• 한국환경보건학회지
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• 제45권1호
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• pp.1-8
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• 2019

Objectives: The purpose of this study was to estimate the ventilation rate of residential homes in Korea through tracer gas methods using indoor and outdoor concentrations of carbon dioxide ($CO_2$) and $CO_2$ generation rates from breathing. Methods: In this study, we calculated the number of occupants in a home by time through data on the average number of people per household from the Korean National Statistical Office and also measured the amount of $CO_2$ generation by breathing to estimate the indoor $CO_2$ generation rate. To estimate the ventilation rate, several factors such as the $CO_2$ generation rate and average volume of residential house provided by the Korean National Statistical Office, indoor $CO_2$ concentrations measured by sensors, and outdoor $CO_2$ concentrations provided by the Korea Meteorological Administration, were applied to a mass balance model for residential indoor environments. Results: The average number of people were 2.53 per household and Koreans spend 61.0% of their day at home. The $CO_2$ generation rate from breathing was $13.9{\pm}5.3L/h$ during sleep and $15.1{\pm}5.7L/h$ in a sedentary state. Indoor and outdoor $CO_2$ concentrations were 849 ppm and 407 ppm, respectively. The ventilation rate in Korean residential houses calculated by the mass balance model were $42.1m^3/h$ and 0.71 air change per hour. Conclusions: The estimated ventilation rate tended to increase with an increase in the number of occupants. Since sensor devices were used to collect data, sustainable data could be collected to estimate the ventilation rate of Korean residential homes, which enables further studies such as on changes in the ventilation rate by season resulting from the activities of occupants. The results of this study could be used as a basis for exposure and risk assessment modeling.

• 한국식품저장유통학회지
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• 제1권2호
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• pp.87-92
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• 1994

For the measurement of the change of respiration rate caused by the gas content of storage atmosphere which furnishes important data for the interpretation of ULO storage, GC was used. It has been shown that the respiration rate and respiratory heat generation rate of Fuji apple is more than doubled in normal low temperature storage when compared with ULO storage, and that in ULO storage the respiration rate and respiratory heat generation rate directly proportional to the concentration of O2 in storage atmosphere as well as inversely proportional to that of CO2. It was possible to establish a functional formula for the respiratory heat generation rate of Fuji apple in all the storage conditions in terms of u=-0.7638+0.0003 O2-0.0007 log(CO2)+0.1369 log(Tb) concerning temperature and the concentration of O2 and CO2

• 전기학회논문지
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• 제59권11호
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• pp.1936-1941
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• 2010

This purpose of this paper is to propose a methodology for optimal generating operation in power system to minimize the cost of generation subject to not only system constraints but also regional $CO_2$ emission constraints. To solve this ELD problem calculated range limit on minimum and maximum power outputs by regional Equal Generator how each regional capacity is connected into one and expressed Equal Fuel Cost Function considering regional $CO_2$ emission constraints. Accordingly, being modified regional load, new power outputs considering regional $CO_2$ emission constraints were calculated by ELD. The proposed model for evaluating availability is tested on IEEE RTS(Reliability Test System)-24 in detail.

• 한국수자원학회논문집
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• 제51권12호
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• pp.1229-1235
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• 2018

본 연구는 우리나라의 1990-2014년 시계열 자료를 활용하여 물 효율성, 경제성장, 전력생산 및 이산화탄소 배출 간의 장 단기 인과관계를 실증적으로 분석하였다. 기존 연구들이 경제성장, 이산화탄소 배출 및 전력 및 에너지에 국한되어 분석을 한 반면 본 연구는 기존 변수들과 더불어 물 효율성과의 관계를 설명하였다는 기여를 가지고 있다. 실증분석결과를 살펴보면, 네 변수들은 단기조정관계를 통해 장기적으로 균형상태에 도달한다는 것과 변수들 간의 인과관계에서 이산화탄소 배출과 경제성장은 물 효율성의 원인이 되고 이산화탄소 배출과 경제성장 및 물 효율성은 전력생산의 원인이 된다는 사실을 발견하였다. 또한 물 효율성에 대한 장기 영향계수 추정결과를 통해 전력생산의 증가와 경제성장 및 이산화탄소 배출의 감소는 물 효율성을 증가시키며, 일정 수준 이상의 경제성장은 물 효율성의 증가속도를 감소시킨다는 경제성장과 물 효율성의 역U자형 관계를 확인하였다.

• 에너지공학
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• 제7권2호
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• pp.223-230
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• 1998

서울특별시 소재 대형 상업건물중 50개 에너지 다소비업체를 선정하여 에너지 사용실태를 조사하였다. 조사대상 건물은 병원, 호텔, 백화점/사무실 등 3개 집단으로 분류하여 시설현황, 에너지사용량, 부하분포특성 등을 분석하였다. 여름철 냉방전력 사용량이 열부하 피크 발생에 직접적인 영향을 미치는 것으로 나타났으며 이를 열병합발전-흡수식 냉동기 방식으로 대체할 경우 전기부하 분포가 연간 비교적 일정하게 변환시킬 수 있어 열부하추종운전방식에 적합함을 알 수 있었다. 그러나, 단일건물의 경우 연간열부하분포가 경제적 규모에 미달하여 단독으로 열병합발전 설비를 도입하기에는 미흡한 점이 있어 다수건물을 대상으로 하는 공동 열병합발전 방식이 보다 유리한 것으로 판단된다. 이를 추진하기에는 전기사업법, 액화천연가스 요금체계 등과 같은 법제도의 정비가 선결되어야 할 것이다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.227-234
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• 2004

For gaseous fuel combustion with inherent $CO_2$ capture and low NOx emission, chemical-looping combustion(CLC) may yield great advantages of savings of energy to $CO_2$ separation and suppressing the effect on environment. In chemical-looping combustor, fuel is oxidized by metal oxide medium (oxygen carrier particle) in a reduction reactor. Reduced particles are transported to oxidation reactor and oxidized by air and recycled to reduction reactor. The fuel and the air are never mixed, and the gases from reduction reactor, $CO_2$ and $H_2O$, leave the system as separate stream. The $H_2O$ can be easily separated by condensation and pure $CO_2$ is obtained without any loss of energy for separation. The purpose of this study is to demonstrate inherent $CO_2$ separation and no NOx emission and to confirm high $CO_2$ selectivity, no side reaction (i.e., carbon deposition, hydrogen generation) by continuous reduction and oxidation experiment in a 50kWtb chemical-looping combustor. NiO/bentonite particle was used as a bed material and $CH_4$ and air were used as reacting gases for reduction and oxidation respectively.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.94.2-94
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• 2002

$\textbullet$ The method to have real-time response at the motion control. $\textbullet$ The trajectory generation method guarantees the continuous acceleration in changing the velocity during the actuator is moving. $\textbullet$ We propose the velocity profile generation algorithm in order to change object position or object velocity with continuous acceleration using blending method.

• Journal of Welding and Joining
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• 제17권4호
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• pp.16-21
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• 1999

• Journal of Welding and Joining
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• 제14권5호
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• pp.106-112
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• 1996

The effects of Ti addition in welding wire on the spatter generation and the droplet transfer phenomena were investigated. With increasing Ti content the spattering rate was decreased but the ratio of large size spatter (D $\geq$ 1. 0mm) was increased in both short circuit and globular transfer mode of $CO_2$welding. In short circuit transfer region, the arcing time was increased and the droplet transfer frequency was decreased with increasing Ti content In globular transfer region, the transition current and voltage to globular transfer was lowered and the welding condition region for stable globular transfer was widened with increasing Ti content.

• Fibers and Polymers
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• 제6권4호
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• pp.284-288
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• 2005

Poly(ethylene terephthalate) was annealed at different temperature and pressure of supercritical carbon dioxide $(CO_2)$ using samples quenched from the melt. Crystallization and molecular relaxation behavior due to $CO_2-annealing$ of samples were investigated using differential scanning calorimetric and dynamic mechanical measurements. The glass transition and crystallization temperatures significantly decreased with increasing temperature and pressure of $CO_2$. The dynamic mechanical measurement of samples annealed at $150^{\circ}C$ in supercritical $CO_2$ showed three relaxation peaks, corresponding to existence of different amorphous regimes such as rigid, intermediate, and mobile domains. As a result, the mobile chains were likely to facilitate crystallization in supercritical state. It also led to the decreased modulus of $CO_2-annealed$ samples with increasing pressure.