Experiments on and design of low-cost aluminum heat exchangers for OTEC plant ships
Successful commercial implementation of ocean thermal energy conversion (OTEC) plant-ships will require achievement of a capital cost competitive with land-based plants. The most expensive components of an OTEC system are the evaporators (heated by warm surface water), the condensers (cooled by water from 700 to 1000 m depth), and the floating ocean platform. To minimize these costs, simple two-phase-flow heat exchangers made of large-diameter aluminium tubes have been designed for integration with a simple, barge-type, reinforced concrete hull. The method of analysis and a concept for assembling these modules are presented. The estimated costs for the sixth and subsequent 500-MW/sub e/(net) commercial plant-ships are $19/m/sup 2/ ($1.77/ft/sup 2/) for the heat exchangers and $573/kW/sub e/ of net onboard power for the OTEC plant-ship. Experiments have been conducted with an ammonia flow loop containing a 77-mm (3.02-in.)-O.D. x 6-m (20-ft)-long aluminum tube simulating one pass in an evaporator. Some flow stratification occurred as expected at these low qualities, but the internal (ammonia-side), two-phase heat transfer coefficients were in agreement with the Chaddock-Brunemann correlation.
- Research Organization:
- Johns Hopkins Univ., Laurel, MD (USA). Applied Physics Lab.
- DOE Contract Number:
- AI01-77ET20342
- OSTI ID:
- 5285919
- Report Number(s):
- CONF-770331-7; ON: DE84005598
- Country of Publication:
- United States
- Language:
- English
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