• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.1
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• pp.61-72
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• 2023

The increase in the rearing intensity of pigs has caused deterioration in the pig house's internal environment such as temperature, humidity, ammonia gas, and so on. Traditionally, the widely used method to control the internal environment was through the manipulation of the ventilation system. However, the conventional ventilation system had a limitation to control the internal environment, prevent livestock disease, save energy, and reduce odor emission. To overcome this problem, the air-recirculated ventilation system was suggested. This system has a semi-closed loop ventilation type. For designing this system, it was essential to evaluate the ventilation rates considering the pressure loss of ducts. Therefore, in this study, pressure loss calculation and experiment were conducted for the quantitative ventilation design of a semi-closed loop system. The results of the experiment showed that the inlet through which external air flows should always be opened. In addition, it was also found that for the optimum design of the semi-closed loop ventilation system, it was appropriate to install a damper or a backflow prevention device rather than a ventilation fan.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.4
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• pp.86-91
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• 2010

New Design configurations of the fighter aircraft igloo diffuser were studied based on the closed ventilation type in contrast to the conventional open distribution type. To validate the enhanced and safe performance, the exhaust flow patterns of the two igloo diffuser types were simulated by both experimental and computational approaches as design tools. Flow visualizations were conducted to investigate the exhaust flow patterns in experimental approach. In addition, the commercial code called Fluent was used to calculate flow field properties. Computational simulations provided detailed parametric studies that significantly reduced the amount of experimentation necessary to alter the design parameters of the existing fighter igloo diffuser. The closed ventilation type of the igloo diffuser was shown the better results.

• Journal of People, Plants, and Environment
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• v.23 no.5
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• pp.545-554
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• 2020

Background and objective: Moth orchids in the vegetative stage are suitable for a multi-layer growing environment in a closed-type plant factory which can be a good alternative that can reduce production costs by reducing cultivation time and energy cost per plant. This study was conducted to find out the optimal rhizospheric environment for different irrigation methods without a potting medium and rhizospheric ventilation for the vegetative growth of young Phalaenopsis hybrid 'Blanc Rouge' (P. KV600 × P. Kang 1) and Phalaenopsis Queen Beer 'Mantefon' in a closed-type plant factory system. Methods: The one-month-old clonal micropropagules with bare roots rapped with a sponges were fixed on the holes of styrofoam plates above growth beds, and were watered using the ebb-and-flow (EBB) and aeroponic (AER) methods with Ichihashi solution (0.5 strength) once a day at 06:00 (P) or 18:00 (S), and both (PS). Rhizospheric ventilation (V) was also applied to change the temperature, relative humidity, and CO₂ concentration of the beds. Plants potted into sphagnum moss and watered once a week were used as the control group. Results: After 12 months of treatment, the growth characteristics of the EBB groups were the best among the treatment groups without a medium, but no effect of irrigation timing was observed. V reduced the temperature, relative humidity and CO₂ concentration of the beds. Whereas, EBB+V (ebb-and-flow with ventilation) improved plant growth and reduced the occurrence of disorders and withering. Especially, EBB+V showed a similar performance to the control group. Conclusion: The results indicated that the optimal irrigation method without a potting medium for producing middle-aged potted moth orchids was the EBB system with forced rhizospheric ventilation. Therefore, further studies on the optimal ventilation method and moisture control of the crown need to be carried out to develop the irrigation system without a potting medium for vertical farming in closed-type plant factories.

• Journal of the Korean Institute of Rural Architecture
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• v.21 no.1
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• pp.45-52
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• 2019

Since 1980's, Countless schools across the nation, particularly in rural areas, have been closed down by the large fall in number of students. Otherwise, an elderly population has been increasing rapidly, so the demand for welfare services for the elderly population is also increasing. However, the supply of elderly welfare facilities remains inadequate. The purpose of this study is to propose remodelling plan of elderly welfare facility using Closed schools. The result of this study were as follows; in unit-based facility plans, Single room type can be used for elder who lives alone or an elderly couple. Senior Congregate Housing type can be used for four to five people. These two types have equal sunlight and ventilation conditions for each room, and are for an old man in relatively good health. Membership resort type is for the healthy senior who lives in the rural area or lives in the city who wants short-term residence. In case of a Nursing home type, the existing one-sided corridor was converted into a central corridor and each classroom is divided into four rooms. This type has advantage for nursing and management, on the other hand, the corridor is narrow and each room has differences for sunlight and ventilation.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.367-372
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• 2005

This study primarily is concerned with a new device which has been developed following the international standards to measure the ventilation performance at elevated temperature. This device can measure duration of ventilation, performance of electricity, static pressure at elevated temperature and also it is having provision to measure reversible performances during fire hazards. Invented device is closed circuit type system which is best suited for korean industrial environment with low cost and high efficiency. International standards has been compared and performance testing has been major using BS 7346 which is tested by Warrington Fire Research Centre.

• Journal of the Korea Safety Management & Science
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• v.3 no.3
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• pp.107-116
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• 2001

The purpose of this paper is to solve the problem that is occuring in assembly process and to progress the productivity by process analysis methods for manu-open and closed model(DWV-20/25DRG), and auto-open and cloesd model(DWV-20/25/DRA)-ventilation fan. Also, this paper is studied by data of ＇D＇ company's product.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.22-28
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• 2008

A closed type crankcase ventilation system has been adopted to engines to prevent emission of blow-by gas to atmosphere. In the early closed type crankcase ventilation system, blow-by gas which contains engine lubricating oil is re-circulated into the intake system. The blow-by gas containing oil mist leads to increased harmful emissions and engine problems. To reduce loss of the engine oil, a highly-efficient oil separation device is required. Principle of a cyclone oil separator is to utilize centrifugal force in the separator and, therefore, oil separator designs depend on rotational flow which causes the centrifugal force. In this paper, flow characteristics and oil separation performances for cyclone type designs are calculated with CFD methodology. In the CFD model, oil particle was injected on a inlet surface with Rosin-Rammler distribution and uniform distribution. The major design parameters considered in the analysis model are inlet area, cone length and outlet depth of the oil separator. As results, reducing inlet area and increasing cone length increase oil separation performance. Changes in outlet depth could avoid interference between rotational flow and outlet flow in the cyclone oil separator.

• Land and Housing Review
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• v.5 no.4
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• pp.325-332
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• 2014

The purpose of this study was to measure the airtightness and Air-Flow Performance for 7th house of small apartment houses adopted window frame-type natural ventilation. All window and living room door is provide with window frame-type natural ventilation, and there is provide with manual controller. As the object of measurement, the 6th type small apartment houses with area of $33m^2$ to $51m^2$ was selected. airtightness performance was measured at the front door using Blower door system. We measured ventilation rate per hour on 50Pa pressure different between inside and outside by the 1st to 6th cases. As a result, when the natural ventilation frame was closed, average amounts are shown as the ventilation rate per hour were 2.27ACH (CASE1). and the result is similar to general apartment house (1.65~4.28ACH). When the natural ventilation frame was open, average amounts are shown as the ventilation rate per hour were 5.87ACH (CASE6). In addition, that's a 3.6ACH increased more than CASE1.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.494-499
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• 2007

The thermal reliability of the closed-type BLDC motor for the high speed axial fans is analyzed by a numerical method in this dissertation. Since the module and the motor part are combined in a closed case, the heat generated from a rotor in the motor and the electronic components in the PCB module can not be effectively removed to the outside. Therefore the module will easily fail by high temperature. The accelerated-life testing was accomplished to formulate the life equation and numerical method is used to predict the inside temperature of the PCB module, which is one of the life equation parameter according to the environment. The experiment for measuring the surface heat flux of the electronic components is carried out to apply the boundary condition of numerical study. When the environment temperature of BLDC motor is 21, 35 and $50^{\circ}C$, the temperature in the PCB space is predicted as 73.4, 87.5 and $102.4^{\circ}C$. Then the life time with the temperature are calculated as 2,239, 863 and 328.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.66-69
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• 2009

New design configurations were developed based on the closed ventilation type igloo nozzle in contrast to the conventional open distribution type. To validate the enhanced performance, the prediction of the exhaust flow patterns of the igloo diffuser was carried out by both experimental and computational simulations. CFD provided detailed parametric studies that significantly reduced the amount of experimentation necessary to alter the design of existing the F-15K igloo exhaust diffuser.