Optimum design point for a closed-cycle OTEC system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ikegami, Yasuyuki; Uehara, Haruo

1994-12-31

Performance analysis is performed for optimum design point of a closed-cycle Ocean Thermal Energy Conversion (OTEC) system. Calculations are made for an OTEC model plant with a gross power of 100 MW, which was designed by the optimization method proposed by Uehara and Ikegami for the design conditions of 21 C--29 C warm sea water temperature and 4 C cold sea water temperature. Ammonia is used as working fluid. Plate type evaporator and condenser are used as heat exchangers. The length of the cold sea water pipe is 1,000 m. This model plant is a floating-type OTEC plant. The objectivemore » function of optimum design point is defined as the total heat transfer area of heat exchangers per the annual net power.« less

Proposed 10 MWe OTEC pilot plant for the Commonwealth of the Northern Mariana Islands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunbar, L.E.; Chan, G.L.

1981-01-01

A preliminary conceptual design of a 10 MWe OTEC pilot plant has been proposed for the island of Saipan in the Commonwealth of the Northern Mariana Islands. This unique small OTEC plant is intended as a prototype for commercial plants in the small Pacific Island territories and nations. The system concept minimizes local construction to accommodate a lack of local skilled labor and facilities. The baseline design is a concrete barge-mounted plant built in Portland, Oregon, towed to Saipan, and permanently anchored in near-shore shallow water. Details of key subsystem design features are provided including a bottom-mounted cold water pipe,more » modular power subsystem, and wave shield for storm protection. The results of economic analyses are presented to illustrate the cost competitiveness of electricity from the OTEC plant compared to the current oil-fired diesel units in Saipan.« less

Proposed 10 MWe OTEC pilot plant for the Commonwealth of the Northern Mariana Islands

NASA Astrophysics Data System (ADS)

Dunbar, L. E.; Chan, G. L.

1981-12-01

A preliminary conceptual design of a 10 MWe OTEC pilot plant has been proposed for the island of Saipan in the Commonwealth of the Northern Mariana Islands. This unique small OTEC plant is intended as a prototype for commercial plants in the small Pacific Island territories and nations. The system concept minimizes local construction to accommodate a lack of local skilled labor and facilities. The baseline design is a concrete barge-mounted plant built in Portland, Oregon, towed to Saipan, and permanently anchored in near-shore shallow water. Details of key subsystem design features are provided including a bottom-mounted cold water pipe, modular power subsystem, and wave shield for storm protection. The results of economic analyses are presented to illustrate the cost competitiveness of electricity from the OTEC plant compared to the current oil-fired diesel units in Saipan.

Small-scale uses and costs of hydrogen derived from OTEC ammonia

NASA Astrophysics Data System (ADS)

Strickland, G.

Ocean Thermal Energy Conversion (OTEC) plantships could produce NH3 from air and water, using energy derived from thermal gradients in tropical oceans. NH3 can serve both as a commodity, for the fertilizer and chemical industries, and as a liquid energy carrier for fuel use. Attention is given to the economic prospects for using OTEC NH3 as a hydrogen transport and storage medium for small users who want to assess the purchase of hydrogen vs. the cost of producing hydrogen at their sites. Hydrogen is readily obtained from NH3 at the point of end use, by dissociation and purification as required, for use as a chemical commodity or fuel. It is shown that high-purity H2 derived from OTEC NH3 might be competitive with H2 made at the point of end use via water electrolysis, or via steam reforming of natural gas.

Warm Water Entrainment Impacts and Environmental Life Cycle Assessment of a Proposed Ocean Thermal Energy Conversion Pilot Plant Offshore Oahu, Hawaii

NASA Astrophysics Data System (ADS)

Hauer, Whitney Blanchard

Ocean thermal energy conversion (OTEC) is a marine renewable energy technology that uses the temperature difference of large volumes of cold deep and warm surface seawater in tropical regions to generate electricity. One anticipated environmental impact of OTEC operations is the entrainment and subsequent mortality of ichthyoplankton (fish eggs and larvae) from the withdrawal of cold and warm seawater. The potential ichthyoplankton loss from the warm water intake was estimated for a proposed 10 MW OTEC pilot plant offshore Oahu, HI based on ambient vertical distribution data. The estimated losses due to entrainment from the warm water intake were 8.418E+02 larvae/1000 m3, 3.26E+06 larvae/day, and 1.19E+09 larvae/year. The potential entrained larvae/year is 1.86 X greater than at the Kahe Generating Station (Kapolei, HI), a 582 MW oil-fired power plant. Extrapolating to age-1 equivalence (9.2E+02 and 2.9E+02 yellowfin and skipjack tuna, respectively), the estimated yearly losses from warm water entrainment of yellowfin and skipjack tuna fish eggs and larvae represent 0.25-0.26 % and 0.09-0.11 % of Hawaii's commercial yellowfin and skipjack tuna industry in 2011 and 2012. An environmental life cycle assessment (LCA) was developed for the proposed OTEC plant operating for 20 and 40 years with availability factors of 0.85, 0.95, and 1.0 to determine the global warming potential (GWP) and cumulative energy demand (CED) impacts. For a 20 year operational OTEC plant, the GWP, CED, energy return on investment (EROI), and energy payback time (EPBT) ranged from 0.047 to 0.055 kg CO2eq/kWh, 0.678 to 0.798 MJ/kWh, 4.51 to 5.31 (unitless), and 3.77 to 4.43 years, respectively. For a 40 year operational OTEC plant, the GWP, CED, EROI, and EBPT ranged from 0.036 to 0.043 kg CO2eq/kWh, 0.527 to 0.620 MJ/kWh, 5.81 to 6.83 (unitless), and 5.85 to 6.89 years, respectively. The GWP impacts are within the range of renewable energy technologies and less than conventional electricity generation, with the exception of nuclear power. As part of the LCA, an ichthyoplankton entrainment impact assessment method was developed to estimate potential loss from the warm water intake for the proposed OTEC plant and for six coastal nuclear power facilities that use once-through cooling technology. Larval fish entrainment (#/kWh) was significantly greater (p<0.026) for the proposed OTEC facility, ranging from 10.0 to 11.7 larvae/kWh due to different capacity factors, than for the six nuclear power facilities that ranged from 0.08 to 0.78 larvae/kWh. While this research did not investigate OTEC technology development and economics, OTEC would be a favorable option for reducing the GWP and the reliance on fossil fuels for electricity generation in HI. The impact of ichthyoplankton mortality due to warm water entrainment for a 10 MW OTEC plant offshore Oahu, HI would likely be acceptable as there are examples of similar water withdrawals for electricity generation. Biological monitoring of a 10 MW facility would verify estimated environmental impacts of the warm water withdrawal and provide new information on the cold water withdrawal before advancing to a commercial (e.g., 100 MW) scale facility.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oney, Stephen K.; Hogan, Timothy; Steinbeck, John

Ocean thermal energy conversion (OTEC) is a marine renewable energy technology with the potential to contribute significantly to the baseload power needs of tropical island communities and remote U.S. military installations. As with other renewable energy technologies, however, there are potential challenges to its commercialization: technological, financial, social, and environmental. Given the large volumes of seawater required to drive the electricity-producing cycle, there is potential for the intakes to negatively impact the marine resources of the source waterbody through the impingement and entrainment of marine organisms. The goal of this project was to identify feasible warm water intake designs formore » a land-based OTEC facility proposed for development in Port Allen, Kauai and to characterize the populations of ichthyoplankton near the proposed warm water intake location that could be at risk of entrainment. The specific objectives of this project were to: • Complete a site-specific assessment of available and feasible warm water intake technologies to determine the best intake designs for minimizing impacts to aquatic organisms at the proposed land-based OTEC site in Port Allen, Kauai. • Complete a field sampling program to collect biological data to characterize the baseline populations of ichthyoplankton near the sites being considered for the warm water intake at the proposed land-based OTEC site in Port Allen, Kauai. Various intake design options are presented with the focus on providing adequate environmental protection to the local ichthyoplankton population while providing an economically viable intake option to the OTEC developer. Further definition by NOAA and other environmental regulators is required to further refine the designs presented to meet all US regulations for future OTEC development.« less

Ocean energy program summary. Volume 2: Research summaries

NASA Astrophysics Data System (ADS)

1990-01-01

The oceans are the world's largest solar energy collector and storage system. Covering 71 percent of the earth's surface, this stored energy is realized as waves, currents, and thermal salinity gradients. The purpose of the Federal Ocean Energy Technology (OET) Program is to develop techniques that harness this ocean energy in a cost effective and environmentally acceptable manner. The OET Program seeks to develop ocean energy technology to a point where the commercial sector can assess whether applications of the technology are viable energy conversion alternatives or supplements to systems. Past studies conducted by the U.S. Department of Energy (DOE) have identified ocean thermal energy conversion (OTEC) as the largest potential contributor to United States energy supplies from the ocean resource. As a result, the OET Program concentrates on research to advance OTEC technology. Current program emphasis has shifted to open-cycle OTEC power system research because the closed-cycle OTEC system is at a more advanced stage of development and has already attracted industrial interest. During FY 1989, the OET Program focused primarily on the technical uncertainties associated with near-shore open-cycle OTEC systems ranging in size from 2 to 15 MW(sub e). Activities were performed under three major program elements: thermodynamic research and analysis, experimental verification and testing, and materials and structures research. These efforts addressed a variety of technical problems whose resolution is crucial to demonstrating the viability of open-cycle OTEC technology. This publications is one of a series of documents on the Renewable Energy programs sponsored by the U.S. Department of Energy. An overview of all the programs is available, entitled Programs in Renewable Energy.

Conceptual design of ocean thermal energy conversion (OTEC) power plants in the Philippines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haruo Uehara; Dilao, C.O.; Tsutomu Nakaoka

1988-01-01

Extensive temperature readings were obtained to determine suitable OTEC power plant sites in the Philippines. An analysis of temperature profiles reveals that surface seawater is in the range of 25 to 29{degree}C throughout the year while seawater at 500 to 700 m depth remains at a low temperature of 8 to 4{degree}C, respectively. In this article, 14 suitable sites within the Philippine seas are suggested. Conceptual designs for a 5-MW onland-type and a 25-MW floating-type OTEC power plant are proposed. Optimum conditions are determined and plant specifications are computed. Cost estimates show that a floating-type 25-MW OTEC power plant canmore » generate electricity at a busbar power cost of 5.33 to 7.57 cents/kW {times} h while an onshore type 5-MW plant can generate electricity at a busbar cost of 14.71 to 18.09 cents/kW {times} h.« less

Analysis of six groups of zooplankton in samples taken in 1978/79 at the proposed OTEC site in the eastern Gulf of Mexico off Tampa Bay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flock, M.E.; Hopkins, T.L.

1981-05-01

Continued analysis has been made of the 33 zooplankton collections made at the proposed OTEC site in the Gulf of Mexico off Tampa Bay. Six groups of zooplankton - siphonophores (Calycophora), pteropods (Thecosomata), chaetognaths, thaliaceans, euphausiids and amphipods were quantitatively investigated. Numbers and biomass were determined for all taxa and diurnal, seasonal and depth trends were discussed. Considering the present study and the previous investigation of the copepod population, this proposed OTEC site is probably one of the faunistically better known locales in the Gulf of Mexico and Caribbean.

Marine mammal fauna of potential OTEC sites in the Gulf of Mexico and Hawaii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Payne, S.F.

1979-05-01

Twenty-seven marine mammal species have been recorded for the Gulf of Mexico, including 7 Mysticetes or baleen whales, 17 Odontocetes or toothed whales, 1 Sirenian (manatee), and 1 or 2 Pinnipeds or seals. The most common species in the Gulf is the bottlenosed dolphin, an inshore species. Offshore, the spotted dolphin, is fairly common. Most other species are recorded from very few sightings or strandings. None of the endangered species is common in potential OTEC sites in the Gulf of Mexico. Twenty-two marine mammals may occur in Hawaii; 2 Mystecetes, 19 Odonotocetes, and the endemic monk seal. The monk seal,more » an endangered species, lives in the extreme northwestern island chain away from potential OTEC sites. Among the most common cetaceans in Hawaii is the endangered humpback whale. The spinner dolphin and the bottlenosed dolphin are also fairly common. The baleen whales feed on zooplankton during the summer in polar waters, and are migratory, while the toothed whales feed mainly on fish and squid, and are found in temperate or tropical regions year-round. The manatee is vegetarian and the pinnipeds are fish- or squid-eaters. Environmental effects of OTEC which may affect mammals are: toxic effects of biocide release or ammonia spill, biostimulating effects of seawater redistribution, oil spills, or effects of the physical presence of OTEC plants.« less

Turboexpanders for OTEC power plants

NASA Astrophysics Data System (ADS)

Holm, J.

1981-12-01

Centripetal (radial inflow) turboexpanders are well adapted to energy conservation schemes. A mini OTEC demonstration program, completed in 1979, uses a closed ammonia cycle to drive a 50 kw turboexpander generator unit. The turboexpander, which incorporates mechanical designs of low temperature and high speed machinery, has very high levels of reliability and efficiency. Stiff shaft designs have eliminated shaft and bearing criticals in the entire operating range. Rotor resonance problems are almost totally eliminated, and thrust bearing problems can be accurately monitored and controlled. Condensing streams and dust in gas can also be handled without erosion. Designs for radial inflow turboexpanders in sizes up to 70 MWe are presently available for use in OTEC and other power plants.

Operational experience of the OC-OTEC experiments at NELH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Link, H

1989-02-01

The Solar Energy Research Institute, under funding and program direction from the US Department of Energy, has been operating a small-scale test apparatus to investigate key components of open- cycle ocean thermal energy conversion (OC-OTEC). The apparatus started operations in October 1987 and continues to provide valuable information on heat-and mass-transfer processes in evaporators and condensers, gas sorption processes as seawater is depressurized and repressurized, and control and instrumentation characteristics of open-cycle systems. Although other test facilities have been used to study some of these interactions, this is the largest apparatus of its kind to use seawater since Georges Claude`smore » efforts in 1926. The information obtained from experiments conducted in this apparatus is being used to design a larger scale experiment in which a positive net power production is expected to be demonstrated for the first time with OC-OTEC. This paper describes the apparatus, the major tests conducted during its first 18 months of operation, and the experience gained in OC-OTEC system operation. 13 refs., 8 figs.« less

OTEC Cold Water Pipe-Platform Subsystem Dynamic Interaction Validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varley, Robert; Halkyard, John; Johnson, Peter

A commercial floating 100-megawatt (MW) ocean thermal energy conversion (OTEC) power plant will require a cold water pipe (CWP) with a diameter of 10-meter (m) and length of up to 1,000 m. The mass of the cold water pipe, including entrained water, can exceed the mass of the platform supporting it. The offshore industry uses software-modeling tools to develop platform and riser (pipe) designs to survive the offshore environment. These tools are typically validated by scale model tests in facilities able to replicate real at-sea meteorological and ocean (metocean) conditions to provide the understanding and confidence to proceed to finalmore » design and full-scale fabrication. However, today’s offshore platforms (similar to and usually larger than those needed for OTEC applications) incorporate risers (or pipes) with diameters well under one meter. Secondly, the preferred construction method for large diameter OTEC CWPs is the use of composite materials, primarily a form of fiber-reinforced plastic (FRP). The use of these material results in relatively low pipe stiffness and large strains compared to steel construction. These factors suggest the need for further validation of offshore industry software tools. The purpose of this project was to validate the ability to model numerically the dynamic interaction between a large cold water-filled fiberglass pipe and a floating OTEC platform excited by metocean weather conditions using measurements from a scale model tested in an ocean basin test facility.« less

Design and cost of near-term OTEC (Ocean Thermal Energy Conversion) plants for the production of desalinated water and electric power

NASA Astrophysics Data System (ADS)

Rabas, T.; Panchal, C. B.; Genens, L.

There currently is an increasing need for both potable water and power for many islands in the Pacific and Caribbean. The Ocean Thermal Energy Conversion (OTEC) technology fills these needs and is a viable option because of the unlimited supply of ocean thermal energy for the production of both desalinated water and electricity. The OTEC plant design must be flexible to meet the product-mix demands that can be very different from site to site. Different OTEC plants are described that can supply various mixes of desalinated water and vapor; the extremes being either all water and no power or no water and all power. The economics for these plants are also presented. The same flow rates and pipe sizes for both the warm and cold seawater streams are used for different plant designs. The OTEC plant designs are characterized as near-term because no major technical issues need to be resolved or demonstrated. The plant concepts are based on DOE-sponsored experiments dealing with power systems, advanced heat exchanger designs, corrosion and fouling of heat exchange surfaces, and flash evaporation and moisture removal from the vapor using multiple spouts. In addition, the mature multistage flash evaporator technology is incorporated into the plant designs where appropriate. For the supply and discharge warm and cold uncertainties do exist because the required pipe sizes are larger than the maximum currently deployed; 40 inch high density polyethylene pipe at Keahole Point in Hawaii.

THE MARINE MAMMAL FAUNA OF POTENTIAL OTEC SITES IN THE GULF OF MEXICO AND HAWAII

DOE Office of Scientific and Technical Information (OSTI.GOV)

Payne, S.F.

1979-05-01

Twenty-seven marine mammal species have been recorded for the Gulf of Mexico, including 7 Mysticetes or baleen whales, 17 Odontocetes or toothed whales, 1 Sirenian (manatee), and 1 or 2 Pinnipeds or seals. The most common species in the Gulf is Tursiops truncatus, the bottlenosed dolphin, an inshore species. Offshore, Stenella plagiodon, the spotted dolphin, is fairly common. Most other species are recorded from very few sightings or strandings. None of the endangered species is common in potential OTEC sites in the Gulf of Mexico. Twenty-two marine mammals may occur in Hawaii; 2 Mystecetes, 19 Odonotocetes, and the endemic monkmore » seal. The monk seal (Monachus schauinslandi), an endangered species, lives in the extreme northwestern island chain away from potential OTEC sites. Among the most common cetaceans in Hawaii is the endangered humpback whale (Megaptera novaeangliae). Stenella longirostris, the spinner dolphin; and Tursiops sp., the bottlenosed dolphin are also fairly common. The baleen whales feed on zooplankton during the summer in polar waters, and are migratory, while the toothed whales feed mainly on fish and squid, and are found in temperate or tropical regions year-round. The manatee is vegetarian and the pinnipeds are fish- or squid-eaters. Environmental effects of OTEC which may affect mammals are: toxic effects of biocide release or ammonia spill, biostimulating effects of seawater redistribution, oil spills, or effects of the physical presence of OTEC plants.« less

Ocean thermal energy conversion: Perspective and status

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, A.; Hillis, D.L.

1990-01-01

The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully be George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that time, the emphasis was on large floating plants miles from shore producing 250--400 MW for maintained grids. When the problems of such plants became better understood and the price of oil reversed its upward trend, the emphasis shifted to smallermore » (10 MW) shore-based plants on tropical islands. Such plants would be especially attractive if they produce fresh water as a by-product. During the past 15 years, major progress has been made in converting OTEC unknowns into knowns. Mini-OTEC proved the closed-cycle concept. Cost-effective heat-exchanger concepts were identified. An effective biofouling control technique was discovered. Aluminum was determined to be promising for OTEC heat exchangers. Heat-transfer augmentation techniques were identified, which promised a reduction on heat-exchanger size and cost. Fresh water was produced by an OTEC open-cycle flash evaporator, using the heat energy in the seawater itself. The current R D emphasis is on the design and construction of a test facility to demonstrate the technical feasibility of the open-cycle process. The 10 MW shore-based, closed-cycle plant can be built with today's technology; with the incorporation of a flash evaporator, it will produce fresh water as well as electrical power -- both valuable commodities on many tropical islands. The open-cycle process has unknowns that require solution before the technical feasibility can be demonstrated. The economic viability of either cycle depends on reducing the capital costs of OTEC plants and on future trends in the costs of conventional energy sources. 7 refs.« less

Ocean thermal energy conversion: Perspective and status

NASA Astrophysics Data System (ADS)

Thomas, Anthony; Hillis, David L.

The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully by George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that time, the emphasis was on large floating plants miles from shore producing 250 to 400 MW for maintained grids. When the problems of such plants became better understood and the price of oil reversed its upward trend, the emphasis shifted to smaller (10 MW) shore based plants on tropical islands. Such plants would be especially attractive if they produce fresh water as a by-product. During the past 15 years, major progress has been made in converting OTEC unknowns into knowns. Mini-OTEC proved the closed cycle concept. Cost effective heat exchanger concepts were identified. An effective biofouling control technique was discovered. Aluminum was determined to be promising for OTEC heat exchangers. Heat transfer augmentation techniques were identified, which promised a reduction on heat exchanger size and cost. Fresh water was produced by an OTEC open cycle flash evaporator, using the heat energy in the seawater itself. The current R and D emphasis is on the design and construction of a test facility to demonstrate the technical feasibility of the open cycle process. The 10 MW shore-based, closed cycle plant can be built with today's technology; with the incorporation of a flash evaporator, it will produce fresh water as well as electrical power; both valuable commodities on many tropical islands. The open cycle process has unknowns that require solution before the technical feasibility can be demonstrated. The economic viability of either cycle depends on reducing the capital costs of OTEC plants and on future trends in the costs of conventional energy sources.

Bringing OTEC Environmental Assessments of the 1980s Up To 21st Century Oceanographic Standards (Invited)

NASA Astrophysics Data System (ADS)

Sansone, F. J.; Comfort, C. M.; Weng, K. C.

2010-12-01

Although the potential environmental effects of OTEC plant construction and operation were evaluated in the 1980s as part of earlier OTEC development, recent OTEC efforts have led to the re-examination of the issues involved. During the intervening years we have significantly increased our understanding of the oceans, and our ability to observe and model the marine environment has improved markedly. For example, OTEC environmental assessments have traditionally included the effects of discharging deep seawater, with its elevated levels of dissolved inorganic nutrients and dissolved inorganic carbon, and depleted levels of dissolved oxygen, into the upper water column. However, the role of trace elements in controlling marine primary production rates is now widely accepted, and their natural vertical distribution in the ocean needs to be considered. Our expanded understanding of ocean biogeochemistry also makes environmental assessment more complicated. For example, discharges of deep seawater within the photic zone of the ocean, but below the surface mixed layer, should result in photosynthetic production that would remove both dissolved nutrients and dissolved carbon dioxide at approximately the same stoichiometric ratio as they are elevated in deep seawater; thus, the only large-scale related environmental impact would involve the fate of the resulting photosynthetically produced organic matter. Similarly, our improved knowledge of marine physical chemistry allows a better understanding of OTEC’s potential impact on the ocean’s inorganic carbon chemistry. For example, the reduction in pressure of deep seawater as it is brought to the surface, and the increase in temperature due to OTEC heat exchange, will both lead to an increase in the deep water’s pH; opposite effects will occur in the shallow seawater used by OTEC. Determination of the net effect will require modeling using predicted pumping rates for warm and cold seawater, the planned intake and discharge depths and temperatures, the inorganic carbon chemistry at the specific site, and recently refined inorganic carbon equilibria data. Ecological data (e.g., primary productivity, the biomass of various trophic levels, biota attraction to floating objects, etc.) should also be updated with the results from more contemporary studies. Additional factors that should be examined include electromagnetic effects of cabling, alterations in the bio-physical coupling of water column as a result of the discharge plume, potential harmful algal bloom development, and low-frequency noise production. Moreover, new ocean observation techniques such as gliders and AUVs allow large areas of the ocean to be monitored in 3-D for extended periods of time. Similarly, new marine modeling techniques, such as regional ocean modeling systems (ROMS), allow OTEC plumes to be studied in the context of a 3-D dynamic ocean, including such features as internal tides and mesoscales eddies, and allow assimilation of 3-D data to improve model performance. As an early step in these efforts, we have used HOT time-series data to determine patterns of seasonal variability in the upper ocean (warm water intake and discharge zone) and in the deep ocean (cold water uptake) near the site for the proposed Kahe Point, Oahu OTEC demonstration plant.

Heat Exchanger Cleaning in Support of Ocean Thermal Energy Conversion (OTEC) - Mechanical Subsystem.

DTIC Science & Technology

1980-12-01

sponge rubber ball, and chlorination systems. In addition, the maintenance procedures utilized at the NCSC test site are provided. jAN 7 1473 EDITION OF...Recirculating Sponge Rubber Balls .. .... ............. 17 Chlorination .. .............. ............. 19 OTEC MAINTENANCE PROCEDURES...C-1 APPENDIX D - RECIRCULATING SPONGE RUBBER BALL. ............... D-1 APPENDIX E - CHLORINATION SYSTEM .. .. ................. E-1 i 1

Master Teachers in Residence: Bringing a Classroom Perspective to Course Reform for NSF's Oklahoma Teacher Education Collaborative (O-TEC).

ERIC Educational Resources Information Center

Ramsey, Sarah; Neathery, Faye; Fholer, Gwen; Weger, Elayne; Voth, Bonnie; Townsend, Joyce; Campbell, DeAnn; Boedecker, Martha

Master teachers can be influential in course revision. The Oklahoma Teacher Education Collaborative (O-TEC) teacher reform effort is a consortium of nine higher education institutions working with the National Science Foundation's (NSF's) reform effort to produce teachers better equipped for teaching science and mathematics. The reform emphasizes…

Turboexpanders for OTEC power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holm, J.

1981-01-01

Centripetal (radial inflow) turboexpanders are well adapted to energy conservation schemes. A mini OTEC demonstration program, completed in 1979, uses a closed ammonia cycle to drive a 50 kw turboexpander generator unit. The turboexpander, which incorporates mechanical designs of low temperature and high speed machinery, has very high levels of reliability and efficiency. Stiff shaft designs have eliminated shaft and bearing criticals in the entire operating range. Rotor resonance problems are almost totally eliminated, and thrust bearing problems can be accurately monitored and controlled. Condensing streams and dust in gas can also be handled without erosion. Designs for radial inflowmore » turboexpanders in sizes up to 70 MWe are presently available for use in OTEC and other power plants.« less

Baseline design of an OTEC pilot plantship. Volume A. Detailed report. [Performance analysis of OTEC power plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

George, J. F.; Richards, D.; Perini, L. L.

1979-05-01

The Applied Physics Laboratory (APL) of the Johns Hopkins University has engineered a baseline design of an Ocean Thermal Energy Conversion (OTEC) pilot plantship. The work was sponsored jointly by the Department of Energy and the US Maritime Administration of the Department of Commerce. The design, drawings, specifications, supporting calculations, and narrative documentation are available through APL for use by the Government and industry for the acquisition of a pilot OTEC system. The baseline design features a platform that is configured to produce up to 20 MW(e) (net) power, using low-cost folded-tube aluminum heat exchangers, while it grazes slowly inmore » tropical waters where the thermal gradient is greatest and the ocean environment is least severe. The design was developed by a team of contractors whose capabilities provided a systems approach to the design process. The work is documented in three volumes. Volume A is the Detailed report, which develops the design rationale, summarizes important calculations, outlines areas for future work, and presents a study of system costs. Volumes B and C, respectively, contain the engineering drawings and specifications.« less

OTEC Potential of East Nusa Tenggara Province in Indonesia

NASA Astrophysics Data System (ADS)

Widyartono, M.; Rahmadian, R.

2018-04-01

Indonesia is the largest archipelago country in the world, located between Indian Ocean and Pacific Ocean. Indonesia has more than 17000 islands with 70 per cent of the region is ocean. The Growth of the economic and population in Indonesia increasing the demand of the electricity annually, in 2015 alone electricity consumption in Indonesia reaching 200 TWh and will continue increasing every year. However, East Nusa Tenggara Province electrification ratio only around 58.64%, this is the second lowest ratio in Indonesia. This electrification ratio describes the level of availability of electrical energy for the community. Power Plant with renewable source placement in East Nusa Tenggara Province or smaller district need to be prioritise to cope with the low electrification ratio. Renewable sources for power plant have a good potential to work with, in example wind power, solar power, geothermal, or biomass. In addition, another renewable source that not yet known is from the ocean itself. Ocean Thermal Energy Conversion (OTEC) is one of the renewable source method from ocean. This paper will uncover the potential of OTEC in East Nusa Tenggara province so it will bring possibility to build an OTEC power plant in the future.

PHYTOPLANKTON AND BIOMASS DISTRIBUTION AT POTENTIAL OTEC SITES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, P.W.; Horne, A.J.

1979-06-01

Net or large phytoplankton species composition and most phytoplankton abundance was measured at three OTEC sites. In the Gulf of Mexico and Hawaii, diatoms dominated while the blue-green algae Trichodesmium was most common at Puerto Rico. The species ratio of diatoms to dinoflagellates was approximately 1:1. The species diversity varied from site to site, Hawaii > Puerto Rico > Gulf of Mexico. Chlorophyll a, which is a measure of the pigment of all algae size ranges, showed a subsurface peak of 0.14-0.4 g per liter at 75 to 125 m. Occasional surface peaks up to 0.4 pg per liter occurred.more » Further refinement of collection techniques is needed to delineate the subtle environmental effects expected by OTEC plant discharges.« less

Phytoplankton and biomass distribution at potential OTEC sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, P.W.; Horne, A.J.

1979-06-01

Net or large phytoplankton species composition and most phytoplankton abundance was measured at three OTEC sites. In the Gulf of Mexico and'Hawaii, diatoms dominated while the blue-green algae Trichodesmium was most common at Puerto Rico. The species ratio of diatoms to dinoflagellates was approximately 1:1. The species diversity varied from site to site, Hawaii > Puerto Rico > Gulf of Mexico. Chlorophyll a, which is a measure of the pigment of all algae size ranges, showed a subsurface peak of 0.14 to 0.4 g per liter at 75 to 125 m. Occasional surface peaks upto 0.4 ..mu..g per liter occurred.more » Further refinement of collection techniques is needed to delineate the subtle environmental effects expected by OTEC plant discharges.« less

Modeling of energy release systems from OTEC plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denno, K.

1983-12-01

This paper presents analytical scope for the controlling functions of OTEC operation for the ultimate production of sizable bulk ..delta..T as well as H/sub 2/, N/sub 2/ and NH/sub 3/. The controlling parametric functions include the oceanic and ammonia Reynolds numbers which depend implicitly and explicitly on the ocean water velocity, mass-volume, duration of ..delta..T extraction, and the inlet and outlet water temperatures internally and externally. Solutions for the oceanic and amonia Reynolds numbers have been established setting the deciding constraints on water velocity, boundary temperatures, mass-volume as well as other plant parameters. Linkage between OTEC plant and other conventionalmore » as well as advanced energy systems has been expressed in terms of a set of balance and coordinating energy equations.« less

NAVFAC Ocean Thermal Energy Conversion (OTEC) Project; OTEC System Design Report

DTIC Science & Technology

2010-11-16

191 Figure 3-129. Web illustration of a magnetically coupled pump ...............................................192 Figure 3-130...utility air at a suitable water dew point. Two 100% capacity rotary screw compressors, dryer and receiver shall be installed to serve process and...remora centerline, with positive TCG out of the paper and negative TCG into the paper . The CG of the remora in its vertical orientation is

OTEC riser cable system, Phase II: conceptual design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1980-10-01

Studies are summarized of conceptual designs of riser cable systems for OTEC pilot plants of both the spar and plantship configurations located at sites off the southeast coast of Puerto Rico. The studies utilize a baseline pilot plant riser cable, the design of which has been developed and reported on in other reports. Baseline riser cable systems for OTEC pilot plants are identified, system hardware consistent with these designs are conceptualized, and comparisons of the various system concepts are provided. It is concluded that there are three riser cable systems feasible for a spar pilot plant platform at the Puntamore » Yeguas site, and two riser cable systems feasible at the plantship pilot plant at the Punta Tuna site. Recommendations for further investigations in the areas of materials, hardware design and pre-installation site surveys are also addressed.« less

Conceptual design study: Cold water pipe systems for self-mounted OTEC powerplants

NASA Astrophysics Data System (ADS)

1981-02-01

The conceptual design and installation aspects of cold water pipes (CWP) systems for shelf mounted OTEC power plants in Puerto Rico and Hawaii are considered. The CWP systems using Fiberglass Reinforced Plastic (FRP) and steel were designed; the FRP, can be controlled by varying the core thickness; and steel is used as a structural material in offshore applications. A marine railway approach was chosen for installation of the CWP. Two methods for pulling the track for the railway down the pipe fairway to its final location are presented. The track is permanently fastened to the sloping seabed with piles installed by a remotely controlled cart that rides on the track itself. Both the marine railway and the shelf mounted platform that houses the OTEC power plant require an anodic or equivalent corrosion protection system.

Open-cycle systems performance analysis programming guide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olson, D.A.

1981-12-01

The Open-Cycle OTEC Systems Performance Analysis Program is an algorithm programmed on SERI's CDC Cyber 170/720 computer to predict the performance of a Claude-cycle, open-cycle OTEC plant. The algorithm models the Claude-cycle system as consisting of an evaporator, a turbine, a condenser, deaerators, a condenser gas exhaust, a cold water pipe and cold and warm seawater pumps. Each component is a separate subroutine in the main program. A description is given of how to write Fortran subroutines to fit into the main program for the components of the OTEC plant. An explanation is provided of how to use the algorithm.more » The main program and existing component subroutines are described. Appropriate common blocks and input and output variables are listed. Preprogrammed thermodynamic property functions for steam, fresh water, and seawater are described.« less

Technical Support and Documentation Management for 25 Ton All Terrain Crane (ATEC).

DTIC Science & Technology

1991-03-11

Rationale Report * Market Investigation and Supplement " Technical Feasibility Test Having considered material contained in the above documents and...Operational issues will be evaluated by OTEC as observers to the qualification testing . A logistics demonstration will be conducted in parallel with PPQT...Organizational OSHA Occupational Safety and Health Administration D-1 APPENDIX D - LIST OF ACRONYMNS (Continued) OTEC Operational Test and Evaluation Command OTP

Impact of novel energy sources: OTEC, wind, goethermal, biomass

NASA Technical Reports Server (NTRS)

Roberts, A. S., Jr.

1978-01-01

Alternate energy conversion methods such as ocean thermal energy conversion (OTEC), wind power, geothermal wells and biomass conversion are being explored, and re-examined in some cases, for commercial viability. At a time when United States fossil fuel and uranium resources are found to be insufficient to supply national needs into the twenty-first century, it is essential to broaden the base of feasible energy conversion technologies. The motivations for development of these four alternative energy forms are established. Primary technical aspects of OTEC, wind, geothermal and biomass energy conversion systems are described along with a discussion of relative advantages and disadvantages of the concepts. Finally, the sentiment is voiced that each of the four systems should be developed to the prototype stage and employed in the region of the country and in the sector of economy which is complimentary to the form of system output.

OTEC cold water pipe design for problems caused by vortex-excited oscillations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffin, O. M.

1980-03-14

Vortex-excited oscillations of marine structures result in reduced fatigue life, large hydrodynamic forces and induced stresses, and sometimes lead to structural damage and to diestructive failures. The cold water pipe of an OTEC plant is nominally a bluff, flexible cylinder with a large aspect ratio (L/D = length/diameter), and is likely to be susceptible to resonant vortex-excited oscillations. The objective of this report is to survey recent results pertaining to the vortex-excited oscillations of structures in general and to consider the application of these findings to the design of the OTEC cold water pipe. Practical design calculations are given asmore » examples throughout the various sections of the report. This report is limited in scope to the problems of vortex shedding from bluff, flexible structures in steady currents and the resulting vortex-excited oscillations. The effects of flow non-uniformities, surface roughness of the cylinder, and inclination to the incident flow are considered in addition to the case of a smooth cyliner in a uniform stream. Emphasis is placed upon design procedures, hydrodynamic coefficients applicable in practice, and the specification of structural response parameters relevant to the OTEC cold water pipe. There are important problems associated with in shedding of vortices from cylinders in waves and from the combined action of waves and currents, but these complex fluid/structure interactions are not considered in this report.« less

NAVFAC Ocean Thermal Energy Conversion (OTEC) Project; OTEC Technology Development Report

DTIC Science & Technology

2010-11-01

platform and CWP. It was a goal of this program to find a material that is high in abrasion resistance and low in friction for the guide layers. Figure...preferred material was a high density urethane. Urethane has very high abrasion resistance – it is often used for marine buoys, fenders, and coatings...design thread in the document. The following is a list of the top level sections in the report. EXECUTIVE SUMMARY  1  1.  INTRODUCTION  2  2

Flow-Induced Oscillations of OTEC Mooring and Anchoring Cables: State of the Art.

DTIC Science & Technology

1982-05-27

general, including heat exchangers , overhead transmission lines, and marine structures and cables. A flowchart that describes the steps necessary to...34Crossflow-Induced Vibrations of Heat Exchanger Tube Banks," Nuc. Engrg. and Design, Vol. 47, 67-86, 1978. 22. O.M. Griffin and S.E. Ramberg, "On...AD-AIlS 462 NAVAL RESEARCH LAB WASHINGTON DC F/6 13/13 FLOW-INOUCED OSCILLATIONS OF OTEC MOORING AND ANCHORING CABLES --ETC(UI MAY 62 0 M GRIFFIN

Heat Exchanger Cleaning in Support of Ocean Thermal Energy Conversion (OTEC) - Electronics Subsystems.

DTIC Science & Technology

1980-12-01

exchangers . The performance of heat exchangers will therefore decide the ultimate success or failure of OTEC . BACKGROUND Hardware development in support...8217AD-AG9 216 NAVAL COASTAL SYSTEMS CENTER PANAMA CITY FL F/S 13/10 HEAT EXCHANGER CLEANING IN SUPPORT OF OCEAN THERMAL ENERGY CONV"-ETC(U) DEC 80 D F...block minI ber) Heat Exchangers Chlorination Cleaning Electronics Thermal Energy Conversion 2%AISTRACT (Centhmes en; rewwe ide it neseer end iftefb Op

Ecological analysis of spatial and temporal patterns of pelagic ecosystem components potentially interacting with an OTEC (Ocean Thermal Energy Conversion) plant near Punta Tuna, Puerto Rico: physical characteristics. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez, J.M.; Tilly, L.J.

1983-01-01

This hydrographic study characterizes the Punta Tuna area as a potential site for an OTEC power plant. Seven cruises were conducted at approximately two month intervals. Each cruise included at least 22 hydrocast stations, six done as serial stations in a small area to reveal temporal and small scale variability. The results of the analysis of these data so far indicate a bi-seasonality in the dynamics. Mesoscale eddies and meanders are a common feature of the circulation pattern on Puerto Rico's southern coast. The time series studies have shown their existence of a very energetic internal wave field with relativelymore » large amplitude waves at the diurnal and semi-diurnal tidal frequencies. The results in terms of an OTEC power plant indicate the thermal resource to be at least a 20C thermal gradient in the upper 100 m year round.« less

Environmental programs for ocean thermal energy conversion (OTEC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilde, P.

1981-07-01

The environmental research effort in support of the US Department of Energy's Ocean Thermal Energy Conversion (OTEC) program has the goal of providing documented information on the effect of proposed operations on the ocean and the effect of oceanic conditions on the plant. The associated environment program consists of archival studies in potential areas serial oceanographic cruises to sites or regions of interest, studies from various fixed platforms at sites, and compilation of such information for appropriate legal compliance and permit requirements and for use in progressive design of OTEC plants. Site/regions investigated are south of Mobile and west ofmore » Tampa, Gulf of Mexico; Punta Tuna, Puerto Rico; St. Croix, Virgin Islands; Kahe Point, Oahu and Keahole Point, Hawaii, Hawaiian Islands; and off the Brazilian south Equatorial Coast. Four classes of environmental concerns identified are: redistribution of oceanic properties (ocean water mixing, impingement/entrainment etc.); chemical pollution (biocides, working fluid leaks, etc.); structural effects (artificial reef, aggregation, nesting/migration, etc.); socio-legal-economic (worker safety, enviromaritime law, etc.).« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolff, W. A.

The thermal resource off the Ivory Coast is quite good for OTEC purposes. There are consistently large ..delta..T (surface temperature--temperature at depth) values throughout the year. The mean ..delta..T at 1000 meters is approximately 22/sup 0/C. A mean annual ..delta..T of 20/sup 0/C can be reached at a depth of only 600 meters. The thermal resource for the coldest month of the year is also adequate at 600 meters. Water 1000 meters deep is available within 35 kilometers from the shore. The waters south of the Ivory Coast do not have a particularly good mixed layer depth. Strong winds andmore » tropical storms are a rare occurrence. Similarly, the sea and swell conditions do not present a problem for OTEC development in this area. Currents are generally moderate, although occasional periods of weak currents less than 1/4 knot can be expected. The consistently large thermal resource without major environmental problems recommends this location as a potential OTEC site.« less

Preliminary design report for OTEC stationkeeping subsystems (SKSS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-12-12

Lockheed Ocean Systems with IMODCO prepared these preliminary designs for OTEC Stationkeeping Subsystems (SKSS) under contract to NOAA in support of the Department of Energy OTEC program. The results of Tasks III, V, and VI are presented in this design report. The report consists of five sections: introduction, preliminary designs for the multiple anchor leg (MAL) and tension anchor leg (TAL), costs and schedule, and conclusions. Extensive appendixes provide detailed descriptions of design methodology and include backup calculations and data to support the results presented. The objective of this effort is to complete the preliminary designs for the barge-MAL andmore » Spar-TAL SKSS. A set of drawings is provided for each which show arrangements, configuration, component details, engineering description, and deployment plan. Loads analysis, performance assessment, and sensitivity to requirements are presented, together with the methodology employed to analyze the systems and to derive the results presented. Life cycle costs and schedule are prepared and compared on a common basis. Finally, recommendations for the Commercial Plant SKSS are presented for both platform types.« less

Technology development plan: Geotechnical survey systems for OTEC (Ocean Thermal Energy Conversion) cold water pipes

NASA Astrophysics Data System (ADS)

Valent, Philip J.; Riggins, Michael

1989-04-01

An overview is given of current and developing technologies and techniques for performing geotechnical investigations for siting and designing Cold Water Pipes (CWP) for shelf-resting Ocean Thermal Energy Conversion (OTEC) power plants. The geotechnical in situ tools used to measure the required parameters and the equipment/systems used to deploy these tools are identified. The capabilities of these geotechnical tools and deployment systems are compared to the data requirements for the CWP foundation/anchor design, and shortfalls are identified. For the last phase of geotechnical data gathering for design, a drillship will be required to perform soil boring work, to obtain required high quality sediment samples for laboratory dynamic testing, and to perform deep penetration in situ tests. To remedy shortfalls and to reduce the future OTEC CWP geotechnical survey costs, it is recommended that a seafloor resting machine be developed to advance the friction cone penetrometer, and also probably a pressuremeter, to provide geotechnical parameters to shallow subseafloor penetrations on slopes of 35 deg and in water depths to 1300 m.

Ecology of Hawaiian marine mammals emphasizing the impact of Ocean Thermal Energy Conversion (OTEC) on endangered species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Payne, S.F.; Hartwig, E.O.

1982-06-01

Twenty-two marine mammal species including 2 baleen whales, 20 toothed whales, and one pinniped occur in Hawaiian waters. Among these are two endangered species, the migratory humpback whale (Megaptera novaengliae) around the main islands, and the non-migratory Hawaiian monk seal (Monachus schauinslandi) in the extreme northwestern island chain. The endangered species are among those most commonly sighted, while spinner dolphins (Stenella spp.), bottle-nosed dolphins (Tursiops sp.), and false killer whales (Pseudorca crassidens) are sighted less frequently. Most Hawaiian cetacean species are Odontoceti, or toothed whales, and feed on fish and squid. The Mysteceti or baleen whales feed on plankton, howevermore » the endangered humpback whale, which migrates to Hawaii to breed and calve, presumably does not feed there. The endangered monk seal feeds on cephalopods and fish. The impact of OTEC on endangered and non-endangered marine mammals results from several direct and indirect effects and is discussed in the text. Careful siting of OTEC plants away from humpback breeding areas and monk seal breeding and feeding areas will avoid adverse effects on these populations.« less

Studies on toxicity of OTEC plant components on marine animals from the Gulf of Mexico. Final report, September 1, 1978-November 30, 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Venkataramiah, A.; Lakshmi, G.J.; Best, C.

1981-06-01

Ammonia and chlorine were chosen for toxicity studies as they pose the greatest potential environmental threat. Acute and chronic bioassays determined the LT/sub 50/, LC/sub 50/ and the behavior of mullet (Mugil cephalus), sargassum shrimp (Latreutes focorum) and filefish (Monocanthus hispidus). The chronic bioassays were carried out mainly in sublethal concentrations of ammonia and chlorine. The findings indicate that high concentrations of ammonia and chlorine from the OTEC plants are toxic to marine animals. Also the level of toxicity is related to the species, their habitats and life stages.

OTEC to hydrogen fuel cells - A solar energy breakthrough

NASA Astrophysics Data System (ADS)

Roney, J. R.

Recent advances in fuel cell technology and development are discussed, which will enhance the Ocean Thermal Energy Conversion (OTEC)-hydrogen-fuel cell mode of energy utilization. Hydrogen obtained from the ocean solar thermal resources can either be liquified or converted to ammonia, thus providing a convenient mode of transport, similar to that of liquid petroleum. The hydrogen fuel cell can convert hydrogen to electric power at a wide range of scale, feeding either centralized or distributed systems. Although this system of hydrogen energy production and delivery has been examined with respect to the U.S.A., the international market, and especially developing countries, may represent the greatest opportunity for these future generating units.

Physical oceanographic data from the OTEC Punta Tuna, Puerto Rico Site, September 1979-June 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frye, D.; Davison, A.; Leavitt, K.

1981-01-01

The first results of an oceanographic measurement program being conducted off the southeast corner of Puerto Rico are presented. The study site is a proposed OTEC site and is located about 20 km off Punta Tuna. The objectives of the measurement program are to document the physical oceanography of the site as related to the engineering and environmental factors involved in OTEC design and operation. Oceanographic measurements include: (1) a subsurface mooring instrumented with five current, temperature, and pressure recorders; and (2) quarterly hydrographic cruises to measure salinity, temperature, and depth profiles on a grid of 33 stations in themore » vicinity of the mooring site. The first cruise, conducted between 16 and 21 June 1980, included the initial mooring deployment and a CTD (conductivity, temperature, and depth) and XBT (expendable bathythermograph) survey. The CTD/XBT measurements are presented. Also included are results of in situ current, temperature, and pressure measurements made during two previous programs. In September 1979, Coastal Marine Research (CMR) deployed a mooring at approximately the same site as the present mooring. Results from three of these instruments are included. The Naval Underwater Systems Center deployed a mooring at this site in February 1979 and partial results from one instrument on this mooring are also presented. (WHK)« less

The effect of biofouling in simulated Ocean Thermal Energy Conversion (OTEC) evaporator tubes at a potential site in Puerto Rico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasscer, D.S.; Morgan, T.O.; Tosteson, T.R.

1980-12-01

Since 29 January 1980, continuous flow of ocean surface water has been maintained through simulated Ocean Thermal Energy Conversion (OTEC) evaporator tubes in order to determine in situ, long-term effects of microbiofouling on heat exchanger efficiency. The experimental apparatus consists of two aluminum and two titanium modules mounted on a research platform moored at the potential OTEC site off Punta Tuna, Puerto Rico. The fouling resistance (R /SUB f/ ), a relative measure of heat transfer efficiency, is being monitored regularly, and the units have been cleaned four times. Postcleaning fouling rates (dR /SUB f/ /dt) for the aluminum unitsmore » have not changed significantly but are considerably higher than the initial fouling rates. At first, post-cleaning fouling rates for the titanium units were less than for the aluminum units, but this value has been progressively increasing and now all units are fouling at approximately the same rate. Cleaning with manually operated M.A.N. brushes did not reduce R /SUB f/ to zero. On four occasions, flow velocity through the units has been increased. Results from these experiments suggest that initially the fouling layer is easily dislodged from the tube surface but that, with time, it becomes more firmly attached.« less

Draft environmental assessment: Ocean Thermal Energy Conversion (OTEC) Pilot Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, S.M.; Sands, M.D.; Donat, J.R.

This Environmental Assessment (EA) has been prepared, in accordance with the National Environmental Policy Act of 1969, for the deployment and operation of a commercial 40-Megawatt (MW) Ocean Thermal Energy Conversion (OTEC) Pilot Plant (hereafter called the Pilot Plant). A description of the proposed action is presented, and a generic environment typical of the candidate Pilot Plant siting regions is described. An assessment of the potential environmental impacts associated with the proposed action is given, and the risk of credible accidents and mitigating measures to reduce these risks are considered. The Federal and State plans and policies the proposed actionmore » will encompass are described. Alternatives to the proposed action are presented. Appendix A presents the navigation and environmental information contained in the US Coast Pilot for each of the candidate sites; Appendix B provides a brief description of the methods and calculations used in the EA. It is concluded that environmental disturbances associated with Pilot Plant activities could potentially cause significant environmental impacts; however, the magnitude of these potential impacts cannot presently be assessed, due to insufficient engineering and environmental information. A site- and design-specific OTEC Pilot Plant Environmental Impact Statement (EIS) is required to resolve the potentially significant environmental effects associated with Pilot Plant deployment and operation. (WHK)« less

Uncertainty analysis routine for the Ocean Thermal Energy Conversion (OTEC) biofouling measurement device and data reduction procedure. [HTCOEF code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bird, S.P.

1978-03-01

Biofouling and corrosion of heat exchanger surfaces in Ocean Thermal Energy Conversion (OTEC) systems may be controlling factors in the potential success of the OTEC concept. Very little is known about the nature and behavior of marine fouling films at sites potentially suitable for OTEC power plants. To facilitate the acquisition of needed data, a biofouling measurement device developed by Professor J. G. Fetkovich and his associates at Carnegie-Mellon University (CMU) has been mass produced for use by several organizations in experiments at a variety of ocean sites. The CMU device is designed to detect small changes in thermal resistancemore » associated with the formation of marine microfouling films. An account of the work performed at the Pacific Northwest Laboratory (PNL) to develop a computerized uncertainty analysis for estimating experimental uncertainties of results obtained with the CMU biofouling measurement device and data reduction scheme is presented. The analysis program was written as a subroutine to the CMU data reduction code and provides an alternative to the CMU procedure for estimating experimental errors. The PNL code was used to analyze sample data sets taken at Keahole Point, Hawaii; St. Croix, the Virgin Islands; and at a site in the Gulf of Mexico. The uncertainties of the experimental results were found to vary considerably with the conditions under which the data were taken. For example, uncertainties of fouling factors (where fouling factor is defined as the thermal resistance of the biofouling layer) estimated from data taken on a submerged buoy at Keahole Point, Hawaii were found to be consistently within 0.00006 hr-ft/sup 2/-/sup 0/F/Btu, while corresponding values for data taken on a tugboat in the Gulf of Mexico ranged up to 0.0010 hr-ft/sup 2/-/sup 0/F/Btu. Reasons for these differences are discussed.« less

Modeling the Physical and Biochemical Influence of Ocean Thermal Energy Conversion Plant Discharges into their Adjacent Waters

DOE Office of Scientific and Technical Information (OSTI.GOV)

PAT GRANDELLI, P.E.; GREG ROCHELEAU; JOHN HAMRICK, Ph.D.

This paper describes the modeling work by Makai Ocean Engineering, Inc. to simulate the biochemical effects of of the nutrient-enhanced seawater plumes that are discharged by one or several 100 megawatt OTEC plants. The modeling is needed to properly design OTEC plants that can operate sustainably with acceptably low biological impact. In order to quantify the effect of discharge configuration and phytoplankton response, Makai Ocean Engineering implemented a biological and physical model for the waters surrounding O`ahu, Hawai`i, using the EPA-approved Environmental Fluid Dynamics Code (EFDC). Each EFDC grid cell was approximately 1 square kilometer by 20 meters deep, andmore » used a time step of three hours. The biological model was set up to simulate the biochemical response for three classes of organisms: Picoplankton (< 2 um) such as prochlorococccus, nanoplankton (2-20 um), and microplankton (> 20 um) e.g., diatoms. The dynamic biological phytoplankton model was calibrated using chemical and biological data collected for the Hawaii Ocean Time Series (HOTS) project. Peer review of the biological modeling was performed. The physical oceanography model uses boundary conditions from a surrounding Hawai'i Regional Ocean Model, (ROM) operated by the University of Hawai`i and the National Atmospheric and Oceanic Administration. The ROM provided tides, basin scale circulation, mesoscale variability, and atmospheric forcing into the edges of the EFDC computational domain. This model is the most accurate and sophisticated Hawai'ian Regional Ocean Model presently available, assimilating real-time oceanographic observations, as well as model calibration based upon temperature, current and salinity data collected during 2010 near the simulated OTEC site. The ROM program manager peer-reviewed Makai's implementation of the ROM output into our EFDC model. The supporting oceanographic data was collected for a Naval Facilities Engineering Command / Makai project. Results: The model was run for a 100 MW OTEC Plant consisting of four separate ducts, discharging a total combined flow rate of 420 m3/s of warm water and 320 m3/s of cold water in a mixed discharge at 70 meters deep. Each duct was assumed to have a discharge port diameter of 10.5m producing a downward discharge velocity of about 2.18 m/s. The natural system, as measured in the HOTS program, has an average concentration of 10-15 mgC/m3. To calibrate the biological model, we first ran the model with no OTEC plant and varied biological parameters until the simulated data was a good match to the HOTS observations. This modeling showed that phytoplankton concentration were patchy and highly dynamic. The patchiness was a good match with the data variability observed within the HOTS data sets. We then ran the model with simulated OTEC intake and discharge flows and associated nutrients. Directly under the OTEC plant, the near-field plume has an average terminal depth of 172 meters, with a volumetric dilution of 13:1. The average terminal plume temperature was 19.8oC. Nitrate concentrations are 1 to 2 umol/kg above ambient. The advecting plume then further dilutes to less than 1 umol/kg above ambient within a few kilometers downstream, while remaining at depth. Because this terminal near-field plume is well below the 1% light limited depths (~120m), no immediate biological utilization of the nutrients occurs. As the nitrate is advected and dispersed downstream, a fraction of the deep ocean nutrients (< 0.5 umol/kg perturbation) mix upward where they are utilized by the ambient phytoplankton population. This occurs approximately twenty-five kilometers downstream from the plant at 110 - 70 meters depth. For pico-phytoplankton, modeling results indicate that this nutrient perturbation causes a phytoplankton perturbation of approximately 1 mgC/m3 (~10% of average ambient concentrations) that covers an area 10x5 km in size at the 70 to 90m depth. Thus, the perturbations are well within the natural variability of the system, generally corresponding to a 10 to 15% increase above the average pico-phytoplankton biomass. This perturbation exhibits a meandering horizontal plume trajectory and spatial extent, but remains similar in magnitude (generally 1-2 mgC/m3). The diatom perturbations become more noticeable after three weeks of the simulation period, when the nearshore diatom population trends towards a greater concentration of 1 to 3 mgC/m3 . Relative to the background concentrations, this increased response is a fraction of the ambient, with perturbations remaining within fluctuations of the existing system. The perturbations were quantified by post-processing each time-step of model simulations without OTEC plants, with identical simulations that included OTEC plumes. Without this post processing, the 10-25% perturbations were obscured by the larger dynamic variations naturally caused by ocean circulation.« less

IECEC '83; Proceedings of the Eighteenth Intersociety Energy Conversion Engineering Conference, Orlando, FL, August 21-26, 1983. Volume 1 - Thermal energy systems

NASA Astrophysics Data System (ADS)

Among the topics discussed are the nuclear fuel cycle, advanced nuclear reactor designs, developments in central status power reactors, space nuclear reactors, magnetohydrodynamic devices, thermionic devices, thermoelectric devices, geothermal systems, solar thermal energy conversion systems, ocean thermal energy conversion (OTEC) developments, and advanced energy conversion concepts. Among the specific questions covered under these topic headings are a design concept for an advanced light water breeder reactor, energy conversion in MW-sized space power systems, directionally solidified cermet electrodes for thermionic energy converters, boron-based high temperature thermoelectric materials, geothermal energy commercialization, solar Stirling cycle power conversion, and OTEC production of methanol. For individual items see A84-30027 to A84-30055

NEOTEC: Negative-CO2-Emissions Marine Energy With Direct Mitigation of Global Warming, Sea-Level Rise and Ocean Acidification

NASA Astrophysics Data System (ADS)

Rau, G. H.; Baird, J.; Noland, G.

2016-12-01

The vertical thermal energy potential in the ocean is a massive renewable energy resource that is growing due to anthropogenic warming of the surface and near-surface ocean. The conversion of this thermal energy to useful forms via Ocean Thermal Energy Conversion (OTEC) has been demonstrated over the past century, albeit at small scales. Because OTEC removes heat from the surface ocean, this could help directly counter ongoing, deleterious ocean/atmosphere warming. The only other climate intervention that could do this is solar radiation "geoengineering". Conventional OTEC requires energy intensive, vertical movement of seawater resulting in ocean and atmospheric chemistry alteration, but this can be avoided via more energy efficient, vertical closed-cycle heating and cooling of working fluid like CO2 or NH3. An energy carrier such as H2 is required to transport energy optimally extracted far offshore, and methods of electrochemically generating H2 while also consuming CO2 and converting it to ocean alkalinity have been demonstrated. The addition of such alkalinity to the ocean would provide vast, stable, carbon storage, while also helping chemically counter the effects of ocean acidification. The process might currently be profitable given the >$100/tonne CO2 credit offered by California's Low Carbon Fuel Standard for transportation fuels like H2. Negative-Emissions OTEC, NEOTEC, thus can potentially provide constant, cost effective, high capacity, negative-emissions energy while: a) reducing surface ocean heat load, b) reducing thermal ocean expansion and sea-level rise, c) utilizing a very large, natural marine carbon storage reservoir, and d) helping mitigate ocean acidification. The technology also avoids the biophysical and land use limitations posed by negative emissions methods that rely on terrestrial biology, such as afforestation and BECCS. NEOTEC and other marine-based, renewable energy and CO2 removal approaches could therefore greatly increase the likelihood of satisfying growing global energy demand while helping to stabilize or reduce atmospheric CO2 and its impacts. Policies supporting the search and evaluation of renewable energy and negative emissions options beyond biotic- and land-based methods are needed.

Current-wave spectra coupling project. Volume I. Hurricane fields and cross sections, surface winds and currents, significant waves and wave spectra for potential OTEC sites: (A) Keahole Point, Hawaii, 100 year hurricane; (B) Punta Tuna, Puerto Rico, 100 year hurricane; (C) New Orleans, Louisiana, 100 year hurricane; (D) West Coast of Florida, 100 year hurricane; and for (E) Hurricane Camille (1969) off Louisiana Coast

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bretschneider, C.L.

1980-06-01

This volume is an extension of and consists of several modifications to the earlier report by Bretschneider (April 1979) on the subject of hurricane design wind, wave and current criteria for the four potential OTEC sites. The 100-year hurricane criteria for the design of OTEC plants is included. The criteria, in addition to the maximum conditions of winds, waves and surface current, include: hurricane fields for wind speed U/sub s/ and significant wave height H/sub s/; hurricane fields for modal wave period f/sub 0//sup -1/ and maximum energy density S/sub max/ of the wave spectrum; the corresponding Ekman wind-driven surfacemore » current V/sub s/; tabulated cross-sections for U/sub s/, H/sub s/, f/sub 0//sup -1/ and S/sub max/ through max U/sub s/ and through max H/sub s/ along traverses at right angles to and along traverses parallel to the forward movement of the hurricane; most probable maximum wave height and the expected corresponding wave period, based on statistical analysis of maximum wave heights from five hurricanes; design wave spectra for maximum U/sub s/ and also maximum H/sub s/, since maximum U/sub s/ and maximum H/sub s/ do not occur simultaneously; the envelope of wave spectra through maximum U/sub s/ and through maximum H/sub s/ along traverses parallel to the forward movement of the hurricane; the above same determinations for Hurricane Camille (1969) as for the four OTEC locations; and alternative methods (suggested) for obtaining design wave spectra from the joint probability distribution functions for wave height and period given by Longuet-Higgins (1975) and C.N.E.X.O. after Arhan, et al (1976).« less

Performance of OTEC Heat Exchanger Materials in Tropical Seawaters

NASA Astrophysics Data System (ADS)

Larsen-Basse, Jorn

1985-03-01

The corrosion of several aluminum alloys in flowing Hawaiian surface seawater and water from 600 m depth for exposure periods up to three years has been studied. The alloys tested in cold water were Alclad (7072) 3003 and 3004; and bare 3004 and 5052). All show some pitting. Pit growth is slow, and pits do not penetrate the cladding. In the warm water, only uniform corrosion has been found. All alloys corrode at the same, low rate of˜3 μm/year after an initial short period of more rapid corrosion. This behavior is closely linked to the formation of a protective inorganic scale film on the surface. It consists of precipitated scale minerals from the seawater and aluminum corrosion products. The results indicate that OTEC evaporator heat exchangers constructed of aluminum alloys should have acceptable service lives.

OTEC platform configuration and integration study. Volume I. Systems engineering and integration. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1978-04-01

The economic success of an Ocean Thermal Energy Conversion (OTEC) system is highly dependent on a platform which provides adequate support for the power system, accommodates reliably the cold water pipe, and is most cost effective. The results of a study conducted for the Department of Energy to assess six generic types of platforms to determine the most satisfactory platform for severl potential sites are presented. The six platform configurations are ship, circular barge, semi-submersible, Tuned Sphere, submersible, and spar. These represent directional and symmetric types of platforms which operate on the surface, at the interface, and submerged. The fivemore » sites for this study were primarily New Orleans, Keahole Point (Hawaii), Brazil, and secondarily Key West and Puerto Rico. Electrical transmission of energy by submarine cable is the planned form of energy transmission for all sites except Brazil, where chemical conversion is to be the method of transmission. This study is devoted to the platform (or ocean systems) of the OTEC plant which is chiefly comprised of the hull and structure, the seawater system, the position control system, and miscellaneous support/assembly systems. The principal elements in the work breakdown structure for the commercial plants are presented. The assessment of the six platform configurations was conducted utilizing a baseline plan (100-MW(e) (Net)) and site (New Orleans) with variations from the baseline to cover the range of interested platforms and sites.« less

Ocean Thermal Energy.

ERIC Educational Resources Information Center

Berkovsky, Boris

1987-01-01

Describes Ocean Thermal Energy Conservation (OTEC) as a method for exploiting the temperature difference between warm surface waters of the sea and its cold depths. Argues for full-scale demonstrations of the technique for producing energy for coastal regions. (TW)

Open-cycle OTEC system performance analysis. [Claude cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewandowski, A.A.; Olson, D.A.; Johnson, D.H.

1980-10-01

An algorithm developed to calculate the performance of Claude-Cycle ocean thermal energy conversion (OTEC) systems is described. The algorithm treats each component of the system separately and then interfaces them to form a complete system, allowing a component to be changed without changing the rest of the algorithm. Two components that are subject to change are the evaporator and condenser. For this study we developed mathematical models of a channel-flow evaporator and both a horizontal jet and spray director contact condenser. The algorithm was then programmed to run on SERI's CDC 7600 computer and used to calculate the effect onmore » performance of deaerating the warm and cold water streams before entering the evaporator and condenser, respectively. This study indicates that there is no advantage to removing air from these streams compared with removing the air from the condenser.« less

OTEC gas desorption studies

NASA Astrophysics Data System (ADS)

Chen, F. C.; Golshani, A.

1982-02-01

Experiments on deaeration in packed columns and barometric intake systems, and with hydraulic air compression for open-cycle OTEC systems are reported. A gas desorption test loop consisting of water storage tanks, a vacuum system, a liquid recirculating system, an air supply, a column test section, and two barometric leg test sections was used to perform the tests. The aerated water was directed through columns filled with either ceramic Raschig rings or plastic pall rings, and the system vacuum pressure, which drives the deaeration process, was found to be dependent on water velocity and intake pipe height. The addition of a barometric intake pipe increased the deaeration effect 10%, and further tests were run with lengths of PVC pipe as potential means for noncondensibles disposal through hydraulic air compression. Using the kinetic energy from the effluent flow to condense steam in the noncondensible stream improved the system efficiency.

Sea thermal power; A survey study for the Arab coastal waters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdell-AAL, H.K.; Khan, M.M.

1990-01-01

One of the promising types of renewable energy resource that has potential applications in the Arab world is proposed and described in this article. Known as ocean thermal energy conversion (OTEC), its feasibility is investigated for the Red Sea and the Arabian Gulf/Gulf of Oman. Data on thermal gradients are surveyed, collected, and reported. Promising parameters have been identified for some specific locations along these coastal waters. The proposed system can serve the dual purpose of providing electric power and desalinated water, which is needed by the Arab world. Construction strategies for the OTEC systems are introduced. Building plant-ship formore » utilizing the generated power in the production of hydrogen is recommended. Thus energy could be transported as LH{sub 2} (liquid hydrogen), MeOH (methanol), or NH{sub 3} (ammonia) for end-use consumption or export.« less

Solar Sea Power

ERIC Educational Resources Information Center

Zener, Clarence

1976-01-01

In their preoccupation with highly complex new energy systems, scientists and statesmen may be overlooking the possibilities of Ocean Thermal Energy Conversion (OTEC). That is the view of a Carnegie-Mellon University physicist who is in the forefront of solar sea power investigation. (Author/BT)

The role of business incentives in the development of renewable energy technologies

NASA Astrophysics Data System (ADS)

A 15% business energy tax credit for renewable energy systems is examined. Witnesses from photovoltaics, solar thermal, wind, and OTEC industries testified about the importance of the credits to their ability to develop and demonstrate new technologies.

Improved OTEC System for a Submarine Robot

NASA Technical Reports Server (NTRS)

Chao, Yi; Jones, Jack; Valdez, Thomas

2010-01-01

An ocean thermal energy conversion (OTEC), now undergoing development, is a less-massive, more-efficient means of exploiting the same basic principle as that of the proposed system described in "Alternative OTEC Scheme for a Submarine Robot" (NPO-43500), NASA Tech Briefs, Vol. 33, No. 1 (January 2009), page 50. The proposed system as described previously would be based on the thawing-expansion/freezing-contraction behavior of a wax or perhaps another suitable phase-change material (PCM). The power generated by the system would be used to recharge the batteries in a battery- powered unmanned underwater vehicle [UUV (essentially, a small exploratory submarine robot)] of a type that has been deployed in large numbers in research pertaining to global warming. A UUV of this type travels between the ocean surface and depths, measuring temperature and salinity. At one phase of its operational cycle, the previously proposed system would utilize the surface ocean temperature (which lies between 15 and 30 C over most of the Earth) to melt a PCM that has a melting/freezing temperature of about 10 C. At the opposite phase of its operational cycle, the system would utilize the lower ocean temperature at depth (e.g., between 4 and 7 C at a depth of 300 m) to freeze the PCM. The melting or freezing would cause the PCM to expand or contract, respectively, by about 9 volume percent. The PCM would be contained in tubes that would be capable of expanding and contracting with the PCM. The PCM-containing tubes would be immersed in a hydraulic fluid. The expansion and contraction would drive a flow of the hydraulic fluid against a piston that, in turn, would push a rack-and-pinion gear system to spin a generator to charge a battery.

Design of land-based, foam OTEC plants for bottoming cycles. [Design of waste-heat power plants based on foam OTEC power cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molini, A. E.; Zener, C.; Fort, T. Jr.

1979-01-01

Open cycle OTEC technology suggests new concepts for the embediment of commercially feasible bottoming processes to recover energy from, and simultaneously minimize the environmental impact of, hot industrial effluents. The approach would make pollution abatement more economically attractive, yielding clean, low temperature flue gases while recovering a large portion of their thermal energy as electricity. The technology opens the use of lower quality fuels without fear of air pollution caused by their flue gases. Scrubbing would clean and cool the gases, yielding a hot fluid which after proper treatment would serve as the working fluid for open cycle systems usingmore » ambient air as the heat sink. Preparatory to demonstrating the Foam Energy Recovery Open Cycle System (FEROCS) at a 1 MW - 10 MW scale, a structural design was initiated for a unit 380 ft high visualized as an inverted, vertical, reinforced concrete U tube of 36 ft I.D. and walls 11 in. thick. The structure is feasible based on present construction practices with reinforced concrete in Puerto Rico. It would cost approximately $1.4 MM and consume 3800 yds/sup 3/ of concrete and 860 tons of reinforcing steel. To accelerate the demonstration of FEROCS, it is proposed to utilize artificially created temperature differences that can be readily obtained between industrial thermal effluents, for example flue gases at > 250/sup 0/F from fossil fuel fired steam generating plants, as the heat source and ambient air as the heat sink. Results are presented of a study made conceptualizing the process using different scrubbing-working fluids.« less

State-of-the-art survey of joinability of materials for OTEC heat exchangers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beaver, R. J.

1978-12-01

Literature and industrial sources were surveyed to assess, on the basis of apparent economics and reliability, the joinability of both shell-and-tube and compact ocean thermal energy conversion (OTEC) heat exchangers. A no-leak requirement is mandatory to prevent mixing seawater and the ammonia working fluid. The operating temperature range considered is 7 to 28/sup 0/C (45 to 82/sup 0/F). Materials evaluated were aluminum, titanium, copper--nickel, AL-6X austenitic stainless steel, singly and in combination with steel and concrete. Many types of welding and brazing processes, roller expansion, magnaforming, O-ring sealing, and adhesive bonding were considered. The automatic gas tungsten-arc welding process andmore » explosion welding processes are the only two joining processes that now appear to offer the high reliability required of no-leak shell-and-tube heat exchangers. Of these two processes, the gas tungsten-arc welding process appears to be the more economically attractive.« less

Jim Green | NREL

Science.gov Websites

NWTC. He was the project lead for the design and construction of the NWTC 5.8 MW dynamometer facility completed in 2013. During 2012-2016, Jim was responsible for operations, safety, and engineering assessment of a successful net-power-producing experiment in Hawaii, a fully-functional and grid-connected OTEC

Hydrogen fuel - Universal energy

NASA Astrophysics Data System (ADS)

Prince, A. G.; Burg, J. A.

The technology for the production, storage, transmission, and consumption of hydrogen as a fuel is surveyed, with the physical and chemical properties of hydrogen examined as they affect its use as a fuel. Sources of hydrogen production are described including synthesis from coal or natural gas, biomass conversion, thermochemical decomposition of water, and electrolysis of water, of these only electrolysis is considered economicially and technologically feasible in the near future. Methods of production of the large quantities of electricity required for the electrolysis of sea water are explored: fossil fuels, hydroelectric plants, nuclear fission, solar energy, wind power, geothermal energy, tidal power, wave motion, electrochemical concentration cells, and finally ocean thermal energy conversion (OTEC). The wind power and OTEC are considered in detail as the most feasible approaches. Techniques for transmission (by railcar or pipeline), storage (as liquid in underwater or underground tanks, as granular metal hydride, or as cryogenic liquid), and consumption (in fuel cells in conventional power plants, for home usage, for industrial furnaces, and for cars and aircraft) are analyzed. The safety problems of hydrogen as a universal fuel are discussed, noting that they are no greater than those for conventional fuels.

Conversion system overview assessment. Volume 1: solar thermoelectrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jayadev, T. S.; Henderson, J.; Finegold, J.

1979-08-01

An assessment of thermoelectrics for solar energy conversion is given. There is significant potential for solar thermoelectrics in solar technologies where collector costs are low; e.g., Ocean Thermal Energy Conversion (OTEC) and solar ponds. Reports of two studies by manufacturers assessing the cost of thermoelectric generators in large scale production are included in the appendix and several new concepts thermoelectric systems are presented. (WHK)

Marine mammals of Puerto Rico: a bibliography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Payne, S.F.

1981-08-01

This bibliography is the product of a literature survey on marine mammals at a proposed OTEC site near Punta Tuna, Puerto Rico. Included are reports of mammal sightings and strandings from Puerto Rico and adjacent Caribbean islands, reports containing information on distribution and abundance migration routes, and feeding ecology of those species known from the area. A few works on the general biology of marine mammals are also included. 96 references.

Ocean Thermal Energy Conversion (OTEC) program. FY 1977 program summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1978-01-01

An overview is given of the ongoing research, development, and demonstration efforts. Each of the DOE's Ocean Thermal Energy Conversion projects funded during fiscal year 1977 (October 1, 1976 through September 30, 1977) is described and each project's status as of December 31, 1977 is reflected. These projects are grouped as follows: program support, definition planning, engineering development, engineering test and evaluation, and advanced research and technology. (MHR)

Corrosion and Biofouling of OTEC System Surfaces - Design Factors

DTIC Science & Technology

1978-11-01

condition between different areas on a given member can lead to accelerated attack by a differential envirornment cell . These differences can be...resistance. As shown in Figure 1, -. gal- vanic cell is essentially a battery/load system. When the intermetallic resistance, R1 , or the environmental...members of a couple should be maximized when possible. Also, insulating or high resistance F bushings, etc., can reduce or el4 !.minate galvanic corrosion

Crevice Corrosion Behavior of 45 Molybdenum-Containing Stainless Steels in Seawater.

DTIC Science & Technology

1981-12-01

Armco, Avesta Jernverks, Cabot, Carpenter Technology, Crucible, Eastern, Firth-Brown, Huntington, Jessup, Langley Alloys, and Uddeholm. 16...Department of Energy, Report ANL/OTEC-BCM-022. 7. Wallen, B., and M. Liljas, " Avesta 254 SMO - A New, High Molybdenum Stainless Steel," presented at NKM8...1977).; 11. Wallen, B., " Avesta 254 SMO - A Stainless Steel for Seawater Service," presented at the Advanced Stainless Steels for Turbine Condensors

Further Studies in Filmwise Condensation of Steam on Horizontal Finned Tubes

DTIC Science & Technology

1992-03-01

which to base their design of Ocean Thermal Energy Conversion ( OTEC ) heat exchangers . ANL used two shell-and-tube heat exchangers , with no inserts, for...throughout the duration of this study. xiii~q I. INTRODUCTON A. BACKGROUND A reduction in size and weight of all types of heat exchangers aboard Naval...vessels will allow more efficient use of space. The benefits might include greater equipment accessibility for maintenance or greater heat exchanger

Concept Study for Military Port Design Using Natural Processes.

DTIC Science & Technology

1982-06-15

exchange methods are so good in this ocean heat sink with its diffused materials because it uses its chemicals to attach the ions and then to make acids...H.L., "Saturation State of Calcium Carbonate in Seawater and its Possible Significance for Scale Formation on OTEC Heat Exchanger ," Abstract...Which Harvest Calcium and Magnesium as Structural Materials E. Forming Structures from Silicates After Ion Exchanging , Using Hot and Cold Forming

Surface Energies and Chemical Analysis of the Initial Stages of Marine Microbiological Fouling.

DTIC Science & Technology

1983-06-20

Surfaces in Model Heat Exchange Cells. pp. 67-87. In: Determination of Microfouling Indicies From Materials Exposed to Sub-Tropical Warm Ocean Water...The Nature of Primary Organic Films in the Marine Environment and Their Significance for Ocean Thermal nery Conservation ( OTEC ) Heat Exchanger ...areas were individually performed during a nine month period between August, 1982 and April, 1983. All tests were done with equipment and materials of

Ocean Thermal Conversion (OTEC) Project Bottom Cable Protection Study: Environmental Characteristics and Hazards Analysis,

DTIC Science & Technology

1981-10-01

Chesaneake Division, Naval Facilities Engineering Command, Washington, DC) 34. "Strait of Belle Isle Crossing HVDC Transmission - Submarine Cable...phenomena; such as wind storm generated wave action, bottom currents, bottom mudslides, or seismic activity; as well as human activity, such as...engaging a cable. Ship anchors are used to develop holding power on the seafloor for mooring a floating body permanently or temporary on site. The major

Developments in Science and Technology

DTIC Science & Technology

1979-01-01

Testing of the APL OTEC Heat Exchanger as an Evaporator 74 P. P. Pandolfini, J. L. Keirsey, antd J. A. Funk Geothermal Energy Market Study on the Atlantic...Wozniak I. J. J. Wozniak, Follow- on Study of the Towed Underwater Launch Platforn (TULP) Concept for Trident It Testing, APL/JIIU PM. 8342, Oct 1978... studies . MAGSAT was shipped to Vandenberg AB, REFERENCES California, on 5 October 1979. Field operations coim- 1 51,(,i1 1srujtl.’ tiim. APt Jil L Sl) 114b

Fiber Optic Multimode Development Study.

DTIC Science & Technology

1982-12-01

techniques. These techniques include chemical vapor deposition, ion exchange and diffusion, dip coating, ion implantation, and laser heating . Three...8i63 p NCLASSIFIED F/G 2916 N S .... .... 2. m. i pa 1 1 1. 1111 0i I 11112.0 L4 2,2 MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARSI 963...NUMBER RADC-TR-82 -315 i, /2S- 3 W 4. TITLE (and Subtitle) LTYP OERPRT&P IOnEEFinai oTec hnica ILeportat Jul 80 - Jul 81 FIBER OPTIC MULTIMODE DEVELOPMENT

OTEC biofouling, corrosion, and materials study from a moored platform at Punta Tuna, Puerto Rico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasscer, D.S.; Tosteson, T.R.; Morgan, T.O.

1981-08-01

During the 404 days between 29 January 1980 and 10 March 1981 the Center conducted an uninterrupted biofouling test at Punta Tuna, Puerto Rico, of periodically cleaned, OTEC evaporator tubes. The fouling resistance (R/sub f), total surface carbon and nitrogen content, ATP, and the wet film thickness (WFT) were determined throughout the test. Visual observations of the fouling film were made by light sectioning and scanning microscopy, and at the end of the test, a study was made of the macrofouling of the flow system. The results of thest tests indicate that a base layer of bacteria and exudated polysaccharidesmore » enhance microbial adhesion and thereby create an environment conducive to rapid film growth. Fouling rates (dR/sub f//dt) for aluminum were generally higher than for titanium but they were linear for both materials and did not exceed 0.3(10/sup -4/)ft/sup 2/-h-/sup 0/F/Btu-day for either material during the 13-month study. Excellent correlation was found to exist between R/sub f/ and WFT which supports the hypothesis that it is the stagnant film of water entrapped by bacteria which is largely responsible for the insulating properties of the biofilm. The macrofouling study identified 61 species of benthic invertebrates representing ten phyla growing in those parts of the flow system, where flow was less than 3 fps but no macrofouling where the flow velocity significantly exceeded 3 fps.« less

Biofouling and corrosion studies. Final report, Part I, May 1, 1976-December 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahalingam, L. M.

1978-01-01

Three sets of biofouling experiments were conducted. Two of these sets were done in the Pacific Ocean at Keahole Point, Hawaii, and one was in the Caribbean at St. Croix, Virgin Islands. Data and results from these experiments are presented and discussed. Heat transfer, biological, and metallurgical measurements are presented. A brief account of the data analysis procedures, and an assessment of the hardware performance are given. Recommendations are made to improve the quality of the current efforts in the OTEC Biofouling, Corrosion and Materials program.

Diel distribution of zooplankton at the Mobil OTEC site (29/sup 0/N 88/sup 0/W) in the Northern Gulf of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steen, Jr, J P; Gunter, G; Hartwig, E O

1982-01-01

In the study 128 copepod species and 43 other zooplankton taxa were identified from four depth strata (0 to 50 m, 50 to 100 m, 100 to 300 m and 300 to 500 m). Duplicate step-oblique tows at six hour intervals over 24 hours were taken at a site in the Gulf of Mexico. The distribution of zooplankton numbers and sizes, and species diversity, richness and evenness through a diel period are described.

Proceedings of the Tri-Service Conference on Corrosion (1987) Held at the Air Force Academy, Colorado on 5-7 May 1987.

DTIC Science & Technology

1987-05-01

j, ’er-,t- -- Case Studies of .- ’." Failures", Proceedinqs, 198O Tri-Ser vice Conference on Corrosion, AFWAL-TR-81- 401(, 1o1. 1, 2’.1-270, (II1). 3...Spiehler, 1981. Gulf of Mexico Study of "v’-. Biofouling on OTEC heat exchanger candidate alloys. Materials Performance 8:16-21. - Little, B. 1980... Case Studies Figure 2 shows the configuration of a straight shank attachment lug without bushing. All lugs, with or without bushing, that were

Alternative OTEC Scheme for a Submarine Robot

NASA Technical Reports Server (NTRS)

Jones, Jack; Chao, Yi

2009-01-01

A proposed system for exploiting the ocean thermal gradient to generate power would be based on the thawing-expansion/ freezing-contraction behavior of a wax or perhaps another suitable phase-change material. The power generated by this system would be used to recharge the batteries in a battery-powered unmanned underwater vehicle [UUV (essentially, a small exploratory submarine robot)] of a type that has been deployed in large numbers in research pertaining to global warming. A UUV of this type travels between the ocean surface and various depths, measuring temperature and salinity. This proposed system would be an alternative to another proposed ocean thermal energy conversion (OTEC) system that would serve the same purpose but would utilize a thermodynamic cycle in which CO2 would be the working fluid. That system is described in Utilizing Ocean Thermal Energy in a Submarine Robot (NPO-43304), immediately following this brief. The main advantage of this proposed system over the one using CO2 is that it could derive a useful amount of energy from a significantly smaller temperature difference. At one phase of its operational cycle, the system now proposed would utilize the surface ocean temperature (which lies between 15 and 20 C over most of the Earth) to melt a wax (e.g., pentadecane) that has a melting/freezing temperature of about 10 C. At the opposite phase of its operational cycle, the system would utilize the lower ocean temperature at depth (e.g., between 4 and 7 C at a depth of 300 m) to freeze the wax. The melting or freezing causes the wax to expand or contract, respectively, by about 8 volume percent.

Test results of heat exchanger cleaning in support of ocean thermal energy conversion

NASA Astrophysics Data System (ADS)

Lott, D. F.

1980-12-01

This report documents tests conducted at the Naval Coastal Systems Center (NCSC) in support of the Department of Energy's Ocean Thermal Energy Conversion (OTEC) Program. These tests covered the period September 1978 to May 1980 and evaluated flow-driven brushes, recirculating sponge rubber balls, chlorination, and mechanical system/chlorination combinations for in-situ cleaning of two potential heat exchanger materials: titanium and aluminum alloy 5052. Tests were successful when fouling resistance was 0.0003 sq. ft. hr-F/Btu. Results indicated systems and cleaning techniques using brushes, soft sponge balls, and various concentrations of chlorine had some potential for maintaining heat transfer efficiency.

Solar Energy: Its Technologies and Applications

DOE R&D Accomplishments Database

Auh, P. C.

1978-06-01

Solar heat, as a potential source of clean energy, is available to all of us. Extensive R and D efforts are being made to effectively utilize this renewable energy source. A variety of different technologies for utilizing solar energy have been proven to be technically feasible. Here, some of the most promising technologies and their applications are briefly described. These are: Solar Heating and Cooling of Buildings (SHACOB), Solar Thermal Energy Conversion (STC), Wind Energy Conversion (WECS), Bioconversion to Fuels (BCF), Ocean Thermal Energy Conversion (OTEC), and Photovoltaic Electric Power Systems (PEPS). Special emphasis is placed on the discussion of the SHACOB technologies, since the technologies are being expeditiously developed for the near commercialization.

Current-wave spectra coupling project. Volume III. Cumulative distribution of forces on structures subjected to the combined action of currents and random waves for potential OTEC sites: (A) Keahole Point, Hawaii, 100 year hurricane; (B) Punta Tuna, Puerto Rico, 100 year hurricane; (C) New Orleans, Louisiana, 100 year hurricane; (D) West Coast of Florida, 100 year hurricane. [CUFOR code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Venezian, G.; Bretschneider, C.L.

1980-08-01

This volume details a new methodology to analyze statistically the forces experienced by a structure at sea. Conventionally a wave climate is defined using a spectral function. The wave climate is described using a joint distribution of wave heights and periods (wave lengths), characterizing actual sea conditions through some measured or estimated parameters like the significant wave height, maximum spectral density, etc. Random wave heights and periods satisfying the joint distribution are then generated. Wave kinetics are obtained using linear or non-linear theory. In the case of currents a linear wave-current interaction theory of Venezian (1979) is used. The peakmore » force experienced by the structure for each individual wave is identified. Finally, the probability of exceedance of any given peak force on the structure may be obtained. A three-parameter Longuet-Higgins type joint distribution of wave heights and periods is discussed in detail. This joint distribution was used to model sea conditions at four potential OTEC locations. A uniform cylindrical pipe of 3 m diameter, extending to a depth of 550 m was used as a sample structure. Wave-current interactions were included and forces computed using Morison's equation. The drag and virtual mass coefficients were interpolated from published data. A Fortran program CUFOR was written to execute the above procedure. Tabulated and graphic results of peak forces experienced by the structure, for each location, are presented. A listing of CUFOR is included. Considerable flexibility of structural definition has been incorporated. The program can easily be modified in the case of an alternative joint distribution or for inclusion of effects like non-linearity of waves, transverse forces and diffraction.« less

Studies on toxicity of OTEC plant components on Eucalanus sp. from the Gulf of Mexico. Annual report, October 1980-September 1981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Venkataramiah, A.; Lakshmi, G.J.; Best, C.

1981-10-01

These bioassays were undertaken as a part of the environmental impact studies of the pollutants from the Ocean Thermal Energy Conversion (OTEC) plants. Ammonia and chlorine were selected as toxicants. Eucalanus pileatus and E. elongatus were used as experimental animals because of their importance in the food cycle of the commercial fisheries. A considerable amount of time was devoted to become familiar with the culturing procedures of the Eucalanus sp. and to adapt those procedures to laboratory needs. Algae cultures were developed with Rhizosolenia alata and Thalassiosira fluviatilis for use as food for the copepods. Collection and maintenance techniques formore » E. pileatus and E. elongatus were developed. Culturing operations were successful through the F/sub 1/ generation for E. pileatus. A mini-flow-through seawater bioassay system was designed and built for these studies. The system can also be used for running the bioassays with small organisms, embryos and larvae of fish, etc. In the chronic exposure the survival rates in the sublethal concentrations did not change significantly from the acute ammonia and chlorine bioassays. However, in the incipient lethal concentrations of ammonia and chlorine the survival rates decreased gradually. It was concluded that oceanic species like sargassum shrimp (Latreutes fucorum), filefish (Monocanthus hispidus) and copepods Eucalanus sp. were apparently more sensitive to toxicants than the mullet (Mugil cephalus) collected in inshore waters. Within the same species the tolerance to toxicity increased significantly with increasing size (age). Among the oceanic forms, sargassum shrimp appeared to be the hardiest of all species with filefish being most sensitive to ammonia. In chlorine sargassum shrimp exhibited a much greater tolerance toward ammonia than the copepods. The tolerance limits of small mullet (0.3 and 0.4g), which evidently were fresh arrivals from offshore, responded similarly to both toxicants as sargassum shrimp.« less

Progress in hydrogen energy; Proceedings of the National Workshop on Hydrogen Energy, New Delhi, India, July 4-6, 1985

NASA Astrophysics Data System (ADS)

Dahiya, R. P.

1987-06-01

The present conference on the development status of hydrogen energy technologies considers electrolytic hydrogen production, photoelectrolytic hydrogen production, microorganic hydrogen production, OTEC hydrogen production, solid-state materials for hydrogen storage, and a thin-film hydrogen storage system. Also discussed are the cryogenic storage of hydrogen; liquid hydrogen fuel for ground, air, and naval vehicles; hydrogen-fuel internal combustion engines; the use of hydrogen for domestic, commercial, and industrial applications; hydrogen fuel-cell development; enzyme electrodes for the use of hydrogen-rich fuels in biochemical fuel cells; an analysis of H2-O2 MHD generators; and hydrogen energy technology characterization and evaluation on the basis of an input-output structure.

NOAA/DOE CWP structural analysis package. [CWPFLY, CWPEXT, COTEC, and XOTEC codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pompa, J.A.; Lunz, D.F.

1979-09-01

The theoretical development and computer code user's manual for analysis of the Ocean Thermal Energy Conversion (OTEC) plant cold water pipe (CWP) are presented. The analysis of the CWP includes coupled platform/CWP loadngs and dynamic responses. This report with the exception of the Introduction and Appendix F was orginally published as Hydronautics, Inc., Technical Report No. 7825-2 (by Barr, Chang, and Thasanatorn) in November 1978. A detailed theoretical development of the equations describing the coupled platform/CWP system and preliminary validation efforts are described. The appendices encompass a complete user's manual, describing the inputs, outputs and operation of the four componentmore » programs, and detail changes and updates implemented since the original release of the code by Hydronautics. The code itself is available through NOAA's Office of Ocean Technology and Engineering Services.« less

Sea, soil, sky - Testing solar's limits

NASA Astrophysics Data System (ADS)

Hopkinson, J.

1981-12-01

The potentials and actualities of large scale biomass, ocean thermal, and satellite solar power systems are discussed. Biomass is an energy already on-line in installations ranging from home-sized wood-burning stoves to utility sized generators fueled by sawdust and forest residue. Uses of wheat straw, fast-growing trees such as eucalyptus and alder, and euphorbia as biofuels are examined, noting restrictions imposed by land use limitations and the necessity for genetic engineering for more suitable plants. Pyrolysis and thermochemical gasification of biomass to form gaseous, solid, and liquid fuels are explored, and mention is made of utility refuse and sewage incineration for power generation. OTEC, satellite solar power systems, and tidal generator plants are considered as promising for further investigation and perhaps useful in limited applications, while solar pond power plants require extremely large areas to be effective.

Composites in energy generation and storage systems - An overview

NASA Astrophysics Data System (ADS)

Fulmer, R. W.

Applications of glass-fiber reinforced composites (GER) in renewable and high-efficiency energy systems which are being developed to replace interim, long-term unacceptable energy sources such as foreign oil are reviewed. GFR are noted to have design flexibility, high strength, and low cost, as well as featuring a choice of fiber orientation and type of reinforcement. Blades, hub covers, nacelles, and towers for large and small WECS are being fabricated and tested and are displaying satisfactory strength, resistance to corrosion and catastrophic failure, impact tolerance, and light weight. Promising results have also been shown in the use of GFR as flywheel material for kinetic energy storage in conjunction with solar and wind electric systems, in electric cars, and as load levellers. Other applications are for heliostats, geothermal power plant pipes, dam-atoll tidal wave energy systems, and intake pipes for OTECs.

A solar-hydrogen economy for U.S.A.

NASA Astrophysics Data System (ADS)

Bockris, J. Om.; Veziroglu, T. N.

The benefits, safety, production, distribution, storage, and uses, as well as the economics of a solar and hydrogen based U.S. energy system are described. Tropical and subtropical locations for the generation plants would provide power from photovoltaics, heliostat arrays, OTEC plants, or genetically engineered algae to produce hydrogen by electrolysis, direct thermal conversion, thermochemical reactions, photolysis, or hybrid systems. Either pipelines for gas transport or supertankers for liquefied hydrogen would distribute the fuel, with storage in underground reservoirs, aquifers, and pressurized bladders at sea. The fuel would be distributed to factories, houses, gas stations, and airports. It can be used in combustion engines, gas turbines, and jet engines, and produces water vapor as an exhaust gas. The necessary research effort to define and initiate construction of technically and economically viable solar-hydrogen plants is projected to be 3 yr, while the technical definition of fusion power plants, the other nondepletable energy system, is expected to take 25 yr.

Current observations offshore Punta Tuna, Puerto Rico, 21 June-7 December 1980. Part A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frye, D.; Leavitt, K.; Whitney, A.

1981-08-01

An oceanographic measurement program was conducted in the vicinity of a proposed ocean thermal energy conversion (OTEC) site about 20 km offshore of Punta Tuna, Puerto Rico. As part of the program, a mooring consisting of five current meters was maintained between 21 June and 7 December, 1980. The current data collected are summarized according to frequency of occurrence within 5 cm/sec speed and 15/sup 0/ direction intervals. Sums and percentages of total occurrence are given for each speed and direction class, along with mean speed, extreme speeds, mean component speeds, and standard deviations. Hourly averages of current speed, truemore » direction, current vector, temperature, and pressure are plotted as a function of time. On 13 December, 1980, a current meter array was deployed at the Punta Tuna site and recovered on May 16, 1981. The processed current data from this current meter array are described. (LEW)« less

Preliminary comparative assessment of land use for the Satellite Power System (SPS) and alternative electric energy technologies

NASA Technical Reports Server (NTRS)

Newsom, D. E.; Wolsko, T.

1980-01-01

A preliminary comparative assessment of land use for the satellite power system (SPS), other solar technologies, and alternative electric energy technologies was conducted. The alternative technologies are coal gasification/combined-cycle, coal fluidized-bed combustion (FBC), light water reactor (LWR), liquid metal fast breeder reactor (LMFBR), terrestrial photovoltaics (TPV), solar thermal electric (STE), and ocean thermal energy conversion (OTEC). The major issues of a land use assessment are the quantity, purpose, duration, location, and costs of the required land use. The phased methodology described treats the first four issues, but not the costs. Several past efforts are comparative or single technology assessment are reviewed briefly. The current state of knowledge about land use is described for each technology. Conclusions are drawn regarding deficiencies in the data on comparative land use and needs for further research.

Progress on alternative energy resources

NASA Astrophysics Data System (ADS)

Couch, H. T.

1982-03-01

Progress in the year 1981 toward the development of energy systems suitable for replacing petroleum products combustion and growing in use to fulfill a near term expansion in energy use is reviewed. Coal is noted to be a potentially heavy pollution source, and the presence of environmentally acceptable methods of use such as fluidized-bed combustion and gasification and liquefaction reached the prototype stage in 1981, MHD power generation was achieved in two U.S. plants, with severe corrosion problems remaining unsolved for the electrodes. Solar flat plate collectors sales amounted to 20 million sq ft in 1981, and solar thermal electric conversion systems with central receivers neared completion. Solar cells are progressing toward DOE goals of $.70/peak W by 1986, while wind energy conversion sales were 2000 machines in 1981, and the industry is regarded as maturing. Finally, geothermal, OTEC, and fusion systems are reviewed.

In-situ biofouling of ocean thermal energy conversion (OTEC) evaporator tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasscer, D.S.; Morgan, T.

1981-05-01

The Puerto Rico Center for Energy and Environmental Research equipped a LCU facility in 1100 m of water near Punta Tuna, Puerto Rico to measure in situ biofouling of simulated Ocean Thermal Energy Conversion evaporator tubes. The system consisted of two 5052 aluminum alloy and two titanium tubes, through which a continuous flow of ocean water was maintained. The tubes were cleaned three times and the fouling resistance was measured, showing only slight differences between the tubes with respect to heat transfer loss resulting from biofouling. In all units, the average fouling rate after cleaning was greater than before cleaning,more » and only after the first cleaning did the aluminum units show greater fouling rates than did the titanium. The titanium units showed a progressive increase in the fouling rates with each cleaning. The subsequent average fouling rates for all units after eight months were between 4 and 4.6 x 0.000010 sq m-k/W-day.« less

Alternative energy technologies for the Caribbean islands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pytlinski, J.T.

1992-01-01

All islands in the Caribbean except Puerto Rico can be classified as developing islands. Of these islands, all except Trinidad and Tobago are oil importers. Uncertainties concerning uninterrupted oil supply and increasing oil prices causes economic, social and political instability and jeopardizes further development of these islands. The paper discusses the energy situation of the Caribbean islands and presents alternative energy options. Several alternative energy projects financed by local, federal and international organizations are presented. Present and future uses of alternative energy technologies are described in different islands. Barrier which handicap developing and implementing alternative energy sources in the Caribbeanmore » are discussed. The potential and possible applications of alternative energy technologies such as: solar-thermal energy, photovoltaics, wind energy, ocean thermal energy conversion (OTEC), ocean currents and tides energy, biomass, peat energy, municipal solid wastes, bioconversion, hydropower, geothermal energy, nuclear energy and energy conservation are discussed in detail as means to alleviate the energy situation in the Caribbean islands.« less

Renewable energy - Target for 2050

NASA Astrophysics Data System (ADS)

Rowe, W. D.

1982-02-01

The possibilities of various renewable energy technologies to supply a projected world demand for 40,000 GW years of energy each year by the year 2050 are examined. Noting that industrial processes consume 50% of all energy needs, fossil fuel reserves are shown to be sufficient for a maximum of 370 yr in the U.S., when all supplies become depleted. Breeder reactors have a doubling time which is 30 yr too long for meeting more than 0.5% of world energy demand in 2050, while fusion, even considering ocean-derived deuterium as a fuel source, will not be supplying energy for another 35-70 yr. Among the solar technologies, the installation of ten million 100 m tall 4 MW wind generators is feasible to meet all the projected energy needs, and solar cells with 10% conversion efficiency could do the same with 14 times less land. Further discussion is given to geothermal, fuel cell, and OTEC technologies, as well as the forty trillion dollars necessary to erect the fully renewable systems.

Use of Biostratigraphy to Increase Production, Reduce Operating Costs and Risks and Reduce Environmental Concerns in Oil Well Drilling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edward Marks

In the Santa Maria Basin, Santa Barbara County, California, four wells were processed and examined to determine the age and environment parameters in the oil producing sections. From west to east, we examined Cabot No. 1 Ferrero-Hopkins,from 3917.7 m (12850 ft) to 4032 m (13225 ft); Sun No. 5 Blair, from 3412 m (11190 ft) to 3722.5 m (12210 ft); Triton No. 10 Blair, from 1552 m (5090 ft) to 1863 m (6110 ft); and OTEC No. 1 Boyne, from 2058 m (6750 ft) to 2528 m (8293 ft). Lithic reports with lithic charts were prepared and submitted on eachmore » well. These tested for Sisquoc Fm lithology to be found in the Santa Maria area. This was noted in the OTEC No. 1 Boyne interval studied. The wells also tested for Monterey Fm. lithology, which was noted in all four wells examined. Composite samples of those intervals [combined into 9.15 m (30 foot) intervals] were processed for paleontology. Although the samples were very refractory and siliceous, all but one (Sun 5 Blair) yielded index fossil specimens, and as Sun 5 Blair samples below 3686 m (12090 ft) were processed previously, we were able to make identifications that would aid this study. The intervals examined were of the Sisquoc Formation, the Low Resistivity and the High Resistivity sections of the Monterey Formation. The Lower Sisquoc and the top of the late Miocene were identified by six index fossils: Bolivina barbarana, Gyroidina soldanii rotundimargo, Bulimina montereyana, Prunopyle titan, Axoprunum angelinum and Glyphodiscus stellatus. The Low Resistivity Monterey Fm. was identified by eight index fossils, all of which died out at the top of the late Miocene, late Mohnian: Nonion goudkoffi, Brizalina girardensis, Cibicides illingi, Siphocampe nodosaria, Stephanogonia hanzawai, Uvigerina modeloensis, Buliminella brevior, Tytthodiscus sp.and the wide geographic ranging index pelagic fossil, Sphaeroidinellopsis subdehiscens. The High Resistivity Monterey Fm. was identified by eight index fossils, all of which died out at the top of the late Miocene, early Mohnian: Bolivina aff hughesi, Rotalia becki, Suggrunda californica, Virgulina grandis, Virgulina ticensis, Bulimina ecuadorana, Denticula lauta and Nonion medio-costatum. Please see Appendix B, Fig. 1, Neogene Zones, p. 91 and Appendix C, chart 5, p. 99 By the use of Stratigraphy, employing both Paleontology and Lithology, we can increase hydrocarbon production, reduce operating costs and risks by the identification of the productive sections, and reduce environmental concerns by drilling less dry holes needlessly.« less

Novel Thermal Powered Technology for UUV Persistent Surveillance

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Chao, Yi

2006-01-01

Buoyancy Generation: Various technology attempts include melting a wax, which pushes directly against a piston (U.S. Patent 5,291,847) or against a bladder (Webb Research), using ammonia or Freon 21 (U.S. Patent 5,303,552), and using solar heat to expand an oil (www.space.com, April, 10, 2002). All these heat-activated buoyancy control designs have thus far proved impractical and have ultimately failed during repeated cycling in ocean testing. JPL has demonstrated fully reversible 10 C encapsulated wax phase change, which can be used to change buoyancy without electrical hydraulic pumps. This technique has greatly improved heat transfer and much better reversibility than previous designs. Power Generation: Ocean Thermal Energy Conversion (OTEC) systems have been designed that transfer deep, cold sea water to the surface to generate electricity using turbine cycles with ammonia or water as the working fluid. JPL has designed several UUV systems: 1) Using a propeller water turbine to generate power on a gliding submersible; 2) Employing a compact CO2 turbine cycle powered by moving through thermoclines; and 3) Using melted wax to directly produce power through a piston-geared generator.

OTEC modular experiment cold water pipe concept evaluation. Volume III. Appendices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-04-01

The Cold Water Pipe System Design Study was undertaken to evaluate the diverse CWP concepts, recommend the most viable alternatives for a 1984 deployment of the 10 to 40 MWe MEP, and carry out preliminary designs of three concepts. The concept evaluation phase reported involved a systems analysis of design alternatives in the broad categories of rigid walled (with hinges), compliant walled, stockade and bottom mounted buoyant. Quantitative evaluations were made of concept performance, availability, deployment schedule, technical feasibility and cost. CWP concepts were analyzed to determine if they met or could be made to meet established system requirements andmore » could be deployed by 1984. Fabrication, construction and installation plans were developed for successful concepts, and costs were determined in a WBS format. Evaluations were performed on the basis of technical and cost risk. This volume includes the following appendices: (A) materials and associated design criteria; (B) summary of results of dynamic flow and transportation analysis; (C) CWP sizing analysis; (D) CWP thermal performance; and (E) investigation of the APL/ABAM CWP design. (WHK)« less

Geysers advanced direct contact condenser research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, J.; Bahning, T.; Bharathan, D.

1997-12-31

The first geothermal application of the Advanced Direct Contact Condenser (ADCC) technology developed by the National Renewable Energy Laboratory (NREL) is now operational and is being tested at The Geysers Power Plant Unit 11. This major research effort is being supported through the combined efforts of NREL, The Department of Energy (DOE), and Pacific Gas and Electric (PG&E). NREL and PG&E have entered into a Cooperative Research And Development Agreement (CRADA) for a project to improve the direct-contact condenser performance at The Geysers Power Plant. This project is the first geothermal adaptation of an advanced condenser design developed for themore » Ocean Thermal Energy Conversion (OTEC) systems. PG&E expects this technology to improve power plant performance and to help extend the life of the steam field by using steam more efficiently. In accordance with the CRADA, no money is transferred between the contracting parties. In this case the Department of Energy is funding NREL for their efforts in this project and PG&E is contributing funds in kind. Successful application of this technology at The Geysers will provide a basis for NREL to continue to develop this technology for other geothermal and fossil power plant systems.« less

OTEC biofouling, corrosion, and materials study from a moored platform at Punta Tuna, Puerto Rico - 1. - fouling resistance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasscer, D.S.; Morgan, T.O.; Rivera, C.

1981-01-01

A biofouling test of 404 days was conducted on evaporator tubes of an ocean thermal energy conversion plant of the Center for Energy and Environmental Research. The fouling resistance (R/sub f/), total surface carbon and nitrogen content, ATP, and the wet film thickness (WFT) were determined throughout the test. Visual observations of the fouling film were made by light sectioning and scanning microscopy, and at the end of the test, a study was made of the macrofouling of the flow system. The results of these tests indicate that a base layer of bacteria and exudated polysaccharides enhance microbial adhesion andmore » thereby create an environment conducive to rapid film growth. Fouling rates (dR/sub f//dt) for aluminum were generally higher than for titanium but they were linear for both materials and did not exceed 0.3(10/sup -4/)ft/sup 2/-hr-/degree/F/Btu-day for either material during the 13-month study. Excellent correlation was found to exist between R/sub f/ and WFT, which supports the hypothesis that it is the stagnant film of water entrapped by bacteria which is largely responsible for the insulating properties of the biofilm. The macrofouling study identified 61 species of benthic invertebrates representing ten phyla growing in those parts of the flow system, where flow was less than 3 fps but no macrofouling where the flow velocity significantly exceeded 3 fps. 24 refs.« less

NASA Tech Briefs, January 2009

NASA Technical Reports Server (NTRS)

2009-01-01

Tech Briefs are short announcements of innovations originating from research and development activities of the National Aeronautics and Space Administration. They emphasize information considered likely to be transferable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. Topics covered include: The Radio Frequency Health Node Wireless Sensor System; Effects of Temperature on Polymer/Carbon Chemical Sensors; Small CO2 Sensors Operate at Lower Temperature; Tele-Supervised Adaptive Ocean Sensor Fleet; Synthesis of Submillimeter Radiation for Spectroscopy; 100-GHz Phase Switch/Mixer Containing a Slot-Line Transition; Generating Ka-Band Signals Using an X-Band Vector Modulator; SiC Optically Modulated Field-Effect Transistor; Submillimeter-Wave Amplifier Module with Integrated Waveguide Transitions; Metrology System for a Large, Somewhat Flexible Telescope; Economical Implementation of a Filter Engine in an FPGA; Improved Joining of Metal Components to Composite Structures; Machined Titanium Heat-Pipe Wick Structure; Gadolinia-Doped Ceria Cathodes for Electrolysis of CO2; Utilizing Ocean Thermal Energy in a Submarine Robot; Fuel-Cell Power Systems Incorporating Mg-Based H2 Generators; Alternative OTEC Scheme for a Submarine Robot; Sensitive, Rapid Detection of Bacterial Spores; Adenosine Monophosphate-Based Detection of Bacterial Spores; Silicon Microleaks for Inlets of Mass Spectrometers; CGH Figure Testing of Aspherical Mirrors in Cold Vacuums; Series-Coupled Pairs of Silica Microresonators; Precise Stabilization of the Optical Frequency of WGMRs; Formation Flying of Components of a Large Space Telescope; Laser Metrology Heterodyne Phase-Locked Loop; Spatial Modulation Improves Performance in CTIS; High-Performance Algorithm for Solving the Diagnosis Problem; Truncation Depth Rule-of-Thumb for Convolutional Codes; Efficient Method for Optimizing Placement of Sensors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Valin, R.; Morse, J.W.

The operation of an OTEC plant will result in the mixing of large volumes of seawater from different depths within the ocean. Because suspended particulate material is intimately involved in marine food webs and transition metals, such as copper, can have toxic effects, it is important to develop a sound methodology for characterizing and quantifying transition metal behavior associated with the solid material. The characterization of solid-phase-associated transition metals in the marine environment has largely been directed at marine sediments. These studies have generally indicated that it is not possible to uniquely identify the solid phases or chemical speciation ofmore » a given metal. There are many reasons for this difficulty, but the probable major analytical problems arise from the fact that many of the transition metals of interest are present only in trace concentrations as adsorbed species on amorphous oxides or as coprecipitates. In one approach transition metals are classified according to how easily they are solubilized when exposed to different types of chemical attack, as defined in chemical extraction schemes. In this study, several of the most widely accepted extraction techniques were compared for many of the most commonly measured transition metals to a variety of marine sediments. Based on the results of this study, the sequential extraction scheme of Tessler et al. (1979) is the recommended method for the characterization of solid-phase associated transition metals. An increase of the reducing agent concentration in the intermediate step and temperature decrease with an additional HCl digestion in the residual step are recommended as improvements, based on the results of the individual extraction method studies.« less

Open cycle ocean thermal energy conversion system structure

DOEpatents

Wittig, J. Michael

1980-01-01

A generally mushroom-shaped, open cycle OTEC system and distilled water producer which has a skirt-conduit structure extending from the enlarged portion of the mushroom to the ocean. The enlarged part of the mushroom houses a toroidal casing flash evaporator which produces steam which expands through a vertical rotor turbine, partially situated in the center of the blossom portion and partially situated in the mushroom's stem portion. Upon expansion through the turbine, the motive steam enters a shell and tube condenser annularly disposed about the rotor axis and axially situated beneath the turbine in the stem portion. Relatively warm ocean water is circulated up through the radially outer skirt-conduit structure entering the evaporator through a radially outer portion thereof, flashing a portion thereof into motive steam, and draining the unflashed portion from the evaporator through a radially inner skirt-conduit structure. Relatively cold cooling water enters the annular condenser through the radially inner edge and travels radially outwardly into a channel situated along the radially outer edge of the condenser. The channel is also included in the radially inner skirt-conduit structure. The cooling water is segregated from the potable, motive steam condensate which can be used for human consumption or other processes requiring high purity water. The expansion energy of the motive steam is partially converted into rotational mechanical energy of the turbine rotor when the steam is expanded through the shaft attached blades. Such mechanical energy drives a generator also included in the enlarged mushroom portion for producing electrical energy. Such power generation equipment arrangement provides a compact power system from which additional benefits may be obtained by fabricating the enclosing equipment, housings and component casings from low density materials, such as prestressed concrete, to permit those casings and housings to also function as a floating support vessel.

Current-wave spectra coupling project. Volume II. Hurricane fields and cross sections, surface winds and currents, significant waves and wave spectra for potential OTEC sites: (A) Keahole Point, Hawaii, 100 year hurricane; (B) Punta Tuna, Puerto Rico, 100 year hurricane; (C) New Orleans, Louisiana, 100 year hurricane; (D) West Coast of Florida, 100 year hurricane; and for (E) Hurricane Camille (1969) off Louisiana Coast. Technical support for Volume I. [HURICA1 and HURICA2 codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bretschneider, C.L.; Huang, T.S.; Endo, H.

1980-07-01

This volume represents the details of the technical development of and the calibration of the two-directional three parameter wave forecasting relationships, which are specially adapted for forecasting hurricane significant wave height, H/sub s/, modal wave period f/sub 0//sup -1/ and the peak of the wave spectrum, S/sub max/. These three parameters lead to the determination of the three-parameter wave spectrum which has been verified by use of hurricane wind generated wave spectra from Hurricane Eloise (1975). The hurricane wind field is still based on the original US Weather Service model as given by Meyers (1954). Hurricane winds, waves and wavemore » spectra data from Hurricane Eloise (1975) published by Withee and Johnson, NOAA (1975), have been used. Although the data is of an analyzed form, the term raw data was used as distinguished from smoothed data. An analysis of the raw data is presented in this volume, and considerable sense of the analysis has been made. A weighted average technique was not used, but could have reduced the scatter in the so-called raw data during the first 2/3 of the storm when the winds and waves were less than gale force and quite variable. There is considerably less variability in the wind and wave data when the wind reaches gale force, and these are the data for which the greatest emphasis is given in the analysis. (WHK)« less

NASA Tech Briefs, May 2010

NASA Technical Reports Server (NTRS)

2010-01-01

Topics covered include: Instrument for Analysis of Greenland's Glacier Mills Cryogenic Moisture Apparatus; A Transportable Gravity Gradiometer Based on Atom Interferometry; Three Methods of Detection of Hydrazines; Crossed, Small-Deflection Energy Analyzer for Wind/Temperature Spectrometer; Wavefront Correction for Large, Flexible Antenna Reflector; Novel Micro Strip-to-Waveguide Feed Employing a Double-Y Junction; Thin-Film Ferro Electric-Coupled Microstripline Phase Shifters With Reduced Device Hysteresis; Two-Stage, 90-GHz, Low-Noise Amplifier; A 311-GHz Fundamental Oscillator Using InP HBT Technology; FPGA Coprocessor Design for an Onboard Multi-Angle Spectro-Polarimetric Imager; Serrating Nozzle Surfaces for Complete Transfer of Droplets; Turbomolecular Pumps for Holding Gases in Open Containers; Triaxial Swirl Injector Element for Liquid-Fueled Engines; Integrated Budget Office Toolbox; PLOT3D Export Tool for Tecplot; Math Description Engine Software Development Kit; Astronaut Office Scheduling System Software; ISS Solar Array Management; Probabilistic Structural Analysis Program; SPOT Program; Integrated Hybrid System Architecture for Risk Analysis; System for Packaging Planetary Samples for Return to Earth; Offset Compound Gear Drive; Low-Dead-Volume Inlet for Vacuum Chamber; Simple Check Valves for Microfluidic Devices; A Capillary-Based Static Phase Separator for Highly Variable Wetting Conditions; Gimballing Spacecraft Thruster; Finned Carbon-Carbon Heat Pipe with Potassium Working Fluid; Lightweight Heat Pipes Made from Magnesium; Ceramic Rail-Race Ball Bearings; Improved OTEC System for a Submarine Robot; Reflector Surface Error Compensation in Dual-Reflector Antennas; Enriched Storable Oxidizers for Rocket Engines; Planar Submillimeter-Wave Mixer Technology with Integrated Antenna; Widely Tunable Mode-Hop-Free External-Cavity Quantum Cascade Laser; Non-Geiger-Mode Single-Photon Avalanche Detector with Low Excess Noise; Using Whispering-Gallery-Mode Resonators for Refractometry; RF Device for Acquiring Images of the Human Body; Reactive Collision Avoidance Algorithm; Fast Solution in Sparse LDA for Binary Classification; Modeling Common-Sense Decisions in Artificial Intelligence; Graph-Based Path-Planning for Titan Balloons; Nanolaminate Membranes as Cylindrical Telescope Reflectors; Air-Sea Spray Airborne Radar Profiler Characterizes Energy Fluxes in Hurricanes; Large Telescope Segmented Primary Mirror Alignment; and Simplified Night Sky Display System.

Utilizing Ocean Thermal Energy in a Submarine Robot

NASA Technical Reports Server (NTRS)

Jones, Jack; Chao, Yi

2009-01-01

A proposed system would exploit the ocean thermal gradient for recharging the batteries in a battery-powered unmanned underwater vehicle [UUV (essentially, a small exploratory submarine robot)] of a type that has been deployed in large numbers in research pertaining to global warming. A UUV of this type travels between the ocean surface and depths, measuring temperature and salinity. The proposed system is related to, but not the same as, previously reported ocean thermal energy conversion (OTEC) systems that exploit the ocean thermal gradient but consist of stationary apparatuses that span large depth ranges. The system would include a turbine driven by working fluid subjected to a thermodynamic cycle. CO2 has been provisionally chosen as the working fluid because it has the requisite physical properties for use in the range of temperatures expected to be encountered in operation, is not flammable, and is much less toxic than are many other commercially available refrigerant fluids. The system would be housed in a pressurized central compartment in a UUV equipped with a double hull (see figure). The thermodynamic cycle would begin when the UUV was at maximum depth, where some of the CO2 would condense and be stored, at relatively low temperature and pressure, in the annular volume between the inner and outer hulls. The cycle would resume once the UUV had ascended to near the surface, where the ocean temperature is typically greater than or equals 20 C. At this temperature, the CO2 previously stored at depth in the annular volume between the inner and outer hulls would be pressurized to approx. equals 57 bar (5.7 MPa). The pressurized gaseous CO2 would flow through a check valve into a bladder inside the pressurized compartment, thereby storing energy of the relatively warm, pressurized CO2 for subsequent use after the next descent to maximum depth.

Corrosion resistance and durability of siloxane ceramic/polymer films for aluminum alloys in marine environments

NASA Astrophysics Data System (ADS)

Kusada, Kentaro

The objective of this study is to evaluate corrosion resistance and durability of siloxane ceramic/polymer films for aluminum alloys in marine environments. Al5052-H3 and Al6061-T6 were selected as substrates, and HCLCoat11 and HCLCoat13 developed in the Hawaii Corrosion Laboratory were selected for the siloxane ceramic/polymer coatings. The HCLCoat11 is a quasi-ceramic coating that has little to no hydrocarbons in its structure. The HCLCoat13 is formulated to incorporate more hydrocarbons to improve adhesion to substrate surfaces with less active functionalities. In this study, two major corrosion evaluation methods were used, which were the polarization test and the immersion test. The polarization tests provided theoretical corrosion rates (mg/dm 2/day) of bare, HCLCoat11-coated, and HCLCoat13-coated aluminum alloys in aerated 3.15wt% sodium chloride solution. From these results, the HCLCoat13-coated Al5052-H3 was found to have the lowest corrosion rate which was 0.073mdd. The next lowest corrosion rate was 0.166mdd of the HCLCoat11-coated Al5052-H3. Corrosion initiation was found to occur at preexisting breaches (pores) in the films by optical microscopy and SEM analysis. The HCLCoat11 film had many preexisting breaches of 1-2microm in diameter, while the HCLCoat13 film had much fewer preexisting breaches of less than 1microm in diameter. However, the immersion tests showed that the seawater immersion made HCLCoat13 film break away while the HCLCoat11 film did not apparently degrade, indicating that the HCLCoat11 film is more durable against seawater than the HCLCoat13. Raman spectroscopy revealed that there was some degradation of HCLCoat11 and HCLCoat13. For the HCLCoat11 film, the structure relaxation of Si-O-Si linkages was observed. On the other hand, seawater generated C-H-S bonds in the HCLCoat13 film resulting in the degradation of the film. In addition, it was found that the HCLCoat11 coating had anti-fouling properties due to its high water contact angle. As candidate materials for a marine construction (e.g. the heat exchangers for ocean thermal energy conversion (OTEC) plants), the HCLCoat11-coated Al5052-H3 proved to be a durable, corrosion resistant combination with anti-fouling characteristics.