• 한국산학기술학회논문지
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• 제19권11호
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• pp.326-331
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• 2018

최근 들어 건물이나 데이터 센터의 공조에 기화식 가습기가 널리 사용된다. 일반적으로 가습 효율은 외기 조건에 관계없이 동일하게 적용된다. 하지만 이 부분에 대해서는 확인이 필요하다. 본 연구에서는 일반 건물과 데이터 센터의 설계 온습도 조건에서 일련의 실험을 수행하고 상기 가정이 적절한지를 판단하였다. 실험에 사용된 소자는 cellulose/PET 재질로 깊이 100mm, 200 mm, 300 mm 세 종류이고 전방 풍속 1.0 m/s에서 4.5 m/s 사이에서 수행되었다. 실험 결과 가습 효율은 외기 조건에 따라 차이가 났다. 데이터 센터 ($25^{\circ}C$ DBT, $15^{\circ}C$ WBT) 조건에서 건물 공조 ($35^{\circ}C$ DBT, $21^{\circ}C$ WBT) 조건보다 크게 나타났는데 그 이유는 입구 영역에서 수분 전달 성능의 차이 때문이다. 심지어 건물 공조 조건에서는 입구 영역에서 제습이 일어났다. 또한 공급수 온도가 외기 공기의 습구온도에 근접할수록 가습 효율이 증가함을 확인하였다. 따라서 가습소자의 성능을 적절히 예측하기 위해서는 입구 영역에 대한 해석 모델이 포함되어야 한다. 한편 소자의 두께가 100 mm에서 200 mm로 되면 가습효율이 29% 증가하고 300 mm가 되면 42% 증가한다. 하지만 압력 손실도 47%, 86% 증가한다.

• 설비공학논문집
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• 제26권10호
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• pp.467-473
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• 2014

Since the operating conditions of HVAC systems are different from those for which they are designed, on-going commissioning is required to optimize the energy consumed and the environment in the building. This study presents a methodology to analyze operational data and its applications. A predicted operation model is to be produced through a statistical data analysis using multiple regressions in SPSS. In this model, the dependent variable is the pre-cooling time, and the independent variables include the power output of the supply air inverter during pre-cooling, the supply air set temperature during pre-cooling, the indoor temperature-indoor set temperature just before pre-cooling, supply heat capacity, and the lowest outdoor air temperature during non-cooling/non-heating hours. The correlation coefficient R2 of the multiple regression model between the pre-cooling hour and the internal/external factors is of 0.612, and this could be used to provide information related to energy conservation and operating guidance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.485-487
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• 1997

Schemes for detecting and diagnosing faults are presented. Faults are detected when residuals change significantly and thresholds are exceed. Two stage artificial neural networks are applied to diagnose faults. The idealized steady state patterns of residuals are defined and learned by ANNs using back propagation algorithm. The first stage ANN is trained to classify the subsystem in which the various faults are located. The first stage ANN could be also used to detect faults with threshold, checking. The second stage ANNs are trained to discriminate the specific cause of a fault at the subsystem level.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.241-246
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• 2005

The objective of this study is to develop a rule-based fault detection and diagnosis algorithm and an experimental verification using air handling unit. To develop an analytical algorithm which precisely detects a faulted component, energy equations at each control volume of AHU were applied. An experimental verification was conducted in the AHU at Green Building in KIER. In the experiment conducted in hot summer condition, the rule based FDD algorithm isolated a faulted sensor from HVAC components.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.807-813
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• 2006

The objective of this study is to develop a rule-based fault detection algorithm and an experimental verification using an artificial air handling unit. To develop an analytical algorithm which precisely detects a tendency of faulty component, energy equations at each control volume of AHU were applied. An experimental verification was conducted on the HVAC simulator. The rule based FDD algorithm isolated a faulted sensor from HVAC components in summer and winter conditions.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제28권4호
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• pp.89-97
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• 2022

Purpose: Because of the recent COVID-19 pandemic, there have been many cases of using portable negative pressure unit to convert general wards into temporary negative pressure isolation wards. The purpose of this study is to analyze the indoor environment of the switching type wards. Methods: Field measurements and experiments were conducted in a medical facility. Air volume, wind speed and pressure difference were measured in non-occupant state. Dispersion tests were performed with gas and particle matter. Results: The pressure difference between the wards and the corridor was higher than -2.5 Pa in normal situation. However, in the gas and particle dispersion tests, it was found that there were concerns about the spread through leakages in low-airtight walls or ceilings. In addition, it was confirmed that the pressure imbalance in ducts through the non-sealed diffusers could cause back flow during portable unit operation. Furthermore, when there was a pressure difference between adjacent wards planned to be at same pressure level, the possibility of the spread through the leakages was found. Implications: When using portable units for making switching type wards, it is necessary to create airtight space and seal the non-operation diffusers. In case of operating the air handling unit, T.A.B must be performed to adjust the duct balancing.

• 한국산업보건학회지
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• 제25권2호
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• pp.202-210
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• 2015

Objectives: The purpose of this study was to examine clean room(C/R) structure, air conditioning and contamination control systems and to provide basic information for identifying a correlation between the semiconductor work environment and workers' disease. Methods: This study was conducted at 200 mm and 300 mm semiconductor wafer fabrication facilities. The C/R structure and air conditioning method were investigated using basic engineering data from documentation for C/R construction. Furthermore, contamination parameters such as airborne particles, temperature, humidity, acids, ammonia, organic compounds, and vibration in the C/R were based on the International Technology Roadmap for Semiconductors(ITRS). The properties of contamination control systems and the current status of monitoring of various contaminants in the C/R were investigated. Results: 200 mm and 300 mm wafer fabrication facilities were divided into fab(C/R) and sub fab(Plenum), and fab, clean sub fab and facility sub fab, respectively. Fresh air(FA) is supplied in the plenum or clean sub fab by the outdoor air handling unit system which purifies outdoor air. FA supply or contaminated indoor air ventilation rates in the 200 mm and 300 mm wafer fabrication facilities are approximately 10-25%. Furthermore, semiconductor clean rooms strictly controlled airborne particles(${\leq}1,000{\sharp}/ft^3$), temperature($23{\pm}0.5^{\circ}C$), humidity($45{\pm}5%$), air velocity(0.4 m/s), air change(60-80 cycles/hr), vibration(${\leq}1cm/s^2$), and differential pressure(atmospheric pressure$+1.0-2.5mmH_2O$) through air handling and contamination control systems. In addition, acids, alkali and ozone are managed at less than internal criteria by chemical filters. Conclusions: Semiconductor clean rooms can be a pleasant environment for workers as well as semiconductor devices. However, based on the precautionary principle, it may be necessary to continuously improve semiconductor processes and the work environment.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.89-93
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• 2004

To numerically construct the sound fields by a plenum fan mostly found in Air-Handling Unit (AHU), the Kirchhoff-BEM approach was applied to the near-field data of a turbo fan. The scattering effects were found to be significant by the plenum box structure for high-frequency components of source. The directivity petterns and sound pressure levels were also dependent upon the helmholts number which must be considered of the design stage for sound reduction program.

• 한국항공운항학회지
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• 제11권2호
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• pp.59-77
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• 2003

Air Traffic Control Tower is one of the most important units in Airport operation. It provides services related to safe and efficient traffic flows that control aircraft on the ground maneuvering area and terminal airspace. Also It is responsible for managing of ground operators. The major objective of this study is to evaluates relative efficiency of ATC towers in Domestic airports using data envelopment analysis so that it helps the ATC authority to improve the tower efficiency, to decide the level of benchmarking target and to establish the best alternative. The results of this study are the following; First, as a result of analysis for the potential improvement, it has analysed that the common problems of each ATC tower are to increase its number of flight and to reduce its number of runway followed by airside area, the number of air traffic controller and the number of stand. Second, it has shown that the each tower in RKPC(8), RKPT(5), RKPK(l) and RKSS(l) are used as the reference set. Especially, the tower in RKPC analyzed as a relatively efficient unit is the most main target for the towers in RKTU, RKTH, RKPS and RKTY to do bench marking and to set up the strategy for improving relative efficiency of the tower. Third, tower is actually not able to control the input and output data in this study except the number of controller, so that ATC authority is recommended to improve inefficiency of the towers through handling the number of controller.

• 분석과학
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• 제27권6호
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• pp.284-291
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• 2014

차량 실내 공기질 대응 프로세스는 두 단계의 시험 방법으로 이루어져 있다. 먼저 모듈 부품평가를 통해 차량 실내 VOCs의 주요 원인을 찾고, 절단 시험편을 이용하여 VOCs가 주로 방출되는 소재를 찾는다. 만약 VOCs가 주로 방출되는 소재를 확인 시, 소재 개선을 통해 차량과 모듈 부품에서 방출되는 VOCs를 줄일 수 있다. 하지만 기존의 절단 시험편을 이용한 시험법은 VOCs 원인을 찾는데는 절단면에서의 방출 문제가 있기 때문에, 구성 부품 단위의 평가방법 적용이 필요하다. ISO 12219-5 시험 방법은 부품 절단없이 평가를 하기 때문에 소재 및 표면적의 영향이 함께 고려되어, 모듈 부품에서 구성 부품의 VOCs 영향도 확인이 가능하였다. 트림과 콘솔의 구성부품 평가를 통해 모듈내의 주요 원인 부품을 확인할 수 있었다. 또한 ISO 12219-5 모듈 부품 시험법과 구성 부품 시험법간의 정량적 상관관계 규명을 통해 품질관리를 위한 관리값을 설정할 수 있었다.