scholarly journals Determine the best location for Ocean Thermal Energy Conversion (OTEC) in Iranian Seas

2016 ◽  
Vol 10 (5) ◽  
pp. 32 ◽  
Author(s):  
Ashrafoalsadat Shekarbaghani
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Caspian Sea ◽  
Power Plants ◽  
Sea Water ◽  
Working Fluid ◽  
The South ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

Two-thirds of the earth's surface is covered by oceans. These bodies of water are vast reservoirs of renewable energy.<strong> </strong>Ocean Thermal Energy Conversion technology, known as OTEC, uses the ocean’s natural thermal gradient to generate power. In geographical areas with warm surface water and cold deep water, the temperature difference can be leveraged to drive a steam cycle that turns a turbine and produces power. Warm surface sea water passes through a heat exchanger, vaporizing a low boiling point working fluid to drive a turbine generator, producing electricity. OTEC power plants exploit the difference in temperature between warm surface waters heated by the sun and colder waters found at ocean depths to generate electricity. This process can serve as a base load power generation system that produces a significant amount of renewable, non-polluting power, available 24 hours a day, seven days a week. In this paper investigated the potential of capturing electricity from water thermal energy in Iranian seas (Caspian Sea, Persian Gulf and Oman Sea). According to the investigated parameters of OTEC in case study areas, the most suitable point in Caspian Sea for capturing the heat energy of water is the south part of it which is in the neighborhood of Iran and the most suitable point in the south water of Iran, is the Chahbahar port.

Performance Analysis of 15 kW Closed Cycle Ocean Thermal Energy Conversion System With Different Working Fluids

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Jianying Gong ◽  
Tieyu Gao ◽  
Guojun Li
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Sea Water ◽  
Working Fluid ◽  
Closed Cycle ◽  
Working Fluids ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Stable Operating ◽  
Ocean Thermal Energy

Closed cycle ocean thermal energy conversion (CC-OTEC) is a way to generate electricity by the sea water temperature difference from the upper surface to the different depth. This paper presents the performance of a 15 kW micropower CC-OTEC system under different working fluids. The results show that both butane and isobutane are not proper working fluids for the CC-OTEC system because the inlet stable operating turbine pressure is in a very narrow range. R125, R143a, and R32, especially R125, are suggested to be the transitional working fluids for CC-OTEC system for their better comprehensive system performance. Moreover, it is recommended that propane should be a candidate for the working fluid because of its excellent comprehensive properties and environmental friendliness. However, propane has inflammable and explosive characteristics. As for the natural working fluid ammonia, almost all performance properties are not satisfactory except the higher net output per unit sea water mass flow rate. But ammonia has relative broader range of the stable operating turbine inlet pressure, which has benefits for the practical plant operation.

Thermodynamic Analysis of Ocean Thermal Energy Conversion System With Different Working Fluids

2017 ◽  
Author(s):  
Dashu Li ◽  
Li Zhang ◽  
Xili Duan ◽  
Xiaosuai Tian
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Thermal Efficiency ◽  
Sea Water ◽  
Working Fluid ◽  
Ocean Temperature ◽  
Water Pump ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

A thermodynamic model is developed for ocean thermal energy conversion (OTEC) systems. Considering the narrow temperature range in the evaporator, different refrigerants including R717, R134a and R600 were analyzed and compared under sub-critical state with practical ocean thermal conditions. The results show that larger ocean temperature differences will lead to higher evaporation pressures, and less pumping power requirements for all pumps, i.e., warm sea water pump, cold sea water pump and pumps for the working fluid. The thermal efficiency of different systems and the net power output were found to be closely related to ocean temperature difference, with a positive linear relationship. It was also found that R717 provides the highest thermal efficiency with the least pump power requirement. This working fluid could potentially be used for OTEC system development. This study provides useful insights to the design and equipment selection of OTEC systems.

A New Improved Ocean Thermal Energy Conversion System With Suitable Floating Vessel Design

2009 ◽  
Author(s):  
Nagan Srinivasan
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Power Plants ◽  
Cold Water ◽  
Deep Ocean ◽  
Capital Cost ◽  
Working Fluid ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

Demand for energy worldwide is increasing significantly. A need for alternate energy sources has been brought to the attention of scientists and engineers. Ocean Thermal Energy Conversion (OTEC) is one among them which is in the development stage for the past three to four decades. Great amount of energy is available in deep-ocean with temperature difference between in upper surface-layer and in deep-ocean layer with maximum range of say up to 25 degree C in localized offshore locations near of equatorial waters. However, the technology is not in commercial operation due to the need of large capital cost. Advances in heat-exchanger material, cold-water pumps and working-fluid are the areas that research has been done extensively to make OTEC successful system. However none of that improvement in the design made OTEC technology attractive for cost effective commercialization. This paper proposes a new feasible OTEC system for about 100 MW power plants with significant change from the conventional system. The main purpose of the proposed new OTEC system is to reduce the capital cost significantly and make it commercial feasible. New types of floating vessels are proposed to support the new OTEC system to achieve cost efficiency. The floaters are very innovatively designed to support the new OTEC system. The new OTEC system with the corresponding floater significantly reduces the capital-cost of the OTEC system compared to the conventional OTEC system. Both the new OTEC system and the supporting floater system are presented herein.

Experimental Studies on the Seawater Desalination System Based on Ocean Thermal Energy Conversion

2013 ◽  
Vol 448-453 ◽  
pp. 3254-3258
Author(s):  
Feng Yun Chen ◽  
Wei Min Liu ◽  
Liang Zhang
Keyword(s):  
Heat Exchanger ◽  
Energy Conversion ◽  
Thermal Energy ◽  
Sea Water ◽  
Economic Benefits ◽  
Seawater Desalination ◽  
Tube Heat Exchanger ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

Seawater desalination system has been established based on the ocean thermal energy conversion in this paper. Through compared finned tube heat exchanger with round tube heat exchanger obtained the fresh water output at different temperature and flow velocity of the warm and cold sea water. In this system the energy of the warm and cold sea water has been fully utilized, and so improved the economic benefits of the ocean thermal energy conversion.

scholarly journals Analysis of Ocean Thermal Energy Conversion Power Plant using Isobutane as the Working Fluid

2018 ◽  
Vol 7 (1) ◽  
Keyword(s):  
Heat Exchanger ◽  
Energy Conversion ◽  
Thermal Energy ◽  
Working Fluid ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Useful Power ◽  
Design Characteristics ◽  
Process Energy ◽  
Ocean Thermal Energy

The use of organic isobutane will be investigated for a closed-cycle Ocean Thermal Energy Conversion (OTEC) onshore plant that delivers 110 MW electric powers. This paper will cover concept, process, energy calculations, cost factoids and environmental aspects. In isobutane cycle, hot ocean surface water is used to vaporize and to superheat isobutane in a heat exchanger. Isobutane vapor then expands through a turbine to generate useful power. The exhaust vapor is condensed afterwards, using the cold deeper ocean water, and pumped to a heat exchanger to complete a cycle. Results show the major design characteristics and equipment's of the OTEC plant along with cycle efficiency and cycle improvement techniques.

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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