Improving the OTEC Power Plant Performance by Metal Hydride Energy Systems

1997 ◽  
Vol 119 (2) ◽  
pp. 145-151 ◽  
Author(s):  
M. Gambini
Keyword(s):  
Power Plant ◽  
Metal Hydride ◽  
Performance Optimization ◽  
Energy System ◽  
Point Of View ◽  
Plant Performance ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

A new system to improve the present OTEC (ocean thermal energy conversion) power plant performance is here presented. This is a metal hydride energy system operating as a “temperature upgrading” device which allows an increase of the OTEC plant working fluid temperature at the turbine inlet. The integrated MHTUP (metal hydride temperature upgrading)—OTEC plant has been investigated, taking into account the dynamic operations of MHTUP system and the OTEC pumping power increase due to the water circulation in the MHTUP system. The results show an increase in the OTEC net power of about 20 percent and the technological feasibility of the proposal. The large amounts of metal hydride and of heat transfer surface required by MHTUP system involve a critical situation from an economical point of view. The further analysis, particularly regarding the performance optimization and new plant arrangement of the MHTUP system, have to be developed in order to attain the economical feasibility of the proposal.

The Ocean Thermal Gradient Hydraulic Power Plant and Its Scope

2003 ◽  
Author(s):  
Earl J. Beck
Keyword(s):  
Power Plant ◽  
Thermal Gradient ◽  
Cold Water ◽  
Working Fluid ◽  
Hydraulic Power ◽  
Tropical Oceans ◽  
Thermal Energy Conversion ◽  
Near Shore ◽  
Power Outputs ◽  
Ocean Thermal Energy

Heretofore, the concept of developing power from the tropical oceans, (Ocean Thermal Energy Conversion, or OTEC) has assumed the mooring of large platforms holding the plants in deep water to secure the coldest possible condensing water. As the Ocean Thermal Gradient Hydraulic Power Plant (OTGHPP) does not depend, on the expansion of a working fluid, other than forming a foam of steam bubbles. It does not need extremely cold water as would be dictated by Carnot’s concept of efficiency and the 2nd Law of Thermodynamics. Plants may be based on or near-shore on selected tropical islands, where cool but not extremely cold water may be available at moderate depths. This paper discusses the above possibilities and two possible plant locations, as well as projected power outputs. The location and utilization of large of amounts of power on isolated islands, where cabling of power to major population centers would not be feasible are discussed. Two that come to mind are the reduction of bauxite to produce aluminum and the of current interest is the electrolyzing of water to produce gaseous hydrogen fuel to be used in fuel cells, with oxygen as a by-product.

scholarly journals THEORETICAL INVESTIGATION OF SOLAR ENERGY HIGH TEMPERATURE HEAT STORAGE TECHNOLOGY BASED ON METAL HYDRIDES

2011 ◽  
Vol 19 (02) ◽  
pp. 149-158 ◽  
Author(s):  
XIANG-YU MENG ◽  
ZE-WEI BAO ◽  
FU-SHENG YANG ◽  
ZAO-XIAO ZHANG
Keyword(s):  
Energy Storage ◽  
Solar Energy ◽  
Metal Hydride ◽  
Performance Optimization ◽  
Storage System ◽  
Metal Hydrides ◽  
Energy System ◽  
Energy Storage System ◽  
Point Of View ◽  
Thermal Release

A solar energy storage system based on metal hydrides was proposed in this paper. The numerical simulation of processes of energy storage and thermal release were carried out. The dynamic behavior of heat and mass transfer in the metal hydride energy system were reported. Some factors which influence the whole system performance were discussed. The paper also made an economic analysis of the system, the results proved that the large amounts of metal hydride materials and the configurations of metal hydrides energy storage system involve a critical situation from an economical point of view. Then further analysis, particularly regarding the performance optimization and new plant arrangement of the metal hydrides energy storage system, has to be developed in order to attain the economical feasibility of the proposal.

Optimization of a Closed-Cycle OTEC System

1990 ◽  
Vol 112 (4) ◽  
pp. 247-256 ◽  
Author(s):  
Haruo Uehara ◽  
Yasuyuki Ikegami
Keyword(s):  
Heat Exchangers ◽  
Sea Water ◽  
Working Fluid ◽  
Turbine Efficiency ◽  
Thermal Energy Conversion ◽  
Calculation Results ◽  
Change Temperature ◽  
Ocean Thermal Energy ◽  
Powell Method ◽  
Method Of Steepest Descent

Optimization of an Ocean Thermal Energy Conversion (OTEC) system is carried out by the Powell Method (the method of steepest descent). The parameters in the objective function consist of the velocities of cold sea water and warm sea water passing through the heat exchangers, the phase change temperature, and turbine configuration (specific speed, specific diameter, ratio of blade to diameter). Numerical results are shown for a 100-MW OTEC plant with plate-type heat exchangers using ammonia as working fluid, and are compared with calculation results for the case when the turbine efficiency is fixed.

Preliminary Design of a 1-MWe OTEC Test Plant

1982 ◽  
Vol 104 (1) ◽  
pp. 3-8 ◽  
Author(s):  
T. Kajikawa
Keyword(s):  
Cold Water ◽  
Working Fluid ◽  
Test Plant ◽  
Mooring System ◽  
Preliminary Design ◽  
Closed Cycle ◽  
Water Pipe ◽  
Thermal Energy Conversion ◽  
Design Value ◽  
Ocean Thermal Energy

An ocean-based, 1-MWe (gross) test plant has been planned to establish the feasibility of OTEC (ocean thermal energy conversion) power generation in the revised Sunshine Project. The preliminary design of the proposed test plant employs a closed-cycle power system using ammonia as the working fluid on a barge-type platform with a rigid-arm-type, detachable, single-buoy mooring system. Two types each of titanium evaporators and condensers are to be included. The steel, cold-water pipe is suspended from the buoy. The design value of the ocean temperature difference is 20 K. The paper presents an overview of the preliminary design of the test plant and the tests to be conducted.

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.

Power Plant Performance Optimization Experiment on Primary Frequency Regulation

2013 ◽  
Vol 437 ◽  
pp. 769-774
Author(s):  
Li Chen ◽  
Nian Su Hu ◽  
Qin Gang Li
Keyword(s):  
Power Plant ◽  
High Power ◽  
Performance Optimization ◽  
Control Model ◽  
Plant Performance ◽  
Frequency Regulation ◽  
Large Power ◽  
Power Plant Operation ◽  
Primary Frequency ◽  
Safety And Stability

As the increment of the power grid scale and the requirement of high power quality, the requirement of the primary frequency regulation (PFR) of large power plant i becomes more and more strictly. In order to improve the PFR performance and to ensure the safety and stability of power plant operation, an experimental analysis was carried out to optimize the control model and parameters of the CCS, DEH and primary frequency.

Adapting the Zero-Emission Graz Cycle for Hydrogen Combustion and Investigation of Its Part Load Behaviour

2016 ◽  
Author(s):  
Wolfgang Sanz ◽  
Martin Braun ◽  
Herbert Jericha ◽  
Max F. Platzer
Keyword(s):  
Power Plant ◽  
High Efficiency ◽  
Energy System ◽  
Hydrogen Combustion ◽  
Pure Oxygen ◽  
Working Fluid ◽  
Parameter Study ◽  
Additional Parameter ◽  
Part Load ◽  
Zero Emission

A modern energy system based on renewable energy like wind and solar power inevitably needs a storage system to provide energy on demand. Hydrogen is a promising candidate for this task. For the re-conversion of the valuable fuel hydrogen to electricity a power plant of highest efficiency is needed. In this work the Graz Cycle, a zero emission power plant based on the oxy-fuel technology, is proposed for this role. The Graz Cycle originally burns fossil fuels with pure oxygen and offers efficiencies up to 65 % due to the recompression of about half of the working fluid. The Graz Cycle is now adapted for hydrogen combustion with pure oxygen so that a working fluid of nearly pure steam is available. The changes in the thermodynamic layout are presented and discussed. The results show that the cycle is able to reach a net cycle efficiency based on LHV of 68.5 % if the oxygen is supplied “freely” from hydrogen generation by electrolysis. An additional parameter study shows the potential of the cycle for further improvements. The high efficiency of the Graz Cycle is also achieved by a close interaction of the components which makes part load operation more difficult. So in the second part of the paper strategies for part load operation are presented and investigated. The thermodynamic analysis predicts part load down to 30 % of the base load at remarkably high efficiencies.

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