• 한국분무공학회지
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• 제15권4호
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• pp.195-201
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• 2010

Due to its carbon-neutral nature, biogas generated from anaerobic digestion or fermentation of biodegradable wastes is one of the important renewable energy sources to reduce global warming. It is mainly composed of methane and various inert gases such as $CO_2$ and $N_2$, and the actual composition of biogas significantly varies depending on the origin of anaerobic digestion process. Therefore, in order to effectively utilize this fuel as an energy source for electricity, it is important to develop power generation engines which can successfully apply biogas with significant composition variations. In this study, efforts have been made to develop a diesel-biogas duel fuel engine as a way to achieve such a stable power generation. The effects of diesel fuel injection quantity and pressure on stable combustion and engine performance were investigated, and an impact of diesel fuel atomization was discussed. The engine test results show that there exists a 2 stage combustion which consists of diesel pilot fuel burning and premixed biogas/air mixture burning in dual fuel engine operation and optimum diesel injection parameters were suggested for biogases with various compositions and heating values.

• 자원리싸이클링
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• 제20권5호
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• pp.52-57
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• 2011

본 연구는 B시 생활폐기물 및 유기성 폐기물의 혼합에 따른 연료화 및 활용방안에 대한 연구를 진행하였다. 반입폐기물, sludge cake와 food wast의 모든 혼합비율의 발열량이 6,000 kcal/kg으로 산출되었고, sludge의 경우 공연비와 온도가 높을수록 발생되는 유해물질 농도가 낮은 것으로 나타났다. 유해물질의 배출기준과 비교하여 보았을 때, 공연비가 2인 경우 800$^{\circ}C$일 때 유해물질 (CO, NOx, SOx)들이 기준이하의 배출 농도를 나타내었으며 혼재 소각 시 소각로 내부 온도 또한 가장 안정되는 것으로 나타났다. 소각시 완전연소가 이루어진다면, 혼합하여 RDF를 제조 시 발열량이 6000 kcal/kg이상으로 연료화 하기에 적합한 것으로 나타났다.

• 한국환경보건학회지
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• 제20권3호
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• pp.13-18
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• 1994

Information on the heating values of municipal solid wastes is very important in evaluating the feasibility of incineration and RDF (Refuse Derived Fuel) manufacture. This paper describes the forecasting methods about the lower heating values of municipal solid wastes. The lower heating values are forecast by the heating values of physical components. The municipal solid wastes consist of paper, food wastes, textiles, plastics, wood and rubber (contained leather). These are the physical components of municipal solid wastes.

• 한국식생활문화학회지
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• 제2권2호
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• pp.169-179
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• 1987

In the life style of the neolithic age, cooking and sleeping space was in one room dugout without differentiation of spaces, so to say one room system. Ro(a kind of primitive fire place) was used for both cooking and heating. However, in the early part of the Iron Age, the uses of Ro were separated into two major uses of cooking and heating. Especially, L-shaped Kudle(an unique under floor heating structure of Korea) was invented for the new system of heating, extending to Koguryo Period. The life style of Koguryo Dynasty could be seen through the mural paintings of tombs. For these mural paintings contain of cooking space(Kitchen), meat storage, and mill house drawing, we can recognize that houses were specialized many quaters according to their function. Also a kitchen fuel hole for preparing food was built without relation to L-shaped Kudle. But during Koryo Period, Kudle could be set up all over the room, the so-called Ondol(the unique Korean panel heating system) settled down. From this development of heating system, room could be adjacent to kitchen, and kitchen fuel hole and heating fuel hole be onething. This system was developed with variety, extending to Chosun Dynasty. In the period of Chosun Dynasty, a kitchen was made close to an Anbang(Woman's living room), and Anbangs Ondol was heated by the warmth of a cooking fireplace. Therefore Handae Puok, outer kitchen was used in summer. As for its storage space, it was seen that there were a pantry near the kitchen and a store house constructed as an independant building. In the latter, it was devided into a firewood storage, a Kimchi storage, and a rice storage, etc. Especially it is a unique feature that 'Handae-Duyju', an outer rice chest which keeps rice, was constructed as an isolated small building.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.37-44
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• 2008

The global warming potential (GWP) of $CO_2$ refrigerant is 1/1300 times lower than that of R134a. Furthermore, the size and weight of the automotive heat pump system can decrease because $CO_2$ operates at high pressure with significantly higher discharge temperature and larger temperature change. The presented $CO_2$ heat pump system was designed for both cooling and heating in fuel cell vehicles. In this study, the performance characteristics of the heat pump system were analyzed for heating, and results for performance were provided for operating conditions when using recovered heat from the stack coolant. The performance of the heat pump system with heater core was compared with that of the conventional heating system with heater core and that of the heat pump system without heater core, and thus the heat pump system with heater core showed the best performance among the selected heating systems. On the other hand, the heating performance of two different types of coolant/air heat pump systems with heater core was compared each other at various coolant inlet temperatures. Furthermore, to use exhausted thermal energy through the radiator, experiments were carried out by changing the arrangement of a radiator and an outdoor evaporator, and quantified the heating effectiveness.

• 한국환경과학회지
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• 제19권1호
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• pp.9-16
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• 2010

This pilot study evaluated fueling feasibility of sewage sludge, which contains a large amount of water content, by applying melting of thermoplastic polyethylene (PE). This study has identified a simultaneous achievement of drying and heating value improvement of the sewage sludge. The sewage sludge collected from a sewage sludge treatment plant during a winter period had a water content of 83.7 wt%, a combustible volatile content of 12.5 wt%, and an ash content of 3.8 wt%. The higher heating value (HHV) of the dried sewage sludge, before impregnation or coating of PE, was 4,600 kcal/kg. The collected sewage sludge was immersed into the melted PE solution, which had a HHV of 11,070 kcal/kg, and kept immersing with increasing reaction time. As the reaction (immersing or coating or impregnation) time increased, the water content of the sludge decreased. However, the HHV of the sludge increased with increasing the reaction time. The HHVs of the sewage sludge immersed or dipped into the melted PE solution for 15 min ranged from 6,780 to 8,170 kcal/kg with water content less than 7 wt%. This result indicates the melted PE solution can be utilized as an improvement technology for dryness and heating value of the sewage sludge with high water content. The sewage sludge impregnated or coated with melted PE can be utilized as potential fuel or energy resources.

• 대한기계학회논문집B
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• 제26권2호
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• pp.328-335
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• 2002

In this study, experiments were performed to investigate the characteristics of flame stabilization of the LFG mixing gas. LFG has merely half heating value compared with liquified natural gas but can be greatly utilized as a commercial fuel. In order to use LFG in practical combustors, Webbe Index and heating value of LFG mixing gas were adjusted by mixing LPG with LFG. The comparisons were conducted between CH$_4$and LFG mixing gas for searching the region of flame stabilization based upon the flame blowout at maximum fuel stream velocity. As a result, the flame stability of LFG mixing gas was not improved with that of CH$_4$in non-swirl and weak swirl diffusion flame. However, LFG mixing gas had wide flame stabilization region rather than CH$_4$with increasing ambient flow rate in strong swirl. It was also found that flame stability was affected by included quantity of inert gas such as CO$_2$in the weak swirl but by heating value of fuel in strong swirl.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.732-733
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• 2004

• 한국자동차공학회논문집
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• 제17권2호
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• pp.126-131
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• 2009

A $CO_2$ heat pump system was designed for both cooling and heating in the cabin of electric vehicles, hybrid vehicles or fuel cell vehicles, In this study, the performance characteristics of the heat pump system without any supplementary heating device were analyzed and the heating performance was compared with the cooling performance for various operating conditions. Experiments were carried out by changing the speed of electric drive compressor, the air flow rate of interior heat exchanger and the air inlet temperature and speed of exterior heat exchanger. Therefore, the cooling/heating capacities and the corresponding COPs are quantified. Also, the heat pump system showed an improved performance for the cooling operation and the heating operation. In this study, the experimental results can be used to evaluate the effect of system design changes on system performance as well as the development of a highly efficient heat pump system.

• 한국자동차공학회논문집
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• 제10권6호
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• pp.72-79
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• 2002

The main objective of this study is to investigate the relationship between chemical structure and higher heating value of reformed diesel fuels by ultrasonic irradiation. In order to analyze the chemical structure changes of the reformed diesel fuels by ultrasonic irradiation, Proton nuclear magnetic resonance spectrometer(1H-NMR) was used and to analyze the effect of higher heating values of these diesel fuels, the bomb calorimeter was used. From the study, following conclusive remarks can be made. 1) The aromatic carbon percentages and higher heating values of the reformed diesel fuels by ultrasonic irradiation increased more than the conventional diesel ones. 2) The aromatics percentages and Branch Index(BI) of the reformed diesel fuels by ultrasonic irradiation decreased more than the conventional diesel ones. 3) The higher heating values on both for conventional fuel and reformed diesel fuels by ultrasonic energy irradiation is directly proportional to aromatic carbon percentages and inversely proportional to aromatic percentages and BI for these fuels.