• KIEAE Journal
• /
• 제13권3호
• /
• pp.71-78
• /
• 2013

A need for building energy efficiency is on the issue since energy demand in the building stock in Korea represents about 24% of the final energy consumption. As a way of improving the thermal performance of buildings for reducing maintenance costs and environmental conservation, a lot of effort is shown to improve the building energy efficiency by applying improvement of envelope insulation performance for buildings whose energy efficiency is low relatively through the remodeling. The windows of building envelopes are areas that lead to the biggest heat loss in the building. So windows are considered to be the primary target of energy efficiency in remodeling and various studies for windows have been done. Currently, however, only U-factor and airtightness of windows performance are regulated. Window wall ratio(WWR) and solar heat gain coefficient(SHGC) of windows are not considered when conducting the remodeling. In this study appropriate performance of windows(U-factor and SHGC) for existing residential is proposed according to the window wall ratio by using EnergyPlus. As the results of this study, the U-factor of windows representing the maximum energy savings is $1.0W/m^2K$ but in case of SHGC, the values that indicate the maximum energy savings are different depending on the window wall ratio. Therefore, when conducting the remodeling of windows, to determine energy efficiency by considering only the U-factor is inadequate so it is necessary that appropriate windows are applied to buildings by considering window wall ratio and windows properties(U-factor and SHGC).

• 한국방재학회 논문집
• /
• 제11권2호
• /
• pp.75-80
• /
• 2011

본 연구의 주목적은 에너지 비율 인자와 위상각을 이용한 연성포장의 피로예측 모델을 개발하는 것이다. 본 연구에서 도입된 에너지 비율 인자와 위상각은 점탄성 재료의 기본적인 성질을 반영하기 위하여 사용되었다. 에너지 비율 인자는 가상 방출 에너지와 시험 중 파괴시 까지의 누적 방출 에너지의 비로 정의된다. 위상각은 아스팔트 혼합물의 응력과 변형률의 차이로부터 발생한다. 아스팔트 콘크리트 혼합물의 실험결과를 이용하여 위상각이 측정 되었으며 초기 stiffness와 초기 위상각의 관계가 제시 되었다. 본 연구 결과 아스팔트 콘크리트 혼합물의 점탄성 재료라는 고유한 성질을 반영할 수 있는 에너지 비율 인자와 위상각을 활용한 연성포장용 피로 예측 모델이 제안되었다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
• /
• pp.161-166
• /
• 2002

The modification factor( k-factor) of equivalent damping ratio utilized in the current state-of-the-practice to account for the imperfection of reinforced concrete structures in hysteresis loop is investigated. From this, it is found that the current modification factor does not include the effect of cyclic loading, one of the important characteristic properties of earthquake loading. This could be taken into account by considering the energy absorption efficiency based on the cummulative plastic deformation. From the study, it is suggested that the current approach for the modification factor for the equivalent damping ratio should be reformed.

• 설비공학논문집
• /
• 제10권2호
• /
• pp.173-179
• /
• 1998

An experimental study was conducted on the effect of compressor capacity control range of heat pump on the seasonal energy efficiency ratio with variation of the maximum and minimum compressor input frequencies. To obtain seasonal energy efficiency ratio, steady state test at the maximum, minimum and intermediate compressor speed and cyclic test at the minimum compressor speed should be conducted. Maximum input frequency was varied to 95Hz, 105Hz, and 115Hz, and the minimum input frequency was varied to 35Hz, 45Hz, and 55Hz. The seasonal energy efficiency ratio increased as the input frequency of the compressor decreased. The maximum input frequency had only slight effects on the SEER.

• 한국태양에너지학회 논문집
• /
• 제28권6호
• /
• pp.70-77
• /
• 2008

The purpose of this study evaluates a feasibility and economical efficiency of new renewable energy. According as weather change is serious problem now days, every people make attention to the reduction of greenhouse gas. The revitalization of new renewable energy creates the variety of energy source, stability of energy supply and reduction of greenhouse gas. In this study evaluates a feasibility and economical efficiency from new renewable energy of various photo voltaics, wind power, small hydro and biogas. Feasibility does in standard of technical characteristic, politic support, marketability, establishment present condition and development aim. Economical efficiency does in standard of developmental unit cost, utilization factor, equipment life, politic support cost, interest ratio. The results of this study were as follows photo voltaics, wind, small hydropower, biogas in order feasibility is high. Developmental unit cost, utilization factor, equipment life, politic support cost and analyzed the relationship of interest ratio fluctuation and economical efficiency. From all new renewable energy the utilization factor most is important in economical efficiency but necessary utilization factor is difficult because environmental problem.

• 대한기계학회논문집
• /
• 제13권5호
• /
• pp.831-836
• /
• 1989

본 연구에서는 이에 대한 검토를 하기 위하여, Kato의 속도장을 수정하여 수치게산한 폭 증가율과 알루미늄을 재료로 실험한 결과를 비교하고, 마찰비와 판폭비 및 압하율의 변화에 따른 폭 증가율의 영향에 대하여 고찰하였다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2009년도 추계학술대회 논문집
• /
• pp.850-854
• /
• 2009

Approximate analysis for a building installed with a friction damper is revisited to get insight of its dynamic behavior. Energy balance equation is used to have a closed analytical form solution of dynamic magnification factor (DMF) for the building with combined viscous and friction damping. It is found out that DMF is dependent on friction force ratio and resonance frequency. Linear transfer function from input external force to output building displacement is obtained by simplifying DMF equation. Root mean square of building displacement is derived under earthquake-like random excitation. Finally, design of friction damper is proposed by processing target control ratio, damping ratio factor, and friction force in sequence.

• 한국태양에너지학회 논문집
• /
• 제34권5호
• /
• pp.117-126
• /
• 2014

This study developed a KRESS program designed to find the optimization ratio for new and renewable energy systems and analyze the effects of building energy consumption characteristics on the ratio. In spite of clear differences in predicted energy consumption and energy consumption by the loads among 18 facilities, the current formula for obligatory supply ratios applies a correction coefficient according to the building purposes based on energy consumption per each unit area in medical facilities and thus reflects no energy consumption characteristics according to the building purposes. The optimization ratio for new and renewable energy systems was the same for all facilities when the correction coefficients by the building purposes and new and renewable energy sources were all applied. When the correction coefficients were not applied, however, the optimization ratio varied according to building energy consumption characteristics. The findings raise a need to test the correction coefficients in order to select new and renewable energy systems that take into account energy consumption characteristics by the building purposes and loads and reflect economy, environmental performance, and technology.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
• /
• pp.92-97
• /
• 2011

Nowdays the most critical problem is global warming and the most important reason is the high emition of carbondioxide. 23% of the use of carbondioxide is used in building and decreasing the use of it is very important. One of the biggest factor that can decrease the use of energy is developing the heat conducting ratio of the materials we use in building. Heat conducting ratio is the important factor in the use of reducing energy comsumation. In this research, there are methods about how to measure the heat conducting ratio, and the existing the representing measuring method which is Heat Flow Meter HFM 436, Laser Flash Analysis and find out about the TCi of the new method C-Therm and compare the results.

• Bulletin of the Korean Chemical Society
• /
• 제21권7호
• /
• pp.697-700
• /
• 2000

A method of calculating the excess Helmholtz free energy from the average of the bent effective acceptance ratio for two-center-Lennard-Jones liquids has been presented. The bent effective acceptance ratio has been newly composed from the acceptan ce ratio for the potential energy difference between a configuration in the Metropolis Monte Carlo procedure and random virtual configuration generated by the separate parallel Monte Carlo procedure and the Boltzmann factor for half the potential energy difference. The excess Helmholtz free energy was calculated directly from the average of the bent effective acceptance ratio through a single Metropolis Monte Carlo run. Because the separate parallel Monte Carlo procedure was used, this method can be applied to molecular dynamics simulations. For two-center-Lennard-Jones liquids, the average of the bent effective acceptance ratio gave better results than use of the modified effective acceptance ratio in the previous work.