• Title/Summary/Keyword: fan ventilation

검색결과 279건 처리시간 0.032초

단프라시트를 적용한 간접식 증발냉각 장치의 냉각 성능 예측 (Prediction of Cooling Performance for Indirect Evaporative Cooling System Using Danpla Sheet)

  • 김명호;김병재
    • 한국산학기술학회논문지
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    • 제21권11호
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    • pp.892-897
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    • 2020
  • 본 연구에서는 간접식 증발냉각 장치의 냉각 성능을 예측하고 다양한 공기 유량 및 물 분무 유량 조건을 만족하는 성능 상관식을 제안한다. 기존의 플라스틱 열교환기는 공조 공간의 크기에 따라 금형을 새로 제작해야 하기 때문에 높은 효율에도 불구하고 잘 사용하지 않았다. 한편 단프라시트는 일반적으로 두께가 얇아 열교환이 우수하고, 특히 제작이 매우 용이하다. 따라서 열교환기를 단프라시트로 제작할 경우 금형이 별도로 필요하지 않아 열교환기 제작 비용을 크게 절감할 수 있다. 이에 본 연구에서는 단프라시트로 다채널 열교환기를 제작하여 간접식 증발냉각 장치를 제작하였다. 성능 실험장치는 열교환기, 물 분사 노즐, 터보홴, 항온조, 순환 펌프, 온도 센서, 습도 센서, 차압식 유량계 및 자료획득 장치로 구성하였다. 증발냉각 시 공기 유량이 증가하면 유용도가 감소하였고, 수공비에 따라 유용도 최적점이 존재하였다. 등온 조건에서 냉각 성능을 예측하는 상관식과 실내 환기 온도와 외기 상태를 반영하는 성능 상관식을 제안하였다. 상관식들의 냉각 성능 오차는 4 % 이내였다.

버어리종 잎담배 건조시 부패방지 II. 건조조건과 보조화력의 영향 (Prevention of Barn Rot during Curing of Burley Tobacco. II. Effect of Curing Conditions and Supplemental Heat.)

  • 배성국;임해건;한철수
    • 한국작물학회지
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    • 제34권4호
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    • pp.331-334
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    • 1989
  • 공시품종을 Burley 21로 하고, 수확한 후 건조실관리에 따른 건조부패엽 방지방법을 체계화하기 위하여 무가온과 가온조건으로 구분하였으며, 무가온건조에서는 달줄간격과 환기조건을 달리하여 처리하였고, 가온조건에서는 화력, 풍화력, 풍력으로 구분하여 처리하였던 바 실험 결과를 요약하면 다음과 같다. 1. 달줄간격을 넓힐수록 온도 차이는 없었으나 습도가 낮아져서 부패엽 발생이 크게 감소되었다. 2. 환기구에서는 온도가 2$^{\circ}C$, 습도가 2.3%가 각각 더 낮아서 밀폐구 보다는 부패엽이 20% 감소되었다. 3. 건조시 당일 25% 패수된 처리는 이후의 기상조건이나 건조실관리에 영향을 받지 않고 부패엽이 발생되지 않았다. 4. 부패시에 35$^{\circ}C$온도로 화력이나 풍화력을 24시간 처리한 구에서는 무퍼리보다 부패엽이 39.7, 47.4%가 각각 감소되었다. 5. 부패시에 48시간 풍격 처리구에서도 무처리보다 34%가 감소되어 건조실내 공기의 강재순환효과가 컸다.

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아로마 시술자들의 건강실태에 관한 연구 (The Study on the Health of Aroma Therapeutist)

  • 김미옥;석귀덕
    • 한국생활과학회지
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    • 제17권1호
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    • pp.171-179
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    • 2008
  • This study focuses on 130 estheticians currently working in and around Daegu and Gyeongbuk region, in order to find out the current state of affairs and side effects related to aromatherapy. This paper is based on a survey. SPSS win 11.0 program was used for the analysis of descriptive statistics and independent t-test. According to the result of analysis, about 33% of the estheticians have had allergy experience. And in terms of installation of an air ventilation fan, which is the most important facility in an treatment room, more than half (50.8%) replied they did not have one. There was a statistically significant difference between those estheticians suffering from allergy and those who did not, in symptoms of stuffy nose/rhinitis (P<0.01) and dry skin/itchiness (P<0.5). (Allergy symptoms from the 33% of estheticians were limited to those which occurred after he or she began career) On work related symptoms, those who had work history at hospitals/clinics or apothecaries were compared. A statistically relevant difference was confirmed between those estheticians with therapy experience and those who had none, in all symptoms except headaches and drowsiness/weariness. In other words, there was difference in symptoms such as dryness of skin/itchiness (P<0.01), stuffy nose/rhinitis, dry throat, tension/nervousness, dizziness, tired eyes(P<0.5), nausea, having trouble with focusing, and fatigue(P<0.1). Those estheticians who had a history of treatment especially suffered most from dryness of skin and itchiness. The rate of regular check-ups and the use of masks, employed for self protection, was lower than average (amounting to 5 points), with the use of masks especially having the lowest average (1.7) points.

통계적 분석을 이용한 터널 환기시스템 적정설계변수의 산정 및 적용에 관한 연구 (The Estimation and Application of Optimum Design Variables for Road Tunnel Ventilation System Based on Statistical Analysis)

  • 이보영;유용호;김진
    • 터널과지하공간
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    • 제14권5호
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    • pp.373-380
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    • 2004
  • 본 연구에서는 도로터널 환기시설 설계기준에 의한 소요환기량 산정 시 오염물질의 기준배출량을 환경부 고시기준에 대해 산정하여 차종별, 속도별로 산정된 기준배출량을 모델터널에 적용하여 시뮬레이션 한 결과 기존의 배출량 기준 적용에 대해 소요환기량은 약 49%로 감소되었다. 또한 터널 내 유동손실로서 작용하는 변수 중 터널마찰계수와 입구저항계수 및 등가저항면적을 통계적 분석기법을 이용하여 이들 계수 중 터널의 환기량 산정에 가장 민감하게 영향을 미치는 인자가 마찰계수이며 시뮬레이션을 통해 실제 적용 가능한 계수 범위가 0.018에서 0.021의 값으로 보정될 수 있을 것으로 예상된다. 검증사례로서 4개소의 터널에 적용하였을 때, 최대 약 19.2%의 소요환기량 감소가 예상되며 이에 대해 기존의 설계운용 중인 Jet Fan 설치 대수의 산정에 있어 감소될 수 있으며, 약 연간 운용비용의 저감에 적용 가능할 것으로 사료된다.

유도공기 및 에어커튼을 이용한 주방 레인지후드 성능 개선에 관한 수치모사 (A Numerical Study on the Performance Improvement of Kitchen Range Hood by Air Induction and Air Curtain)

  • 손덕영;임지홍;최윤호;박재훈
    • 설비공학논문집
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    • 제19권4호
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    • pp.321-327
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    • 2007
  • In an apartment house that is generally air-tight and well insulated, the combustion gas from cooking devices is the major source of air pollution in the kitchen. It spreads throughout the house affecting the overall Indoor all quality. In this study, the performance of the kitchen range hood which employs air induction and air curtain was investigated by numerical simulation. The results are compared with that of two other kitchen range hoods which are in general use. The two general types of range hoods considered in the present calculations are box and plate type range hoods. The former has a large capture space between the filter and suction duct, while the latter has little. It was found that the capture efficiency of the kitchen range hood with air induction and air curtain Is higher than that of the general types of range hoods by 20% approximately The reason may be because the air induction and the air curtain block the air stream escaping from the front and the side part of range hoods effectively and because an additional fan for air induction and air curtain increases suction flow rates.

Indoor distribution characteristics of airborne bacteria in pig buildings as influenced by season and housing type

  • Kim, Ki Youn;Ko, Han Jong
    • Asian-Australasian Journal of Animal Sciences
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    • 제32권5호
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    • pp.742-747
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    • 2019
  • Objective: A concentration of airborne bacteria generated from swine houses is recognized to be relatively higher than other work places and it is essential to optimally manage it to prevent farmers' respiratory diseases. This study was conducted to assess the distribution characteristics of airborne bacteria in swine houses located at South Korea. Methods: A total 27 pig buildings of the enclosed type operated with mechanical ventilation system by a side wall fan and deep-pit manure system with slats were surveyed. Air samples were collected at 1.0 m above the middle floor in pig housing room. A six-stage viable particulate cascade impactor was used to identify the distribution of the sizes of particles in diameter. Results: Seasonal mean levels of airborne bacteria in the housing rooms of gestation/farrowing pigs, nursery pigs and growing/fattening pigs were 3,428(${\pm}1,244$) colony forming unit $(cfu)/m^3$, $8,325({\pm}3,209)cfu/m$, and $13,254({\pm}6,108)cfu/m^3$ for spring; $9,824({\pm}2,157)cfu/m^3$, $18,254({\pm}5,166)cfu/m^3$, and $24,088({\pm}9,274)cfu/m^3$ for summer; $1,707({\pm}957)cfu/m^3$, $4,258({\pm}1,438)cfu/m^3$, and $8,254({\pm}2,416)cfu/m^3$ for autumn; and $2,322({\pm}1,352)cfu/m^3$, $6,124({\pm}1,527)cfu/m^3$ and $12,470({\pm}4,869)cfu/m^3$ for winter, respectively. Conclusion: Concentrations of airborne bacteria according to pig housing type were highest in growing/fattening housing room followed by nursery housing room and gestation/farrowing housing room. In terms of seasonal aspect, the pig building showed the highest levels of airborne bacteria in summer followed by spring, winter and autumn. The respirable airborne bacteria which are ranged between 0.6 and $4.7{\mu}m$ accounted for approximately 60% compared to total airborne bacteria regardless of pig housing type.

설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제27권7호
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

터널환기 무창육계사의 분진크기별 분포와 배출농도에 관한 연구 (Dust Spatial Distribution and Emission of Tunnel Ventilated Windowless Broiler Building)

  • 최희철;연규영;송준익;강희설;권두중;유용희;양창범;천상석;김용국
    • 한국축산시설환경학회지
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    • 제12권3호
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    • pp.115-122
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    • 2006
  • 본 연구는 터널환기 무창육계사의 계사내부의 위치별 먼지 농도 분포와 배기홴에서 배출된 먼지의 확산범위를 알아보고자 수행하였으며 결과는 다음과 같다. 1. 입기구 방향의 계사 1/4 지점의 먼지농도는 TSP의 경우 $301.0{\sim}1,366.0\;{\mu}g/m^3$으로 입기구의 위치에 따라 차이가 있었다. 2. 터널홴 앞 3m 지점에서는 TSP $2065.8{\sim}3,092.2\;{\mu}g/m^3$, PM 2.5 $27.6{\sim}36.3\;{\mu}g/m^3$, PM 1.0 $8.3{\sim}11.3\;{\mu}g/m^3$으로 입기구에 비하여 증가하였다. 3. 배기홴으로부터 3m의 지점의 먼지 배출량은 TSP $354.8{\sim}574.8\;{\mu}g/m^3$으로 매우 높았으며 PM10 $94.4{\sim}156.2\;{\mu}g/m^3$, PM2.5 $14.6{\sim}18.0\;{\mu}g/m^3$, PM1.0 $6.0{\sim}6.4\;{\mu}g/m^3$ 이었다. 4. 배기홴으로부터 50m 떨어진 지점에서의 분진농도는 TSP $25.1\;{\mu}g/m^3$, PM10 $8.8\;{\mu}g/m^3$, PM2.5 $5.6\;{\mu}g/m^3$, PM1.0 $4.9\;{\mu}g/m^3$으로 매우 낮은 분진농도를 보였다. 5. 입기구와 배기구 간 분진농도의 차이는 TSP의 경우 입기구에서 $317.9\;{\mu}g/m^3$인데 비하여 배기구는 $2,678.5\;{\mu}g/m^3$로 8.42배 높았으며 PM10 7.4배, PM2.5 3.4배, PM1.0 1.6배 높았다. 6. 배기홴으로부터 거리별 분진의 배출농도는 3m 지점에서 $446.6\;{\mu}g/m^3$ 이었으나 20 m 지점에서는 $156.3\;{\mu}g/m^3$로 34.9% 수준이었고 PM10 34.9%, PM2.5 48.7%, PM1.0 86.8% 수준이었다.

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Effects of Tropical Climate on Reproduction of Cross- and Purebred Friesian Cattle in Northern Thailand

  • Pongpiachan, P.;Rodtian, P.;Ota, K.
    • Asian-Australasian Journal of Animal Sciences
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    • 제16권7호
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    • pp.952-961
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    • 2003
  • In the first part of the study, rates of estrus occurrence and success of A.I. service in the Thai-native and Friesian crossbred, and purebred Friesian cows fed in the National Dairy Training and Applied Research Institute in Chiang Mai, Thailand were traced monthly throughout a year. An electric fan and a water sprinkler cooled the stall for the purebred cows during the hot season (March-September). Both rates in pure Friesians were at their highest in the cold-dry season (October- February), but they decreased steadily during the hot-dry season (March-May) and were at their lowest in the hot-wet season (June-September). Seasonal change of a similar pattern was observed in the incidence of estrus, but not in the success rate of insemination in the crossbred cows. By the use of reproductive data, compiled in the same institute, on the 75 % cross- and purebred Friesian cows, and climatological data in Chiang Mai district, effects of ambient temperature and humidity on the reproductive traits of cows were examined by regression analysis in the second half of the study. Significant relationships in the crossbred, expressed by positive-linear and parabola regressions, were found between reproductive parameters such as days to the first estrus (DTFE), A.I. service (DTFAI), and conception, the number of A.I. services required for conception and some climatic factors. However, regarding this, no consistent or intelligible results were obtained in purebred cows, perhaps because electric fans and water sprinklers were used for this breed in the hot season. Among climatic factors examined, the minimum temperature (MINT) in early lactation affected reproductive activity most conspicuously. As the temperature during one or two months prior to the first estrus and A.I. service rose, DTFE and DTFAI steadily became longer, although, when MINT depleted below $17-18^{\circ}C$, the reproductive interval tended to be prolonged again on some occasions. The maximum temperature also affected DTFE and DTFAI, but only in limited conditions. The effect of humidity was not clear, although the inverse relationship between DTFE and minimum humidity during 2 months before the first estrus in the crossbred seemed to be significant. Failure to detect any definite effect of climate on the reproductive traits of pure Friesians seemed to indicate that forced ventilation by electric fans and water sprinklers were effective enough to protect the reproductive ability of this breed from the adverse effects of a hot climate.

흡수성 Biofilter 를 이용한 농촌 소규모 오수처리 시설의 성능 (Performance for a small on-site wastewater treatment system using the absorbent biofilter in rural areas)

  • 권순국;윤춘경
    • 한국환경농학회지
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    • 제18권4호
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    • pp.310-315
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    • 1999
  • 본 연구에서는 생물막법의 일종인 흡수성 Biofilter 시스템(ABS)을 설치하여 14개월의 실험기간 동안 건국대 농생대 구내의 염기성 부패조로부터 유입수를 3가지 수리부하율로 처리하여 시험하였다. 모니터링 결과에 의하면 ABS는 평균농도 $BOD_5=6.2mg/l$, TSS=4.4mg/l 이라는 아주 낮은 유기성 유출수를 연속적으로 발생시킬 수 있음이 확인되었다. 이러한 저농도 유출수는 현재 우리나라 오분법의 특정지구(상수원 보호구역)에 대한 방류수 기준($BOD_5=10mg/l$, TSS=10mg/l)에도 훨씬 못 미치는 양호한 농도로서 ABS의 우수한 유기성오수 처리성능이 입증되었다. 특히 유출수내의 TSS 농도가 지극히 낮아서 슬러지의 발생이 거의 없으므로 침전조를 생략할 수 있어 설치비용이 저렴해지고, 유지관리가 단순한 장점을 지니고 있음을 알 수 있었다. 그러나 ABS시설이 농촌에 널리 보급되어 실용적인 시스템이 되기 위해서는 앞으로 T - N과 T- P의 처리효율 향상 방안, 겨울철에 대한 Biofilter탱크내 임계온도 유지문제, 광역모니터링 및 신속보수 유지관리체계 확립에 대한 계속적인 연구가 필요하다. 이러한 문제점만 어느정도 해결된다면 ABS는 우리나라 농촌의 소규모 현장 오수처리시설로서 앞으로 미래가 밝은 차세대형 시스템이 될 것으로 확신한다.

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