• 한국수소및신에너지학회논문집
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• 제21권6호
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• pp.570-579
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• 2010

Since the temperature of waste heat source is relatively low, it is difficult to maintain high level of efficiency in power generation when the waste heat recovery is employed in the system. In an effort to improve the thermal efficiency and power output, use of ammonia-water mixture as a working fluid in the power cycle becomes a viable option. In this work, the performance of ammonia-water mixture based Rankine cycle is thoroughly investigated in order to maximize the power generation from the low temperature waste heat. In analyzing the power cycle, several key system parameters such as mass fraction of ammonia in the mixture and turbine inlet pressure are studied to examine their effects on the system performance. The results of the cycle analysis find a substantial increase both in power output and thermal efficiency if the fraction of ammonia increases in the working fluid.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.320-327
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• 2002

In concert with the growing emphasis placed on distributed power generation there will be a need, in the first decade of the 21th century, for a compact thermal energy system capable of providing the total energy needs of individual homes. A natural gas fueled co-generation micro-turbine with ultra low emission will meet this need. Market opportunities for a distributed micro turbine co-generation system are projected to increase dramatically. In this paper, It was determined that with current state of art component performance levels, metrallic materials, thermal efficiency goal of $28\%$ at sea level standard day conditions are attainable. Higher overall thermal efficiency of $78\%$ is attainable with micro-turbine combined with exhaust fired boilers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.354-356
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• 2000

This paper describes the strategy of a daily optimal operational scheduling on cogeneration systems with each other generation mode. The cogeneration systems consists of three generators. auxiiiary devices which are three auxiliary boilers, two waste boilers and three sludge incinerators. One unit that using the back pressure turbin generates the electrical and the thermal energy. The other two units that using the extraction condensing turbine generate the energy. Auxiliary devices operate to supplement the thermal energy to the thermal load with three units. The cogeneration system has a large capacity which is able to supply enough the thermal energy to the thermal load, however the electric power generated is insufficient to satisfy the electrical load. Therefore the insufficient electric energy is supplemented by buying electrical energy from the utility. Simulation was carried out using optimization toolbox. The result reveals that the proposed modeling and strategy can be effectively applied to cogeneration systems with each other generation mode.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.14-19
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• 2021

The reduction of carbon dioxide emissions becomes a global issue, the main source of carbon dioxide emissions in the Asian region is the energy conversion sector, especially coal-fired power plants. We are working to develop technologies that will at least limit the increase in carbon dioxide emissions from the thermal power plants as one way to reduce carbon dioxide emissions. Our research aims to reduce carbon dioxide emissions by removing iron oxide scale from the feedwater system of thermal power plants using a superconducting high-gradient magnetic separation (HGMS) system, thereby reducing the loss of power generation efficiency. In this paper, the background of thermal power plants in Asia is outlined, followed by a case study of the introduction of a chemical cleaning line at an actual thermal power plant in Japan, and the possibility of introducing it into the thermal power plants in China based on the results.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.235-240
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• 2008

The recent development of efficient thermal prime movers for distributed generation id changing the focus of the production of electricity from large centralized power plants to local generation units scattered over the territory. The scientific communality is addressing the analysis and planning of the distributed energy resources(der) with wide spread approaches, taking into account technical, environmental, economical and social issues. The coupling of cogeneration system to absorption/electric chillers or heat pumps as well as the interactions with renewable sources, allow for setting up multi-generation systems for building cooling heating and power(BCHP) systems of different energy vectors such as electricity, heat(at different enthalpy levels), cooling power, hydrogen, various chemical substances and so forth. Adoption of the composite multi-generation systems may lead to significant benefits in term of higher efficiency, reduced $CO_2$ emissions and enhanced economy. This paper outlines the main aspects of the BCHP system framework, illistrating its characteristics and summarizing the relevant distributed multi-generation structures.

• 수산해양기술연구
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• 제60권2호
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• pp.194-206
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• 2024

This study focuses on analyzing the energy-saving effects of the recirculation aquaculture system using seawater source heat pumps and solar power generation. Based on the thermal load analysis conducted using the transient system simulation tool, the annual energy consumption of the recirculation aquaculture system was analyzed and the energy-saving effects of utilizing the photovoltaic system was evaluated. When analyzing the heat load, the sea areas where the fish farms are located, the type of breeding tank, and the circulation rate of breeding water were taken into consideration. In addition, a method for determining the appropriate capacity for each operation time was examined when applying the energy storage system instead of the existing diesel generator as an emergency power, which is required to maintain the water temperature of breeding water during power outage. The results suggest that, among the four seas considered, Jeju should be estimated to achieve the highest energy-saving performance using the solar power generation, with approximately 45% energy savings.

• 한국수소및신에너지학회논문집
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• 제20권6호
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• pp.534-539
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• 2009

One of the most efficient techniques improving the heat transfer performance of a diesel electric generation is a corrosion control in jacket cooling water system. The environmental parameters most affecting corrosion are dissolved salt concentration, temperature, and pH of cooling water. No corrosion occurs in carbon steel probe at pH 11 in normal operating condition of diesel electric generation cooling water. pH control agent in this study is trisodium phosphate. pH control appears to be the most convenient way to enhance the thermal performance of a diesel electric generation.

• 대한전기학회논문지
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• 제37권6호
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• pp.339-349
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• 1988

The simplified simulation technique for the best generation mix is developed and the studied results are described. The best generation mix over study time from the economic point of view can be easily constructed by this technique. Generator maintenance, the operation of pumpgenerator and LNG thermal generator with limited energy are simulated variously, so a role of each generator is also easily evaluated. Through parametric analysis, useful planning guide points are obtained for the best generation mix transition, nuclear power plant construction cost, ruanium cost , oil cost, coal cost and midnight factor in the study case corresponding to real power system size model.

• 한국수소및신에너지학회논문집
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• 제20권5호
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• pp.384-389
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• 2009

KEPRI (Korea Electric Power Research Institute) has studied planar type solid oxide fuel cell (SOFC) stacks using anode-supported cells and kW class co-generation systems for residential power generation. In this work, a 1 kW SOFC system consisted of a hot box part, a cold BOP (balance of plant) part, and a hot water reservoir. The hot box part contained a SOFC stack made up of 48 cells, a fuel reformer, a catalytic combustor, and heat exchangers. Thermal management and insulation system were especially designed for self-sustainable operation in that system. A cold BOP part was composed of blowers, pumps, a water trap, and system control units. When the 1 kW SOFC stack was tested using hydrogen at $750^{\circ}C$, the stack power was about $1.2\;kW_e$ at 30 A and $1.6\;kW_e$ at 50 A. Turning off an electric furnace, the SOFC system was operated using hydrogen and city gas without any external heat source. Under self-sustainable operation conditions, the stack power was about $1.3\;kW_e$ with hydrogen and $1.2\;kW_e$ with city gas respectively. The system also recuperated heat of about $1.1\;kW_{th}$ by making hot water.

• 한국수소및신에너지학회논문집
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• 제34권6호
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• pp.667-672
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• 2023

This study proposes polymer electrolyte membrane fuel cell (PEMFC) based cogeneration system for greenhouse heating and cooling. The main scope of this study is to examine the proposed cogeneration system's suitability for the 660 m²-class greenhouse. A 25 kW PEMFC system generates electricity for two identical air-cooled heat pumps, each with a nominal heating capacity of 70 kW and a cooling capacity of 65 kW. Heat recovered from the fuel cell supports the heat pump, supplying hot water to the greenhouse. In cooling mode, the adsorption system provides cold water to the greenhouse using recovered heat from the fuel cell. As a result, the cogeneration system satisfies both heating and cooling capability, performing 175 and 145 kW, respectively.