회전 환경에서의 축류 터빈 성능평가

윤용상,송성진,김홍원,조성희,Yoon, Yong-Sang,Song, Seung-Jin,Kim, Hong-Won,Cho, Sung-Hee 한국유체기계학회 2001 한국유체기계학회 논문집 Vol.4 No.3

This paper describes a turbine test program conducted at Seoul National University(SNU). To measure blades' aerodynamic performance, either linear(2-Dimensional) or annular(3-Dimensional) cascades are often used. However, neither cascade can consider effects such as those due to rotation or rotor-stator interaction. Therefore, a rotating test facility for axial turbines has been designed and built at SNU, and its description is given in this paper. The results from an axial turbine performance test are presented. At the design point, the measured efficiency agrees with the efficiency predicted by a meanline analysis. At off design points, however, the measured and predicted efficiencies diverge. The most likely cause is hypothesized to be the inaccuracy of correlations used in the meanline analysis at off design points.

공동주택의 최적 Glazing 구성에 관한 연구

윤용상(Yoon, Yong-Sang),윤재훈(Yoon, Jae-Hoon),현종훈(Hyun, Jong-Hoon),황우진(Hwang, Woo-Jin),신재규(Shin, Jae-Gue),최원기(Choi, Won-Ki),문선혜(Mun, Sun-Hye) 대한건축학회 2012 대한건축학회논문집 Vol.28 No.10

This study focuses on thermal performance variations according to insulating glazing units and the set point temperature. We used the EnergyPlus rating, which is validated by the U.S. DOE. The results are as follows: In the case of a non-extended-type household: (1) The influence of SHGC rather than that of U-factor was found to be relatively high. Therefore the composition of glazing that may maintain SHGC at 0.5 or greater is deemed to be more desirable for energy savings. (2) When the manufacturing method of Low-e glass varies, the influence on the building energy consumption can change. Therefore, the designer is required to understand the composition of glazing in advance at the planning stages of the building. (3) In the case of Low-e insulating glass and Low-e triple glass, almost no difference exists between the influences of such on the energy demands of the building; however, Low-e insulating glass is deemed to be more reasonable from the economical aspect. In the case of an extended-type household: (1) The entire energy consumption increases in this case as compared with a non-extended-type household (2) In the case where a window faces the outdoor air, unlike a non-extended-type household, the U-factor and SHGC all have great influence on the building energy consumption, and therefore the construction of glazing in consideration of this is desirable. Lastly, as the set point temperature increases/decreases by 1℃, cooling/heating loads were found to increase/decrease by approximately 16% representing that the change in living patterns greatly influences on the reduction of building energy consumption. Further comprehensive studies on the influence of change in set point temperatures on the consumption of building energy should be conducted based on the expanded scope such as a block, unit complex, or district unit in order to recommend the method for reducing energy in apartment type housing.

자치단체의 온실가스 감축이행 평가를 위한 탄소지수 활용 방안에 관한 연구

윤용상(Yoon Yong-Sang),심명희(Sim Myung-Hee),권가란(Gwon Ga-Ran) 한국건축친환경설비학회 2014 한국건축친환경설비학회 논문집 Vol.8 No.1

As frequent natural disasters are under the influence of climate change, there is a growing interest of the international community in the issues of climate change. The United Nations makes efforts to reduce the emissions of greenhouse gases regarded as the main culprit of global warming, by 50% by 2050 in relation to 1990 levels. In responding to the efforts of the international community for greenhouse gas reduction, our government set the 30% reduction target in greenhouse gas emissions compared to the national greenhouse gas emission projections of 2020 (BAU) and established measures for the reduction plan. However, objective evaluation criteria for the greenhouse gas reduction commitments are still absent. Therefore, this study intended to derive correlations among greenhouse gas emissions projections for each of the local governments, greenhouse gas reduction obligations of the year and actually reduced greenhouse gas emissions. Also, represented in carbon reduction indices, the results enabled the extent of the greenhouse gas reduction commitments made by the country and local governments to be determined, and the comparison and evaluation for the reduction target to be performed.

Blade Loading에 의한 팁와류의 특성

윤용상(Yong Sang Yoon),송성진(Seung Jin Song) 한국유체기계학회 2002 유체기계 연구개발 발표회 논문집 Vol.- No.-

The characteristics of tip vortex within a blade tip region were examined experimentally in various flow coefficients by the way of changing tip clearance and blade stagger angle in an axial Low Speed Research Compressor(LSRC). The objective was to identify the unsteady pressure distribution in the blade passage by ensemble average technique acquired from high-frequency response pressure transducers and the tip vortex by root mean square value(RMS value). Data were reduced statistically using phase-lock technique for detailed pressure distributions.

고 분말시멘트를 활용한 프리캐스트 콘크리트 연구

윤용상(Youn, Yong Sang),서신석(Seo, Shin Seok),윤용선(Yoon, Yong Sun),김근(Kim, Geun),전용희(Jeon, Yong Hee),홍성윤(Hong, Sung Yoon) 한국콘크리트학회 2014 한국콘크리트학회 학술대회 논문집 Vol.2014 No.5

지역의 기후특성이 반영된 외피의 열적 성능에 관한 연구

윤용상(Yoon Yong-Sang),권가란(Gwon Ga-Ran),심명희(Sim Myung-Hee) 한국건축친환경설비학회 2014 한국건축친환경설비학회 논문집 Vol.8 No.2

In this study, we analyzed the performance of the envelopes (average heat transmission coefficient and energy transmittance of outer walls and window systems) of E+ Green Homes to meet the heating energy requirements of 15 kWh/㎡·yr under different climate conditions in 7 regional areas in Korea, and derived the correlation between climate and envelope performance to propose its thermal performance with regional climate variabilities reflected. The correlation analysis of the heating energy requirements and envelope performance indicated that the heating energy conditions required for E+ Green Home can be satisfied in the areas with low heating energy requirements by choosing a high heat transmission coefficient for outer walls and glazing systems or a low energy transmittance for glazing systems. Besides, we derived heating degree hour, heating energy requirements, and average heat transmission coefficient of envelopes from average outside temperature of heaters, and as a result, calculated the thermal insulation performance appropriate to the climate characteristics of specific regional area. In the future, to strengthen energy conservation as efficiently as E + Green Homes, it is required to study the correlation between heating energy requirements and thermal insulation performance in areas other than the 7 regional areas, and to consider whether it is possible to apply the correlation of outside air temperature and average heat transmission coefficient to the buildings with different shape and size other than ones applied in the present study.

오피스 건물의 창면적비와 일사열취득계수에 따른 최적의 창호 구성에 관한 기초 연구

윤용상(Yoon, Yong-Sang),윤재훈(Yoon, Jae-Hoon),최원기(Choi, Won-Ki),권영철(Kwon, Young-Cheol) 한국건축친환경설비학회 2012 한국건축친환경설비학회 논문집 Vol.6 No.1

The office buildings with the curtain wall structure are weak in the cooling load, because of the high frequency of usage and the high interior gains during a day. Controlling Window to Wall Ratio and applying low U-factor windows are used to improve this, but they have the limitation of the improvement. In this study, a building energy simulation was conducted. And the influence on the energy performance was analyzed according to Window to Wall Ratio(WWR), Visible light Transmittance(VLT), Solar Heat Gain Coefficient(SHGC) and U-value. The results of this study are as follows; 1) WWR can be an independent index of energy performance of the office buildings with dimming control system. 2) As SHGC of glazing is higher, cooing energy is increased, heating energy is decrease. And total energy is increased. That is the change of SHGC more influence on cooling energy than heating energy. 3) As SHGC of glazing is lower, the turning point of cooling and total energy in a high WWR. And the energy reverse is occurred when WWR is so low. That is increase of lighting energy is higher than decrease of cooling energy, when WWR is so low. 4) The planning for energy saving of office buildings with dimming control system is considered SHGC and VLT first and WWR after.

커튼월 건물의 에너지 성능 특성에 관한 연구

윤용상(Yoon, Yong-Sang),최원기(Choi, Won-Ki),심명희(Sim, Myung-Hee) 대한건축학회 2013 대한건축학회논문집 Vol.29 No.7

Most of the newly built office buildings contains curtain wall structures with a high window-to-wall ratio, which raise concerns over the excessive energy consumption due to the glass with a relatively high heat transmission coefficient. However, when an office building has high insulation performance as high as the walls of residential buildings due to larger cooling load compared to heating load and the high heating value generated within the building, the reduction of conductive heat loss can cause an increase in energy demand. Therefore, in this study, fundamental research on the characteristics of energy performance based on the conditions of glazing performance, window area ratio and internal heat generation when planning office buildings, was carried out and the results are as follows. An increase in internal heating value caused slight decrease in heating energy while increasing significantly cooling energy demand. Also, low heat transmission coefficient of glazing reduced conductive heat loss, increasing the energy demand. As window area ratio decreased at SHGC greater than 0.3, the energy demand was also reduced. In the future, reasonable standards for the glazing performance (U-factor, SHGC, VLT) to reduce the energy consumption in office buildings are to be derived through the analysis of the energy demands based on more diverse building sizes, and also, using the standards, glazing design guidelines to afford appropriate selection of glazing in the planning stages of buildings should be developed.

제로에너지빌딩 평가 방법에 대한 고찰

윤용상(Yoon, Yong Sang) 대한건축학회 2011 建築 Vol.55 No.10

Effects of Asymmetric Tip Clearance on Centrifugal Compressor Flow

윤용상(Yong Sang Yoon),송성진(Seung Jin Song) 한국유체기계학회 2005 유체기계 연구개발 발표회 논문집 Vol.- No.-

Compared to axial compressors, an analytical model capable of analyzing the flow in centrifugal compressor lacks because of the difficulty in governing equations for radial duct. Therefore, this paper presents a new model to predict flow field in a centrifugal compressor with a sinusoidal asymmetric tip clearance. To predict the 2 dimensional flow in the inlet and exit of the centrifugal compressor, the two flow fields are connected with compressor characteristic based on Moore-Greitzer model. Contrary to axial compressors, the nonuniformity of impeller exit pressure in centrifugal compressor decreases as flow coefficient decreases. In addition, that is sensitive to the slope of pressure rise by eccentricity. The maximum velocity exists right before the maximum tip clearance.