• Journal of National Security and Military Science
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• s.1
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• pp.423-446
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• 2003

While the demand for energy has shown a sharp increase recently, the supply seems to be limited by the fact that the conventional fossil fuel energy or nuclear energy has its own environmental problems such as, for example, global warming or nuclear waste disposal. To overcome such limited supply of energy, the utilization of natural thermal energy such as river water and seawater as well as treated sewage can be a substantial supplement. The potential use of the unused energy has become more and more feasible these days as the heat pump technology has been advanced. In the present study, the unused energy resources are estimated on regional and monthly basis for each resource by the method proposed here in order to establish the fundamental data for its utilization. The potential use of the unused energy is a1so discussed.

• Proceedings of the KWS Conference
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• v.43
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• pp.118-120
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• 2004

Recently 9Cr-1Mo azzoy is used in the Nuclear power plant due to its special properties. This material has the merit of high-strength resistance and corrosion resistance. Therefore the demand for this alloy is dramatically increased in the Nuclear power, petro-chemical complex etc. Re various research has been conducted to improve the material properties of this alloy. In spite of this circumstance, detail research in the area of welding process of this alloy is yet to be expanded In this study the numerical non-linear heat transfer analysis of laser welding which may possibly replace the conventional SMAW fabrication of 9Cr-1Mo steel has been carried out.

• Journal of Energy Engineering
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• v.8 no.1
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• pp.76-84
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• 1999

The demand of Small Self-generating System (SSS) including Small Cogeneration System (SCS) is constantly increasing with the need of electricity and/or thermal in office, hospital, hotel, and small factory, etc. It is especially recommended to operate SCS in the heat-following mode to maximize the efficiency of generator. In case of the heat-following mode SCS has got to be connected to distribution system so as to send surplus power to the utility or receive the short power from utility. But the interconnection of SSS with distribution system causes a few problems such as the bad power quality, and low security. If SSS is not promptly disconnected after faults occur (Islanding of SSS), it can not only damage equipment of utility and adjacent customers but also endanger life of human due to overvoltage or overcurrent. In this paper it has been deeply discussed if interconnection of engine self-generator/control system satisfies the protective requirement for SSS or not. 500 kW engine generator running in the Jodo island has been used to perform the analysis of interconnection.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.10
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• pp.767-772
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• 2009

The demand for a boiler with low NOx burner is increasing with the recent strict NOx regulation. Staged burner is a common low NOx burner to suppress the formation of thermal NOx by yielding local fuel rich and lean condition. The staged burner gives fire with bigger frontal area and length compared with a conventional burner, which changes heat transfer characteristics in the combustion chamber. The heat transfer and exhaust gas characteristics have been studied in the present study for a 0.5 t/h class furnace type boiler adopting the staged burner. A numerical simulation has been conducted to clarify the detailed physics inside the combustion chamber.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.26-33
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• 1998

It has been referred as a problem that heat source/sink is distance from heat demand area in using unused energy. To solve the distance problem in using unused energy, the water from city water system like tap water, rain water, waste water used as unused energy. To survey the potential of the water of city water system, it is developed that the calculation method of the potential using unit method. The amount of theoretical unused energy and energy saving in the Osaka City, Japan were estimated by using that method.

• Journal of Environmental Science International
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• v.15 no.5
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• pp.493-501
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• 2006

The increase in environmental loads and energy consumptions has resulted in the need of developed new forms of energy for a sustainable use for the society. Recently, the viability of using unused energy has attracted a great deal of attention. From the view point of using unused energy, the most critical problem can be referred to as the distance between the heat source/sink and heat demand area. The water resource in the city water system was used to solve this distance problem with unused energy. The calculation method of the potential use unit was used to survey the potential of the water resource in the city water system. The amount of theoretical unused energy and energy savings in the model city were estimated using this method. It is estimated that the amounts of energy savings and $CO_2$ reduction correspond to 131.3 GWh and 29280[t-C], respectively, per annual basis.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.127-128
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• 2010

As P-new-city is planned and constructed, district eating utilizing an existing near-by power plant's waste heat is considered as an economic and environment friendly way of providing heating to the new city. Many pipeline diameters and pumping station location and capacity were assumed, investigated and optimized, to satisfy the customers' heat demand considering common district heating pipe-network design and construction practice, and also and construction, pumping station land price and construction and the pumping energy cost during lifetime of DH systems.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.555-558
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• 2008

The demand for a boiler with low NOx burner is increasing with the recent strict NOx regulation. Staged burner is a common low NOx burner to suppress the formation of thermal NOx by yielding local fuel rich and fuel lean condition. The staged burner gives fire with bigger frontal area and length compared with a conventional burner, which changes heat transfer characteristics in the combustion chamber. The heat transfer and exhaust gas characteristics has been studied in the present study for a 0.5 t/h class furnace type boiler adopting the staged burner. A numerical simulation has been conducted to clarify the detailed physics inside the combustion chamber.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.11
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• pp.1547-1554
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• 1998

The object of this study was to develop an economic assessment program for the optimal design of the cogeneration systems composed of combining engine, generator, waste heat recovery exchanger, absorption chiller, and boiler, etc. The energy demand categorized by electric power, heating, cooling and water supply was determined by statistical data of the existing cogeneration systems. An economic assessment was performed by comparing the total cost of cogeneration system with that of non-cogeneration system. The total cost was evaluated by adding initial investment to operational cost considering efficiency of equipment, cost of equipment, fuel and electricity. To confirm the validity of the developed program, a hotel building with an area of $127,960m^2$ was selected, and the simulated results were compared with the measured data. The difference between the simulated and the measured values for the selected hotel building was approximately 12% for annual electric consumption.

• KIEAE Journal
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• v.2 no.4
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• pp.65-72
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• 2002

In this study, the evaluation of environmental performance of the building energy system of domestic commercial sector was carried out. Based on the theory of linear programming model, we established an evaluation model satisfying object functions and constraint conditions. Employing the model, the evaluation of building energy system was performed under the consideration of cost and environmental constraint conditions. As an evaluation tool, MARKAL (MARKet Allocation) known as a market distribution model was employed. We analyzed scenarios of Case I (Base Scenarios) through Case IX established by the combination of the components of building energy system such as glazing, building skin, core, and heat source system. According to the results of the evaluation, highest contribution on the useful energy demand was obtained from the building energy system combined with solar heat source system, when the total amounts of $CO_2$ exhaust as an environmental constraint condition is assumed to be the level of 1995.