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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 55 records · Page 3

A comparison of Stirling engines for use with a 25 kW dish-electric conversion system

Two designs for an advanced Stirling conversion system (ASCS) are described. The objective of the ASCS is to generate about 25 kW of electric power to an electric utility grid at an engine/alternator target cost of $300.00/kW at the manufacturing rate of 10,000 unit/yr. Both designs contain a free-piston Stirling engine (FPSE), a heat transport system, solar receiver, a means to generate electric power, the necessary auxiliaries, and a control system. The major differences between the two concepts are: one uses a 25 kWe single-piston FPSE which incorporates a linear alternator to directly convert the energy to electricity on the utility grid; and in the second design, electrical power is generated indirectly using a hydraulic output to a ground based hydraulic motor coupled to a rotating alternator. Diagrams of the two designs are presented.

Shaltens, Richard K.↗

Status of the advanced Stirling conversion system project for 25 kW dish Stirling applications

Technology development for Stirling convertors directed toward a dynamic power source for space applications is discussed. Space power requirements include high reliability with very long life, low vibration, and high system efficiency. The free-piston Stirling engine has the potential for future high power space conversion systems, either nuclear or solar powered. Although these applications appear to be quite different, their requirements complement each other. The advanced Stirling conversion system (ASCS) project at NASA Lewis Research Center is described. Each system design features a solar receiver/liquid metal heat transport system and a free-piston Stirling convertor with a means to provide nominally 25 kW of electric power to utility grid while meeting the US Department of Energy (DOE) performance and long term cost goals. The design is compared with other ASCS designs.

Shaltens, Richard K.↗

Dynamic modeling and sensitivity analysis of solar thermal energy conversion systems

Since the energy input to solar thermal conversion systems is both time variant and probabilistic, it is unlikely that simple steady-state methods for estimating lifetime performance will provide satisfactory results. The work described here uses dynamic modeling to begin identifying what must be known about input radiation and system dynamic characteristics to estimate performance reliably. Daily operation of two conceptual solar energy systems was simulated under varying operating strategies with time-dependent radiation intensity ranging from smooth input of several magnitudes to input of constant total energy whose intensity oscillated with periods from 1/4 hour to 6 hours. Integrated daily system output and efficiency were functions of both level and dynamic characteristics of insolation. Sensitivity of output to changes in total input was greater than one.

Hamilton, C. L.↗

Comparison of conceptual designs for 25 kWe advanced Stirling conversion systems for dish electric application

The Advanced Stirling Conversion System (ASCS) Project is managed by NASA Lewis Research Center through a cooperative interagency agreement with DOE. Conceptual designs for the ASCS's were completed under parallel contracts in 1987 by Mechanical Technology Inc. (MTI) of Latham, NY, and Stirling Technology Company (STC) of Richland, WA. Each design features a free-piston Stirling engine, a liquid metal heat pipe receiver, and a means to provide about 25 kW of electric power to a utility grid while meeting DOE's long term performance and cost goals. An independent assessment showed that both designs are manufacturable and have the potential to easily meet DOE's long term cost goals.

Shaltens, Richard K.↗

Comparison of conceptual designs for 25 kWe advanced Stirling conversion systems for dish electric applications

The Advanced Stirling Conversion System (ASCS) Project is managed by NASA Lewis Research Center through a cooperative interagency agreement with DOE. Conceptual designs for the ASCS's were completed under parallel contracts in 1987 by Mechanical Technology Inc. (MTI) of Latham, NY, and Stirling Technology Company (STC) of Richland, WA. Each design features a free-piston Stirling engine, a liquid metal heat pipe receiver, and a means to provide about 25 kW of electric power to a utility grid while meeting DOE's long term performance and cost goals. An independent assessment showed that both designs are manufacturable and have the potential to easily meet DOE's long term cost goals.

Shaltens, Richard K.↗

High voltage DC power conversion system and method of operating the same

A fraction rated conversion system for coupling a plurality of high voltage direct current (HVDC) power strings in parallel to an HVDC transmission system includes at least one fraction rated power converter coupled to the plurality of HVDC power strings and at least one capacitive device coupled to the at least one fraction rated power converter. The at least one fraction rated power converter and the at least one capacitive device regulate a differential voltage across each HVDC power string of the plurality of HVDC power strings to be substantially similar to each other.

17 WIND ENERGY↗

Systems definition space-based power conversion systems

Potential space-located systems for the generation of electrical power for use on Earth are discussed and include: (1) systems producing electrical power from solar energy; (2) systems producing electrical power from nuclear reactors; and (3) systems for augmenting ground-based solar power plants by orbital sunlight reflectors. Systems (1) and (2) would utilize a microwave beam system to transmit their output to Earth. Configurations implementing these concepts were developed through an optimization process intended to yield the lowest cost for each. A complete program was developed for each concept, identifying required production rates, quantities of launches, required facilities, etc. Each program was costed in order to provide the electric power cost appropriate to each concept.

Source record↗