Ocean thermal power plants heat exchangers. Final report
The Ocean Thermal Energy Conversion (OTEC) power cycle will generate electrical power, using the temperature difference between warm surface water and cold deep level water in the tropical ocean. The cycle considered herein is a closed Rankine system, in which a working fluid (ammonia or propane) is evaporated and condensed in heat exchange with the seawater streams. The cost-performance characteristics of OTEC heat exchangers were studied. Corrosion, biofouling, and material selection were discussed in great detail. In order to decrease the exchanger cost, the use of heat transfer enhancements were studied, including a nucleation promoter (a layer of porous metal) for the evaporator, a surface tension motivated condensate film-thinner (fluted surface) for the condenser, and boundary layer turbulence promoters for the seawater flows. The heat exchagers can only be optimized as part of the entire plant, as a system, in order to properly apportion temperature differences between the evaporator, condenser, and turbine, and to make optimum choice of the internal power consumptions. An optimization program was written and used to obtain the optimum systems designs. The hydraulic problems involved in the evaporator design were studied. The sprayed bundle evaporator was found to be preferable to the flooded bundle design. For a 100 MW plant, using the sprayed evaporator concept, the exchangers (evaporator plus condenser), using unenhanced tubes, cost a total of 1408 $/KW. Using enhanced tubes, the total cost was 942 $/KW, or 33% less than with plain tubes. The maximum flooded bundle depth is approximately 15 feet. The cost penalty for substituting multiple flooded bundles for sprayed evaporator bundles is 325 $/KW.
- Research Organization:
- Union Carbide Corp., Tonawanda, NY (USA). Linde Div.
- DOE Contract Number:
- EX-76-C-01-2448; NSF-G-43441
- OSTI ID:
- 7299336
- Report Number(s):
- ERDA/NSF/43441-76/1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HEAT EXCHANGERS
OPTIMIZATION
OCEAN THERMAL POWER PLANTS
BIOLOGICAL FOULING
BOUNDARY LAYERS
CONDENSERS
CORROSION
COST
DESIGN
HEAT TRANSFER
HYDRAULICS
MATERIALS
RANKINE CYCLE
CHEMICAL REACTIONS
ENERGY TRANSFER
FLUID MECHANICS
FOULING
LAYERS
MECHANICS
POWER PLANTS
SOLAR POWER PLANTS
THERMODYNAMIC CYCLES
140800* - Solar Energy- Ocean Energy Systems