• Title/Summary/Keyword: air circulation

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Development of Heating and Cooling System with Heat Pump for Nutrient Solution Bed In Greenhouse (열펌프를 이용한 양액베드 냉난방시스템 개발)

  • Kang, Geum-Chun;Kim, Yeong-Jung;Yu, Yeong-Seon;Baek, Lee
    • Journal of Biosystems Engineering
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    • v.27 no.6
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    • pp.565-572
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    • 2002
  • In order to control the root-zone temperature of greenhouse crops in the hydroponics at hot and cold season, heat pump system for cooling and heating was built and tested in this work. The system was air-to-water type and vapour compression type. The heating and cooling mode was selected by the four way valve. Capacity of the compressor was 3.75㎾ and heat transfer area of the evaporator and the condenser were 3.05㎡ and 0.6㎡, respectively. According to the performance test, it could supply heat of 42,360 to 64,372kJ/h depending on the water circulation rate of 600 to 1,500ℓ/h, respectively, when indoor air temperature was 10∼20$\^{C}$. COP of heat pump system was 3.0 to 4.0 in the heating mode. But, COP of the cooling mode was 1.3 to 2.1 at indoor temperature of 20∼35$\^{C}$. The feasibility test in the greenhouse the developed heating and cooling system was installed, showed that the heating cost of the developed system was only about 13% of that of the conventional heating system. The heating cost of the developed system was 367won/day(electric consumption 9.7㎾h/day), while that of the conventional system was 2,803won/day(oil consumption 7.7ℓ/day) at the same heating mode.

The Effects of Reactive Nitrogen (Nr) Compounds on the Acidification in Soil and Water Environment Ecosystems and the Mitigation Strategy (반응성 질소화합물로 인한 토양 및 물 환경 생태계의 산성화 영향 및 대응방안)

  • Cho, Youngil;Kang, Hyesoon;Jeon, Eui-Chan
    • Korean Journal of Ecology and Environment
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    • v.49 no.1
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    • pp.1-10
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    • 2016
  • The increases of industrial and technological development and human activities have disturbed the balance of natural nitrogen (N) circulation. These phenomena have induced that large amounts of N are to be present in excess in air, soil and water environment. We investigated the effects of excess of reactive nitrogen ($N_r$) compounds on soil and water environment ecosystems through literature and case studies, and suggested the strategy of mitigating the acidification in soil and water ecosystems. $N_r$ moves to air, soil and water media, can be converted to different types, and interacts with other chemical compounds. As an efficient N management plan, the evaluation (application of monitoring and safety index) and the chemical restoration (research and development) of the acidification in soil and water environment ecosystems are required to minimize the effects of $N_r$ as well as policies to regulate the various emission sources and amounts of $N_r$.

Water Balance Change of Watershed by Climate Change (기후변화에 따른 유역의 물수지 변화)

  • Yang, Hea-Kun
    • Journal of the Korean Geographical Society
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    • v.42 no.3 s.120
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    • pp.405-420
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    • 2007
  • This study is intended to analyze and evaluate the effects of Seomjingang Dam and Soyanggang Dam Catchment on water circulation in order to examine water balance change of watershed by climate change. Obviously, air temperature and precipitation showed a gradually increasing trend for the past 30 years; evapotranspiration vary in areas and increasing annual average air temperature is not always proportional to increasing evapotranspiration. Based on Penman-FAO24, climatic water balance methods and measured values are shown to be significantly related with each other and to be available in Korea. It is certainly recognized that increasing annual rainfall volume leads to increasing annual runoff depth; for fluctuation in annual runoff rates, there are some difference in changes in measured values and calculated values. It is presumably early to determine that climate changes has a significant effect on runoff characteristic at dam catchment. It is widely known that climate changes are expected to cause many difficulties in water resources and disaster management. To take appropriate measures, deeper understanding is necessary for climatological conditions and variability of hydrology and to have more careful prospection and to accumulate highly reliable knowledge would be prerequisites for hydrometric network.

Numerical Simulation of Effect on Atmospheric Flow Field by Development of Coastal Area (임해지역의 개발이 기상장에 미치는 영향예측)

  • Lee, Sang-Deug;Mun, Tae-Ryong
    • Journal of Environmental Science International
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    • v.15 no.10
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    • pp.919-928
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    • 2006
  • The present study applied an atmospheric flow field model in Gwangyang-Bay which can predict local sea/land breezes formed in a complex terrain lot the development of a model that can predict short term concentration of air pollution. Estimated values from the conduct of the atmospheric flow field were used to evaluate and compare with observation data of the meteorological stations in Yeosu and the Yeosu airport, and the effect of micrometeorology of surround region by the coastal area reclamation was predicted by using the estimated values, Simulation results, a nighttime is appeared plainly land breezes of the Gwangyang-bay direction according to a mountain wind that formed in the Mt. of Baekwooun, Mt. of Youngchui. Land winds is formed clockwise circulation in the north, clockwise reverse direction in the south with Gangyang-bay as the center. Compared with model and observation value, Temperature is tend to appeared some highly simulation value in the night, observation value in the daytime in two sites all, but it is veil accorded generally, the pattern of one period can know very the similarity. And also, wind speed and wind direction is some appeared the error of observation value and calculation results in crossing time of the land wind and sea land, it can see that reproducibility is generally good, is very appeared the change land wind in the nighttime, the change of sea wind in the daytime. And also, according to change of the utilization coefficient of soil before and after development with Gwangyang-Bay area as the center. Temperature after development was high $0.55\sim0.67^{\circ}C$ in the 14 hoots, also was tend to appear lowly $0.10\sim0.22^{\circ}C$ in the 02 hours, the change of u, v component is comparatively tend to reduced sea wind and land wind, it is affected ascending air current and frictional power of the earth surface according to inequality heating of the generation of earth surface.

Research on Step-Type Chemical Liquid Deodorizer using Liquid Catalyst

  • WOO, Hyun-Jin;KWON, Lee-Seung;JUNG, Min-Jae;YEO, Og-Gyu;KIM, Young-Do;KWON, Woo-Taeg
    • The Korean Journal of Food & Health Convergence
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    • v.6 no.5
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    • pp.19-25
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    • 2020
  • The purpose of this study was to research and develop a step-type chemical liquid deodorizer including a liquid catalyst that can prevent civil complaints due to odor due to its excellent deodorizing performance. The main composition of chemical liquid deodorizer including liquid catalyst is cleaning deodorization, catalyst deodorization, chemical deodorization, water film plate, deodorization water circulation device, deodorization water injection device, catalyst management system, gas-liquid separation device, chemical supply device, deodorizer control panel, etc. It consists of a device. The air flow of the step-type liquid catalyst chemical liquid deodorizer is a technology that firstly removes basic odor substances, and the liquid catalyst installed in the subsequent process stably removes sulfur compounds, which are acidic odor substances, to discharge clean air. The efficiency of treating the complex odor of the prototype was 98.5% for the first and 99.6% for the second, achieving the target of 95%. The hydrogen sulfide treatment efficiency of the prototype was 100% for the first and 99.9% for the second, which achieved 95%, which was the target of the project. As a result, ammonia was removed by the reaction of ammonia and hydrogen sulfide.

3-D Simulation of Air Flow in Cold Storage Room for Uniform Temperature Distribution (저온저장고 내부의 균일한 온도분포를 위한 3차원 공기유동 분석)

  • 성제중;고학균;조성인;양길모
    • Journal of Biosystems Engineering
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    • v.25 no.4
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    • pp.279-286
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    • 2000
  • Most of the domestic cold storage rooms are inefficient for agricultural products because of temperature gradients inside the storage rooms. Temperature gradients are developed mainly by improper airflow pattern inside the storage room, which is a main cause of the spoilage of the agricultural products. There proper airflow pattern is essential to minimize these temperature gradients and the spoilage. The performance and characteristics of a cold storage room were determined as a function of airflow pattern and temperature distribution in forced circulation cold storage room. A commercial CFD(computational fluid dynamics) code was used to simulate 3-D airflow in the cold storage room. Solving the flow equations for the storage room, a standard k-$\varepsilon$ turbulent model was implemented to calculate steady state turbulent velocity distribution. The CFD prediction results were compared with temperature measurements inside the cold storage room. In case of pallet storage, Temperature gradients inside pallet storage was reduced because the contact area of cold air expanded through an alley of airflow in storage. But is case of bulk storage, the last temperature of storage considerably rose more than the initial temperature of storage. The reason was that bulk storage didn't include any alley of airflow in storage.

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A Study on the Stabilization of a System for Big Data Transmission of Intelligent Ventilation Window based on Sensor and MCU (센서 및 MCU기반 지능형 환기창 빅데이터전송용 시스템 안정화에 관한 연구)

  • Ryoo, Hee-Soo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.16 no.3
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    • pp.551-558
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    • 2021
  • In this paper, we made the integrated intelligent air ventilation of the actuator module that can be remotely controlled based on IoT and sensors. we implemented a ventilation window system by configuring an algorithm design and a driving circuit to control the operation of the actuator to open and close the ventilation port based on a predetermined number of data that detects indoor gas/CO2/humidity temperature and outdoor fine dust related indoor/outdoor environment. It is difficult to store, manage, and analyze data due to the large number of sensors and conditions for the transmission data of indoor air circulation module. The remote monitoring and remote wireless control screens were constructed to automate the separation and operation conditions by extracting and managing the state. We apply MQTT to enhance big data transmission and construct the system using Rocket MQ to ensure safe transmission of operational big data against system errors.

Study on the Utilization of Drinking Water Supply System of Air-water Heat Pumps Applicable to Laying Hen (산란계에 적용 가능한 공기-물 히트펌프의 음용수 공급시스템 이용기술에 관한 연구)

  • Paek, Yee;Kang, Suk-Won;Jang, Jae-Kyung;Kwon, Jin-Kyung
    • Journal of the Korean Society of Mechanical Technology
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    • v.20 no.6
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    • pp.917-923
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    • 2018
  • The drinking water supply system applicable to the laying hen consists of air-water heat pumps, drinking water tanks, heat stroage tank, circulation pumps, PE pipes, nipples, and control panels. When the heat pump system has power of 7.7 to 8.7 kW per hour, the performance coefficient is between 3.1 and 3.5. The supply temperature from the heat pump to the heat stroage tank was stabilized at about $12{\pm}1^{\circ}C$, but the return temperature showed a variation of from 8 to $14^{\circ}C$. Stratified temperature in the storage tank appeared at $12.^{\circ}C$, $13.5^{\circ}C$ and $14.4^{\circ}C$, respectively. The drinking water supply temperature remained set at $15^{\circ}C$ and $25^{\circ}C$, and the conventional tap water showed a variation for $23^{\circ}C$ to $30^{\circ}C$. As chickens grow older, the amount of food intake and drinking water increased. $y=-0.0563x^2+4.7383x+8.743$, $R^2=0.98$ and the feed intake showed $y=-0.1013x^2+8.5611x$. In the future, further studies will need to figure out the cooling effect on heat stress of livestock.

Investigations on the emergency operation status of existing medical facilities to prepare for emerging infectious diseases in the post-COVID-19 era (포스트 코로나 시대 신종 감염병 대비를 위한 기존 의료시설의 비상시 운영사례 조사 및 분석)

  • Lee, Sejin;Lee, Wonseok;Kim, Eunseok;Yeo, Myoungsouk
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.29 no.1
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    • pp.43-51
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    • 2023
  • Purpose: To accommodate the increasing number of patients during the COVID-19 pandemic, numerous portable HEPA filter units (PHUs) were installed in the general wards of existing medical facilities(EMFs) to convert them into emergency conversion facilities (ECFs). The purpose of this study was to build a dataset in preparation for emerging infectious diseases in the post-COVID-19 era by analyzing the construction and operation of ECFs. Methods: Field investigations were conducted during ECF operation periods based on the analysis of heating, ventilation, and air conditioning (HAVC) system design documents for six ECFs across Korea. Interviews were conducted with facility managers during the field investigations. Results: When constructing an ECF within an EMF, the installation status and characteristics of the existing system should be considered. Field investigations and verifications of the operation of HAVC systems must be conducted beforehand for smooth ECF operations. If heating and cooling are required with indoor air circulation type equipment in an ECF zone, the implementation of a heating and cooling method that can satisfy the comfort requirements of the occupants while minimizing cross-contamination is essential. When using PHUs that do not meet the performance standards required by medical equipment, the noise level resulting from such equipment operation must be evaluated and improved. Implications: For EMFs, various guidelines that can be referred to for the construction and operation of ECFs must be developed to prepare for emerging infectious diseases in the future.

On Extratropical Transition of Tropical Cyclone MINDULLE (태풍 민들레의 온대저기압화 과정에 대하여)

  • Kwon, H. Joe;Kim, Ji-Young
    • Atmosphere
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    • v.15 no.1
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    • pp.17-25
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    • 2005
  • A significant number of tropical cyclones move into the midlatitudes and go through transformation procedure into extratropical cyclones. This process is generally referred to as extratropical transition of the tropical cyclone. In this study, MIDULLE(0407) case is selected. A thorough analysis is made using the GDAPS analysis data and MTM (Moving-nest Typhoon Model) model output. It is found that during the extratropical transition an important dynamics in the environmetal flow field occurs in which colder, drier (warm, moist) air penetrates in the western (eastern) quadrant of MINDULLE's outer circulation, which in turn initiates an asymmetry in the distribution of wind and temperature of the tropical cyclone. Simulated MTM result also reveals similar properties as in GDAPS analysis data. MTM result shows the gradual transition to the asymmetric distribution of wind and thickness as the extratropical transition proceeds. It is also found that the warm core disappears during the extratropical transition stage. Also, vortex tube is shown tilting towards the west during the transition. And the precipitation expands poleward of the center and the maximum precipitation appears to the left of MINDULLE which is consistent to the observations.