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Cooperative effort for industrial energy data collection (IEDC)

Description: The expanding research effort in recent years in industrial energy use has created a need for detailed data on specific industrial processes. To meet this need and eliminate multiple contacts with individual plants, a cooperative effort to collect and centralize industrial energy-use data has been organized by several solar research organizations. To date, a centralized list has been produced of industrial plants and trade associations that have been contracted, and a data format has been created for use by all organizations interested in participating in this effort.
Date: October 1, 1979
Creator: Green, H.J.
Partner: UNT Libraries Government Documents Department

HYBRID2 -- A versatile model of the performance of hybrid power systems

Description: In 1993, the National Renewable Laboratory (NREL) made an assessment of the available tools from the United States and Europe for predicting the long-term performance of hybrid power systems. By hybrid power the authors mean combinations of two or more power sources wind turbines, photovoltaics (PV), diesel gensets, or other generators into integrated systems for electric power generation in remote locations. Their conclusion was that there was no single, user-friendly tool capable of modeling the full range of hybrid power technologies being considered for the 1990s and beyond. The existing tools were, in particular, lacking flexibility in system configuration and in dispatch of components. As a result, NREL developed a specification for a model, called HYBRID2, for making comparisons of competing technology options on a level playing field. This specification was prepared with a range of potential users in mind including not only the US Department of Energy (DOE) renewable energy programs, but also the US wind industry, technical consultants, international development institutions/banks, and rural electrification programs in developing countries. During 1994, NREL and subcontractor, the University of Massachusetts (UMass), began development of HYBRID2 with funding from the DOE Wind Energy Program. It builds on the wind/diesel model, HYBRID1, developed previously by UMass, and expands that model to accommodate the wider array of technologies used in hybrid power systems. This paper will provide an overview of the model`s features, functions, and status.
Date: April 1, 1995
Creator: Green, H.J. & Manwell, J.
Partner: UNT Libraries Government Documents Department

The IEEE Grid Interconnection Standard: How Will it Affect Wind Power?

Description: In December 1998, the Institute of Electrical and Electronic Engineers (IEEE) began writing a standard for the interconnection of distributed resources with electric power systems. This standard will prescribe technical requirements for the interconnection of distributed resources that are connected to primary or secondary voltages in electric distribution systems. It is expected to play a significant role in facilitating a new, emerging market for small, distributed, primarily gas-fired electric generators, including new technologies such as fuel cells and micro-turbines. Once published, this new standard will be enforced for the interconnection of distributed wind power applications, as well. The co-authors of this paper have been active with this standard from the beginning, focusing on issues most likely to affect interconnection of wind power. This paper describes the standard-writing process and highlights technical issues critical to wind power, with the intent of soliciting feedback from an encouraging broader participation by the wind industry.
Date: August 30, 2000
Creator: Green, H.J. & Wind, 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

Optimal control of remote hybrid power systems. Part 1: Simplified model

Description: In this two-part study, time-series models are used to determine optimal dispatch strategies, in conjunction with optimally-sized components, in remote hybrid power systems. The objective of the dispatch optimization is to minimize the costs associated with diesel fuel, diesel starts, and battery erosion, based on a thorough economic analysis of present worth life-cycle cost. An ideal predictive control strategy is used as a basis of comparison. In Part 1 (reported here), a simplified time-series model is used to obtain preliminary conceptual results. These results illustrate the nature of the optimal dispatch strategy and indicate that a simple SOC setpoint strategy can be practically as effective as the ideal predictive control. In Part 2 (at a later date), a more detailed model will be used to obtain more accurate, quantitative results. The authors anticipate that these results will be correlated to dimensionless economic, design, and performance parameters, rendering them useful as design guidelines over a wide variety of load profiles, climates, equipment specifications, and economic variables.
Date: April 1, 1995
Creator: Barley, C D; Winn, C B; Flowers, L & Green, H J
Partner: UNT Libraries Government Documents Department

Current experience with net metering programs

Description: Net metering is a utility metering practice that encourages direct consumer investment in renewable energy technologies. Laws and regulations that establish net metering practices now exist in 22 states. Net metering enables electricity customers with small generators to receive a higher value for some or all of the electricity they generate. This is accomplished by allowing the electric meters of such customers to turn backward when there is more generation than demand. It effectively allows customers with small generators to use the electricity they generate to offset their usage over an entire billing period. This paper reports on the current status of net metering laws and rules in the US. In particular, the extent of the net metering authority in each state is highlighted. Differing requirements for grid-interconnection have introduced significant variations in the actual implementation of net metering programs. Interconnection requirements from specific utilities are collected to understand how net metering programs have been affected.
Date: May 1, 1998
Creator: Wan, Y.H. & Green, H.J.
Partner: UNT Libraries Government Documents Department

Software Quality-Control Guidelines for Codes Developed for the NWTC

Description: Members in the wind-energy research, development, deployment, and production communities use computer codes for many things. They base important decisions on the results from the codes. It is important that the developers of these codes scrutinize them to assure an appropriate level for quality. The National Wind Technology Center (NWTC) and its subcontractors have developed many computer codes now in use in the United States and around the world. This document will present some guidelines for ensuring the quality of programs that are developed for the NWTC.
Date: June 16, 1999
Creator: Buhl, M. L., Jr. & Green, H. J.
Partner: UNT Libraries Government Documents Department

Open cycle OTEC system with falling jet evaporator and condenser

Description: A configuration for the open cycle (OC) Ocean Thermal Energy Conversion (OTEC) system is presented incorporating a countercurrent falling jet evaporator and a concurrent falling jet condenser. The parameters governing performance of the proposed configuration are discussed and the sizing of equipment for a 100-MWe net power output OC OTEC plant is performed, based on recent experimental falling jet heat and mass transfer results. The performance of an OC OTEC plant with falling jet evaporator-condenser is compared with the Westinghouse conceptual design that uses an open-channel evaporator and a surface condenser. Preliminary calculations indicate that falling jet heat and mass transfer, when applied in the proposed configuration, leads to a very simple and compact plant assembly resulting in substantial capital cost savings.
Date: July 1, 1980
Creator: Kogan, A.; Johnson, D. H.; Green, H. J. & Olson, D. A.
Partner: UNT Libraries Government Documents Department

Wind/hybrid power system test facilities in the United States and Canada

Description: By 1995, there will be four facilities available for testing of wind/hybrid power systems in the United States and Canada. This paper describes the mission, approach, capabilities, and status of activity at each of these facilities. These facilities have in common a focus on power systems for remote, off-grid locations that include wind energy. At the same time, these facilities have diverse, yet complimentary, missions that range from research to technology development to testing. The first facility is the test facility at the Institut de Recherche d`Hydro-Quebec (IREQ), Hydro-Quebec`s research institute near Montreal, Canada. This facility, not currently in operation, was used for initial experiments demonstrating the dynamic stability of a high penetration, no-storage wind/diesel (HPNSWD) concept. The second facility is located at the Atlantic Wind Test Site (AWTS) on Prince Edward Island, Canada, where testing of the HPNSWD concept developed by Hydro-Quebec is currently underway. The third is the Hybrid Power Test Facility planned for the National Wind Technology Center at the National Renewable Energy Laboratory (NREL) in Golden, Colorado, which will focus on testing commercially available hybrid power systems. The fourth is the US Department of Agriculture (USDA) Conservation and Production Research Laboratory in Bushland, Texas, where a test laboratory is being developed to study wind-energy penetration and control strategies for wind/hybrid systems. The authors recognize that this summary of test facilities is not all inclusive; for example, at least one US industrial facility is currently testing a hybrid power system. Our intent, though, is to describe four facilities owned by nonprofit or governmental institutions in North America that are or will be available for ongoing development of wind/hybrid power systems.
Date: May 1, 1994
Creator: Green, H J; Clark, R N; Brothers, C & Saulnier, B
Partner: UNT Libraries Government Documents Department

Testing of a 50-kW Wind-Diesel Hybrid System at the National Wind Technology Center

Description: In remote off-grid villages and communities, a reliable power source is important in improving the local quality of life. Villages often use a diesel generator for their power, but fuel can be expensive and maintenance burdensome. Including a wind turbine in a diesel system can reduce fuel consumption and lower maintenance, thereby reducing energy costs. However, integrating the various components of a wind-diesel system, including wind turbine, power conversion system, and battery storage (if applicable), is a challenging task. To further the development of commercial hybrid power systems, the National Renewable Energy Laboratory (NREL), in collaboration with the New World Village Power Corporation (NWVP), tested a NWVP 50-kW wind-diesel hybrid system connected to a 15/50 Atlantic Orient Corporation (AOC) wind turbine. Testing was conducted from October 1995 through March 1996 at the National Wind Technology Center (NWTC). A main objective of the testing was to better understand the application of wind turbines to weak grids typical of small villages. Performance results contained in this report include component characterization, such as power conversion losses for the rotary converter system and battery round trip efficiencies. In addition, system operation over the test period is discussed with special attention given to dynamic issues. Finally, future plans for continued testing and research are discussed.
Date: July 1, 1996
Creator: Corbus, D. A.; Green, H. J.; Allderdice, A.; Rand, K.; Bianchi, J. & Linton, E.
Partner: UNT Libraries Government Documents Department

Hybrid2: The hybrid power system simulation model

Description: There is a large-scale need and desire for energy in remote communities, especially in the developing world; however the lack of a user friendly, flexible performance prediction model for hybrid power systems incorporating renewables hindered the analysis of hybrids (including wind turbines, PV, diesel generators, AC/DC energy storage) as options to conventional solutions. A user friendly model was needed with the versatility to simulate the many system locations, widely varying hardware configurations, and differing control options for potential hybrid power systems. To meet these ends, NREL and U. Mass. researchers developed the Hybrid2 software. This paper provides an overview of the capabilities, features, and functionality of the Hybrid2 code, discusses its validation and future plans. Model availability and technical support provided to Hybrid2 users are also discussed.
Date: July 1, 1996
Creator: Baring-Gould, E I; Green, H J; van Dijk, V A.P. & Manwell, J F
Partner: UNT Libraries Government Documents Department

Conceptual design of an open-cycle ocean thermal energy conversion net power-producing experiment (OC-OTEC NPPE)

Description: This report describes the conceptual design of an experiment to investigate heat and mass transfer and to assess the viability of open-cycle ocean thermal energy conversion (OC-OTEC). The experiment will be developed in two stages, the Heat- and Mass-Transfer Experimental Apparatus (HMTEA) and the Net Power-Producing Experiment (NPPE). The goal for the HMTEA is to test heat exchangers. The goal for the NPPE is to experimentally verify OC-OTEC's feasibility by installing a turbine and testing the power-generating system. The design effort met the goals of both the HMTEA and the NPPE, and duplication of hardware was minimal. The choices made for the design resource water flow rates are consistent with the availability of cold and warm seawater as a result of the seawater systems upgrade carried out by the US Department of Energy (DOE), the state of Hawaii, and the Pacific International Center for High Technology Research. The choices regarding configuration of the system were made based on projected performance, degree of technical risk, schedule, and cost. The cost for the future phase of the design and the development of the HMTEA/NPPE is consistent with the projected future program funding levels. The HMTEA and NPPE were designed cooperatively by PICHTR, Argonne National Laboratory, and Solar Energy Research Institute under the guidance of DOE. The experiment will be located at the DOE's Seacoast Test Facility at the Natural Energy Laboratory of Hawaii, Kailua-Kona, Hawaii. 71 refs., 41 figs., 34 tabs.
Date: July 1, 1990
Creator: Bharathan, D.; Green, H.J.; Link, H.F.; Parsons, B.K.; Parsons, J.M. & Zangrando, F.
Partner: UNT Libraries Government Documents Department

Carbon dioxide release from ocean thermal energy conversion (OTEC) cycles

Description: This paper presents the results of recent measurements of CO{sub 2} release from an open-cycle ocean thermal energy conversion (OTEC) experiment. Based on these data, the rate of short-term CO{sub 2} release from future open-cycle OTEC plants is projected to be 15 to 25 times smaller than that from fossil-fueled electric power plants. OTEC system that incorporate subsurface mixed discharge are expected to result in no long-term release. OTEC plants can significantly reduce CO{sub 2} emissions when substituted for fossil-fueled power generation. 12 refs., 4 figs., 3 tabs.
Date: September 1, 1990
Creator: Green, H.J. (Solar Energy Research Inst., Golden, CO (USA)) & Guenther, P.R. (Scripps Institution of Oceanography, La Jolla, CA (USA))
Partner: UNT Libraries Government Documents Department

Results of scoping tests for open-cycle OTEC (ocean thermal energy conversion) components operating with seawater

Description: This report presents comprehensive documentation of the experimental research conducted on open-cycle ocean thermal energy conversion (OC-OTEC) components operating with seawater as a working fluid. The results of this research are presented in the context of previous analysis and fresh-water testing; they provide a basis for understanding and predicting with confidence the performance of all components of an OC-OTEC system except the turbine. Seawater tests have confirmed the results that were obtained in fresh-water tests and predicted by the analytical models of the components. A sound technical basis has been established for the design of larger systems in which net power will be produced for the first time from OC-OTEC technology. Design and operation of a complete OC-OTEC system that produces power will provide sufficient confidence to warrant complete transfer of OC-OTEC technology to the private sector. Each components performance is described in a separate chapter written by the principal investigator responsible for technical aspects of the specific tests. Chapters have been indexed separately for inclusion on the data base.
Date: September 1, 1990
Creator: Zangrando, F; Bharathan, D; Green, H J; Link, H F; Parsons, B K; Parsons, J M et al.
Partner: UNT Libraries Government Documents Department