• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.276-284
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• 2014

The purpose of this study is to establish the designing method of ORC(Organic Rankine Cycle) radial inflow turbines. RTDM(Radial Turbine Design Modeler) Ver.2.1 which is a preliminary design program of radial inflow turbines was developed to achieve this purpose. The 200kW-class radial inflow turbine for OTEC(Ocean Thermal Energy Conversion) was designed by using the RTDM Ver.2.1 and CFD(Computational Fluid Dynamics) simulation was performed to verify the accuracy of RTDM Ver.2.1. With the result of simulation, the accuracy of RTDM Ver.2.1 was almost 94.6% based on the designed total enthalpy drop of the radial inflow turbine. Strategy of adjusting the mass flow rate was adopted on this study to satisfy the requirements of its power and rotor outlet's conditions for the designed radial inflow turbine. The mass flow rate was consequently increased to 21.2 kg/s for the designed 200kW-class radial inflow turbine for OTEC, and then Total to total and Total to static efficiency are 89.8% and 85.36% respectively.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.836-842
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• 2013

In this paper, the 20 kW Ocean Thermal Energy Conversion(OTEC) is newly proposed in order to select the refrigerant that makes the cycle performance be optimized and the performance of 20 kW OTEC applying 15 pure refrigerants and 16 mixed refrigerants is analyzed. The efficiency of system, the mass flow of working fluids and TPP, which is new concepts, are analyzed. In view of cycle efficiency, R32/R152a (87:13) is the highest efficiency among the refrigerants. At the mass flow of working fluid to make the 20 kW electricity, R717 is shown as the lowest value. And in view of TPP in this study, R32/R134a 70:30 is the most optimized refrigerant. The analysis can confirm that the refrigerant is different along with the part of the system, so it is necessary to select the optimized refrigerant for 20 kW OTEC.

• Journal of the Korean Association of Geographic Information Studies
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• v.1 no.2
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• pp.44-55
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• 1998

This study was carried out to investigate the feasibility of OTEC(Ocean Thermal Energy Conversion) operation, in the East Sea of Korea. Accumulated cruise data of NFRDI (National Fisheries Research and Development Institute) over the period 1966~1995 were used to locate appropriate spot by season as well as by latitude which would show the difference at least $15^{\circ}C$ or more between the surface layer and each depth of 50, 100, 150, 200, 250, 300, 400 and 500m. Our results showed that the coastal areas of Pohang city met the requirement of more than $20^{\circ}C$ difference for OTEC plant from August to October. In contrast, in case that $15^{\circ}C$ would be possible thermal difference to operate OTEC plant, most coastal areas in the East Sea including Pohang from June to December are potential candidates for this future energy source. Therefore, we present in this paper the first option to locate the best place for OTEC plant operation using Geographical Information System (GIS), which is currently used for multi-dimensional space analysis.

• 전기의세계
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• v.33 no.11
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• pp.683-690
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• 1984

본고의 내용은 다음과 같다. 1. 배경 2. 열역학 사이클 3. OTEC 구조와 입지 4. 문제점 및 향후과제

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1002-1006
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• 2015

In this paper, design and analysis of permanent magnet synchronous generator for ocean thermal energy conversion (OTEC) considering magnetically coupled turbine-rotor system is discussed. In particular, the rotor dynamics considering bearing span and journal shaft diameter is highlighted. The two topologies of permanent magnet synchronous generator with magnetic coupling are employed for comparison of computed rotor dynamics and generating characteristics. The analysis results show that the critical speed of the turbine-rotor system is higher when the rotor is coupled by magnetically coupling. Finally, the experimental results confirmed the validity of the proposed design and analysis scheme and successful development.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.10
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• pp.1002-1008
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• 2001

The energy is the basis for almost all industrial activities and domestic needs. But recently there are increasing concerns internationally over environmental problems and consequent climate changes caused by the excessive use of fossil fuels. Furthermore the price of crude oil is increasing steadily with unstable supplies. In order to solve these national energy problems, the utilization of Ocean Energy is introduced as one of the best alterative technologies for the future. OTEC Power Plant has been installed at the West Inchon Power Plant Site. Temperature differences of$20~25^{\circ}C$ been utilized for plant operations, where R22 is used as a working fluid. The system is composed of low pressure turbine, plate type heat exchanger, and pumps. In the present investigation the experimental results, such as gross power, net power and objective function, are analysed when temperature differences change from the reference design point.

• Journal of Power System Engineering
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• v.17 no.3
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• pp.5-11
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• 2013

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1030-1035
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• 2012

In this research, we analysed design and CFD analysis of an inflow radial turbine for OTEC with an output power of 8kW using an working fluid of ammonia. The inflow radial turbine consists of scroll casing, vain nozzle with 18 blade numbers and rotor blade with 13 blade numbers. Mass flow rate, and inlet temperature are 0.5kg/s and $25^{\circ}C$ respectively, and variable rotational speeds were applied between 12,000 and 36,000 with 3,000 rpm intervals. As the results according to the rotational speeds, the designed speed is 24,000 rpm where maximum efficiency exists. The maximum efficiency and output power are 88.66% and 8.52kW, respectively. Through this study, we expect that the analysed results will be used as the design material for the composition of the turbine optimal design parameters corresponding to the target output power under various working material conditions.

• Journal of Power System Engineering
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• v.20 no.6
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• pp.87-92
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• 2016

This research dealt with performance characteristics of OTEC system applying an ejector and additional pump. Each system using five kinds of working fluids was analyzed, and primary parameters with respect to entrainment ratio were examined: Turbine gross power, evaporation capacity, pump work, efficiency and volume flow ratio. The primary results were as following. The efficiency of ejector-pump OTEC system was dependent on entrainment of the ejector. The degree of efficiency change was different from applied working fluid, and amount of pump work was turned out to be primary factor affected system efficiency. Meanwhile, optimized entrainment ratio was different from applied working fluid since their different vapor density. System efficiency at optimized entrainmet ratio of each working fluid was around 5%, showing minor difference each other.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.218-218
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• 2012