloads increasing rapidly with increase in thrusting times. Payload capabilities exceeding those attainable with chemical propulsion are possible using state-of-the-art electric propulsion technology.

Byers, D. C.↗
NASA NTRS1983

Evaluation of Gas-Cooled Pressurized Phosphoric Acid Fuel Cells for Electric Utility Power Generation

Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas-cooling was already demonstrated in atmospheric pressure stacks. Theoretical and experimental investigations of gas-cooling for pressurized PAFC are presented. Two approaches to gas cooling, Distributed Gas-Cooling (DIGAS) and Separated Gas-Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

Faroque, M.↗
NASA NTRS2019

Simulaneous optimization of spacecraft and trajectory design for interplanetary missions utilizing solar electric propulsion

A major challenge in formulating interplanetary mission concepts utilizing electric propulsion is the large number of trajectory variables that must be considered (thrust profile, flyby options, launch vehicle delivery), all of which are affected by spacecraft design variables (power, mass, thruster, payload, staging). This is significantly more complex than traditional ballistic/chemical mission design and early concepts are often suboptimal as a result, potentially missing valuable options. This paper presents a novel tool (MORT) for simultaneously optimizing the spacecraft design alongside the trajectory given mission constraints and objectives, including example results relevant to the exploration of Mars.

Lock, Rob↗
NASA NTRS1989

Toward an electrical power utility for space exploration

Future electrical power requirements for space exploration are discussed. Megawatts of power with enough reliability for multi-year missions and with enough flexibility to adapt to needs unanticipated at design time are some of the criteria which space power systems must be able to meet. The reasons for considering the power management and distribution in the various systems, from a total mission perspective rather than simply extrapolating current spacecraft design practice, are discussed. A utility approach to electric power integrating requirements from a broad selection of current development programs, with studies in which both space and terrestrial technologies are conceptually applied to exploration mission scenarios, is described.

Bercaw, Robert W.↗