Accession Number PB2013-107493
Title Technical Readiness of Ocean Thermal Energy Conversion (OTEC) November 3-5, 2009.
Publication Date Nov 2009
Media Count 246p
Personal Author N/A
Abstract The decreasing supply, and increasing cost, of fossil-fuel based energy has intensified the search for renewable alternatives. Although traditionally more expensive, renewable energy sources have many incentives, including increased national energy security, decreased carbon emissions, and compliance with renewable energy mandates and air quality regulations. In remote islands where increased shipping costs and economies of scale result in some of the most expensive fossil-fuel based energy in the world, renewable energy sources are particularly attractive. Many islands, including Guam and Hawaii, contain strategic military bases with high energy demands that would greatly benefit from an inexpensive, reliable source of energy independent of the fossilfuel based economy. The oceans are natural collectors of solar energy and absorb billions of watts of energy from the sun in the form of solar radiation daily. In the tropical latitudes, intense sunlight and longer days result in significant heating of the upper 35 to 100 m of the oceans, yielding comparatively warm (27 - 29DGC) oceanic surface waters. Below this warm layer the temperature gradually decreases to an average of about 4.4DGC. When the second law of thermodynamics is considered, this temperature differential represents a significant amount of potential energy which, if extracted, would be a completely renewable source of energy. One method of extracting this energy is Ocean Thermal Energy Conversion (OTEC). OTEC facilities take advantage of the Rankine cycle, a process which converts thermal energy into kinetic energy via turbines. The turbines can then be used to drive generators, producing electricity. There are two major OTEC facility designs: open-cycle, and closed-cycle. In an open-cycle OTEC facility seawater is used as a working fluid. Warm surface water is exposed to a vacuum, causing it to boil and generate steam. The cold water from deep in the ocean is then pumped through a condenser, causing the steam to condense (Figure 1). This constant vaporization and condensation is used to drive a turbine, converting thermal energy into mechanical energy. The open-cycle process has the added advantage of creating fresh water as a byproduct.
Keywords Conversion
Environmental impacts
Heat exchangers
Ocean thermal energy
Ocean thermal power plants

Source Agency National Oceanic and Atmospheric Administration
NTIS Subject Category 97I - Electric Power Production
97N - Solar Energy
97O - Miscellaneous Energy Conversion & Storage
Corporate Author New Hampshire Univ., Durham.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1320
Contract Number N/A

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