최근 지구온난화로 인해 발생하는 폭우 및 강설과 같은 비정상적인 기상 패턴으로 인해 도로 표면 결빙(블랙 아이스)으로 인 한 사고와 인명 피해가 증가하고 있으며, 이는 주요 문제로 대두되고 있습니다. 이러한 문제를 완화하기 위해 본 연구에서는 열저장 능력을 갖춘 상변화 물질(PCM)을 시멘트 복합재료에 포함시켰습니다. PCM은 상변화 과정에서 열에너지를 흡수, 저장 및 방출할 수 있어 온도 변동으로 인한 결빙을 최소화할 수 있습니다. PCM은 먼저 미세 캡슐화된 후 시멘트 복합재료에 강화되어 기계적 및 열적 성능 검증 연구가 수행되었습니다. 또한, 열전달 효율과 기계적 특성을 향상시키기 위해 다중벽 탄소나노튜브(CNT)와 실리카 퓸이 추 가되었습니다. 미세 캡슐화된 PCM의 열 성능은 열 거동을 측정하기 위한 재료 실험을 통해 검증되었습니다. 이후, 제조된 시멘트 복 합재의 기계적 및 열적 성능 테스트가 그 효과를 평가하기 위해 수행되었습니다. 이러한 테스트 동안 일정 온도와 습도 챔버를 사용한 열 주기 테스트가 열 성능을 검증하기 위해 수행되었습니다. 기계적 성능 실험에서는 CNT와 실리카 퓸의 포함이 미세 캡슐화된 PCM 의 포함으로 인한 강도 저하를 완화하는 것을 확인하였습니다. 더욱이, 열 주기 테스트를 통해 고효율 열저장 시멘트 복합재가 결빙 조건에서도 영하의 온도를 유지할 수 있음을 보여주었으며, 이는 효율적인 열저장 성능을 입증하였습니다.

PURPOSES : This study aimed to develop a transportation-energy linkage model and performance evaluation indicators to improve the sustainability operation and technology of smart city transportation-energy services. METHODS : This study derived a new transportation-energy linkage system model for 15 services designated by the national pilot city. Evaluation indicators for energy-oriented transportation services in smart cities were selected, and a methodological framework was proposed for selecting quantitative evaluation indicators based on text mining and importance-performance analysis (IPA). RESULTS : Twenty indicators, confirmed as crucial for successful transportation-energy linkage in smart cities, were selected. These covered data linkage between services, IoT-based information linkage driving rate, and network and energy efficiency indicators. The proposed quantitative methodological framework can complement expert subjective evaluation by identifying meaningful implications in research literature that experts may have missed. The methodology can consistently derive indicators even when new services are added, aiding policymakers’ decisions. CONCLUSIONS : The methodological framework can contribute to minimizing operational risks in smart city transportation-energy expansion. It can also be used to prioritize service investment in smart cities by estimating benefit effects through quantitative indicators.

Thermoelectric (TE) energy harvesting, which converts available thermal resources into electrical energy, is attracting significant attention, as it facilitates wireless and self-powered electronics. Recently, as demand for portable/wearable electronic devices and sensors increases, organic-inorganic TE films with polymeric matrix are being studied to realize flexible thermoelectric energy harvesters (f-TEHs). Here, we developed flexible organic-inorganic TE films with p-type Bi0.5Sb1.5Te3 powder and polymeric matrices such as poly(3,4-eethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and poly (vinylidene fluoride) (PVDF). The fabricated TE films with a PEDOT:PSS matrix and 1 wt% of multi-walled carbon nanotube (MWCNT) exhibited a power factor value of 3.96 μW ‧ m-1 ‧ K-2 which is about 2.8 times higher than that of PVDF-based TE film. We also fabricated f-TEHs using both types of TE films and investigated the TE output performance. The f-TEH made of PEDOT:PSS-based TE films harvested the maximum load voltage of 3.4 mV, with a load current of 17.4 μA, and output power of 15.7 nW at a temperature difference of 25 K, whereas the f-TEH with PVDF-based TE films generated values of 0.6 mV, 3.3 μA, and 0.54 nW. This study will broaden the fields of the research on methods to improve TE efficiency and the development of flexible organic-inorganic TE films and f-TEH.

As the environmental impacts of fossil fuel energy sources increase, the South Korean government has tried to change non-environmental- friendly enery sources to environmental-friendly energy sources in order to mitigate environmental effects, which lead to global warming and air pollution. With both a limited budget and limited time, it is essential to accurately evaluate the economic and environmental effects of renewable energy projects for the efficient and effective operation of renewable energy plants. Although the traditional economic evaluation methods are not ideal for evaluating the economic impacts of renewable energy projects, they can still be used for this purpose. Renewable energy projects involve many risks due to various uncertainties. For this reason, this study utilizes a real option method, the Geske compound model, to evaluate the renewable energy projects on Jeju Island in terms of economic and environmental values. This study has developed an economic evaluation model based on the Geske compound model to investigate the influences of flexibility and uncertainty factors on the evaluation process. This study further conducts a sensitivity analysis to examine how two uncertainty factors (namely, investment cost and wind energy production) influence the economic and environmental value of renewable energy projects.

In gamma-ray spectrometry for volume samples, the self-attenuation effect should be considered in the case of differences in chemical composition and density between the efficiency calibration source for quantitative analysis of sample and the sample actually measured. In particular, the lower the gamma-ray energy, the greater the gamma-ray attenuation due to the self-attenuation effect of the sample. So, the attenuation effect of low-energy gamma-rays in the sample should be corrected to avoid over- or under-estimation of its radioactivity. One of the most important factors in correcting the self-attenuation effect of the sample is the linear attenuation coefficient for the sample, which can be directly calculated using a collimator. The larger the size of the collimator, the more advantageous it is to calculate the linear attenuation coefficient of the sample, but excessive size may limit the use of the collimator in a typical environmental laboratory due to its heavy weight. Therefore, it is necessary to optimize the collimator size and structure according to the measurement environment and purpose. This study is to optimize a collimator that can determine the effective linear attenuation coefficient of low-energy gamma-rays, and verify its applicability. The overall structure of the designed collimator was optimized for gamma-ray energy of less than 100 keV and cylindrical plastic bottle with diameter of 60 mm and a height of 40 mm. The materials of optimized collimator consisted of tungsten. Acryl and acetal were used to form the housing of the collimator, which fixes the central axis of the bottle, collimator and point-like source. In addition, using the housing, the height of the tungsten is adjusted according to the height of the sample. For applicability evaluation of the optimized collimator, IAEA reference material in solid form were used. The sample was filled in the bottle with heights of 1, 2, 3 and 4 cm respectively. Using the collimator and point-like source of 210Pb (46.5 keV), 241Am (59.5 keV), and 57Co (121.1 keV), the linear attenuation coefficient and the radioactivity for the samples were calculated. As a result, to calculate the linear attenuation coefficient using the optimized collimator, a relatively high sample height is required. However, the optimized collimator can be used to determine the linear attenuation coefficients of low-energy gamma-rays for the self-attenuation correction regardless of the sample height. It is concluded that the optimized collimator can be useful to correct the sample selfattenuation effect.

지구온난화 완화를 위한 노력이 전 세계적으로 계속되고 있는 가운데 우리나라는 2030년 온실가스 배출량을 Business As Usual (BAU) 대비 37% 감축하는 목표를 설정하고 이산화탄소 순 배출 제로 달성을 목표로 하는 ‘2050탄소중립 시나리오’를 발표하였다. 이러한 상황에서 케나프 (Kenaf)는 높은 탄소흡수율과 빠른 성장으로 인해 대체 해결방안으로 제안된다. 시료선정에 대한 분석결과, 케나프 잎은 질소 함량이 높아 적합하지 않은 것으로 나타났고, 줄기와 잎-줄기 혼합 케나프는 Biomass-Solid Refuse Fuel (Bio-SRF) 등급을 충족했다. Bio-SRF 등급을 만족하였지만, Bio-SRF 등급으로 이용할 수 있는 활용처가 뚜렷하지 않다. 따라서 케나프의 연료품질을 반탄화 공정을 통해 개선하여 보다 효율적으로 활용하고자 한다. 반탄화 공정의 공시재료로 줄기만 사용하는 것보다 시료 이용률이 높은 잎-줄기 혼합 케나프를 선택하였다. 반탄화 공정은 여섯가지의 공정 온도 (200·210·220·230·240·250℃)와 다른 세 가지 공정 시간(20·30·40 min)에서 수행되었다. 반탄화 공정결과, 공정시간이 길수록 230℃, 240℃, 250℃ 온도에서 질량감소가 크기 때문에 에너지수율이 낮았다. 따라서 본 연구에서는 200℃·20 min, 200℃·30 min, 210℃·20 min, 220℃·20 min의 에너지 수율이 높고 질량감소가 작아 최적 반탄화 공정 조건으로 선정하였다.

정삼투 공정(forward osmosis, FO)은 역삼투 공정(reverse osmosis, RO)에 비해 저압으로 운영되므로 오염 제어, 유지 보수, 막 세정 및 잠재적 에너지 저감 측면에서 큰 이점이 있어 다양한 분야에 적용할 수 있는 기술이다. 특히, 정삼투 공정의 막오염층이 비교적 느슨하고 분산된 특성을 가지므로 역삼투 공정과 달리 물리세정만으로도 충분한 막오염 제어가 가능하다. 하지만 기존 연구들의 경우 정삼투 물리세정에 적합한 세정 유속을 적용하지 않아 최적화 운전을 하지 못했다는 한계가 있다. 따라서 이 연구는 경제적인 에너지량으로 높은 효율의 세정을 보일 수 있는 적절한 유속의 정당성 평가를 목적으로 한다. 정삼투 공정 막오염 실험을 8.54 cm/s 순환 유속으로 유지하고 세 가지 세정유속으로 회복률과 SEC(specific energy consumption) 비교 평가하였다. 이 실험의 결과로 2배속 세정이 3배속 세정의 수투과도 회복률 만큼의 높은 효율을 보 이는 동시에, 2배속 세정이 높은 세정효율 및 경제적인 SEC를 보이는 적절한 유속이라는 것을 확인하였다.

The paper presents the results of a multi-criteria comparative evaluation of 12 feasible Russian nuclear energy deployment scenarios with thermal and fast reactors in a closed nuclear fuel cycle. The comparative evaluation was performed based on 6 performance indicators and 5 different MCDA methods (Simple Scoring Model, MAVT / MAUT, AHP, TOPSIS, PROMETHEE) in accordance with the recommendations elaborated by the IAEA/INPRO section. It is shown that the use of different MCDA methods to compare the nuclear energy deployment scenarios, despite some differences in the rankings, leads to well-coordinated and similar results. Taking into account the uncertainties in the weights within a multi-attribute model, it was possible to rank the scenarios in the absence of information regarding the relative importance of performance indicators and determine the preference probability for a certain nuclear energy deployment scenario. Based on the results of the uncertainty/sensitivity analysis and additional analysis of alternatives as well as the whole set of graphical and attribute data, it was possible to identify the most promising nuclear energy deployment scenario under the assumptions made.

겨울철에 열손실을 줄이기 위해 많은 온실에서 보온커튼을 사용하고 있다. 그러나 적절한 보온커튼을 선택할 때 판단 자료로 활용할 수 있는 명확한 기준이 없는 실정이며 이를 위해서는 보온재의 보온 특성에 대한 정량적인 값이 필요하다. 본 연구에서는 BES를 사용하여 보온커튼의 관류열전달계수를 산정하는 시뮬레이션 모델을 개발하였다. 일중 및 이중 PE필름 피복에 대한 관류열전달계수의 실험값을 사용하여 시뮬레이션 결과를 검증하였다. 검증된 모델을 사용하여 문헌에서 제시된 각종 열적 특성을 가진 보온커튼에 대한 관류열전달계수를 산정하고 비교분석하였다. 개발된 시뮬레이션 모델은 다양한 보온커튼의 관류열전달계수를 산정하는데 활용될 수 있을 것이며, 제시된 관류열전달계수는 보온커튼의 성능을 정량적으로 비교하는데 유용하게 활용 될 수 있을 것으로 판단된다.

PURPOSES : A geo-grid pavement, e.g., a stress-absorbing membrane interlayer (SAMI), can be applied to an asphalt-overlay method on the existing surface-pavement layer for pavement maintenance related to reflection cracking. Reflection cracking can occur when a crack in the existing surface layer influences the overlay pavement. It can reduce the pavement life cycle and adversely affect traffic safety. Moreover, a failed overlay can reduce the economic value. In this regard, the objective of this study is to evaluate the bonding properties between the rigid pavement and a SAMI by using the direct shear test and the pull-off test. The predicted fractural energy functions with the shear stress were determined from a numerical analysis of the moving average method and the polynomial regression method. METHODS : In this research, the shear and pull-off tests were performed to evaluate the properties of mixtures constructed using no interlayer, a tack-coat, and SAMI with fabric and without fabric. The lower mixture parts (describing the existing pavement) were mixed using the 25-40-8 joint cement-concrete standard. The overlay layer was constructed especially using polymer-modified stone mastic asphalt (SMA) pavement. It was composed of an SMA aggregate gradation and applied as the modified agent. The sixth polynomial regression equation and the general moving average method were utilized to estimate the interlayer shear strength. These numerical analysis methods were also used to determine the predictive models for estimating the fracture energy. RESULTS: From the direct shear test and the pull-off test results, the mixture bonded using the tack-coat (applied as the interlayer between the overlay layer and the jointed cement concrete) had the strongest shear resistance and bonding strength. In contrast, the SAMI pavement without fiber has a strong need for fractural energy at failure. CONCLUSIONS : The effects of site-reflection cracking can be determined using the same tests on cored specimens. Further, an empiricalmechanical pavement-design analysis using the finite-element method (FEM) must be done to understand the appropriate SAMI application. In this regard, the FEM application analysis and bonding property tests using cored specimens from public roads will be conducted in further research.

Gas hydrate desalination process is based on a liquid to solid (Gas Hydrate, GH) phase change followed by a physical process to separate the GH from the remaining salty water. The GH based desalination process show 60.5-90% of salt rejection, post treatment like reverse osmosis (RO) process is needed to finally meet the product water quality. In this study, the energy consumption of the GH and RO hybrid system was investigated. The energy consumption of the GH process is based on the cooling and heating of seawater and the heat of GH formation reaction while RO energy consumption is calculated using the product of pressure and flow rate of high pressure pumps used in the process. The relation between minimum energy consumption of RO process and RO recovery depending on GH salt rejection, and (2) energy consumption of electric based GH process can be calculated from the simulation. As a result, energy consumption of GH-RO hybrid system and conventional seawater RO process (with/without enregy recovery device) is compared. Since the energy consumption of GH process is too high, other solution used seawater heat and heat exchanger instead of electric energy is suggested.

본 연구에서는 LED 광원에 대하여 재실자의 업무 효율성과 에너지 저감 효과를 알아보기 위한 실험을 실시하 였다. 이를 위해 LED 광원의 특성인 펄 스 폭변조(PWM, pulse width modulation)와 조도(lux)를 제어하여 총 9가 지의 다양한 조명환경을 구성하였다. LED 조명의 펄스변조 비율은 각각 R:G:B=1:1:1, R:G:B=4:1:5, R:G:B=8:7:7 으로 하였으며, 조도는 각각 400 lx, 700 lx, 1000 lx 으로 설정하였다. 또한, 실내환경은 온도 20∼24℃, 습도 50∼ 60%, 착의량 1 clo 로 설정하였다. 각각의 주어진 9개의 조명환경에서 업무 효율성과 에너지 소비에 대해 분석하 였다. 업무 효율성 분석을 위해 오류검색수정 작업을 실시하였으며, 에너지 소비 분석을 위해 각 조명환경에서 누적 소비전력을 측정하였다. 제안한 조명환경을 통해 실험한 결과, 업무 효율성은 400 lx 보다 700 lx 이상에서 정확도 및 소요시간의 효율이 좋았으며, 소요시간의 경우 제안한 펄스변조 R:G:B=8:7:7 에서 가장 좋은 효율을 나타냈다. 또한, 각각의 조도에 대한 소비전력은 펄스변조 R:G:B=8:7:7 > RGB=1:1:1 > R:G:B=4:1:5의 순으로 낮게 나타났다. 따라서, 본 논문에서 제안한 펄스 폭 변조 효과가 업무효율성 및 에너지 저감에 영향을 미치는 것을 확인할 수 있었다.

Korean foods have the strengths to addresssome of the health problems of modern man. To assess the properties of Korean noodles, daily value %, DVS, DDS and energy density were compared between many kinds of noodles from around the world. Using a variety of reference materials, a nutritional database of noodles was built for this study. For carbohydrate, lipid, vitamin A, vitamin K, vitamin C, niacin, zinc, and copper, the daily values % of western noodles were significantly higher. Also, the serving size of Korean noodles was significantly small. Comparing the average energy density of the noodles, they showed 1.87±0.93 kcal/g (Korean noodles), 2.42±1.08 kcal/g (western noodles) and 1.84±0.84 kcal/g (other noodles). The dietary fiber, polyphenols, and flavonoids content of the noodles showed no significant difference. Neither DVS nor DDS showed a statistically significant difference. In the Korean noodles, the GMDFV pattern showed a diverse choice of food groups. Korean noodles show a lower energy density, and the small serving size to have favorable for the prevention of obesity. Thus, Korean noodles are an excellent choice in terms of diversity and energy density.

A pilot plant (Q=5 m3/d) study was implemented for small and medium sized personal wastewater treatment plant effluent to evaluate MBR and A/O processes utilizing self-sufficient energy composed of wind and solar energy. The removal efficiencies of BOD, SS, turbidity and color were sufficient for legal water quality standards for gray water. However, those of nitrogen and phosphorus could not meet legal regulations which suggested that further removal of those contaminants were needed for reuse of the treated water.Self-sufficient energy rate was 100 % for the pilot plant due to excessive design capacity. In this research, wind and solar energy system was applied considering geological characteristics, which significantly improved energy self-sufficiency. Substantial improvement on energy self-sufficiency can be obtained by optimized investment and operation at a full scale wastewater treatment plant.

Bioenergy is classified to one of the renewable energy resources such as solar, wind, hydro and tidal energies. It should be noted that all the renewable energies contribute to the reduction of greenhouse gases emission. In some cases, energy from wastes was also categorized as a renewable energy in our country even though it has only negligible effect on the emission reduction. In this paper, we tried to identify the bioenergy in order to follow the global indices of the renewable energy. The indices evaluated here were whether a resource is renewable, iogenic, biodegradable, combustible and organic. Biogenic and combustible were selected as the indices to identify the bioenergy. It was also suggested that combustible as an index can be exchangeable to organic.

This project is mainly related to evaluation of total energy consumption of low energy house, the exterior envelope of which was wholly composed of structural insulated panels(SIP). The U-value of applied SIP was in the range of 0.189 to 0.269W/㎡․K and the U-value of pair glass from 0.78 to 1.298W/㎡․K was applied for window dependent to its function respectively. For comparison of total energy performance, the energy simulation for pilot house was performed to compare with the control house having insulation criteria of Korean building regulation in 2009. Based on simulation of dynamic energy performance, the pilot house saved 48.3% of annual energy consumption while the control house in 2009 consumed as 85.7GJ/y. In case of heating, the result showed that the energy saving ratio amounted to 76.7%. For CO₂ emission, the pilot house diminished approximately 35.4% from 6,208.4kgCO₂ to 4,009.2kgCO₂. In payback period to early investment, it was analyzed the pilot house took 7.8 years, when the low energy house built by other insulation method with same thermal perfusion took 11.5 years. From this result, it is considered that the SIP is more effective, economic to Green Home application.