• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.148-153
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• 2009

This paper considers the age of air in a ventilated space with multiple supply inlets. The local mean age of air at a point from one supply inlet is different from those from the other supply inlets. It is the purpose of the present paper to investigate theoretically the relations between the LMA's from each supply and overall combined LMA whether or not to trace the origins of supply air. Transient concentration distributions are calculated with a step-up injection of tracer gas at each supply inlet, and at both inlets simultaneously. The steady state concentration with a continuous tracer injection at a supply inlet works as a weighting factor for the corresponding LMA in calculating the average overall LMA from multiple inlets.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.7
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• pp.578-584
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• 2012

In this study, the analysis on the distribution of indoor airflow velocity and temperature by using numerical simulation has carried out to make fundamental data for establishing the optimum design of laboratory animal facilities. From the results, it was found that replacement of cage lacks, air supply and exhaust system, supply air temperature, supply air velocity affect to the optimum design of laboratory animal facilities as a important element.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.782-790
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• 2016

When a fire occurs on a ship that has mechanical ventilation facilities, the air supply and exhaust systems directly effect smoke diffusion. And there is a high possibility that occupant's visibility will be harmed because of smoke. In this study, the effects and risks of air supply and exhaust systems with regard to smoke diffusion given a shipboard fire analyzed with a Fire Dynamic Simulator(FDS). Suggested measures are also provided for using air supply and exhaust systems more efficiently. The results showed that, when air supply and exhaust systems were both working at the time of a fire, rather than stopping these systems as previously encouraged, continuing to operate both was an effective measure to gain evacuation time. When a fire occurred and the exhaust system was operating, also starting the air supply system near the origin of the fire was another effective approach to gain evacuation time. However, when only the air supply system was operating and a fire occurred, the air supply system accelerated smoke diffusion, so it was necessary to stop the air supply system to detect smoke diffusion as much as possible.

• Journal of the Korean housing association
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• v.12 no.3
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• pp.141-148
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• 2001

To design mechanical ventilation for bathroom of apartment houses where air supply and exhaust are taken into consideration, mock-ups of ventilation systems, widely used in bathroom of apartment houses with an area of 100$\textrm{m}^2$, were made and installed in a laboratory. These ventilation mock-ups were available for control of air supply and exhaust, and the sizes of supply openings were 40cm${\times}$1cm, 40cm${\times}$3cm, and 40cm${\times}$5cm. They were installed at five positions, spaced 45cm at a height of 5cm from the floor. The exhaust fan was designed for its operating voltage to be set to five steps(100V, 130V, 150V, 180V and 220V) in order to control its air flow rates. When the size and position of each supply opening were changed with the wind velocity of the exhaust fan set to the step 5, the ventilation rates were measured and analyzed by the concentration decay method of tracer gas method, in order to present an efficient mechanical ventilation system. The results of the study revealed that the ventilations rates would increase in the presence of supply openings, compared to the absence of supply openings, and that the larger the size of the supply opening, the more the ventilation rates. Therefore, it was found necessary to take air supply into consideration.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.434-439
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• 2008

Dome stadiums give thermal unpleasant feeling to occupants because of the radiant heat and the indoor and outdoor haet exchange from roogs or lightweight building envelopes of sidewalls. This study analyzed the indoor temperature and velocity distribution according to various air supply and return sustems in dome stadiums in summer.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.14 no.4
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• pp.13-19
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• 2018

The Effects of hot water supply temperature on indoor thermal characteristics for floor radiant heating system in residential apartment were researched by computer simulation. The parametric study on hot water supply temperatures with different outdoor air temperatures was done with regard to energy performance and control characteristics, respectively. As a result, the maximum overshoot of indoor air temperature and energy consumption were reduced by adjusting the hot water supply temperatures with outdoor air temperatures.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.3
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• pp.595-604
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• 2001

As an improvement in the standard of living and economic growth, the demand for air conditioning equipment is increasing rapidly. Nowadays, air conditioning equipments are being used for industry, large building, house and car. There equipments were concentrated on improving heat efficiency of economic aspects while thy design heat exchanger for cooling and heating. These air conditioning equipments using heat exchanger cause a discomfort to user due to generating mist at the beginning of operating. Therefore, the user demand air of high class and quality. In this experimental study, to acquire elementary data for development of heat exchanger which be able to supply air of high quality, that is to say, possess a restraint effect of mist generation. We estimate an effect on cooling plate quality, supply air velocity, supply air temperature, cooled plate temperature and supply air relative humidity which have an influence on outlet air condition of heat exchanger.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.5
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• pp.439-445
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• 2003

The purpose of this study is to suggest the improvement strategies for exhaust performance in composite kitchen hoods. The Exhaust only hood, the 2-way compensating hood and the 3-way compensating hood were selected, and the laboratory experiments were performed to compare the local exhaust efficiency and the indoor temperature distributions according to the variations of the hood type and supply/exhaust air velocity. The results of this study can be summarized as follows. The compensating hood has better performance than exhaust only hood in the aspect of local exhaust efficiency and temperature distribution. The 3-way compensating hood shows the best performance when the supply air velocity is about 2.7 m/s, and the 2-way compensating hood at the supply air velocity of 3.5 w/s. In the same exhaust rate condition, if the exhaust area of the hood is increased and therefore the exhaust velocity is lowered, the supply air velocity is also lowered to get the optimum performance. The optimum exhaust velocity range of the commercial kitchen hood which derived from this study is 0.48 ∼ 0.55 m/s.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.1
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• pp.100-107
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• 1998

Ventilation of the marine engine room is very important for the health of the workers as well as the nomal operation of machines. To find proper ventilation conditions of this engine room, numerical simulation with standard k-.epsilon. model was carried out. In the present study, the marine engine room is considered as a closed space with a heat source and forced ventilation ducts. The injection angle of air supply is found to be important. Injection with downword angle depresses recirculation flow, causing a strong steam in the wider space of the room. Ventilation and removal of the released heat are promoted with this pattern. There is a possibility of local extreme heating at the upper surface of engine when supply and exhaust ports of air are in bilateral symmetry. The effect of the increase of exhaust port area on ventilation decreases as the number of supply port increases.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.40-48
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• 2008

Air mixing system which is composed of air pressure control system, hot pipe system and air mixer, is the facility for mixing hot air($1000^{\circ}C$, 10kg/s) from storage air heater (SAH) and decompressed air($20^{\circ}C$, 15kg/s) from high pressure air supply system. Air pressure control system reduce the pressure of the air, from 32MPa to 3.5 MPa and supply the decompressed air to air mixer. The hot pipe system supply hot air from SAH to air mixer which mix hot with the decompressed air from air pressure control system. Fully mixed air flow rate is 25kg/s and mixed temperature is up to $400^{\circ}C$. So, we can expand the operating envelop of the supersonic ground test facility to low Mach number and low altitude region.