• 대기
• /
• 제29권5호
• /
• pp.567-583
• /
• 2019

In this study, the high-resolution numerical simulations considering detailed anthropogenic heat, albedo, emission and roughness length are analyzed by using single layer Urban Canopy Model (UCM) in Weather Research Forecast (WRF). For this, improved urban parameter data for Seoul Metropolitan Area (SMA) was collected from global data. And then the parameters were applied to WRF-UCM model after it was processed into 2-dimensional topographical data. The 6 experiments were simulated by using the model with each parameter and verified against observation from Automated Weather Station (AWS) and flux tower for the temperature and sensible heat flux. The data for sensible heat flux of flux towers on Jungnang and Bucheon, the temperature of AWS on Jungnang, Gangnam, Bucheon and Neonggok were used as verification data. In the case of summer, the improvement of simulation by using detailed anthropogenic heat was higher than the other experiments in sensible flux simulation. The results of winter case show improved in all simulations using each advanced parameters in temperature and sensible heat flux simulation. Improvement of urban parameters in this study are possible to reflect the heat characteristics of urban area. Especially, detailed application of anthropogenic heat contributed to the enhancement of predicted value for sensible heat flux and temperature.

• 한국조경학회지
• /
• 제40권1호
• /
• pp.12-22
• /
• 2012

최근 들어 서울시를 비롯한 대도시에 건립되는 초고층건물은 주변 공기의 대류를 변화시켜 난류현상을 유발하여 빌딩바람과 도시열섬 및 대기오염 물질 집적 등 주변 환경에 영향을 미치고 있다. 그 중에서도 고층건물의 주변지역의 기온의 공간적 변화는 환경 경사가 심한 것으로 판단된다. 이에 본 연구에서는 서울시 강남구의 초고층건물 지역과 인접 지역의 기온차이를 파악하고자 2008년 3월 16일부터 2009년 3월 15일까지 고정관측과 이동관측을 수행하였다. 타워팰리스(TPL)와 숙명여고(SMG)의 거리는 불과 200m이지만 두 관측지점의 연평균 기온차는 $0.7^{\circ}C$로 관측되었고, TPL의 열대야 일수는 13일, SMG는 5일이었다. TPL의 기온이 다른 곳보다 높은 것은 고층건물에 의한 도로협곡으로 인해 sky view factor가 현저히 낮아 장파복사의 대기 중 방출이 억죄되 도시열섬현상을 가중시키고 냉난방의 단위면적 당 전력 수요가 높아, 이로 인한 인공폐열이 도로협곡에 갇혀 고층건물 지역인 TPL의 열섬현상이 인접 지역보다 높은 것으로 관측되었다.

• 상하수도학회지
• /
• 제35권2호
• /
• pp.113-120
• /
• 2021

High voltage impulse (HVI) has been gained attention as an alternative technique that could control the CaCO₃ scale problems encountered in water main, pipe, cooling tower and heat exchanger vessels. The aim of this study was to investigate the effect of electric field (E) and contact time (t) of HVI on reduction of Ca²⁺ concentration at two different temperatures of 25℃ and 60℃. A kinetic model on the effect of E and t was investigated too. As the E and t increased, the Ca²⁺ concentration decreased more than that of the control (= no HVI). The Ca²⁺ concentration decreased up to 81% at 15 kV/cm at 60℃, which was nearly 2 times greater than the control. With these experimental data-set of reduction of Ca²⁺ concentration under different E and t, the kinetic model was developed. The relationship between E and t required to reduce the concentration of Ca²⁺ by 30% was modeled at each temperature. The empirical model equations were; E^0.83· t = 60.3 at 25℃ and E^0.08· t = 1.1 at 60℃. These equations state the products of Eⁿ and t is always constant, which means that the required contact time can be reduced in accordance with the increment of E and vice versa.

• 한국주거학회:학술대회논문집
• /
• 한국주거학회 2006년도 추계학술발표대회 논문집
• /
• pp.109-114
• /
• 2006

Since 1970, concentrated development in Gang-nam caused serious differences with Gang-buk, such as housing environment, education, culture, industry, economy, and consumption behavior as well as Urban Infrastructure. In this result, the government has executed New Town project to solve these matters, but the residents' opinion wasn't reflected. The purpose of this study is to research New Town project district residents' consciousness and prefered image for housing and this research will be applied to basic study for housing environment improvement policy in future. The results of this study are summerized as follows : First, living satisfaction is revealed almost low level, and the most demands for improvement are to solve lacks of park and green yard. Second, image of Gang-nam, which of housing environment is better than Gang-buk, is expressed as the words, 'Complicated', 'Complex', 'Polished', 'Convenient', 'Rich'. Third, prefered types of housing are high-rise Residental Complex, Apartment mixed with detached housing, and tower-type apartment. And These are connected with there values

• 한국주거학회:학술대회논문집
• /
• 한국주거학회 2006년도 추계학술발표대회 논문집
• /
• pp.352-356
• /
• 2006

This study aims to analyze the current status and characteristics of apartment house unit plans towards spatial differentiation. The 172 house units from 32 housing complexes were selected for this analysis. In this study, factors of residential space plan especially in an apartment house are categorized into general characteristics on floor plan and factors for spatial floor plan. The Primary findings are as follows: (1) General characteristics on floor plan are analyzed based on space organization, area and number of bays. Among apartment houses over 40 pyeong, it seems that differentiation is well applied with various space plans available. (2) A result of an analysis on the factors for spatial floor plan shows that planning a living room with two-open-sides seems to be more common in the tower-shaped apartment blocks which are now on the increase. Moreover, many of them are adopting movable partitions to reflect resident's various demands on space plan. Among all, the extra kitchen in the balcony is planned high portion of 80.4%. And diningroom is positioned on the front side of the residential space along with a livingroom(19.2%). More frequently, dining area tends to face the living room(30.2%) according to the result. Besides dress rooms begin to be placed in each of the bedroom, once planned in one bedroom only while 18.6% of the apartment houses are placing new storages in the entrance to solve lack of storage space due to balcony extension.

• 한국대기환경학회지
• /
• 제21권5호
• /
• pp.507-513
• /
• 2005

Increasing amounts of anthropogenic $CO_2$ emitted to the atmosphere are believed to be a significant factor in global climate change. Hence, the method of chemical absorption has been suggested to separate and recover acid gases such as $CO_2$. In this study, the characteristics of absorption and regeneration of $CO_2$ for the absorbent which adding HMDA (hexamethylenediamine) into AMP (2-amino-2-methyl-1-propanol), hindered amine, was investigated in lab-scale absorption/regeneration reactor. As a result of this study, the removal efficiency of $CO_2$ increased when adding $5.9\%,\;11.7\%\;and\;23.4\%$ HMDA into $30\%$ AMP respectively. Also, the removal efficiency of $CO_2$ increased $6.5\%,\;8.4\%,\;10.3\%$ respectively as compared to AMP alone when the gas flow rate was 7.5 SL/min. In addition, all absorbents used in the study revealed the high stripping efficiency, which was almost $99\%$, at the temperature of $110^{\circ}C$. Thus, the regeneration tower should be operated at $110^{\circ}C$. At this time, the concentration of exhausted $CO_2$ was higher than $99\%$.

• 대한산업공학회지
• /
• 제40권5호
• /
• pp.462-476
• /
• 2014

The Korean government has been implementing diverse policies with programs to generate better outcomes and results of university-industry collaboration since 1990s. In this paper, we analyze the effect of universities' competency factors on the performance of technology commercialization and start-ups respectively. We employ multiple regression models using 154 data sets from university information posting system of the Korean Council for University Education. Through conducting statistical analyses with diverse data manipulations, we obtained a high degree of significance on hypotheses, and also could compare mutual differences between the effects of university competence on technology commercialization and start-ups. The technology transfer and commercialization specifically depends on professors' patent applications and technology holding company, while start-ups does professionals in industry-university cooperation. We suggest government to spur on the ongoing customization of university-industry collaboration policy, and university to properly cope with global atmosphere changing from ivory tower to academic capitalism and start-ups promotion.

• Journal of Electrical Engineering and Technology
• /
• 제12권6호
• /
• pp.2268-2277
• /
• 2017

As constantly increasing wind power penetrates power grid, wind power plants (WPPs) are exerting a direct influence on the traditional power system. Most of WPPs are using variable speed constant frequency (VSCF) wind turbines equipped with doubly fed induction generators (DFIGs) due to their high efficiency over other wind turbine generators (WTGs). Therefore, the analysis of DFIG has attracted considerable attention. Precisely measuring optimum reference speed is basis of utilized maximum wind power in electric power generation. If the measurement of wind speed can be easily taken, the reference of rotation speed can be easily calculated by known system's parameters. However, considering the varying wind speed at different locations of blade, the turbulence and tower shadow also increase the difficulty of its measurement. The aim of this study is to design fuzzy controllers to replace the wind speedometer to track the optimum generator speed based on the errors of generator output power and rotation speed in varying wind speed. Besides, this paper proposes the fuzzy adaptive PID control to replace traditional PID control under rated wind speed in variable-pitch wind turbine, which can detect and analyze important aspects, such as unforeseeable conditions, parameters delay and interference in the control process, and conducts online optimal adjustment of PID parameters to fulfill the requirement of variable pitch control system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.327_328
• /
• 2009

The insulator being used for transmission line is to mount the charged conductor on the tower or other supports. The insulators are classified according to its material: porcelain, glass and polymer. Polymer insulators are also called as composite insulator or non ceramic insulator (NCI). Insulators are a major element of a power transmission system. Since a faulty insulator can lead to a wide spreading blackout, it must have sufficient mechanical and electrical strength. It must be durable, have high electrical insulation and be able to withstand a leakage current. It must also be able to withstand the toughest weather conditions. In Korea, porcelain insulators have been used widely. However, to make compact equipment and keep up with global trends, we have enhanced domestic production of polymer insulator and are encouraging its applications. Accordingly, this thesis will look at types of insulators, use and trends, and prospects of insulators application in the field.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 춘계학술대회
• /
• pp.698-701
• /
• 2007

DAHAN, the first 1 MWe Solar Power Tower system locates north to Beijing where nearby The Great Wall is now under construction with cooperation between China and Korea. Results in predicting the preliminary performance of this central receiver system are presented in this paper. Operating cycles under some typical weather condition days are simulated and commented. These results can be used to assess the impact of alternative plant designs or operating strategies on annual energy production, with the final objective being to optimize the design of central receiver power plants. Two subsystems are considered in the system simulation: the solar field and the power block. Mathematic models are used to represent physical phenomena and relationships so that the characteristics of physical processes involving these phenomena can be predicted. Decisions regarding the best position for locating heliostats relative to the receiver and how high to place the receiver above the field constitute a multifaceted problem. Four different kinds of field layout are designed and analyzed by the use of ray tracing and mathematical simulation techniques to determine the overall optical performance ${\eta}_{field}$ and the spillage ${\eta}_{spill}$.The power block including a Rankine cycle is analyzed by conventional energy balance methods.