• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.2
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• pp.1-6
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• 2013

In high-speed vehicle, selection of fuel, configuration of components and cooling system are required to solve the heating issue by aerodynamic heating and inner combustion process. This subsystem consists of fuel tank, supply pump, various control valve, heat exchanger, including reactor, connecting line, adiabatic structures and insulations. In this paper, applicable fuel property is considered at flight characteristic of hypersonic vehicles. In this regard, current state of fuel/cooling system technology is identified.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.1
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• pp.83-89
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• 2002

The goal of this research is to understand the NOx emission in direct injected diesel engine with premixed hydrogen fuel. Hydrogen fuel was supplied into the test engine through the intake pipe. Amount of hydrogen-supplemented fuel was 70 % basis on heating value of the total input fuel. The effects of intake air temperature and exhaust gas recirculation(EGR) on NOx emission were studied. The intake air temperatures were varied from $23^{\circ}C$ to $0^{\circ}C$ by using liquid nitrogen. Also, the exhaust gas was recirculated to the intake manifold and the amount of exhaust gas was controlled by the valve. The major conclusions of this work include: ( i ) nitrogen concentrations in the intake pipe were increased by 30% and cylinder gas temperature was decreased by 24% as the intake air temperature were changed from $23^{\circ}C$ to $0^{\circ}C$; ( ii ) NOx emission per unit heating value of supplied fuel was decreased by 45% with same decrease of intake air temperature; and (iii) NOx emission was decreased by 77% with 30% of EGR ratio. Therefore, it may be concluded that EGR is effective method to lower NOx emission in hydrogen fueled engine.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.316-323
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• 2007

This study was carried out to obtain the basic data for the development of the solid fuel with investigating the characteristics of mixtures of animal wastes and wasted coal and supply it as an energy resource to agricultural farms for heating of agricultural facilities. It was investigated for the characteristics of animal wastes (swine waste, swine waste with sawdust, cattle waste), wasted coal, the mixtures of animal wastes and wasted coal with or without mixing seawater. The characteristics of solid fuel according to the mixture ratio of animal wastes and wasted coal were analyzed. The effects of seawater affecting on calorific value and thermal pyrolysis of solid fuels were investigated. The results of this study are as follows: 1) The calorific value was improved with mixing seawater into wasted coal due to chemical reaction. 2) The diverse solid fuels of various calorific values can be made with adjusting the ratio of animal wastes and wasted coal. 3) Animal wastes and wasted coal had each different reaction temperature of thermal pyrolysis and the decreasing rate of weight. 4) The mixture of animal wastes and wasted coal would be ignited easily. Therefore, the solid fuel could be ignited more conveniently when seawater is mixed with it.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.5
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• pp.404-414
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• 1991

The purpose of this study is to compare the amount of heating, domestic hot water, and cooking fuel consumption with that of heating fuel consumption by the existing calculation method and to provide rational heating system design and energy conservation through presenting the simplified equation which can anticipate the amount of heating, domestic hot water, and cooking and the load mechanical equipments. The affecting factors to the amount of energy consumption are the case of Heating, Domestic Hot Water and Cooking in addition to the energy conservation intention.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.673-680
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• 2019

This study investigates the validity of applying new carbon nanotube (CNT, Carbon Nano Tube) surface heaters, which are applied in combination with various products, to the vessel's materials, and proposes the commercializable products accordingly. In order to actually apply a CNT surface heating system technology to the ship's equipment for the first time in Korea, we carried out the interview of experts in the technology field and the due diligence of the shipyard, and presented the technology road map for the selected three items. Finally, for "Heating System of Ship Fuel Tank" with the highest commercialization potential, we proposed a conceptual diagram to enable the final development of the product through the product analysis.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.2
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• pp.51-55
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• 2013

This research conducted component analysis of pellet fuel using livestock waste and agricultural by-product and combustion characteristics. As the result of analyzing the characteristics of solid fuel using livestock waste, three components, element analysis, and heating value were suitable for the standard of solid fuel. In addition, content of ash consisted of high concentration of K, P, Na indicating the possibile usage as a soil conditioner. However, it was not suitable for solid fuel using only livestock waste due to the relatively low heating value. To improve the heating value and early ignition, we mixed agricultural by-products (i.e., chaff and sawdust) into livestock waste. The mixed material showed significant increase of combustibles and heating value with decrease of moisture content compared to the livestock waste only.

• Journal of Biosystems Engineering
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• v.37 no.5
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• pp.296-301
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• 2012

Purpose: Combustion and fuel qualities of the animal-fats biodiesel as a heating fuel for agricultural hot air heater were studied. Methods: Biodiesel (BD) was made from animal-fats by reacting with methanol and potassium hydroxide in the laboratory. The biodiesel made in the laboratory was tested for fuel and combustion qualities. Results: The kinematic viscosity and the calorific values of the biodiesels were measured. Kerosene based biodiesel, BD20 (K) showed 18 cSt at $-20^{\circ}C$. It seemed that BD100 was not suitable for a heating fuel under some temperature. As BD content increased, the calorific value decreased up to 40,000 J/g for BD100, while the calorific value of light oil was 45,567 J/g showing difference of 5,567 J/g, about 12% difference. Several different fuels including BD20 (biodiesel 20% + light oil 80%), BD50 (biodiesel 50% + light oil 50%), BD100 (biodiesel 100%), and light oil were tested for fuel combustion qualities for agricultural hot air heater, and their combustion performances were compared and analyzed. Flame dimensions of biodiesels and light oils were almost the same shape at the same combustion condition. Generally, the $CO_2$ amounts of BDs were greater than light oil. However, in this study the differences were minor, so there was no significant difference existed between the BDs combustion and light oil. Conclusions: It seemed that quality was good for heating oil for agricultural hot air heater because of showing no barriers for continuous combustion and proper exhaust gas temperature and $CO_2$ amount discharged. But, for fuel fluidity for higher BD content fuel could be a detrimental problem in situations where the outdoor temperature is lowered. As BD content increased, calorific value decreased up to 40,000 J/g for BD100. Calorific value difference between BD20 and light oil was about 1,360 J/g.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.2
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• pp.57-69
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• 2022

This study analyzes the fuel conditions and environmental effects of converting heating in rural villages that rely on fossil fuels into wood fuel. In particular, we tried to derive the most important considerations when using wooden chips as fuel in aging agricultural villages where various variables such as weather, facility characteristics, fuel quality, and maintenance capabilities work. Above all, an experiment was conducted by comparing it with oak trees to determine whether Italian poplar, a representative attribute water created to supply fuel wood in Korea, is suitable for heating fuel. Through experiments, 1) Even though the supply of poplar wood chips during 10 hours of operation was 60.74 kg less than that of hardwood chips, the production of hot water was 140 kWh higher. 2) The higher the exhaust gas temperature, the proportional (increase) oxygen concentration and inversely (decrease) PM and CO emissions. 3) Poplar has twice as much ash content as hardwood and three times more fine dust has been detected, but it meets all the standards for wood quality at the Korea Forest Science Institute. 4) Under the condition that there is a difference in water content (7.7%), hardwood cost 1.13 times more wood chips per 1 MWh than poplar, and even if the water content is corrected equally, hardwood cost 1.05 times more per 1 MWh than poplar. 5) In conclusion, it was proved that the fuel possibility, economic possibility, and environmental possibility of poplar wood chips are sufficient.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.71-73
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• 2008

Different biosolid fuel (wood pellet) properties between trunk and root of pine (Pinus densiflora) biomass were investigated. Trunk has more organic solvent extracts and Klason lignin content which has higher heating values than root biomass component. In root biomass, polysaccharides content was higher than trunk biomass. Based on Higher Heating Value (HHD) analysis and ash content, trunk biomass showed better solid fuel characteristics than root biomass. But pine root biomass had lower HHD than trunk biomass, its HHD values were higher than other hardwood or annual plant lignocellulosic biomass.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.11
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• pp.1021-1027
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• 2004

Design performances of various configurations of hybrid systems combining an atmospheric pressure molten carbonate fuel cell and a gas turbine have been analyzed. Two different fuel reforming methods (internal and external reforming) were considered. Influences of turbine inflow heating method, location of fuel combustor and associated component arrangements were investigated. In general, internal reforming leads to higher system efficiencies. The optimum design pressure ratio varies among different system configurations. In particular, the design point selection is closely related to the allowable turbine inlet temperature. Configurations with direct heating of turbine inlet flow may realize both higher efficiency and higher specific power than those with indirect heating.