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Water flows from slotted pipes

Description: Results of experiments and analyses that determine jet flow distribution from slotted pipes of dimensions typical for OC-OTEC evaporators or condensers are described. For a pipe with a 6.3-cm inside diameter and 0.64-cm wide slot, the measured and predicted jet flow was low and nearly parallel to the pipe at the entrance, and high and perpendicular to the pipe only near the closed end. Slot lengths ranged from 1.5 m to 4.6 m, and inlet flow rates varied from 6 kg/s to 17 kg/s. Friction reduces the pressure in the entrance and intermediate portions of the pipe, while the rapidly decelerating flow produces high pressure recovery as it approaches the closed end. In the region of high flow next to the closed end, the ratio of slot area (slot length times width) to pipe cross-sectional area is less than two. To use a slotted pipe for generating falling jets in an OC-OTEC plant, the slot length should be 1 m or less (for a pipe with a 6.3-cm inside diameter and a 0.64-cm wide slot).
Date: April 1, 1981
Creator: Olson, D.A.
Partner: UNT Libraries Government Documents Department

Land-use implications of wind-energy-conversion systems

Description: An estimated 20 utilities in the United States are now investigating potential wind machine sites in their areas. Identifying sites for wind machine clusters (wind farms) involves more than just finding a location with a suitable wind resource. Consideration must also be given to the proximity of sites to existing transmission lines, environmental impacts, aesthetics, and legal concerns as well as the availability of and alternative uses for the land. These issues have made it increasingly difficult for utilities to bring conventional power plants on-line quickly. Utilities are now required, however, to give careful consideration to specific legal, social, and environmental questions raised by the siting of wind energy conversion systems (WECS).
Date: February 1, 1981
Creator: Noun, R.J.
Partner: UNT Libraries Government Documents Department

Photoconversion of organic substrates into hydrogen using photosynthetic bacteria

Description: Under nitrogen-limited conditions, photosynthetic bacteria photoconvert a wide variety of organic substrates nearly totally into H/sub 2/ and CO/sub 2/. More than 98% of the chemical energy of defined organic compounds even from dilute solutions can be recovered as combustible energy of the H/sub 2/ produced. Not calculating the chemical energy input, radiant (solar) energy recoveries are approximately 5% over a wide range of incident light intensities. Batch cultures can photoproduce H/sub 2/ at rates of 175 ml per gram dry weight of cells per hour (equal to a volume of H/sub 2/ per equivalent volume of liquid medium every 4 to 6 hours) when incubated in saturating light. With periodic refeeding, rates remain constant for several weeks. In closed containers H/sub 2/ pressures of 735 psig can be generated. In principle, this pressure can be used to decrease storage volume of the gas, to move it through pipelines or to provide required process pressures. Alcohol stillage and food processing wastes are excellent photoconvertible substances. When non-photosynthetic bacteria synthesizing appropriate polysaccharases are included in co-culture with photosynthetic bacteria, cellulose and other polysaccharides can be converted to H/sub 2/ and CO/sub 2/, albeit at low rates. Prospects for enhancing the photoconversion reactions of photosynthetic bacteria by environmental and genetic manipulations are discussed.
Date: March 1, 1981
Creator: Weaver, P. F.
Partner: UNT Libraries Government Documents Department

Preparation and properties of evaporated CdTe films compared with single-crystal CdTe. Progress report No. 8, August 1-October 31, 1982

Description: The goal of the research is to develop efficient thin-film CdTe solar cells using the method of hot-wall vacuum evaporation for CdTe film deposition. A series of undoped CdTe film depositions was performed. Ampoules with small apertures were designed for Zone 3 and Zone 4 of the furnace (dopant zone, and Cd or Te zone) to allow the temperatures of these zones to be raised near that of the substrate and thus prevent deposition of Te in these zones during a deposition run. Weighing these ampoules also provides a convenient test of material evaporated. The first set of depositions with As impurity to produce p-type CdTe:As films was carried out. No large effect of As doping was observed in these early runs, but some system improvements have been made for the future. A CdTe homojunction with a 0.15 ..mu..m n-type CdTe:In layer on a p-type CdTe:P single crystal substrate has been analyzed. Modelling of the spectral response of the quantum efficiency suggests the presence of a thin inactive layer at the surface, possibly a depletion layer in the n-type film. Large values of the diode factor A indicate non-simple homojunction structures. A light spot scanning apparatus has been constructed using a He-Ne laser and a 4 ..mu..m optical fiber. This apparatus will be used to measure the recombination characteristics of grain boundaries covered by transparent Schottky barriers. The electrical conductivity of p-type CdTe films prepared by close-spaced vapor transport is markedly increased by heat treatment in H/sub 2/. Some recovery of the film resistivity is seen after 1 week in air.
Date: January 1, 1982
Creator: Bube, R Hl
Partner: UNT Libraries Government Documents Department

Recent technological advances in thin film solar cells

Description: High-efficiency, low-cost thin film solar cells are an exciting photovoltaic technology option for generating cost-effective electricity in 1995 and beyond. This paper reviews the substantial advances made by several thin film solar cell technologies, namely, amorphous silicon, copper indium diselenide, cadmium telluride, and polycrystalline silicon. Recent examples of utility demonstration projects of these emerging materials are also discussed. 8 refs., 4 figs.
Date: March 1, 1990
Creator: Ullal, H.S.; Zwelbel, K. & Surek, T.
Partner: UNT Libraries Government Documents Department

Study of falling-jet flash evaporators

Description: Experimental results of flash evaporation from sheets of water, 3.2 mm and 6.3 mm thick and 27.9 cm wide, falling freely in the presence of their own vapor, are reported. With no flashing the jets fall in coherent sheets, but with flashing the jets were observed to spread and break up into droplets. Flashing was characterized by an effectiveness parameter, which was found to increase with increasing water temperature and jet length. Variations in water flow rate and heat flux did not influence the effectiveness appreciably.
Date: November 1, 1982
Creator: Kreith, F.; Olson, D.A.; Bharathan, D. & Green, H.J.
Partner: UNT Libraries Government Documents Department

Technical and economic evaluation of a Brayton-Rankine combined-cycle solar-thermal power plant

Description: The objective of this study is to conduct an assessment of gas-liquid direct-contact heat exchange and of a new storage-coupled system (the open-cycle Brayton/steam Rankine combined cycle). Both technical and economic issues are evaluated. Specifically, the storage-coupled combined cycle is compared with a molten salt system. The open Brayton cycle system is used as a topping cycle, and the reject heat powers the molten salt/Rankine system. In this study the molten salt system is left unmodified, the Brayton cycle is integrated on top of a Martin Marietta description of an existing molten salt plant. This compares a nonoptimized combined cycle with an optimized molten salt system.
Date: May 1, 1981
Creator: Wright, J. D.
Partner: UNT Libraries Government Documents Department

Solar energy storage researchers information user study

Description: The results of a series of telephone interviews with groups of users of information on solar energy storage are described. In the current study only high-priority groups were examined. Results from 2 groups of researchers are analyzed: DOE-Funded Researchers and Non-DOE-Funded Researchers. The data will be used as input to the determination of information products and services the Solar Energy Research Institute, the Solar Energy Information Data Bank Network, and the entire information outreach community should be preparing and disseminating.
Date: March 1, 1981
Creator: Belew, W.W.; Wood, B.L.; Marle, T.L. & Reinhardt, C.L.
Partner: UNT Libraries Government Documents Department

Measured performance results: low-cost solar water heating systems in the San Luis Valley

Description: The measured performance of seven low-cost solar water heating systems in the San Luis Valley of southern Colorado is summarized. During the summer and fall of 1981, SERI monitored a variety of low-cost solar water heating system designs and components. Five systems had site-built collectors, and four included low-cost tank-in-jacket heat exchanger/storage tank components. Two were air-to-water systems. The five liquid-based systems included a drain-down design, a propylene glycol-charged thermosiphon system, and three pumped-glycol systems. The pumped-liquid systems performed the best, with system efficiencies greater than 20% and solar fractions between 40% and 70%. Tjhe air-to-water systems did not perform as well because of leakage in the collectors and heat exchangers. The thermosiphon system performed at lower efficiency because the collector flows were low.
Date: January 1, 1983
Creator: Swisher, J.
Partner: UNT Libraries Government Documents Department

CO sub 2 sources for microalgae-based liquid fuel production

Description: Researchers in the Aquatic Species Program at the Solar Energy Research Institute are developing species of microalgae that have high percentages of lipids, or oils. These lipids can be extracted and converted to diesel fuel substitutes. Because microalgae need carbon dioxide (CO{sub 2}) as a nutrient, optimal microalgae growth occurs in CO{sub 2}-saturated solutions. For this reason, the authors of this study sought to identify possible large-scale sources of CO{sub 2} for microalgae-based liquid fuels production. The authors concluded that several such promising sources exist. 42 refs., 14 figs., 10 tabs.
Date: August 1, 1990
Creator: Feinberg, D. & Karpuk, M.
Partner: UNT Libraries Government Documents Department

Comparative ranking of 0. 1 to 10 MW(e) solar thermal electric power systems. Volume I. Summary of results. Final report

Description: This report is part of a two-volume set summarizing the results of a comparative ranking of generic solar thermal concepts designed specifically for electric power generation. The original objective of the study was to project the mid-1990 cost and performance of selected generic solar thermal electric power systems for utility applications and to rank these systems by criteria that reflect their future commercial acceptance. This study considered plants with rated capacities of 1 to 10 MW(e), operating over a range of capacity factors from the no-storage case to 0.7 and above. Later, the study was extended to include systems with capacities from 0.1 to 1 MW(e), a range that is attractive to industrial and other non-utility applications. This volume summarizes the results for the full range of capacities from 0.1 to 10 MW(e). Volume II presents data on performance and cost and ranking methodology.
Date: August 1, 1980
Creator: Thornton, J.P.; Brown, K.C.; Finegold, J.G.; Gresham, J.B.; Herlevich, F.A.; Kowalik, J.S. et al.
Partner: UNT Libraries Government Documents Department

Simple energy-calculation method for solar industrial-process-heat steam systems

Description: Designing a solar industrial-process heat (IPH) system, sizing its components and predicting its annual energy delivery requires a method for calculating solar system performance. A calculation method that is accurate, easy to use, accounts for the impact of all important system parameters, and does not require use of a computer is described. Only simple graphs and a hand calculator are required to predict annual collector field performance and annual system losses. The energy-calculation method is applicable to a variety of solar-system configurations. The calculation method applied only to parabolic-trough steam-generation systems that do not employ thermal storage is described. Both flash tank and unfired-boiler steam systems are covered.
Date: January 1, 1983
Creator: Gee, R.
Partner: UNT Libraries Government Documents Department

Second thermal storage applications workshop

Description: On February 7 and 8, 1980, approximately 20 persons representing the management of both the Solar Thermal Power Systems Program (TPS) of the US Department of Energy (DOE) Division of Central Solar Technology (CST) and the Thermal Energy Storage Program (TES) of the DOE Division of Energy Storage Systems (STOR) met in San Antonio, Texas, for the Second Thermal Storage Applications Workshop. The purpose of the workshop was to review the joint Thermal Energy Storage for Solar Thermal Applications (TESSTA) Program between CST and STOR and to discuss important issues in implementing it. The meeting began with summaries of the seven major elements of the joint program (six receiver-related, storage development elements, and one advanced technology element). Then, a brief description along with supporting data was given of several issues related to the recent joint multiyear program plan (MYPP). Following this session, the participants were divided into three smaller groups representing the program elements that mainly supported large power, small power, and advanced technology activities. During the afternoon of the first day, each group prioritized the program elements through program budgets and discussed the issues defined as well as others of concern. On the morning of the second day, representatives of each group presented the group's results to the other participants. Major conclusions arising from the workshop are presented regarding program and budget. (LEW)
Date: June 1, 1980
Creator: Wyman, C.E. & Larson, R.W.
Partner: UNT Libraries Government Documents Department

Preparation and properties of evaporated CdTe films compared with single crystal CdTe. Progress report No. 1, October 1, 1980-January 31, 1981

Description: This program is concerned with the investigation of the materials properties of CdTe thin films deposited by hot-wall vacuum evaporation and of CdTe single crystalline material, particularly those relevant to solar cell applications in which CdTe is the absorbing member. Progress is reported on: (a) an evaluation of CdTe homojunctions formed by HWVE of CdTe by Walter Huber at the laboratory of Dr. Adolfo Lopez-Otero at the Institut fuer Physik of the University of Linz, using single crystal p-type CdTe from Stanford as a substrate; (b) the design and construction of a HWVE apparatus at Stanford; and (c) properties of grain boundaries in large grain polycrystalline CdTe.
Date: January 1, 1981
Creator: Bube, R. H.
Partner: UNT Libraries Government Documents Department

Status of current IPH applications

Description: The US Department of Energy has funded a series of field tests since 1977 to gain operational experience in the application of solar energy to industrial process heat requirements. To date, 34 design studies or actual installations have been funded utilizing technologies ranging from flat plates to line-focus concentrators to central receiver industrial systems. The types of solar systems include hot air, hot water, and steam production applied to a broad spectrum of industrial processes. The program elements are identified and put in perspective relative to transport fluid, temperature level, and size of the solar field. The status of these programs ranges from design studies to operational systems. Solar enhanced oil recovery and repowering have been studied. The chronological history of each program is tabulated. (LEW)
Date: March 1, 1981
Creator: Kearney, D. W.
Partner: UNT Libraries Government Documents Department

Solar central receiver systems comparative economics

Description: Several major conceptual design studies of solar central receiver systems and components have been completed in the last year. The results of these studies are used to compare the projected cost of electric power generation using central receiver systems with that of more conventional power generation. The cost estimate for a molten salt central receiver system is given. Levelized busbar energy cost is shown as a function of annual capacity factor indicating the fraction of the cost due to each of the subsystems. The estimated levelized busbar energy cost for a central receiver (70 to 90 mills per kilowatt hour) is compared with the levelized busbar energy cost for a new coal fired Rankine cycle plant. Sensitivities to the initial cost of coal and the delta fuel escalation are shown. (WHK)
Date: April 1, 1980
Creator: Eicker, P J
Partner: UNT Libraries Government Documents Department

PSTAR: Primary and secondary terms analysis and renormalization: A unified approach to building energy simulations and short-term monitoring

Description: This report presents a unified method of hourly simulation of a building and analysis of performance data. The method is called Primary and Secondary Terms Analysis and Renormalization (PSTAR). In the PSTAR method, renormalized parameters are introduced for the primary terms such that the renormalized energy balance equation is best satisfied in the least squares sense, hence, the name PSTAR. PSTAR allows extraction of building characteristics from short-term tests on a small number of data channels. These can be used for long-term performance prediction (''ratings''), diagnostics, and control of heating, ventilating, and air conditioning systems (HVAC), comparison of design versus actual performance, etc. By combining realistic building models, simple test procedures, and analysis involving linear equations, PSTAR provides a powerful tool for analyzing building energy as well as testing and monitoring. It forms the basis for the Short-Term Energy Monitoring (STEM) project at SERI.
Date: September 1, 1988
Creator: Subbarao, K.
Partner: UNT Libraries Government Documents Department

Atmospheric performance of the special-purpose Solar Energy Research Institute (SERI) thin-airfoil family

Description: The Solar Energy Research Institute (SERI), in cooperation with SeaWest Energy Group, has completed extensive atmospheric testing of the special-purpose SERI thin-airfoil family during the 1990 wind season. The purpose of this test program was to experimentally verify the predicted performance characteristics of the thin-airfoil family on a geometrically optimized blade, and to compare it to original-equipment blades under atmospheric wind conditions. The tests were run on two identical Micon 65/13 horizontal-axis wind turbines installed side-by-side in a wind farm. The thin-airfoil family 7.96 m blades were installed on one turbine, and AeroStar 7.41 m blades were installed on the other. This paper presents final performance results of the side-by-side comparative field test for both clean and dirty blade conditions. 7 refs., 11 figs., 1 tab.
Date: September 1, 1990
Creator: Tangler, J; Smith, B; Jager, D & Olsen, T
Partner: UNT Libraries Government Documents Department

Federal income taxation of the U. S. petroleum industry and the depletion of domestic reserves. Final report

Description: This paper models in a dynamic framework the production activities of the United States petroleum industry in an attempt to measure the effects of the federal income tax on reserve depletion. This model incorporates general corporate taxes, including the capital subsidies, excess depreciation and the investment tax credit, and taxes unique to the industry: drilling subsidies and percentage depletion. Because corporate response to tax incentives depends on market power and behavior, three behavioral assumptions are tested for consistency with the 1960 to 1974 data period before the tax policies are simulated. These assumptions are perfect competition, profit monopoly, and sales monopoly. The tax policies simulated at the end of this paper present six possible alternatives for future petroleum industry taxation. Sales monopoly is selected as the behavioral assumption that best describes petroleum industry behavior. Tax simulations under sales monopoly reveal that historical income tax policies have kept oil prices artificially low, stimulating (subsidizing) reserve depletion.
Date: October 1, 1978
Creator: Flaim, S. J. & Mount, T. D.
Partner: UNT Libraries Government Documents Department

Solar energy education: where do we stand

Description: The purpose of this paper is to examine in detail the contents of the Education Data Base by analyzing the current distributions of solar energy courses, programs, and curricula offered in our nation's post-secondary educational institutions. A summary of the data base indicates that 892 educational institutions in the United States offer 2308 solar-related courses and 367 programs. The interest in these programs is reflected in the fact that in 1979, 760 institutions offered 1740 solar-related courses and 243 programs. The conclusion is that our nation's post-secondary institutions are responding to student demand and interest in solar energy.
Date: March 1, 1981
Creator: O'Connor, J. K.
Partner: UNT Libraries Government Documents Department

Wind energy systems information user study

Description: This report describes the results of a series of telephone interviews with potential users of information on wind energy conversion. These interviews, part of a larger study covering nine different solar technologies, attempted to identify: the type of information each distinctive group of information users needed, and the best way of getting information to that group. Groups studied include: wind energy conversion system researchers; wind energy conversion system manufacturer representatives; wind energy conversion system distributors; wind turbine engineers; utility representatives; educators; county agents and extension service agents; and wind turbine owners.
Date: January 1, 1981
Creator: Belew, W.W.; Wood, B.L.; Marle, T.L. & Reinhardt, C.L.
Partner: UNT Libraries Government Documents Department

Yearly average performance of the principal solar collector types

Description: The results of hour-by-hour simulations for 26 meteorological stations are used to derive universal correlations for the yearly total energy that can be delivered by the principal solar collector types: flat plate, evacuated tubes, CPC, single- and dual-axis tracking collectors, and central receiver. The correlations are first- and second-order polynomials in yearly average insolation, latitude, and threshold (= heat loss/optical efficiency). With these correlations, the yearly collectible energy can be found by multiplying the coordinates of a single graph by the collector parameters, which reproduces the results of hour-by-hour simulations with an accuracy (rms error) of 2% for flat plates and 2% to 4% for concentrators. This method can be applied to collectors that operate year-around in such a way that no collected energy is discarded, including photovoltaic systems, solar-augmented industrial process heat systems, and solar thermal power systems. The method is also recommended for rating collectors of different type or manufacturer by yearly average performance, evaluating the effects of collector degradation, the benefits of collector cleaning, and the gains from collector improvements (due to enhanced optical efficiency or decreased heat loss per absorber surface). For most of these applications, the method is accurate enough to replace a system simulation.
Date: January 1, 1981
Creator: Rabl, A.
Partner: UNT Libraries Government Documents Department

Relevance of behavioral and social models to the study of consumer energy decision making and behavior

Description: This report reviews social and behavioral science models and techniques for their possible use in understanding and predicting consumer energy decision making and behaviors. A number of models and techniques have been developed that address different aspects of the decision process, use different theoretical bases and approaches, and have been aimed at different audiences. Three major areas of discussion were selected: (1) models of adaptation to social change, (2) decision making and choice, and (3) diffusion of innovation. Within these three areas, the contributions of psychologists, sociologists, economists, marketing researchers, and others were reviewed. Five primary components of the models were identified and compared. The components are: (1) situational characteristics, (2) product characteristics, (3) individual characteristics, (4) social influences, and (5) the interaction or decision rules. The explicit use of behavioral and social science models in energy decision-making and behavior studies has been limited. Examples are given of a small number of energy studies which applied and tested existing models in studying the adoption of energy conservation behaviors and technologies, and solar technology.
Date: November 1, 1980
Creator: Burns, B.A.
Partner: UNT Libraries Government Documents Department