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At least 271 records · Page 15

All sources NASA NTRS DOE OSTI

NASA NTRS1984

Space commercialization: Analysis of R and D investments with long time horizons

By following a single hypothetical example through a series of variations, the way different potential investors might look at the opportunity to participate in space commercialization is described. The example itself is fairly typical of commercial opportunities in space. The chief characteristics are a steadily increasing requirement for capital infusion over an 8 year period, followed by a very generous stream of profits running another decade or more beyond. There is a decision point at 3 years, at the conclusion of laboratory R&D; and another at 6 years, following 2 initial space flights.

Sheahen, T. P.↗

NASA NTRS1984

Overview of waste heat utilization systems

The heavy truck diesel engine rejects a significant fraction of its fuel energy in the form of waste heat. Historically, the Department of Energy has supported technology efforts for utilization of the diesel exhaust heat. Specifically, the Turbocompound and the Organic Rankine Cycle System (ORCS) have demonstrated that meaningful improvements in highway fuel economy can be realized through waste heat utilization. For heat recovery from the high temperature exhaust of future adiabatic diesel engines, the DOE/NASA are investigating a variety of alternatives based on the Rankine, Brayton, and Stirling power cycles. Initial screening results indicate that systems of this type offer a fuel savings advantage over the turbocompound system. Capital and maintenance cost projections, however, indicate that the alternative power cycles are not competitive on an economic payback basis. Plans call for continued analysis in an attempt to identify a cost effective configuration with adequate fuel savings potential.

Bailey, M. M.↗

NASA NTRS1984

Power for Commercial Space Applications

Since the proposed space station is intended to be a permanent installation, used in part by commercial organizations, its design requirements differ fundamentally from those in previous manned spacecraft. In particular, commercialization on a significant scale depends critically on the ability to control capital and operational costs, including the cost of energy, and this demands new approaches to systems such as the power supply for the space station. These considerations suggest guidelines for power plant development. The cost of energy in space, guidelines for power supply development, quality standards, and the role of government are discussed.

Chapman, P. K.↗

NASA NTRS1984

Lightning research: A user's lament

As a user of devices and procedures for lightning protection, the author is asking the lightning research community for cookbook recipes to help him solve his problems. He is lamenting that realistic devices are scarce and that his mission does not allow him the time nor the wherewithal to bridge the gap between research and applications. A few case histories are presented. In return for their help he is offering researchers a key to lightning technology--the use of the Eastern Test Range and its extensive resources as a proving ground for their experiment in the lightning capital of the United States. A current example is given--a joint lightning characterization project to take place there. Typical resources are listed.

Golub, C. N.↗

NASA NTRS1984

GaAs and 3-5 compound solar cells status and prospects for use in space

Gallium arsenide solar cells equal or supass the best silicon solar cells in efficiency, radiation resistance, annealability, and in the capability to produce usable power output at elevated temperatures. NASA has been involved in a long range research and development program to capitalize on these manifold advantages, and to explore alternative III-V compounds for additional potential improvements. The current status and future prospects for research and development in this area are reviewed and the progress being made toward development of GaAs cells suitable for variety of space missions is discussed. Cell types under various stages of development include n(+)/p shallow homojunction thin film GaAs cells, x100 concentration ratio p/n and n/p GaAs small area concentrator cells, mechanically-stacked, two-junction tandem cells, and three-junction monolithic cascade cells, among various other cell types.

Flood, D. J.↗

NASA NTRS1981

Manufacturing cost analysis of a parabolic dish concentrator (General Electric design) for solar thermal electric power systems in selected production volumes

The manufacturing cost of a General Electric 12 meter diameter concentrator was estimated. This parabolic dish concentrator for solar thermal system was costed in annual production volumes of 100 - 1,000 - 5,000 - 10,000 - 50,000 100,000 - 400,000 and 1,000,000 units. Presented for each volume are the costs of direct labor, material, burden, tooling, capital equipment and buildings. Also presented is the direct labor personnel and factory space requirements. All costs are based on early 1981 economics.

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NASA NTRS1984

Investigation of test methods, material properties, and processes for solar cell encapsulants

Photovoltaic (PV) modules consist of a string of electrically interconnected silicon solar cells capable of producing practical quantities of electrical power when exposed to sunlight. To insure high reliability and long term performance, the functional components of the solar cell module must be adequately protected from the environment by some encapsulation technique. The encapsulation system must provide mechanical support for the cells and corrosion protection for the electrical components. The goal of the program is to identify and develop encapsulation systems consistent with the PV module operating requirements of 30 year life and a target cost of $0.70 per peak watt ($70 per square meter) (1980 dollars). Assuming a module efficiency of ten percent, which is equivalent to a power output of 100 watts per square meter in midday sunlight, the capital cost of the modules may be calculated to be $70.00 per square meter. Out of this cost goal, only 20 percent is available for encapsulation due to the high cost of the cells, interconnects, and other related components. The encapsulation cost allocation may then be stated as $14.00 per square meter, included all coatings, pottant and mechanical supports for the cells.

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NASA NTRS1985

Practical aspects of photovoltaic technology, applications and cost (revised)

The purpose of this text is to provide the reader with the background, understanding, and computational tools needed to master the practical aspects of photovoltaic (PV) technology, application, and cost. The focus is on stand-alone, silicon solar cell, flat-plate systems in the range of 1 to 25 kWh/day output. Technology topics covered include operation and performance of each of the major system components (e.g., modules, array, battery, regulators, controls, and instrumentation), safety, installation, operation and maintenance, and electrical loads. Application experience and trends are presented. Indices of electrical service performance - reliability, availability, and voltage control - are discussed, and the known service performance of central station electric grid, diesel-generator, and PV stand-alone systems are compared. PV system sizing methods are reviewed and compared, and a procedure for rapid sizing is described and illustrated by the use of several sample cases. The rapid sizing procedure yields an array and battery size that corresponds to a minimum cost system for a given load requirement, insulation condition, and desired level of service performance. PV system capital cost and levelized energy cost are derived as functions of service performance and insulation. Estimates of future trends in PV system costs are made.

Rosenblum, L.↗

NASA NTRS1984

The application of cryogenics to high Reynolds number testing in wind tunnels. I - Evolution, theory, and advantages

During the time which has passed since the construction of the first wind tunnel in 1870, wind tunnels have been developed to a high degree of sophistication. However, their development has consistently failed to keep pace with the demands placed on them. One of the more serious problems to be found with existing transonic wind tunnels is their inability to test subscale aircraft models at Reynolds numbers sufficiently near full-scale values to ensure the validity of using the wind tunnel data to predict flight characteristics. The Reynolds number capability of a wind tunnel may be increased by a number of different approaches. However, the best solution in terms of model, balance, and model support loads, as well as in terms of capital and operating cost appears to be related to the reduction of the temperature of the test gas to cryogenic temperatures. The present paper has the objective to review the evolution of the cryogenic wind tunnel concept and to describe its more important advantages.

Kilgore, R. A.↗

NASA NTRS1986

A method for screening of plant species for space use

A cost-effective methodology which monitors numerous dynamic aspects of carbon assimilation and allocation kinetics in live, intact plants is discussed. Analogous methods can apply to nitrogen uptake and allocation. This methodology capitalizes on the special properties of the short-lived, positron-gamma emitting isotope C-11 especially when applied as CO2-11 in a special extended square wave (ESW) pattern. The 20.4 minute half-life allows for repeated or continuous experiments on the same plant over periods of minutes, hours, days, or weeks. The steady-state isotope equilibrium approached during the ESW experiments, and the parameters which can be analyzed by this technique are also direct results of that short half-life. Additionally, the paired .511 MeV gamma rays penetrate any amount of tissue and their 180 deg opposite orientation provides good collimation and allows coincidence counting which nearly eliminates background.

Goeschl, J. D.↗

NASA NTRS1985

Design and evaluation of fluidized bed heat recovery for diesel engine systems

The potential of utilizing fluidized bed heat exchangers in place of conventional counter-flow heat exchangers for heat recovery from adiabatic diesel engine exhaust gas streams was studied. Fluidized bed heat recovery systems were evaluated in three different heavy duty transport applications: (1) heavy duty diesel truck; (2) diesel locomotives; and (3) diesel marine pushboat. The three applications are characterized by differences in overall power output and annual utilization. For each application, the exhaust gas source is a turbocharged-adiabatic diesel core. Representative subposed exhaust gas heat utilization power cycles were selected for conceptual design efforts including design layouts and performance estimates for the fluidized bed heat recovery heat exchangers. The selected power cycles were: organic rankine with RC-1 working fluid, turbocompound power turbine with steam injection, and stirling engine. Fuel economy improvement predictions are used in conjunction with capital cost estimates and fuel price data to determine payback times for the various cases.

Hamm, J. R.↗

NASA NTRS1985

Aquaculture: A Component of Low Cost Sanitation Technology

The paper discusses all phases of aquaculture, including commercial viability, sanitary and biological considerations, public health, financial/economic and sociological aspects. Current studies are detailed and options are discussed for their potential applicability to developing countries, considering requirements for capital and labor skills as well as physical needs such as land.

Edwards, P.↗

NASA NTRS1986

Japan's participation in space station design: Feasibility study of GaAs solar cells for space station applications

The report gives the results of feasibility studies and a cost analysis done on GaAs solar battery cells for space stations. The studies and their results are as follows: (1) Cell size - The 2 x 4 cm cell size was found superior to the 4 x 4 cm cell; (2) Manufacturing technology - Overall, LPE crystal growth was found more suitable than MO-CVD. Current technology for post-growth processes and applying large-area cover glass can be used with few or no modifications; (3) Cell assemblies - Tests for mechanical and thermal stresses encountered from assembly through operation are recommended; (4) Procuring materials - Steps should be taken to avoid sharp price increases due to a speculative gallium market. There are no problems with arsenic materials; (5) Production facilities - The capital investment needed remains to be determined, but a working area of 4000 m2 will be required; (6) Cell costs to be determined; (7) Cell development-supply plan - Two-year lead time will be needed to develop the necessary technology and prepare for production.

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NASA NTRS1985

Integrated risk/cost planning models for the US Air Traffic system

A prototype network planning model for the U.S. Air Traffic control system is described. The model encompasses the dual objectives of managing collision risks and transportation costs where traffic flows can be related to these objectives. The underlying structure is a network graph with nonseparable convex costs; the model is solved efficiently by capitalizing on its intrinsic characteristics. Two specialized algorithms for solving the resulting problems are described: (1) truncated Newton, and (2) simplicial decomposition. The feasibility of the approach is demonstrated using data collected from a control center in the Midwest. Computational results with different computer systems are presented, including a vector supercomputer (CRAY-XMP). The risk/cost model has two primary uses: (1) as a strategic planning tool using aggregate flight information, and (2) as an integrated operational system for forecasting congestion and monitoring (controlling) flow throughout the U.S. In the latter case, access to a supercomputer is required due to the model's enormous size.

Mulvey, J. M.↗

NASA NTRS1986

Sensitivity analysis for solar plates

Economic evaluation methods and analyses of emerging photovoltaic (PV) technology since 1976 was prepared. This type of analysis was applied to the silicon research portion of the PV Program in order to determine the importance of this research effort in relationship to the successful development of commercial PV systems. All four generic types of PV that use silicon were addressed: crystal ingots grown either by the Czochralski method or an ingot casting method; ribbons pulled directly from molten silicon; an amorphous silicon thin film; and use of high concentration lenses. Three technologies were analyzed: the Union Carbide fluidized bed reactor process, the Hemlock process, and the Union Carbide Komatsu process. The major components of each process were assessed in terms of the costs of capital equipment, labor, materials, and utilities. These assessments were encoded as the probabilities assigned by experts for achieving various cost values or production rates.

Aster, R. W.↗

NASA NTRS1986

Processes and process development in Japan

The commercialization of solar power generation necessitates the development of low cost manufacturing method of silicon suitable for solar cells. The manufacturing methods of semiconductor grade silicon (SEG-Si) and the development of solar grade silicon (SOG-Si) in foreign countries was investigated. It was concluded that the most efficient method of developing such materials was the hydrogen reduction process of trichlorosilane (TCS), using a fluidized bed reactor. The low cost reduction of polysilicon requires cost reductions of raw materials, energy, labor, and capital. These conditions were carefully reviewed. The overall conclusion was that a development program should be based on the TCS-FBR process and that the experimental program should be conducted in test facilities capable of producing 10 tons of silicon granules per year.

Noda, T.↗

NASA NTRS1984

The US re-usable launch system - The Space Shuttle

The NASA Space Shuttle furnishes a range of readily available, and either already planned or yet-to-be-defined services, which already encompass satellite on-orbit servicing, refueling and repair, and satellite retrieval services. A gradual expansion will be made of services that capitalize on the presence of a large crew during commercial and scientific operations, while pursuing the development of automated, standardized procedures for the handling of experiments in order to reduce research costs.

Lee, C. M.↗

NASA NTRS1985

Solar photochemical process engineering for production of fuels and chemicals

The engineering costs and performance of a nominal 25,000 scmd (883,000 scfd) photochemical plant to produce dihydrogen from water were studied. Two systems were considered, one based on flat-plate collector/reactors and the other on linear parabolic troughs. Engineering subsystems were specified including the collector/reactor, support hardware, field transport piping, gas compression equipment, and balance-of-plant (BOP) items. Overall plant efficiencies of 10.3 and 11.6 percent are estimated for the flat-plate and trough systems, respectively, based on assumed solar photochemical efficiencies of 12.9 and 14.6 percent. Because of the opposing effects of concentration ratio and operating temperature on efficiency, it was concluded that reactor cooling would be necessary with the trough system. Both active and passive cooling methods were considered. Capital costs and energy costs, for both concentrating and non-concentrating systems, were determined and their sensitivity to efficiency and economic parameters were analyzed. The overall plant efficiency is the single most important factor in determining the cost of the fuel.

Biddle, J. R.↗