• 한국입자에어로졸학회지
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• 제9권3호
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• pp.139-147
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• 2013

The performances of indoor air cleaners including particle cleaning capacity and collection efficiency are usually tested at the condition of the maximum air flow rate of the air cleaners. However, the power consumption of the air cleaners is highly dependent on the air flow rate of the individual air cleaners. Therefore, there seems to be an optimized air flow rate for the air cleaning capacity considering power consumption. In this study, clean air delivery rate(or standard useful area as suggested room size) and power consumption have been investigated for different maximum air flow rates of 15 air cleaners and then compared those for different air flow rate modes of the individual 5 air cleaners selected from the 15 cleaners. For the maximum air flow rate conditions of 15 air cleansers, the power consumption per unit area was less related to the maximum air flow rate. However, for the different air flow rate modes of the selected 5 air cleaners, the lower power consumption per unit area was corresponding to the lower air flow rate mode of the individual air cleaners. When considering the operation time to the desired particle concentrations, there was an optimized one in the medium air flow rate modes for the individual air cleaners. Therefore, not only the maximum air flow rate but also lower air flow rates of individual air cleaners should be considered for estimating air cleaning capacity based on energy consumption per unit area.

• 한국연소학회지
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• 제8권2호
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• pp.7-16
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• 2003

The transfer of air pollutants between passenger room and service room in train are investigated by the computational analysis. The effects of service room temperature, inlet velocity, initial concentration and heating are studied. The flow induced by the difference of density between two rooms is found to take the major role in transfer of polluted air. Low temperature of service room enhances the polluted air flow into passenger room along the floor. Exhaust fan above the door between two rooms is not effective for this case. Strong inlet flow is found to suppress polluted air flow from service room. The heating of passenger room can promote air pollution.

• 한국환경과학회지
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• 제14권1호
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• pp.1-8
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• 2005

CFD code are used for numerically testing a new concept of large space air control system. A workshop with air-conditioners products lines and air-conditioned by several floor type air-containers is tested. The whole room air distribution is controlled by boosters installed in a middle height horizontal plane. First, calculated results are compared with measured data to confirm the validity and applicability of the prediction method. Next, the method is applied to case studies heating seasons. Results under some operating conditions show effectiveness in avoid the temperature stratification in winter.

• 설비공학논문집
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• 제13권6호
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• pp.532-540
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• 2001

The objectives of this study are to analyze the control variables according to condensation occurrence, to find the range in floor surface temperature and frequency of condensation, and to evaluate the control methods through simulations when the radiant heating system is used for cooling. Through the simulation analysis the control methods such as on/off control, variable flow control and outdoor reset with indoor temperature feedback control are evaluated and compared. The results show that the lowest floor surface temperature is around $23^{\circ}C$, the surface condensation can be prevented by controlling indoor humidity within 20g/kg(DA0, and that outdoor reset with indoor temperature feedback control is more appropriate than on/off control and variable flow control with regard to prevention of the condensation and thermal comfort.

• Journal of Advanced Marine Engineering and Technology
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• 제30권2호
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• pp.267-274
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• 2006

There are no solar loads through windows and heat transfer from outer walls of the building to the interior This study analyzes indoor air temperature and air flow distribution for the interior of buildings or vessels occupying space. Numerical method is adopted to visualize the indoor side environmental situation. that is without heat transmission to outside the building in various cooling load conditions; supply ventilation lighting. occupancy and infiltration in conditioned spaces. Reaching time of an air conditioner is predicted theoretically by cooling load variations. Theoretical modelling of the reaching time shows good agreement with experimental results.

• 설비공학논문집
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• 제28권2호
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• pp.69-74
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• 2016

Most hot water heating valves for apartments are constant-flow types, which limit the flow rate through an individual household for even distribution of heating water to other households. The constant-flow type is implemented by an on-off control. As a result, heating water is supplied intermittently and hence, indoor air temperature also fluctuates. Returning water temperature is also high, which reduces energy efficiency. To implement continuous feedback control, the indoor temperature dynamics was simulated to fit a measured temperature history by a state-of-the-art physical model. From the model, it was found that the most important disturbance is outdoor temperature and its effect on indoor temperature lasts about an hour. To cope with the slow response and the significant disturbance, a prediction control with proportional feedback is proposed. The control was found to be successful in implementing continuous heating water flow and improved indoor temperature control.

• 설비공학논문집
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• 제23권9호
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• pp.604-609
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• 2011

The increased quality of life requires indoor illumination environment to have illumination with higher intensity. The increase in indoor illumination goes hand in hand with increase in indoor heat load. Of late, the internal heat in the cooling load has been growing gradually and the proportion of the lighting load has been bigger in the cooling load. The objective of the experiment here is to estimate the proper exhaust air flow displacement to remove heat from different types of lighting equipment. The heat causing the cooling load in lighting equipment is the ratio of heat per watt and the ratio of space for heat. Experimental measurements of the constant temperature and humidity in chambers that exhaust air flow by changing the exhaust calorific value was measured. Using the Airflow exhaust heat from lighting fixture of this study should help to reduce House cooling load.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.207-208
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• 2003

Increasing interest in indoor air quality (IAQ) control has been found because of its serious effect on human health. To evaluate IAQ, thermal comfort in terms of temperature and velocity distributions of indoor air has to be analyzed in detail. Choice of location for installation of air-conditioner in a building will affect the performance of cooling effect and thermal comfort on the occupants, which in turn will affect the indoor air quality (IAQ) of the building. In this paper, we present a discussion on the proper location of the air-conditioner in order to obtain good thermal comfort for occupant of a typical bedroom in Macao. A set of carefully designed numerical experiments is run with the Computational Fluid Dynamics (CFD) software FLOVENT 3.2 [1]. Reynolds averaged Navier-Stokes equations are solved with finite volume technique and turbulence effects upon the mean flow characteristics is modeled with the k - & model. Assumption of steady state environment is made and only convective and conductive heat transfer from the occupant and air-conditioner are being concerned.

• 한국농촌건축학회논문집
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• 제23권4호
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• pp.38-45
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• 2021

In this study, air quality conditions were identified and analyzed in real time, at the same time, living habits and ventilation methods were maintained in the daily life of residents, and thus, this present study focuses on the lifestyles of residents. Previous studies showed a difference from this study, focusing on the study on the effects of changes in indoor air quality on human health according to the indoor air quality process test standards of the Ministry of Environment. Formaldehyde concentrations exceeded all ventilation standards, but satisfied the organic standards of the Ministry of Environment when ventilation devices and air purifiers were activated. As such, it was investigated that a large amount of formaldehyde emission in the condo is initially ventilated, but a certain concentration is maintained. The change in PM2.5 concentration according to the ventilation method showed a clear difference. As a result of simulating indoor air flow during natural ventilation, the effects of wind speed and wind direction affect the flow rate of indoor air, and indoor polluted air is stagnant even in the presence of wind and is not completely discharged. When the risk assessment results are averaged on the day of measurement, the trends of change between adults and children are almost equivalent, but the results address that children are more sensitive to risk than adults.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.957-963
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• 2008

The refrigerant-induced noise of the air conditioner is one of the irregular noises which occurs at the indoor unit. Because the air-conditioner makers are always trying to reduce the sound pressure level radiated from indoor unit, reducing the refrigerant-induced noise at low cooling mode is very important problem. But it is very difficult to estimate whether the refrigerant-induced noise occurs or not before it becomes problem. In this paper, a method to predict the refrigerant-induced noise is suggested using flow pattern map. It is estimated that the irregular noise from the refrigerant comes from the slug flow in a pipe.