Earticle

본 논문은 한국에서의 석탄산업이 신기후체제의 출범 이후에도 여전히 중요하며, 일정한 물량의 석탄 비축을 통해 에너지원의 수급을 조절할 수 있는 능력을 지닐 필요성에 대한 근거를 제시하는데 있다. 최근 신재생에너지의 비중 증가는 석탄이나 석유와 같은 화석연료의 의존도를 낮출 것으로 전망된다. 그리고 이에 따라 석탄의 사용도 감소할 것으 로 전망되지만, 아직 에너지원별 수요의 면에서나 전력 공급의 면에서 석탄이 에너지원으로서의 지위가 여전히 큰 것이 확인되었다. 석탄의 최적 비축 규모는 기존 연구의 연간 수요를 기준으로 추정하였다. 이러한 점에서 지속가능한 성장을 위한 산업적 정책으로서 석탄산업의 유지와 연간 최적 비축 규모의 결정은 매우 중요한 문제이다.

The purpose of this study is to recognize the importance of sustaining the coal industry in spite of the declaration of new climate change regime. Due to the importance to have the ability to control the supply and demand for energy source, this study will present the ground supporting the need to save some fixed amount of coal to carry out this task. The relative quantity of fossil fuel like coal and oil consumed as an energy source is reduced due to the increasing portion of renewable energy sources. Nevertheless, we can verify the fact that the position as a main energy source in demand for and supply of electric power is still valid. And the optimal amount of coal storage is estimated through the average annual amount of demand derived from preceding studies. In this context, it is very urgent problem to maintain the coal industry as a industrial policy for the sustainable national economic growth through the coal storage policy and to determine the optimal amount of annual storage.

Depending on the living styles, the types of energy consumed by households have changed, and the consumption has increased rapidly. Consequently, those have led to environmental issues, such as exhaustion of energy and the climate changes. As one of solutions to such issues, energy efficiency can be approached. Therefore, in this study, the gas water heater(115S type Rheem products) that made in Germany and obtain hot water using gas as a heat source is selected. a 1.0㎥ water tank with a 6kW electronic heater is installed and a water temperature and pressure is maintain constantly also thermometer is injected. Two of gas meter, one of pressure regulator and three of time measurement devices are installed in a combustion facility and fuelling facility with a magnet valve so it can observe and record combustion reactions. Quantity of hot water that heated by boiler is recorded using a quantity measurement tank, and have been heated by the boiler have been to record and measure the amount and utilized the data acquired through measurement of all factors that are applied to acquire hot water in order to calculate the use rate of final energy. In conclusion, this researcher drew the economic strong points of the hot water generated by gas.

본 연구는 울산광역시의 국가산업단지에서 발생하는 폐수슬러지의 에너지 자원화를 위한 기초자료로 활용하기 위해 특성을 조사하였으며, 19개 기업에서 채취된 폐수슬러지를 대상으로 삼성분, 원소조성, 열량, 중금속 농도, 메탄발생량을 분석하였다. 삼성분(%)은 수분함량, 가연분, 회분이 각각 53.0~84.3, 14.1~33.2, 1.7~20.2로 나타났으며, 건조고위발열량(kcal/kg)은 석유화학제조업, 자동차제조업, 식음료제조업, 화학제품제조업, 펄프제지제조업이 각각 2544~4561, 3602, 2868~4250, 1292~4593, 1304~1444으로 나타났다. 중금속분석결과는 화학제품제조업에서 채취한 하나의 시료를 제외하고는 폐기물의 해양배출 및 지정폐기물 판정 기준 농도 이하로 나타났으며, 메탄발생량(ml CH4/g VS)은 펄프제지제조업, 식음료제조업, 화학제품제조업, 석유화학제품제조업, 자동차제조업이 각각 121~152, 92~175, 16~179, 31~139, 85으로 나타났다. 폐수처리슬러지의 에너지 자원화방안으로 소각과 혐기성 분해를 고려할 수 있으며, 슬러지 특성 분석결과, 사업장에서 발생하는 폐수슬러지는 열량, 메탄생성량 등 에너지 잠재량의 변동이 크므로, 에너지 자원화를 위해서는 이들 방법에 적합하게 특성의 체계적인 관리가 필요한 것으로 나타났다.

The characterization of organic sludges collected from wastewater treatment facilities of various companies located in Ulsan national industrial complexes was done for their moisture content, volatile solid content, fixed solid content, elemental composition, heating value, heavy metal concentration, and methane yield. The range(%) of moisture content, volatile solid content and fixed solid content were 53.0~84.3, 14.1~33.2, and 1.7~20.2, respectively. The higher heating value (kcal/kg, HHV, dry basis) of sludges from petrochemical industry, automobile industry, food and beverage industry, chemical industry, pulp and paper industry were 2544~4561, 3602l, 2868~4250, 1292~4593, and 1304~1444, respectively. All the sludges except that from chemical industry, contained heavy metals lower than the standard for ocean dumping. The methane yield (ml CH4/gVS) of the sludges from pulp and paper, food and beverage, chemical, petrochemical, and automobile industries were 121~152, 92~175, 16~179, 31~139, and 85.0, respectively. As potential energy recovery methods, incineration and anaerobic digestion of wastewater sludges may be considered, in which case the characterization results indicated that the sludges have a large variation in their energy production potential (as revealed from their heating value and methane yield). Thus, based on their characteristics, systematic management of sludges by appropriate technology is required for efficient energy recovery.

The study evaluated the effects of dietary fiber and energy levels administered during two growing periods (d 0?28 and d 29?56) for pigs exposed to a high temperature. A total of 96 growing pigs were used in six treatments as: Two treatments in thermoneutral temperature (21℃?24℃) with dietary energy of 3,300 and the inclusion of high or low fiber, two treatments in heat stress (30℃?34℃) with dietary energy of 3,300 and the inclusion of high or low fiber, and two treatments in heat stress with dietary energy of 3,450 and the inclusion of high or low fiber. Among standard energy level treatments, heat-stressed pigs showed lower average daily gain (ADG), feed intake, digestibility of dry matter, gross energy, crude protein, and crude fiber in phases 1 and 2. Moreover, higher concentrations of acetate, propionate, butyrate, and total short-chain fatty acid (SCFA) in feces were shown in pigs fed high fiber diets. There was a negative interaction between dietary fiber and energy for the fecal concentration of isobutyrate in phase 1 and valerate in phase 2. Pigs in heat stress treatments showed a higher rectal temperature, respiratory rate, hair cortisol, plasma zonulin, and fecal lipocalin-2. Among heat stress treatments, the overall ADG was increased in pigs fed high fiber. Pigs fed high dietary fiber showed a greater concentration of acetate, propionate, butyrate, and total SCFA. High fiber treatments decreased plasma zonulin. In conclusion, the inclusion of beet pulp, soluble fiber, at the level of 4% looks necessary in pigs diet during heat stress.

Asia-Pacific countries have tropical and subtropical climate with high rainfall each year. Indonesia is a country in Southeast Asia which has a tropical climate and very high rainfall, that has two seasons per year, they are rainy season and dry season. Rain drops that fall to the earth's surface occur through a long process called the hydrologic cycle. The cycle starts from the evaporation of water in the earth's surface by the heat of the sun, the condensation of water vapor to form clouds, until the clouds become saturated and eventually become rain. Rain water that absorb by the soil is very useful, such as ground water. Moreover, the rain has potential force and kinetic force. Thus, if the force that contain in the rain can be utilized as much as possible, we will get great benefits, especially for Indonesia, which is a tropical country with high rainfall. In addition, by using this system as an alternative electrical energy source, we do not need to worry about the power outages, because when it is rain, this system could produce electrical energy. This is the main idea why the author has decided to study about this research.

The increasing price of liquefied petroleum gas (LPG) has forced many households to shift to firewood/charcoal in the Philippines, causing tremendous pressure on the dwindling forest. This transition is more obvious in the rural area where firewood price is almost half of that in the cities. Both problems on big demand for firewood and the pressure on our forest can be partly solved by going into firewood plantation. After all, the country has vast track of idle lands, both private and government lands, waiting to be developed. What the government can do are: a) aggressive promotion of firewood plantation, b) simplify further the old technology on establishing firewood plantation to encourage more farmers, c) improve charcoal processing and d) promote the use of efficient stoves. This write up discusses the need for firewood plantation, areas available for planting, where to plant in farms, what species to plant in a particular soil type/location for optimum growth, planting methods, harvesting, marketing, and the side lights on the ecological benefits derived from plantation aside from wood.

The need of electrical energy is still depend on the fossil energy. Based on the data, Indonesian fossil energy reserves are decreasing, example oil reserves are merely enough for the next 23 years. While gas reserves are assumed will last until 50 years into the future and then coal for the next 80 years. If Indonesia only depends on fossil energy sources for the next 23-80 years, Indonesia will face a lack of energy supply. Therefore to overcome the case above, there is should be an effort to produce a renewable energy.. In this research, we took the initiative to take advantage of the wind gusts from the passing motor vehicles using helical windmill to overcome the unstable wind speed as an alternative source for lighting on roads, especially highways. The purpose of this study is to improve the effectivity of aerodynamic to the moving helical windmill as a source of an alternative energy.And the advantage of this blade is it can rotate continuously because it can recieve the wind from all direction and although the wind energy is very small the blade can still rotate. This study begins with designing a helical windmill, then a generator which is able to convert wind power into electricity. The generator designed consists of eight coils (1000 windings per coil), a saving current using 6 volt of battery, 1 ampere of transformer and the maximum rotation obtained is 12 volts. From this research, it can be concluded that the rotation speed of 367 rpm will produce 6.1 volts voltage, rotation speed of 406 rpm will produce 6.8 volts voltage, and rotation speed of 451 will be obtained 7.3 volts voltage.

Background: Industrial X-ray CT system is normally applied to non-destructive testing (NDT) for industrial product made from metal. Furthermore there are some special CT systems, which have an ability to inspect nuclear fuel assemblies or rocket motors, using high power and high energy (more than 6 MeV) pulsed X-ray source. In these case, pulsed X-ray are produced by the electron linear accelerator, and a huge number of photons with a wide energy spectrum are produced within a very short period. Consequently, it is difficult to measure the X-ray energy spectrum for such accelerator-based X-ray sources using simple spectrometry. Due to this difficulty, unexpected images and artifacts which lead to incorrect density information and dimensions of specimens cannot be avoided in CT images. For getting highly precise CT images, it is important to know the precise energy spectrum of emitted X-rays. Materials and Methods: In order to realize it we investigated a new approach utilizing the Bayesian estimation method combined with an attenuation curve measurement using step shaped attenuation material. This method was validated by precise measurement of energy spectrum from a 1 MeV electron accelerator. In this study, to extend the applicable X-ray energy range we tried to measure energy spectra of X-ray sources from 6 and 9 MeV linear accelerators by using the recently developed method. Results and Discussion: In this study, an attenuation curves are measured by using a step-shaped attenuation materials of aluminum and steel individually, and the each X-ray spectrum is reconstructed from the measured attenuation curve by the spectrum type Bayesian estimation method. Conclusion: The obtained result shows good agreement with simulated spectra, and the presently developed technique is adaptable for high energy X-ray source more than 6 MeV.

Background: Radiation portal monitors (RPMs) involving plastic scintillators installed at the border inspection sites can detect illicit trafficking of radioactive sources in cargo containers within seconds. However, RPMs may generate false alarms because of the naturally occurring radioactive materials. To manage these false alarms, we previously suggested an energy-weighted algorithm that emphasizes the Compton-edge area as an outstanding peak. This study intends to evaluate the identification of radioactive sources using an improved energy-weighted algorithm. Materials and Methods: The algorithm was modified by increasing the energy weighting factor, and different peak combinations of the energy-weighted spectra were tested for source identification. A commercialized RPM system was used to measure the energy-weighted spectra. The RPM comprised two large plastic scintillators with dimensions of 174 × 29 × 7 cm3 facing each other at a distance of 4.6 m. In addition, the in-house-fabricated signal processing boards were connected to collect the signal converted into a spectrum. Further, the spectra from eight radioactive sources, including special nuclear materials (SNMs), which were set in motion using a linear motion system (LMS) and a cargo truck, were estimated to identify the source identification rate. Results and Discussion: Each energy-weighted spectrum exhibited a specific peak location, although high statistical fluctuation errors could be observed in the spectrum with the increasing source speed. In particular, 137Cs and 60Co in motion were identified completely (100%) at speeds of 5 and 10 km/hr. Further, SNMs, which trigger the RPM alarm, were identified approximately 80% of the time at both the aforementioned speeds. Conclusion: Using the modified energy-weighted algorithm, several characteristics of the energy weighted spectra could be observed when the used sources were in motion and when the geometric efficiency was low. In particular, the discrimination between 60Co and 40K, which triggers false alarms at the primary inspection sites, can be improved using the proposed algorithm.

생활 오폐수 열원이 고온임에도 불구하고 활용하지 않은 이유에는 경제성 부족과 시스템에 대한 신뢰성 부족이다. 본 연구는 기존 시스템의 문제점을 보완하여 오폐수열원을 이용하여 건축물의 냉난방 시스템으로 적용될 수 있도록 연구하였다. 기존 오폐수 열 교환 시스템의 구조적인 문제점인 Slime과 Scale에 대하여 많은 어려움을 보여주고 있으며 본 연구는 다른 획기적인 방법을 제시하였 다. 그것은 워터케이싱 이라는 열 회수기술과 복합열원 축⋅열 수조라는 열 축전 방식을 제안하였다. 그리고 생활 오폐수라는 특수한 조건의 열원을 사용하면서 외기온도와의 상관관계를 밝혀내었다. 이러한 연구를 통해 이제까지 버려왔던 생활 오폐수와 같은 소규모 미활용에너지를 축⋅열하여 유 효의 에너지로 변환시킴으로써 에너지 재활용에 대한 인식 변화는 물론 냉난방시스템으로 적용함으 로써 제로에너지건축물 인증 의무화 제도 및 신재생 설비 설치 의무화 제도에 기여할 수 있다고 본다.

A reason for not using the heat source of waste water despite the high temperature of life is that a lack of economic efficiency and a lack of trust in the system. This study has been studied so that problems in the existing system can be supplemented and applied to the heating and cooling system of buildings using a waste water source. The structural problems of the existing waste water heat exchange system, Slime and Scale, show a lot of difficulties. Because of these difficulties, this study suggested other innovative methods. It proposed a heat recovery technique called water casing and a heat accumulator called combined heat source heat accumulator water tube. It also found a correlation with ambient air temperature by using a special condition of heat source by life sewage. Through these studies, we will convert the amount of small, unused energy such as living sewage that we have throw away throw away throw awaythrowed out into effective energy by accumulating heat. Also, not only do we change our perception of energy recycling, but also apply it as a heating and cooling system. We believe that these efforts can contribute to the mandatory certification of zero-energy buildings and the mandatory installation of new and renewable facilities.

본 논문에서는 미래 에너지로서 가스 하이드레이트를 이해하기 위해, 가스 하이드레이트의 구조, 물리/화학 적 특성, 생성 기원과 세계 분포, 매장량과 생산기법, 하이드레이트의 지구환경적 영향에 대해 논의하였다. 하이드레 이트의 구조에 대한 명확한 이해는 자연계에 매장된 하이드레이트의 특성 분석, 분포와 매장량 산출에 필수적일 것으 로 판단된다. 안정적인 에너지 회수를 위해 고려해야 할 하이드레이트의 물리/화학적 특성으로는 하이드레이트의 상 평형, 해리 엔탈피, 열전도도, 비열, 열확산도, 유체투과율 등이 있다. 하이드레이트의 물리/화학적 특성을 고려하여 개발된 생산기법으로는 감압법, 열자극법, 억제제 주입법, 맞교환기법이 있으며, 감압법이 현재까지 해상 및 육상 하 이드레이트에 대해 모두 시험생산에 적용된 유일한 기법이다. 또한, 하이드레이트의 해리에 따른 온실가스 배출에 의 한 지구환경적 영향의 가능성에 대해서도 고찰하였다.

This paper reviews the structures, physical and chemical properties, origins and global distribution, amount of energy resources, production technologies, and environmental impacts of gas hydrates to understand the gas hydrates as future energy sources. Hydrate structures should be studied to clarify the fundamentals of natural gas hydrates, hydrate distributions, and amount of energy sources in hydrates. Phase equilibria, dissociation enthalpy, thermal conductivity, specific heat, thermal diffusivity, and fluid permeability of gas hydrate systems are important parameters for the the efficient recovery of natural gas from hydrate reservoirs. Depressurization, thermal stimulation, inhibitor injection, and chemical exchange methods can be considered as future technologies to recover the energy sources from natural gas hydrates, but so far depressurization is the only method to have been applied in test productions of both onshore and offshore hydrates. Finally, we discuss the hypotheses of environmental impacts of gas hydrates and their contribution to global warming due to hydrate dissociation.

As known as, the GSHP(Ground Source Heat Pump) system is a kind of the renewable energy system that use the geothermal energies for heating and cooling in the building. In recently, many GSHP systems was installed in the building for reducing the Green House Gases and the energy cost. However, published studies of Life Cycle Costing on GSHP system were rare case. Therefore, this study aim is Life Cycle Cost comparison of the GSHP system with the conventional diesel boiler system and city gas boiler system through the renewal case of building mechanic equipment in the temperate region.(Case Building; Childcare Center, 2,199.20m2, 105RT GSHP, Seoul Korea) In this study, the initial cost of GSHP system is 2.4 times to the diesel boiler system, 2.1 times to the city gas boiler system. And the running cost of GSHP system is 84.1% lower than the diesel boiler system, 59.5% lower than the city gas boiler system. In conclusion, the LCC16 of the GSHP system is 63.0% lower than the diesel boiler system, 19.9% lower than the city gas boiler system.(This study used the Present Value Method. This study used the data which are the interest; 6.5%, the oil price escalation index; 15.13%, the city gas price escalation index; 10.56%, the electric price escalation index; 6.43%, the system's Life Cycle; 16years.)

드론 비행의 위치 인식에 있어 GPS 신호의 절대적 의존성, 비행 안정성, 배터리 한계로 인한 비행시간 문제는 드론 산업 발전의 큰 제약이 되고 있다. 특히 20분 내외의 짧은 임무 비행시간은 드론 활용에 있어 큰 걸림돌이 되고 있으며, 이를 극복하기 위해 액체수소를 에너지원으로 이용한 드론개발이 활발히 진행되고 있다. 하지만 액체수소 드론개발의 속도보다 현재의 규제 및 인증 제도 개정의 속도가 더뎌 개발 드론의 시험, 인증, 상용화에 어려움을 겪고 있으며, 이는 결국 드론 시장 선점의 문제점이 되고 있다. 본 논문에서는 수소 에너지 기반 드론개발 동향을 분석하며 규제와 인증 제도의 한계점을 소개하고 해결방안을 간략히 제시한다.

The absolute dependence on GPS signals for positioning, unstable flight, and short flight time due to battery limitations are the major problems to extend the practical use of drones in the industry. In particular, the short flight time of about 20 minutes is a big issue to the use of drones, and to overcome this, the liquid hydrogen powered drone is being actively developed. However, the revision of the current regulation and certification system for liquid hydrogen powered drone has not been completed yet, making it difficult to test, certify, and commercialize the hydrogen powered drone, which eventually becomes a problem in pre-occupying the increasing drone market. In this paper, we analyze the development trends of hydrogen powered drone and provide the current issues on regulations and certification systems for hydrogen powered drone.