• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.2
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• pp.50-64
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• 2019

According to the Maritime Safety Act, there are all 34 routes including 5 traffic safety zones, 3 traffic separation schemes, 26 routes designated by regional maritime affairs departments in the Republic of Korea. In the SOLAS convention, the route information should be is effectively used for the safe navigation. However, the route information is complicatedly composed of the location of the route, the navigation rule by each route, the restriction of the navigation, and the anchorages. Moreover, the present method of providing information using the navigational chart and other publications is not effective for users to grasp the navigational information. Therefore, it was conducted to study the design of the S-100 based routing information data model developed by the International Hydrographic Organization to find ways to more effectively provide route information. To do this, the analysis of route requirement, selection of items, encoding test and users' review were carried out. Through expert user review, it was evaluated that the study on the design of the route information data model can be utilized as a good basic data for the route information integration service. Future research on the development of route information data models is expected to provide integrated route information services.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.647-655
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• 2021

The IMO (International Maritime Organization) is discussing the improvement of energy ef iciency of ships in order to reduce greenhouse gas emissions from ships. Currently, by applying an ORC power generation system using waste heat generated from ships, high energy conversion efficiency can be expected from ships. This technology uses an organic medium based on Freon or hydrocarbons as the working fluid, which evaporates at a lower temperature range than water. Through this, it is possible to generate steam (gas) and generate power at a low and low temperature relatively. In this study, the analysis of heat flow between the refrigerant and waste heat in the ORC power generation system, which is an organic Rankine cycle, is analyzed using 3D simulation techniques to determine the temperature change, velocity change, pressure change, and mass change of the fluid flowing of the WHRU (Waste Heat Recovery Unit) inside and the outside the structure. The purpose of this study is to analyze how the mass change affects the structure, and this study analyzed the heat transfer of the heat exchanger from the refrigerant and the exhaust gas of the ship's main engine in the ORC power generation system using this technique.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.916-922
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• 2018

Recently, power plant effluent condensers received a Renewable Energy Certificate as components of hydrothermal energy (weighted 1.5 times) as one target item of the Renewable Portfolio Standard (RPS) policy. Accordingly, more attention is being paid to the value of thermal wastewater as a heat source. However, for utilization of thermal wastewater from power plants in high-turbidity areas like the West Sea of Korea, a turbidity reducing system is required to reduce system contamination. In this study, an experimental test was performed over a month on thermal wastewater from power plants located in the West Sea of Korea. It was found that water turbidity was reduced by more than 80 % and that the concentration of organic materials and nutrient salts was partially reduced due to the reduction of floating/drifting materials. To conduct a comparative analysis of the level of contamination of the heat exchanger when thermal wastewater flows in through a turbidity reducing system versus when the condenser effluent flows in directly without passing through the turbidity system, we disassembled and analyzed heat exchangers operated for 30 days. As a result, it was found that the heat exchanger without a turbidity reducing system had a higher level of contamination. Main contaminants (scale) that flowed in to the heat exchanger included minerals such as $SiO_2$, $Na(Si_3Al)O_8$, $CaCO_3$ and NaCl. It was estimated that marine sediment soil flowed in to the heat exchanger because of the high level of turbidity in the water-intake areas.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.439-446
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• 2020

The IMO has adopted emission standards through Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL) that strictly prohibit the use of bunker C oil for vessels. In this study, we have adopted the turret-moored Floating LNG-Bunkering Terminal (FLBT) which is designed to receive the LNG from LNGCs and transfer it to LNG-bunkering shuttles in side-by-side moored condition. Numerical analyses were carried out using the high-order boundary-element method for four vessels at various relative distances. Mean wave drift forces were compared in an operational sea state. A model test was performed in the ocean engineering basin at the Korea Research Institute of Ships & Ocean Engineering (KRISO) to verify the safety of the berthing/unberthing operation. In the model test, a jig was designed to simulate tug boats pushing or pulling the bunkering vessels, so that the friction force of the g operation was not affected. Safety depended on the environmental direction, with more stable operation possible if the heading-control function of FLBT is applied to avoid beam-sea conditions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.672-680
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• 2023

Weight is a critical factor in the ship design process given that it has a substantial impact on the hydrodynamic performance of ships. Typically, ships are optimally designed for specific conditions with a fixed draft and displacement. However, in reality, weight and draft can vary within a certain range owing to operational activities, such as fuel consumption, ballast adjustments, and loading conditions . Therefore, we investigated how resistance changes under three different loading conditions, namely overload, design-load, and lightship, for small craft, using both model experiments and numerical simulations. Additionally, we examined the sensitivity of weight changes to resistance to enhance the performance of ships, ultimately reducing power requirements in support of the International Maritime Organization's (IMO) goal of reducing CO2 emissions by 50% by 2050. We found that weight changes have a more significant impact at low Froude Numbers. Operating under overload conditions, which correspond to a 5% increase in draft and an 11.1% increase in displacement, can lead to a relatively substantial increase in total resistance, up to 15.97% and 14.31% in towing tests and CFD simulations, respectively.

• Journal of Ocean Engineering and Technology
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• v.29 no.6
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• pp.418-426
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• 2015

Recently, shipping operators have been making efforts to reduce the fuel cost in various ways, such as trim optimization and bulb re-design. Furthermore, IMO restricts the hydro-dioxide emissions to the environment based on the EEDI (Energy Efficiency Design Index), EEOI (Energy Efficiency Operational Indicator), and SEEMP (Ship Energy Efficiency Management Plan). In particular, ship speed is one of the most important factors for calculating the EEDI, which is based on methods suggested by ITTC (International Towing Tank Conference) or ISO (International Standardization Organization). Many shipbuilding companies in Korea have carried out speed trials around the Korea Straits. However, the conditions for these speed trials have not been exactly the same as those for model tests. Therefore, a ship’s speed is corrected by measured environmental data such as the seawater temperature, density, wind, waves, swell, drift, and rudder angle to match the conditions of the model tests. In this study, fundamental research was performed to evaluate the ship resistance performance due to changes in the water temperature and salinity, comparing the ISO method and numerical simulation. A numerical simulation of a KCS (KRISO Container ship) with a free-surface was performed using the commercial software Star-CCM+ under three conditions that were assumed based on the water temperature and salinity data in the Korea Straits. In the simulation results, the resistance increased under low water temperature & high salinity conditions, and it decreased under high water temperature & low salinity conditions. In addition, the ISO method showed the same result as the simulation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.366-373
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• 2020

According to Article 77 of the Ship Safety Act and Article 97(2) of the Enforcement Ordinance of the Ministry, the Recognized Organization (RO) personnel (ship surveyors) responsible for statutory survey shall have educational qualifications and experience in a specific field or obtain a license under the National Technical Qualifications Act. However, graduates from maritime high schools and those who completed the short-term course of the Ocean Polytec did not satisfy the qualification standards for the RO personnel since they did not graduate from the departments of maritime/fisheries or shipbuilding. Major shipping countries such as the United Kingdom, the United States, and Canada use the IACS (International Association of Classification Societies) regulations, and the Ship Safety Act in Japan has eliminated the qualification requirements for ship surveyors. In particular, under the IMO (International Maritime Organization) and IACS regulations, the RO personnel shall have as a minimum the following formal educational background: a degree or equivalent qualification from a tertiary institution recognized within a relevant field of engineering or physical science (minimum two years' program); or a relevant qualification from a marine or nautical institution and relevant sea-going experience as a certified ship officer; and competency in the English language commensurate with their future work. Considering that Article 17 of the Enforcement Decree on Public Officials Appointment Examinations prohibits educational restrictions and there are no educational restrictions on the qualifications of British and Japanese surveyors, if the maritime high school graduates have sufficient sea-going experience, education, and training, they could be recognized as meeting the qualification requirements. Moreover, those who completed the short-term course of the Ocean Polytec could also be recognized as meeting the qualification requirements because they are required to have at least a professional bachelor's degree (in the case of a third-class CoC (Certificate of Competancy)) and some sea-going experience after completion.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.697-703
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• 2023

As a part of the global industrial efforts to reduce environmental pollution owing to air pollution, regulations have been established by the International Maritime Organization (IMO). The IMO has implemented various regulations such as EEXI, EEDI, and CII to reduce air pollution emissions from ships. They are also promoting measures to decrease the power consumption in ships, aiming to conserve energy. Most of the power used in ships is consumed by electric motors. Among the motors installed on ships, the engine room blower that takes up a significant load, operates at a constant irrespective of demand. Therefore, energy savings can be expected through frequency control. In this study, we demonstrated the efficacy of energy savings by controlling the frequency of the electric motor of the generator blower that supplies combustion air to the generator's turbocharger. The system was modeled based on the output data of the turboharger outlet temperature in response to the blower frequency inpu. A PI control system was established to control the frequency with the target being the turbocharger outlet temperature. By maintaining the turbocharger design standard outlet temperature and controlling the blower frequency, we achieved an annual energy saving of 15,552kW in power consumption. The effectiveness of energy savings through frequency control of blower fans was verified during the summer (April to September) and winter (March to October) periods. Based on this, we achieved annual fuel cost savings of 6,091 thousand won and reduction of 8.5 tons of carbon dioxide, 2.4 kg of SOx, and 7.8 kg of NOx air pollutants on the training ship.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.437-445
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• 2018

IMO (International Maritime Organization) has been strengthening the regulations of ship emission gas such as sulfur oxides (SOX), nitrogen oxides (NOX) and carbon dioxides (CO2) to protect the marine environment. Especially, ECA (Emission Control Area) has been set and operated in the USA and US. As a countermeasure against these environmental regulations, the demand for environmentally, friendly and highly efficient vessels has led to a growing interest in technology related research with respect to electric propulsion systems capable of reducing exhaust gas. Container ships were excluded from the application coverage of the electric propulsion systems for reasons of operation at economical speed. However, in the future, the need for electric propulsion system is expected to rise, because it is easy to monitor and control so that it can be an applicate to smart ship which are represented by fourth industrial revolution technology. In this study, research was carried out to design a generator and battery capacity through the load analysis of the 6,800TEU container ship to apply the electric propulsion system of the container ship. A capacity design based on the load analysis has an advantage that the generator can be operated in a high efficiency section through the load distribution control using the battery.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.610-619
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• 2022

Hydrogen is emerging as an alternative fuel for eco-friendly ships because it reacts with oxygen to produce electrical energy and only water as a by-product. However, unlike regular fossil fuels, hydrogen has a material with a high risk of explosion due to its low ignition point and high flammability range. In order to safely use hydrogen in ships, it is an essential task to study the flow characteristics of hydrogen leakage and diffusion need to be studied. In this study, a numerical analysis was performed on the effect of leakage, ventilation, etc. on ventilation performance when hydrogen leaks in an enclosed space such as inside a ship. ANSYS CFX ver 18.1, a commercial CFD software, was used for numerical analysis. The leakage rate was changed to 1 q, 2 q, and 3 q at 1 q = 1 g/s, the ventilation rate was changed to 1 Q, 2 Q and 3 Q at 1 Q = 0.91 m/s, and the ventilation method was changed to type I, type II, type III to analyze the ventilation performance was analyzed. As the amount of leakage increased from 1 q to 3 q, the HMF in the storage room was about 2.4 to 3.0 times higher. Furthermore, the amount of ventilation to reduce the risk of explosion should be at least 2 Q, and it was established that type III was the most suitable method for the formation of negative pressure inside the hydrogen tank storage room.