Gas Desorption From Seawater in Open-Cycle Ocean Thermal Energy Conversion Barometric Upcomers

1990 ◽  
Vol 112 (3) ◽  
pp. 204-215 ◽  
Author(s):  
S. M. Ghiaasiaan ◽  
A. T. Wassel ◽  
A. A. Pesaran
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Water Evaporation ◽  
Bubble Liquid ◽  
Desorption Process ◽  
Ocean Thermal Energy Conversion ◽  
Gas Desorption ◽  
Thermal Energy Conversion ◽  
Open Cycle ◽  
Ocean Thermal Energy

Gas desorption from warm and cold seawater under open-cycle ocean thermal energy conversion (OC-OTEC) conditions is addressed in this paper. The desorption process of dissolved O2, N2, and CO2 in the barometric upcomers of an OTEC plant is simulated mathematically. The model considers the growth of bubbles originating in the ocean and bubbles formed in the upcomers. Bubble growth is induced by gas mass transfer and water evaporation at the bubble-liquid interface, as well as by the decreasing hydrostatic pressure. Heterogeneous nucleation at pipe wall crevices and on suspended particles in the water stream is also modeled. Bubble coalescence due to turbulent shear and differential buoyancy is simulated. The results generated show the deaeration efficiency as a function of flow and geometric parameters. The calculations show that gas desorption in the barometric upcomers can be appreciable. Such desorption is enhanced by increasing the concentration of the incoming and/or the heterogeneously formed bubbles. Results of existing experiments are discussed and predictions are shown for the selected test conditions.

Optimum Design of a Low-Pressure, Double Inflow, Radial Steam Turbine for Open-Cycle Ocean Thermal Energy Conversion

1990 ◽  
Vol 112 (1) ◽  
pp. 71-77 ◽  
Author(s):  
T. Schobeiri
Keyword(s):  
Energy Conversion ◽  
Steam Turbine ◽  
Optimum Design ◽  
Thermal Energy ◽  
Low Pressure ◽  
Design Concept ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Open Cycle ◽  
Ocean Thermal Energy

This paper describes the thermo-fluid design concept of a low-pressure, radial inflow steam turbine for the Open-Cycle Ocean Thermal Energy Conversion (OTEC). For the optimum design consideration, the necessary theoretical tools are developed. The design concept permits the utilization of single-stage and multistage configurations for small and medium power ranges, respectively.

Optimum Design of a Low Pressure, Double Inflow, Radial Steam Turbine for Open-Cycle Ocean Thermal Energy Conversion

1989 ◽  
Author(s):  
T. Schobeiri
Keyword(s):  
Energy Conversion ◽  
Steam Turbine ◽  
Optimum Design ◽  
Thermal Energy ◽  
Low Pressure ◽  
Design Concept ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Open Cycle ◽  
Ocean Thermal Energy

This paper describes the thermo-fluid design concept of a low pressure, radial inflow steam turbine for the Open-Cycle Ocean Thermal Energy Conversion (OTEC). For the optimum design consideration, the necessary theoretical tools are developed. The design concept permits the utilization of single-stage and multi-stage configuration for small and medium power range, respectively.

Ocean Thermal Energy Conversion Primer

2002 ◽  
Vol 36 (4) ◽  
pp. 25-35 ◽  
Author(s):  
L. A. Vega
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Heat Engine ◽  
Bottom Layer ◽  
Working Fluid ◽  
Turbine Generator ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Open Cycle ◽  
Ocean Thermal Energy

The vertical temperature distribution in the open ocean can be simplistically described as consisting of two layers separated by an interface. The upper layer is warmed by the sun and mixed to depths of about 100 m by wave motion. The bottom layer consists of colder water formed at high latitudes. The interface or thermocline is sometimes marked by an abrupt change in temperature but more often the change is gradual. The temperature difference between the upper (warm) and bottom (cold) layers ranges from 10°C to 25°C, with the higher values found in equatorial waters. This implies that there are two enormous reservoirs providing the heat source and the heat sink required for a heat engine. A practical application is found in a system (heat engine) designed to transform the thermal energy into electricity. This is referred to as OTEC for Ocean Thermal Energy Conversion. Several techniques have been proposed to use this ocean thermal resource; however, at present it appears that only the closed cycle (CC-OTEC) and the open cycle (OC-OTEC) schemes have a solid foundation of theoretical as well as experimental work. In the CC-OTEC system, warm surface seawater and cold seawater are used to vaporize and condense a working fluid, such as anhydrous ammonia, which drives a turbine-generator in a closed loop producing electricity. In the OC-OTEC system, seawater is flash-evaporated in a vacuum chamber. The resulting low-pressure steam is used to drive a turbine-generator. Gold seawater is used to condense the steam after it has passed through the turbine. The open-cycle can, therefore, be configured to produce desalinated water as well as electricity.

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