• 제목/요약/키워드: heat mitigation

검색결과 151건 처리시간 0.024초

열병합발전을 이용한 집단에너지사업의 온실가스 감축효과 (Effects of District Energy Supply by Combined Heat and Power Plant on Greenhouse Gas Emission Mitigation)

  • 신경아;동종인;강재성;임용훈;김다혜
    • 한국기후변화학회지
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    • 제8권3호
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    • pp.213-220
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    • 2017
  • The purpose of this study is to analyze effects of Greenhouse Gas (GHG) emission reduction in district energy business mainly based on Combined Heat and Power (CHP) plants. Firstly this paper compares the actual carbon intensity of power production between conventional power plants and district energy plants. To allocate the GHG from CHP plants, two of different methods which were Alternative Generation Method and Power Bonus Method, have been investigated. The carbon intensity of power production in district energy plants ($0.43tonCO_2e/MWh$) was relatively lower than conventional gas-fired power plants ($0.52tonCO_2e/MWh$). Secondly we assessed the cost effectiveness of reduction by district energy sector compared to the other means using TIMES model method. We find that GHG marginal abatement cost of 'expand CHP' scenario (-$134/ton$CO_2$) is even below than renewable energy scenario such as photovoltaic power generation ($87/ton$CO_2$). Finally the GHG emission reduction potential was reviewed on the projected GHG emission emitted when the same amount of energy produced in combination of conventional power plants and individual boilers as substitution of district energy. It showed there were 10.1~41.8% of GHG emission reduction potential in district energy compared to the combination of conventional power plants and individual boilers.

수원시 덕영대로의 가로수 건강성 평가 및 주요 영향요인 분석 (Analysis of Health Status of Street Trees and Major Affecting Factors on Deogyeong-daero in Suwon)

  • 김은영;정경민
    • 한국환경복원기술학회지
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    • 제22권2호
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    • pp.49-57
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    • 2019
  • The street trees increase the liveability of cities by reducing stormwater runoff, improving air quality, storing carbon, providing shade, and ameliorating the urban heat-island effect. In this study, the health status of street trees in Suwon was evaluated, and the factors affecting the growth of the trees were also derived. In order to evaluate the growth and health of street trees, field survey was carried out on a total of 125 trees in 25 sections of the Deogyeong-daero where is through the city. During the field survey, the following items were examined: Street trees health status (i.e. species, height, DBH (diameter at breast height), planting types, vigor, etc.), soil factors (i.e. soil temperature, humidity, pH, hardness, etc.), and environmental factors (i.e. landuse, road width, etc.). As the results of field survey, the main species of the street trees was Zelkova serrata, which was healthy in most of the sections. The factors such as planting types, soil temperatures, tree root cover, road extension, distance from the road were derived to affect the growth and health of street trees, and the differences were significant. The results of this study were derived the following conclusions for vigorous street trees: First, it is important to install and maintain the protection facilities like tree root cover for the growth of trees. Second, it is necessary to discuss how to plant multiple trees in narrow spaces like a street green space. Third, it is important to provide appropriate soil conditions continuously for growth of threes. Finally, it should be utilized as a mitigation measure of urban heat island effects.

EXPERIMENTAL INVESTIGATIONS RELEVANT FOR HYDROGEN AND FISSION PRODUCT ISSUES RAISED BY THE FUKUSHIMA ACCIDENT

  • GUPTA, SANJEEV
    • Nuclear Engineering and Technology
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    • 제47권1호
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    • pp.11-25
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    • 2015
  • The accident at Japan's Fukushima Daiichi nuclear power plant in March 2011, caused by an earthquake and a subsequent tsunami, resulted in a failure of the power systems that are needed to cool the reactors at the plant. The accident progression in the absence of heat removal systems caused Units 1-3 to undergo fuel melting. Containment pressurization and hydrogen explosions ultimately resulted in the escape of radioactivity from reactor containments into the atmosphere and ocean. Problems in containment venting operation, leakage from primary containment boundary to the reactor building, improper functioning of standby gas treatment system (SGTS), unmitigated hydrogen accumulation in the reactor building were identified as some of the reasons those added-up in the severity of the accident. The Fukushima accident not only initiated worldwide demand for installation of adequate control and mitigation measures to minimize the potential source term to the environment but also advocated assessment of the existing mitigation systems performance behavior under a wide range of postulated accident scenarios. The uncertainty in estimating the released fraction of the radionuclides due to the Fukushima accident also underlined the need for comprehensive understanding of fission product behavior as a function of the thermal hydraulic conditions and the type of gaseous, aqueous, and solid materials available for interaction, e.g., gas components, decontamination paint, aerosols, and water pools. In the light of the Fukushima accident, additional experimental needs identified for hydrogen and fission product issues need to be investigated in an integrated and optimized way. Additionally, as more and more passive safety systems, such as passive autocatalytic recombiners and filtered containment venting systems are being retrofitted in current reactors and also planned for future reactors, identified hydrogen and fission product issues will need to be coupled with the operation of passive safety systems in phenomena oriented and coupled effects experiments. In the present paper, potential hydrogen and fission product issues raised by the Fukushima accident are discussed. The discussion focuses on hydrogen and fission product behavior inside nuclear power plant containments under severe accident conditions. The relevant experimental investigations conducted in the technical scale containment THAI (thermal hydraulics, hydrogen, aerosols, and iodine) test facility (9.2 m high, 3.2 m in diameter, and $60m^3$ volume) are discussed in the light of the Fukushima accident.

FTIR 가스분석에 의한 고분자재료의 연소가스독성 평가 (A study on combustion gas toxicity of polymeric materials using FTIR gas analysis)

  • 이두형;공영건
    • 한국방재학회 논문집
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    • 제5권4호
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    • pp.79-84
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    • 2005
  • 건축물, 운송수단에 많이 사용되는 고분자재료는 화재에 노출되면 다량의 열 및 연소가스를 발생시켜 피해를 야기시키는데 특히 유독성 연소가스는 인명피해의 주된 원인이 된다. 본 연구에서는 화재시 발생되는 다양한 종류의 연소가스를 동시에 연속적으로 분석할 수 있는 새로운 분석방법인 FTIR(Fourier Transform Infrared) 분석방법을 이용하여 ASTM E 1678 실험장치에서 발생시킨 PVC, FRP, SMC 및 Ureathane foam 4종의 고분자재료 연소가스를 분석하였고, 분석된 연소가스 데이터를 NIST에서 개발한 FED 독성 모델에 적용하여 연소가스 유해성을 정량적으로 제시하였다. 또한 현재 우리나라에서 사용되고 있는 마우스를 사용한 KS F 2271 가스유해성 실험결과와 비교분석을 하였으며, FTIR 연소가스 분석방법을 이용하면 동물을 사용하지 않고서도 연소가스 유해성을 정량적이고 정확하게 평가할 수 있음을 알 수 있었다.

섬유혼입 고강도 콘크리트의 열전달 및 역학적 거동 해석모델에 대한 연구 (Study on The Heat Transfer and Mechanical Modeling of Fiber-Mixed High Strength Concrete)

  • 신영섭;한동석;염광수;전현규
    • 한국방재학회 논문집
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    • 제11권2호
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    • pp.45-52
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    • 2011
  • 고강도 콘크리트의 폭렬현상을 억제하여 내화 성능을 개선하기 위한 방법으로 고온에서 수증기가 콘크리트 표면으로 이동할 수 있도록 경로를 제공하여 주는 섬유를 혼입하는 방안이 있다. 본 연구에서는 섬유혼입 고강도 콘크리트 기둥에 대한 재하 내화 실험을 수행하였고, 내부 철근의 온도분포 예측을 위한 열전달 모델과 고온에서 콘크리트 기둥의 역학적 거동에 대한 재료모델을 제시하였다. 화재 시 콘크리트 내부의 물리적인 현상과 콘크리트의 열적 특성을 고려하여 선행 연구의 재료모델을 수정하였다. 수정한 모델을 이용한 섬유혼입 고강도 콘크리트의 유한요소 해석을 실행하였고, 재하 내화실험과의 비교를 통하여 재료모델을 제안하였다.

터널 화재 시 열감지기 작동 온도의 비교에 관한 실험적 연구 (An Experimental Study on the Comparison of Operating Temperatures in Thermal Detector due to Tunnel Fire)

  • 노형기;박광영;임석빈
    • 한국방재학회 논문집
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    • 제11권1호
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    • pp.23-27
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    • 2011
  • 건설 기술 발전과 국토의 효율적인 활용으로 인하여 건설되고 있는 터널은 지하 공간과 같은 폐쇄 공간의 특성으로 화재 시발생하는 연기와 열은 인명 및 물적 피해에 영향을 주는 매우 큰 위험요소이다. 본 연구에서는 광케이블을 이용하여 온도 변화를 측정하는 화재 감지 시스템을 설치하여 감지기가 동작한 온도 변화 값 및 시간과 실 화재 실험과 동일한 조건으로 화재 시뮬레이션을 수행하여 온도센서의 온도 변화 값 및 시간을 비교, 분석하였다. 실험 결과 화재실험과 화재 시뮬레이션의 온도변화는 점화 후 1분 이내에 화재를 감지하여 신호를 경보하는 것으로 나타났으며, 화재 감지기와 시뮬레이션 온도 센서의 온도변화 특성은 터널 내부의 기류 속도와 밀접한 관계를 가지는 것으로 나타났다. 또한 터널 화재는 연기의 방향에 의해 피난과 소방대 진입에 영향을 미치므로 화재 지점과 화재 방향을 파악할 수 있어야 한다.

Sustainability and Challenges of Climate Change Mitigation through Urban Reforestation - A Review

  • Ogunbode, Timothy O.;Asifat, Janet T.
    • Journal of Forest and Environmental Science
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    • 제37권1호
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    • pp.1-13
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    • 2021
  • The realities of Climate change and its untold implications on the livelihood of man are no longer new worldwide. In attempts to subdue the negative implications of Climate change scenario globally, several measures have being suggested and being put in place. One of such measures is urban reforestation especially in the developing nations where forest resources have extremely and uncontrollably exploited. Most of cities in developing nations are almost devoid of regularly maintained trees for whatever purpose. Thus, the enormous roles which urban tree performs are lacked in most cities. In order to subdue excessive heat in cities arising from exposure of urban land areas urban reforestation exercise needs to be embarked upon. The investigation was carried out through desk studies and review of relevant publications to examine what it entails to have a sustainable reforestation programme in cities. The study revealed that several factors need to be taken into consideration if sustainable urban reforestation will be achieved, especially in developing countries. These factors include urban soil nutrients status investigation, appropriate tree type study, public perception about the tree types, relevant legal instrument to achieve successful reforestation exercise in cities among others were found to be salient to this exercise. Urban reforestation has enormous potentials to subdue Climate change consequences, including urban renewal if adequate provision is made for its sustainability, especially in developing countries. To ensure this is realized it is recommended that relevant ministry/agency could be put in charge for the maintaining, cutting and replanting of urban tree and all that are involved in urban tree sustainability.

가로수와 바닥 포장 표면 알베도의 도시 열 환경 개선 효과 (Impact of Urban Thermal Environment Improvement by Street Trees and Pavement Surface Albedo)

  • 김나연;김은섭;윤석환;박정강;김상혁;남상준;제화준;이동근
    • 한국환경복원기술학회지
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    • 제26권1호
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    • pp.47-59
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    • 2023
  • Due to climate change and urbanization, abnormally high temperatures and heat waves are expected to increase in urban and deteriorate thermal comfort. Planting of street trees and changing the albedo of urban surfaces are the strategies for mitigating the thermal environment of urban, and both of these strategies affect the exposure and blocking of radiative fluxes to pedestrians. After measuring the shortwave and longwave radiation according to the ground surface with different albedo and the presence of street trees using the CNR4 net radiometer, this study analyzed the relationship between this two strategies in terms of thermal environment mitigation by calculating the MRT(Mean Radiant Temperature) of each environment. As a result of comparing the difference between the downward shortwave radiation measured under the right tree and at the control, the shortwave radiation blocking effect of the tree increased as the downward shortwave radiation increased. During daytime hours (from 11 am to 3 pm), the MRT difference caused by the albedo difference(The albedo of the surfaces are 0.479 and 0.131, respectively.) on surfaces with no tree is approximately 3.58℃. When tree is present, the MRT difference caused by the albedo difference is approximately 0.49℃. In addition, in the case of the light-colored ground surface with high albedo, the surface temperature was low and the range of temperature change was lower than the surrounding surface with low albedo. This result shows that the urban thermal environment can be midigate through the planting of street trees, and that the ground surface with high albedo can be considered for short pedestrians. These results can be utilized in planning street and open space in urban by choosing surfaces with high albedo along with the shading effect of vegetation, considering the use by various users.

PASTELS project - overall progress of the project on experimental and numerical activities on passive safety systems

  • Michael Montout;Christophe Herer;Joonas Telkka
    • Nuclear Engineering and Technology
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    • 제56권3호
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    • pp.803-811
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    • 2024
  • Nuclear accidents such as Fukushima Daiichi have highlighted the potential of passive safety systems to replace or complement active safety systems as part of the overall prevention and/or mitigation strategies. In addition, passive systems are key features of Small Modular Reactors (SMRs), for which they are becoming almost unavoidable and are part of the basic design of many reactors available in today's nuclear market. Nevertheless, their potential to significantly increase the safety of nuclear power plants still needs to be strengthened, in particular the ability of computer codes to determine their performance and reliability in industrial applications and support the safety demonstration. The PASTELS project (September 2020-February 2024), funded by the European Commission "Euratom H2020" programme, is devoted to the study of passive systems relying on natural circulation. The project focuses on two types, namely the SAfety COndenser (SACO) for the evacuation of the core residual power and the Containment Wall Condenser (CWC) for the reduction of heat and pressure in the containment vessel in case of accident. A specific design for each of these systems is being investigated in the project. Firstly, a straight vertical pool type of SACO has been implemented on the Framatome's PKL loop at Erlangen. It represents a tube bundle type heat exchanger that transfers heat from the secondary circuit to the water pool in which it is immersed by condensing the vapour generated in the steam generator. Secondly, the project relies on the CWC installed on the PASI test loop at LUT University in Finland. This facility reproduces the thermal-hydraulic behaviour of a Passive Containment Cooling System (PCCS) mainly composed of a CWC, a heat exchanger in the containment vessel connected to a water tank at atmospheric pressure outside the vessel which represents the ultimate heat sink. Several activities are carried out within the framework of the project. Different tests are conducted on these integral test facilities to produce new and relevant experimental data allowing to better characterize the physical behaviours and the performances of these systems for various thermo-hydraulic conditions. These test programmes are simulated by different codes acting at different scales, mainly system and CFD codes. New "system/CFD" coupling approaches are also considered to evaluate their potential to benefit both from the accuracy of CFD in regions where local 3D effects are dominant and system codes whose computational speed, robustness and general level of physical validation are particularly appreciated in industrial studies. In parallel, the project includes the study of single and two-phase natural circulation loops through a bibliographical study and the simulations of the PERSEO and HERO-2 experimental facilities. After a synthetic presentation of the project and its objectives, this article provides the reader with findings related to the physical analysis of the test results obtained on the PKL and PASI installations as well an overall evaluation of the capability of the different numerical tools to simulate passive systems.

LANDSAT영상을 이용한 서울시 행정구역 단위의 열섬효과 분석 (Analysis of the Effect of Heat Island on the Administrative District Unit in Seoul Using LANDSAT Image)

  • 이경일;류지은;전성우;정휘철;강진영
    • 대한원격탐사학회지
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    • 제33권5_3호
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    • pp.821-834
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    • 2017
  • 도시화로 인한 산업비율 증가는 도시의 기온이 주변지역보다 높아지는 도시 열섬(Urban Heat Island)현상을 유발하였으며 기후변화와 함께 그 강도가 점점 증가하고 있다. 열섬현상이 발생하는 여러 도시 중에서도 서울시는 각 구 또는 동별로 시가화 정도, 녹지율, 에너지소비량, 인구밀도가 다 다르기 때문에 열섬현상의 강도역시 다르다. 따라서 본 연구에서는 서울특별시를 대상으로 행정구, 행정동 단위 열섬현상강도(UHI Intensity)를 추출하여 행정구역별 차이를 확인하고 세 가지 범주(기상상태, 인위적 열 발생, 토지이용특성)에 포함되는 변수들과 선형회귀분석을 실시하여 각 행정구역의 열섬현상강도 차이의 원인을 살펴보았다. 분석결과 UHI Intensity는 행정구별, 행정동별 특징 및 주변 환경에 따른 차이가 존재하며 행정동 단위에서 차이가 더 크게 나타났고 구의 UHI Intensity와 구에 속한 동의 UHI Intensity분포 또한 차이가 존재하였다. 선형회귀분석결과 평균 풍속, 개발정도, 토양보정식생지수(SAVI), 정규화시가지지수(NDBI) 값이 행정구역별 열섬현상강도 차이를 발생시키는 유의한 변수로 나타났다. 토양보정식생지수와 정규화시가지지수는 행정동단위 까지 그 값의 차이가 존재하는 것으로 나타났으며, 열섬현상 완화를 위한 바람길 환경 조성은 행정동 차원에서의 시행이 필요한 사항이다. 따라서 토지피복 개선 계획, 바람길 조성 계획, 개발지역에 대한 벽면 녹화계획 등 열섬현상 완화를 위한 사업들은 행정구 단위의 차이만을 고려하기보단 구안에 속한 행정동까지 고려할 필요가 있을 것으로 판단된다. 본 연구의 결과는 도시 도시열섬현상 완화를 위해 행정동 단위에서의 분석의 필요성과 고려해야할 변수를 도출하여 향후 도시 열환경 설계 및 정책 개발 시 접근방향을 제공할 것으로 기대한다.