• 설비공학논문집
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• 제16권12호
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• pp.1227-1233
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• 2004

Air handling unit (AHU)'s air filter pressure difference is important for energy consumption and indoor air quality. Both energy Performance data and air filter differential pressure of AHU in real office buildings were monitored and analyzed to investigate quantitatively energy impact as dust buildup level on air filter grows. We also modeled and simulated CAV system using HVACSIM＋ program to examine the energy effect of dust buildup on filters. Through analysis of time series pressure drop data, the filter pressure difference rate has been increased due to cumulative supply air flow rate increase. As filter pressure drop increased to 1 inch water column, it is found that the supply air flow rate was decreased by 10%, the chilled water flow rate was increased by 5.9% and the pump energy consumption was increased to 5.9%.

• 설비공학논문집
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• 제25권7호
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• pp.371-376
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• 2013

Recently, many studies related to reducing the energy consumption in data centers have been conducted. These studies have mainly focused on the air intake and exhaust system of a computer room air handling unit (CRAH) in the server room, diffuser type, suppression and discharge of the heat generated from the server, and the air-side economizer system. In this study, the energy consumption of the conventional central chilled water cooling system is compared with the energy consumption of the air-side economizer system. We also examined how changes of differential pressure by each filter have influenced energy consumption, using the power usage effectiveness (PUE). Results show that the PUE was improved, and energy consumption decreased, by applying the air-side economizer system.

• Composites Research
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• 제35권3호
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• pp.216-221
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• 2022

Recently, the worldwide demand for disposable masks has increased due to COVID-19 infections and severe air pollution. Personal masks should reduce breathe resistance while maintaining filtering performance. In this study, a solution blowing process is used to produce composite nanofiber filters to co-spin two polymers at once. The manufacture process of the various fiber diameter filter was designed, and the filtration performance and differential pressure of the prepared filter was investigated. Poly vinylidene fluoride-hexafluoropropylene (PVDF-HFP) and Polylactic acid (PLA) fibers were chosen to be entangled together in a layer with a diameter of 1.05 ㎛ and 0.33 ㎛. Composite nanofilters showed up to 87% filtration efficiency and 32 Pa differential pressure.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권1호
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• pp.67-75
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• 2015

Differential pressure sensor for DPF (Diesel Particulate Filter) is the important part of a automobile exhaust system. This device measures the pressure of before DOC and after DPF to determine whether the DPF regenerate. In this paper reliability assessment criteria for DPF differential pressure sensor are established on terms of quality calcification test and lifetime test. The former quality certification test comprises general performance test and environmental test. Items which pass the test undergo lifetime test which guarantees the extent of mean lifetime with certain confidence.

• 한국기계가공학회지
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• 제18권8호
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• pp.82-90
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• 2019

We propose an equivalent model of a sintered metal mesh filter calculated by Ergun's equation and polynomial regression for the CFD analysis of breakaway devices at a hydrogen fueling station. CFD analysis of filters that cause high pressure loss is essential because breakaway devices in high-pressure hydrogen conditions require low pressure loss. A differential pressure experiment with a filter was performed in a low-pressure air condition considering similarities. An equivalent model was developed by deriving the resistance value by the polynomial regression using the experimental results. The results of CFD analysis using the equivalent model show that there was almost no error in the operating condition of the breakaway device compared to the experimental results. Through this work, we believe that the proposed equivalent model of a filter can be applied to the analysis of breakaway devices in hydrogen fueling stations. We will study how to optimize the shape and position of the filter in breakaway devices using the developed equivalent model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.358-363
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• 1987

It is widely noted that pressure feedback systems have been devised to damp the fluid resonance effectively in precision speed control-for large inertia system. A compensation technique preserving the natural output disturbance discrimination characteristics at lower frequencies is proposed The load pressure across positive displacement acceleration. The technique involves feeding back load differential pressure, sensed by pressure transducers, though a simple analog compensatory circuit (high pass filter). The effectiveness of the damping is determined by the filter time donstant and loop gain. Nonlinear total hydraulic simulation results verify the possibility of linear model predictions of extending the closed loop bandwidth beyond the uncompensated frequency.

• 설비공학논문집
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• 제6권4호
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• pp.417-426
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• 1994

Filter media performance was evaluated using monodisperse NaCl particles with Differential Mobility Analyzer and Ultrafine Condensation Particle Counter. Low or medium performance filters show that the most penetrating particles size(MPPS) is around $0.3{\mu}m$ in diameter and is shifted to smaller sizes as the filter face velocity increases. However, HEPA and ULPA filters show MPPS is around $0.15{\mu}m$ in diameter and is also shifted to $0.1{\mu}m$ in diameter as the face velocity increases. In case of electret filter, the MPPS is found around $0.04{\mu}m$ region for Boltzmann charge equilibrium particles. There is a tendency of strong collection efficiency decrease for large particles as the face velocity increases on the contrary to the other filters. One of the medium performance filter efficiency was compared with filtration theory and the good agreetment was found in the experimental range.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.334-335
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• 2004

원자력 관련시설에서는 방사선 오염공기가 시설 밖으로 누출되지 않도록 시설 내부를 상시 부압으로 유지하고, 또한 내부를 방사선 준위 별로 구분하여 구역 칸 차압을 유지하는 것이 중요하다. 환기설비 운영 중에 부압의 변동이 일어나기 쉬운데 HEPA 필터의 눈메꿈과 각 구역 간 출입문 개폐의 영향이 가장 크다. 환기계통운전에 있어서는 출입문 개폐상태 감시확인 및 HEPA 필터 등의 각 뱅크에 차압계를 설치하여 필터의 눈메꿈 상태를 주기적으로 측정하고 교체함으로써 방사성폐기물처리시설 내 부압 및 각 구역 간 차압을 일정하게 유지할 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.440-447
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• 2002

본 연구에서는 호흡량 측정에 영향을 주는 요인들로부터 정확한 유량을 산출해내는 방법에 대해 고찰하고, 마취용 인공호흡기에 적용하여 수술환자의 호홉특성을 알아내는 호흡측정기를 구현하였다. 차동압력형 유량센서를 이용하여 압력, 온도, 가스구성의 상관관계에 따라 호흡량을 계측하였으며, 휴대형 기기에 적합하도록 전력 효율을 최대화 할 수 있게 시스템을 설계하였다. 구현 시스템은 크게 아날로그 인터페이스(analog interface)부, 신호처리부, 그리고 화면출력부로 나눌 수 있다. 아날로그 인터페이스부는 차동 압력 유량 센서와 차동 압력 센서로 구성된다. 전력소모를 최소화하기 위하여 여러 가지 기능을 단일소자로 수행할 수 있고, 저전력의 8비트 RISC 계열인 AVR프로세서를 중앙처리장치로 선택하였다. 데이터 전송부에서는 직렬(serial)통신(RS232, SPI)으로 측정된 값들의 출력 파형을 PC화면에 표시하거나 마취기로 전송한다. 차동 압력과 유량의 비선형적 관계를 선형화하였고, 센서 보정 기능은 일정 주기로 보정을 자동적으로 수행함으로써, 보다 안정적인 동작이 가능하게 한다. 아날로그 필터와 고속의 디지털 신호처리 알고리즘 구현으로 생체신호의 노이즈를 줄일 수 있었다. 작고, 가벼우며, 저전력인 시스템의 특징은 응급 환자나 이동중인 환자에게 적용될 수 있으며, 가래, 침, 습기와 같은 이물질에 영향이 적은 유량 센서의 사용으로 점액의 발생이 많은 마취기에서 유용하게 사용될 수 있다.

• 한국염색가공학회지
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• 제33권4호
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• pp.302-308
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• 2021

Air filters are being used in countless places from industrial sites to everyday life. The spread of the COVID-19 virus, which started in 2019, is disrupting people's daily lives, and the importance of air filters as a basic means to prevent the spread of these diseases is further highlighted. In this study, the purpose was to develop another type of air filter media with excellent barrier properties that can replace PP meltblown nonwoven fabrics widely used commercially due to its excellent electrostatic properties, differential pressure and filtration efficiency. Therefore, wet-laid nonwoven for air filters were manufactured using plexi-filaments formed through flash spinning and having various fiber diameter from hundreds of nanometers to tens of micrometers, and its applicability as an air-filter media was investigated compared to the meltblown nonwoven. As a result of the performance evaluation, it was found that the filtration efficiency and barrier performance at 0.3㎛ was superior to that of the meltblown nonwoven of the same weight, although the differential pressure was high due to morphological properties of the plexi-filament.