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중앙 냉방시스템의 냉동기 유형에 따른 에너지 사용 특성 비교 연구
유병천,김정욱 한국건축친환경설비학회 2019 한국건축친환경설비학회 논문집 Vol.13 No.5
This study conducted positive performance test and economy analysis on energy saving effect of improvement of old central heating and air conditioning system in the main building of Presbyterian University and Theological Seminary. Existing heat source system alternatively operates 22-year-old two absorption chiller-heaters and provides air conditioning and heating to main building, library, and chapel. Considering the building type, cooling and heating system, load analysis, chiller type, and operation status, the old absorption chiller-heaters have been replaced with oil-free inverter turbo chiller. Also, BEMS has been used to check the characteristics of change in energy consumption. This study conducted a comparative analysis on energy consumption before and after the improvements by collecting the data from May to October in 2018. The analysis result showed that the gas consumption for air conditioning with existing chiller-heater was 30,587 Nm3 a year. On the other hand, the turbo chiller monitored with BEMS consumed 29,370 kWh. The analysis result proved the energy saving of about 24.75 TOE (Ton of Oil Equivalent) by introducing the oil-free inverter turbo chiller for efficient operation. Such hybrid heat source system and efficient BEMS operation allow effective investment in the perspective of energy.
탄도미사일의 비행궤적 예측 방법 연구 - 탄종별 비행경로각과 사거리를 중심으로 -
유병천,김주현,권용수,최봉완,Yoo, Byeong Chun,Kim, Ju Hyun,Kwon, Yong Soo,Choi, Bong Wan 한국시스템엔지니어링학회 2020 시스템엔지니어링학술지 Vol.16 No.2
The characteristics of ballistic missiles are changing rapidly but studies have mostly focused on fragmentary flight trajectory analysis estimating the changing characteristics of some types, while there is a lack of research on comprehensive and efficient ballistic search, detection and prediction for missiles including the new types that have been gaining attention lately. This paper analyzes the flight trajectory characteristics of ballistic missiles at various ranges considering flight path angle adjustment, specific impulse and drag force with altitude based on the optimized equations of motion reflecting the parameters of North Korea's general and new types of ballistic missiles. The flight trajectory characteristics of representative ranges for each ballistic missile were analyzed by adjusting the flight path angle in the minimum energy method, lofted method, and depressed method. In addition, High value target can attacked by ballistic missiles considering flight path angle adjustment at various points. It's expected to be used to Threat Evaluation and Weapon Allocation, and deployment of defense systems by interpreting the analysis of the latest Iskander-class ballistic missiles and the new multiple rocket launcher.