Improvement of Ocean Thermal Energy Conversion (OTEC) Efficiency by Using Ammonia-Water Zeotropic Mixture Working Fluid

2021 ◽  
Author(s):  
Burhanddin Halimi ◽  
I.K. Ariel Generanta
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Working Fluid ◽  
Ammonia Water ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Zeotropic Mixture ◽  
Ocean Thermal Energy

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.

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.

MODELLING PERFORMANCE OF OCEAN-THERMAL ENERGY CONVERSION CYCLE ACCORDING TO DIFFERENT WORKING FLUIDS

2016 ◽  
Vol 78 (11) ◽  
Author(s):  
Norazreen Samsuri ◽  
Sheikh Ahmad Zaki Shaikh Salim ◽  
Md Nor Musa ◽  
Mohamed Sukri Mat Ali
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Rankine Cycle ◽  
Developmental Model ◽  
Water Mixture ◽  
Ammonia Water ◽  
Working Fluids ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

Ocean Thermal Energy Conversion (OTEC) is a promising renewable energy technology with the concept to harness the energy stored at the surface seawater (SSW) and the cold deep seawater (DSW). The operation is based on the Rankine cycle, and involves at a minimum temperature difference of 20 K of the SSW and DSW to generate electricity. This research focuses on the economic efficiency of different working fluids used in the OTEC Rankine cycle. The various working fluids include ammonia, ammonia-water mixture (0.9), propane, R22, R32, R134a, R143a, and R410a. Most of the existing commercial OTEC systems use ammonia as the working medium despite its toxic nature. This study shows that the ammonia-water mixture still gives the best results in terms of heat transfer characteristics because of its greater transport properties and stability compared to other fluids. However, fluids such as propane and R32 can also be used as a substitute for ammonia-water mixture despite having slightly lower efficiency, because they are non-toxic and safer towards the environment. The same developmental model was used to present the proposed modified OTEC Rankine cycle, which shows a 4% increase in thermal cycle efficiency. This study reveals economically efficient and environmentally friendly working fluids.

Sign in / Sign up

Export Citation Format

Share Document