• Title/Summary/Keyword: 자연 환기

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Evaluation of Air Quality in the Compost Pilot Plant with Livestock Manure by Operation Types (축분 퇴비화시스템 운용방식에 따른 실내 대기오염 평가)

  • Kim, K.Y.;Choi, H.L.;Ko, H.J.;Kim, C.N.
    • Journal of Animal Science and Technology
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    • v.46 no.2
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    • pp.283-294
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    • 2004
  • Air quality in the livestock waste compost pilot plant at the Colligate Livestock Station was assessed to quantity the emissions of aerial contaminants and evaluate the degree of correlation between them for different operation strategies; with the ventilation types and agitation of compost pile, in this study. The parameters analyzed to reflect the level of air quality in the livestock waste compost pilot plant were the gaseous contaminants; ammonia, hydrogen sulfide, and odor concentration, the particulate contaminants; inhalable dust and respirable dust, and the biological contaminants; total airborne bacteria and fungi. The mean concentrations of ammonia, hydrogen sulfide, and odor concentration in the compost pilot plant without agitation were 2.45ppm, 19.96ppb, and 15.8 when it was naturally ventilated, and 7.61ppm, 31.36ppb, and 30.2 when mechanically ventilated. Those with agitation were 5.50ppm, 14.69ppb, and 46.4 when naturally ventilated, and 30.12ppm, 39.91ppb, and 205.5 when mechanically ventilated. The mean concentrations of inhalable and respirable dust in the compost pilot plant without agitation were 368.6${\mu}g$/$m^3$ and 96.0${\mu}g$/$m^3$ with natural ventilation, and 283.9${\mu}g$/$m^3$ and 119.5${\mu}g$/$m^3$ with mechanical ventilation. They were also observed with agitation to 208.7${\mu}g$/$m^3$ and 139.8${\mu}g$/$m^3$ with natural ventilation, and 209.2${\mu}g$/$m^3$ and 131.7${\mu}g$/$m^3$ with mechanical ventilation. Averaged concentrations of total airborne bacteria and fungi in the compost pilot plant without agitation were observed to 28,673cfu/$m^3$ and 22,507cfu/$m^3$ with natural ventilation, and 7,462cfu/$m^3$ and 3,228cfu/$m^3$ with mechanical ventilation. They were also observed with agitation to 19,592cfu/$m^3$ and 26,376cfu/$m^3$ with the natural ventilation, and 18,645cfu/$m^3$ and 24,581cfu/$m^3$ with the mechanical ventilation. It showed that the emission rates of gaseous pollutants, such as ammonia, hydrogen sulfide, and odor concentration, in the compost pilot plant operated with the mechanical ventilation and with the agitation of compost pile were higher than those with the natural ventilation and without the agitation. While the concentrations of inhalable dust and total airborne bacteria in the compost pilot plant with the natural ventilation and with the agitation, the concentrations of respirable dust and total airborne fungi in the compost pilot plant with the mechanical ventilation and agitation were higher than those with the natural ventilation and without the agitation of compost pile. It was statistically proved that indoor temperature and relative humidity affected the release of particulates and biological pollutants, and ammonia and hydrogen sulfide were believed primary malodorous compounds emitted from the compost pilot plant.

JET MOMENTUM CRITERIA FOR INLET CONTROL TO REDUCE WIND EFFECTS ON THE AIR DISTRIBUTION IN A SIDE-WALL-INLET VENTILATION SYSTEM (SIDE-WALL-INLET 환기시스템 축사에서 유입구의 컨트롤을 위한 젯트모멘텀)

  • ;Guoqiang Zhang
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 1997.11a
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    • pp.51-55
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    • 1997
  • 국내의 축사는 윈치커튼의 위치를 조절하여 줌으로써 내부의 기류를 교환하는 개방형 축사가 대부분을 차지하고 있다. 개방형 축사의 환기는 외기풍속의 영향에의해 내부 기류의 흐름이 형성되어 바람이 없는 고온기에는 내부의 기류혼합이 잘 되지 않기 때문에 고온으로 인한 내부의 환경이 열악하다. 따라서 자연환기 축사에 배기팬 또는 입기팬을 설치하는 조합형 환기 축사가 주를 이를 것으로 판단된다. (중략)

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Comparison of natural ventilation ability according to window configuration using CFD simulation (CFD 시뮬레이션을 이용한 연동온실의 환기창 조건별 자연환기 성능 비교)

  • 윤남규;김문기;남윤일
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2002.07a
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    • pp.249-254
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    • 2002
  • 온실에서 환기는 외기와의 공기교환을 통한 온도 및 습도의 조절뿐만 아니라 이산화탄소 등의 가스농도를 조절함으로써 온실내 공기의 쾌적성 확보와 실내기류의 형성으로 인한 작물의 생육촉진에도 중요한 역할을 담당한다. 그러므로, 작물생육환경의 최적화를 통한 품질향상 및 수확량 증대를 목적으로 하는 온실재배에 있어서 환기특성 분석 및 공기유동 예측은 가장 기본적인 설계요소라 할 수 있다. (중략)

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Preestimate Airflow in Greenhouse by CFD Simulation Method (CFD 시뮬레이션 기법에 의한 온실내 공기유동 예측)

  • 윤남규;김문기
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 1999.11a
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    • pp.118-121
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    • 1999
  • 환기는 온실내 미기상에 중요한 영향을 미치는 물리적 과정임에도 불구하고 이에 대한 연구는 아직까지 빈약해 왔다. 환기는 온실내의 온도, 습도 그리고 이산화탄소 등의 가스농도를 최적으로 제어하기 위한 수단으로 사용되어진다(Bailey, 1988). 강제환기시스템은 대부분의 온실에서 그 사용이 보편화되지 못하였으므로, 일반적으로 자연환기가 원예시설의 공기교환을 위한 유일한 수단이 되고 있다. (중략)

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Efficiency of Different Roof Vent Designs on Natural Ventilation of Single-Span Plastic Greenhouse (플라스틱 단동온실의 천창 종류에 따른 자연환기 효과)

  • Rasheed, Adnan;Lee, Jong Won;Kim, Hyeon Tae;Lee, Hyun Woo
    • Journal of Bio-Environment Control
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    • v.28 no.3
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    • pp.225-233
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    • 2019
  • In the summer season, natural ventilation is commonly used to reduce the inside air temperature of greenhouse when it rises above the optimal level. The greenhouse shape, vent design, and position play a critical role in the effectiveness of natural ventilation. In this study, computational fluid dynamics (CFD) was employed to investigate the effect of different roof vent designs along with side vents on the buoyancy-driven natural ventilation. The boussinesq hypothesis was used to simulate the buoyancy effect to the whole computational domain. RNG K-epsilon turbulence model was utilized, and a discrete originates (DO) radiation model was used with solar ray tracing to simulate the effect of solar radiation. The CFD model was validated using the experimentally obtained greenhouse internal temperature, and the experimental and computed results agreed well. Furthermore, this model was adopted to compare the internal greenhouse air temperature and ventilation rate for seven different roof vent designs. The results revealed that the inside-to-outside air temperature differences of the greenhouse varied from 3.2 to $9.6^{\circ}C$ depending on the different studied roof vent types. Moreover, the ventilation rate was within the range from 0.33 to $0.49min^{-1}$. Our findings show that the conical type roof ventilation has minimum inside-to-outside air temperature difference of $3.2^{\circ}C$ and a maximum ventilation rate of $0.49min^{-1}$.

브로일러 수익성은 사육환경이 결정한다

  • 유일웅
    • KOREAN POULTRY JOURNAL
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    • v.24 no.3 s.269
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    • pp.140-142
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    • 1992
  • 브로일러를 생산하는데 있어서 환기가 매우 중요한 요인의 하나가 되는 것은 말 할 필요도 없다. 그러나 브로일러 농장의 실태를 볼 때 환기조작이 적절하지 않은 예가 있는 것으로 보인다. 중요한 것은 기상조건의 변화를 예측해 보는 것이 필요한데 이는 환기가 브로일러의 발육과 건강을 위해 이상적인 환경을 만들어 내는데 중요하기 때문이다. 사내환경이 부적절 할 때 브로일러의 발육저하가 발생되며 성장률도 나빠지고 사료효율도 저하된다. 또 깃털상태도 좋지 않아 상품의 질이 떨어져 결국 수익저하로 이어진다. 현재 국내에서 사용하고 있는 브로일러 계사는 환기가 좋지않은 경우가 많이 보이는데 커텐을 사용할 때 자연환기를 이용하는 계사에서는 주의깊은 점검을 필요로 하고 결국은 보다 안정된 환경을 공급해 주는 것이 필요하다. 현재 양계장에서 활용하고 있는 강제환기법은 기본적으로 팬을 이용해 계사내의 공기유동을 조정하는 것으로 되어 있으나 강제환기에는 계사내에 공기를 끌어들이는 방식과 계사내의 공기를 외부로 배출시켜 나가는 방식이 있다.

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Experimental Study on the Effect of the Area Ratio between Shaft and Tunnel and Heat Release Rate on the Plug-holing Phenomena in Shallow Underground Tunnels (저심도 도로터널에서 터널과 수직환기구의 단면적 비와 열방출률이 Plug-holing 현상에 미치는 영향에 관한 실험연구)

  • Hong, Kibea;Na, Junyoung;Ryou, Hong Sun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.4
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    • pp.619-625
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    • 2019
  • It is difficult to design because of the plug-holing phenomenon in which the amount of smoke discharged from the vertical vent is smaller than the designed amount of smoke. In this study, the effect of cross-sectional area ratio of tunnel and natural ventilation and heat release rate of fire source on plug-holing phenomenon occurring in natural ventilation system was experimentally analyzed. In the experiment model reduced to 1/20 size, the aspect ratio of the tunnel and the vertical vent was fixed, and the influence on the plug-holing phenomenon was confirmed by varying the sectional area ratio of the tunnel and the vertical vent. Experimental results show that the plug-holing phenomenon is caused by the comparison of the smoke boundary layer temperature with the temperature in the vertical vents, and the flow and temperature distribution characteristics under the vertical vents are changed as the cross-sectional area ratio of the tunnel and vertical vents increases. The plug-holing phenomenon is affected by the cross-sectional area ratio between the tunnel and the vertical ventilation. The greater the cross-sectional area ratio, the greater the probability of plug-holing.