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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

Analysis of the application of thermogalvanic cells to the conversion of low grade heat to electricity

Description: Aqueous thermogalvanic cells, the solution analogs of solid-state thermoelectric devices, are compared for power generation. Measurements on the copper/copper formate/copper system yield thermoelectric powers, (..delta..E/..delta..T)/sub I=O/, of 1.25 - 1.9 mV/degree, which are higher than those exhibited by other copper systems. In these solutions three copper formate complexes are present. Practical cells were built and tested. The power output is largely limited by cell resistance, though mass and charge transfer contribute to the observed overvoltages. The coupling of this thermogalvanic system with an electrochemical photovoltaic effect (a photothermogalvanic cell) is briefly described.
Date: August 1, 1980
Creator: Chum, H. L.; Fahlsing, R. F. & Jayadev, T. S.
Partner: UNT Libraries Government Documents Department

Applied research in the solar thermal-energy-systems program

Description: Within the Solar Thermal Research and Advanced Development (RAD) program a coordinated effort in materials research, fuels and chemical research and applied research is being carried out to meet the systems' needs. Each of these three program elements are described with particular attention given to the applied research activity.
Date: March 1, 1981
Creator: Brown, C. T. & Lefferdo, J. M.
Partner: UNT Libraries Government Documents Department

Mobile home weatherization measures: A study of their effectiveness

Description: The Solar Energy Research Institute (SERI) was funded by the Department of Energy's Office of Buildings and Community Systems (DOE OBCS) in FY 1987 and 1988 to investigate cost effective ways to weatherize mobile homes constructed prior to the enactment of HUD Thermal Standards in 1976. In FY 1987 SERI studied the effectiveness of a variety of infiltration-reducing retrofits by monitoring 20 units in the field before, during, and after applications of air tightening measures. In FY 1988 we began studying measures intended to reduce envelope conduction losses. These measures included storm windows, insulated skirting, and wall, roof, and floor insulation. This part of the project resulted in the development of a short-term testing method for measuring the thermal impact of individual conduction-reducing retrofits.
Date: December 1, 1988
Creator: Judkoff, R.; Hancock, E.; Franconi, E.; Hanger, R. & Weiger, J.
Partner: UNT Libraries Government Documents Department

Fuels from microalgae: Technology status, potential, and research requirements

Description: Although numerous options for the production of fuels from microalgae have been proposed, our analysis indicates that only two qualify for extensive development - gasoline and ester fuel. In developing the comparisons that support this conclusion, we have identified the major areas of microalgae production and processing that require extensive development. Technology success requires developing and testing processes that fully utilize the polar and nonpolar lipids produced by microalgae. Process designs used in these analyses were derived from fragmented, preliminary laboratory data. These results must be substantiated and integrated processes proposed, tested, and refined to be able to evaluate the commercial feasibility from microalgae. The production of algal feedstocks for processing to gasoline or ester fuel requires algae of high productivity and high lipid content that efficiently utilize saline waters. Species screening and development suggest that algae can achieve required standards taken individually, but algae that can meet the integrated requirements still elude researchers. Effective development of fuels from microalgae technology requires that R and D be directed toward meeting the integrated standards set out in the analysis. As technology analysts, it is inappropriate for us to dictate how the R and D effort should proceed to meet these standards. We end our role by noting that alternative approaches to meeting the feasibility targets have been identified, and it is now the task of program managers and scientists to choose the appropriate approach to assure the greatest likelihood of realizing a commercially viable technology. 70 refs., 39 figs., 35 tabs.
Date: August 1, 1986
Creator: Neenan, B.; Feinberg, D.; Hill, A.; McIntosh, R. & Terry, K.
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

Making solar laws work. A study of state solar energy incentives

Description: The results of a research investigation of solar financial and research, demonstration, and development R D and D) incentive programs in 18 states are summarized. The investigation focuses upon implementation - the organization and administrative processes required to convert a law into a viable program. Eleven financial and 12 RD and D programs were investigated. Results indicate that four conditions are common to successful implementation of both types of incentive programs: the opportunity to use solar energy as a heating source; characteristics of the agency selected to complement the law; involvement of outside groups in program implementation; and the specificity of guidance given to those responsible for implementation. Other conditions specific to the implementation of each type of program are discussed as well as the implications of these findings for state and federal policy makers.
Date: November 1, 1980
Creator: Roessner, J.D.
Partner: UNT Libraries Government Documents Department

State solar energy incentives primer: a guide to selection and design

Description: Basic design principles are discussed for the creation of several types of state financial incentives and the major advantages and disadvantages of a number of incentive options are cited. The financial incentives included are income tax strategies, loan programs, property tax exemptions, and excise/sales tax exemptions. Information is cited to maximize the effectiveness of solar energy programs. Four basic elements of a state solar energy program are program planning; institutional barriers mitigation; research, development, and demonstration projects; and information outreach efforts. A matrix of state solar legislation by type is shown and organizational contacts are listed. (MHR)
Date: December 1, 1979
Creator: None
Partner: UNT Libraries Government Documents Department

Passive solar energy information user study

Description: The results of a series of telephone interviews with groups of users of information on passive solar heating and cooling are described. These results, part of a larger study on many different solar technologies, identify types of information each group needed and the best ways to get information to each group. The overall study provides baseline data about information needs in the solar community. An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from seven passive groups respondents are analyzed in this report: Federally Funded Researchers, Manufacturer Representatives, Architects, Builders, Educators, Cooperative Extension Service County Agents, and Homeowners. 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: November 1, 1980
Creator: Belew, W.W.; Wood, B.L.; Marle, T.L. & Reinhardt, C.L.
Partner: UNT Libraries Government Documents Department

Assessment of existing studies of wind loading on solar collectors

Description: In developing solar collectors, wind loading is the major structural design consideration. Wind loading investigations have focused on establishing safe bounds for steady state loading and verifying rational but initial and conservative design approaches for the various solar collector concepts. As such, the effort has been very successful, and has contributed greatly to both the recognition and qualitative understanding of many of the physical phenomena involved. Loading coefficients corresponding to mean wind velocities have been derived in these prior studies to measure the expected structural loading on the various solar collectors. Current design and testing procedures for wind loading are discussed. The test results corresponding to numerous wind tests on heliostats, parabolic troughs, parabolic dishes, and field mounted photovoltaic arrays are discussed and the applicability of the findings across the various technologies is assessed. One of the most significant consistencies in the data from all the technologies is the apparent benefit provided by fences and field shielding. Taken in toto, these data show that load reductions of three or possibly more seem feasible, though a more thorough understanding of the phenomena involved must be attained before this benefit can be realized. It is recommended that the required understanding be developed to take advantage of this benefit and that field tests be conducted to correlate with both analyses and tests.
Date: February 1, 1981
Creator: Murphy, L. M.
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

Fuel from microalgae lipid products

Description: The large-scale production of microalgae is a promising method of producing a renewable feedstock for a wide variety of fuel products currently refined from crude petroleum. These microalgae-derived products include lipid extraction products (triglycerides, fatty acids, and hydrocarbons) and catalytic conversion products (paraffins and olefins). Microalgal biomass productivity and lipid composition of current experimental systems are estimated at 66.0 metric tons per hectare year and 30% lipid content. Similar yields in a large-scale facility indicate that production costs are approximately six times higher than the average domestic price for crude, well-head petroleum. Based on achievable targets for productivity and production costs, the potential for microalgae as a fuel feedstock is presented in context with selected process refining routes and is compared with conventional and alternative feedstocks (e.g., oilseeds) with which microalgae must compete. 24 references, 9 figures, 4 tables.
Date: April 1, 1984
Creator: Hill, A.M. & Feinberg, D.A.
Partner: UNT Libraries Government Documents Department

Active solar heating and cooling information user study

Description: The results of a series of telephone interviews with groups of users of information on active solar heating and cooling (SHAC). An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from 19 SHAC groups respondents are analyzed in this report: DOE-Funded Researchers, Non-DOE-Funded Researchers, Representatives of Manufacturers (4 groups), Distributors, Installers, Architects, Builders, Planners, Engineers (2 groups), Representatives of Utilities, Educators, Cooperative Extension Service County Agents, Building Owners/Managers, and Homeowners (2 groups). 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: January 1, 1981
Creator: Belew, W.W.; Wood, B.L.; Marle, T.L. & Reinhardt, C.L.
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

Direct-contact condensers for open-cycle OTEC applications: Model validation with fresh water experiments for structured packings

Description: The objective of the reported work was to develop analytical methods for evaluating the design and performance of advanced high-performance heat exchangers for use in open-cycle thermal energy conversion (OC-OTEC) systems. This report describes the progress made on validating a one-dimensional, steady-state analytical computer of fresh water experiments. The condenser model represents the state of the art in direct-contact heat exchange for condensation for OC-OTEC applications. This is expected to provide a basis for optimizing OC-OTEC plant configurations. Using the model, we examined two condenser geometries, a cocurrent and a countercurrent configuration. This report provides detailed validation results for important condenser parameters for cocurrent and countercurrent flows. Based on the comparisons and uncertainty overlap between the experimental data and predictions, the model is shown to predict critical condenser performance parameters with an uncertainty acceptable for general engineering design and performance evaluations. 33 refs., 69 figs., 38 tabs.
Date: October 1, 1988
Creator: Bharathan, D.; Parsons, B.K. & Althof, J.A.
Partner: UNT Libraries Government Documents Department

Design approaches for solar industrial process-heat systems: nontracking and line-focus collector technologies

Description: The design methodology for solar industrial process heat systems is described, and an overview is given of the use of solar energy in industry. A way to determine whether solar energy makes sense for a particular application is described. The basic system configurations used to supply hot water or steam are discussed, and computer-generated graphs are supplied that allow the user to select a collector type. Detailed energy calculations are provided, including the effects of thermal losses and storage. The selection of subsystem components is described, and control systems, installation and start-up details, economics, and safety and environmental issues are explained. (LEW)
Date: August 1, 1982
Creator: Kutscher, C.F.; Davenport, R.L.; Dougherty, D.A.; Gee, R.C.; Masterson, P.M. & May, E.K.
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

Ground-coupling techniques for cooling in desert regions

Description: Results compiled from a parametric study of several variables that effect ground-coupling techniques for buildings in hot, arid regions are discussed. Finite difference models were devised and analyzed by the computer program SPICE to quantify these effects. Earlier results showed that berming or burying a structure to a depth of 3.6 m and insulating only the roof plane reduce the cooling load by 40% and virtually eliminate the heating load compared to a well-insulated building on the surface. Soil isotherm contours and heat flux results from surface and earth-integrated buildings are presented to further compare their thermal behavior.
Date: April 1, 1981
Creator: Bircher, T. L.
Partner: UNT Libraries Government Documents Department