• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.4 s.235
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• pp.469-476
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• 2005

Numerical modeling has been carried out to investigate the two-dimensional air flow in automobile interior with a forced exhaust close to main air inlet for typical ventilation modes. The characteristics such as streamlines and temperature fields in the passenger compartment room with the forced exhaust are analyzed with comparison of the cases without a forced exhaust. The simulation results show that air flow on the floor near the front seat is increased with the forced exhaust for all ventilation modes. Flow recirculation in the cabin is most active in mode 2 with a vertical suction inlet in comparison with other two modes. In particular, less time is taken for air temperature to reach the inlet temperature due to the forced exhaust for the ventilation modes. Finally, it could be predicted that ventilating air flow is much improved with the forced exhaust in the interior Modeling results in this study can be applied to the optimal design of automobile interior fur air ventilation system.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.217-222
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• 2005

Building energy consumption according to the ventilation has been considered to be an important subject. The purpose of this study is to investigate the cooling loads in a test space with a forced ventilating system. In the test space, on/off controlled air-conditioning and forced ventilating facility were operated between 8:30 to 21:00 during 4 days and some important data like temperatures and energy consumption were measured to obtain actual cooling loads. The simulation was carried out in a mode of temperature level control using a TRNSYS 15.3 with a precisely measured air change amount and performance data of air-conditioner. Cooling loads including sensible and latent were compared between by experiment and by simulation. Both of cooling loads associated with ventilation show a close agreement within an engineering tolerance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.12
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• pp.947-954
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• 2006

Building energy consumption according to the ventilation has been considered to be an important subject. The purpose of this study is to investigate the cooling and heating loads in a test space with a forced ventilating system. In the test space, on/off controlled air-conditioning and forced ventilating facility were operated between 8 : 30 to 21 : 00 during 4 days and some important data like temperatures and energy consumption were measured to obtain actual thermal loads. The simulation was carried out in a mode of temperature level control using a TRNSYS 15.3 with a precisely measured air change amount and performance data of air-conditioner. Heating load and cooling load including sensible and latent were compared between by experiment and by simulation. Both of thermal loads associated with ventilation show a close agreement within an engineering tolerance.

• Clean Technology
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• v.13 no.4
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• pp.281-286
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• 2007

VOCs from the heat recovery ventilation system (total heat exchanger) are measured in this study. Two different types of element (L and M type) from heat recovery ventilating system are tested to study the intial release characteristics of VOCs under KS cooling and heating standard conditions. VOCs are measured for the various flow rates and different operating times. Considering errors in the test method and the measuring instrument, the tested heat recovery ventilating systems was found to release 6 major VOCs, such as acetic acid, 2-butanone (MEK), 2-(methylthio )ethylamine, toluene, styrene, and x-acids (Ion 57). The concentrations of released VOCs are not quite much affected by operating conditions. The results show much larger VOCs concentrations in the cooling mode than in the heating mode, due to the high operating temperatures.

• Journal of the Korean Society of Visualization
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• v.8 no.1
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• pp.25-30
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• 2010

The flow characteristics under recirculation cool vent mode is numerically studied using commercial fluid dynamic code(CFX). For the reliable analysis, real vehicle and human FE model is employed in grid generation process. The geometrical location and shape of panel vent, and exhaust vent is set as that of real vehicle model. The flowrate of the working fluid is determined as 330CMH which is equivalent to 70 percent of maximum capacity of HVAC system. The high velocity regions are formed around 4 each panel vent. Because of the non-symmetrically located exhaust, non-uniform flow and partial backflow near the door trim is observed. Streaklines start from each panel vent show the flow pattern of the airflow in the passenger's compartment very well.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.684-687
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• 2005

Ground source heat pump systems are used for heating, ventilating and air-conditioning systems in commercial buildings, schools, and factories because of low operating and maintenance costs. These systems use the earth as a heat source in heating mode and a heat sink in cooling mode. Ground heat exchangers are classified by a horizontal type and vertical type according to the installation method. A horizontal type means that a heat exchanger is laid in the trench bored in 1.2 to 1.8 m depth. The solar heat and the rainwater are affected by the performance of heat exchanger and causes mutual influence among heat exchangers. In this study, to evaluate the performance of straight type, slinky type, and spiral type of horizontal ground heat exchangers designed on 1 RT scale, test sections are buried on the earth and experimental apparatus is installed. Therefore the performance of these is estimated.

• Journal of computational fluids engineering
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• v.11 no.4 s.35
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• pp.20-25
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• 2006

In the present study, flow characteristics inside a road tunnel are simulated for the ventilation flows due to jet fan system and flows induces by the traffic. Traffic ventilation is numerically simulated by multiple reference frame. From the results of steady state simulation of tunnel ventilation, it is found that the proper ventilation is achieved by the designed jet fan system along with ventilating flow induced by the traffic. A transient simulation is also performed for the case of vehicle fire in the tunnel reversing the direction of rotation of some fans. The results suggest that the heat and smoke can be controlled by the proper changing of fan operation mode. The present results can be used to design proper ventilation system and effective smoke control system as well.

• Journal of the Korean Society of Visualization
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• v.7 no.1
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• pp.3-8
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• 2009

Most vehicles have a heating, ventilating and air conditioning (HVAC) device to control the thermal condition and to make comfortable environment in the passenger compartment. The improvement of ventilation flow inside the passenger compartment is crucial for providing comfortable environment. For this, better understanding on the variation of flow characteristics of ventilation air inside the passenger compartment with respect to various ventilation modes is strongly required. Most previous studies on the ventilation flow in a car cabin were carried out using computational fluid dynamics (CFD) analysis or scale-down water-model experiments. In this study, whole ventilation flow discharged from the air vent of a real passenger car was measured using a special PIV (particle image velocimetry) system for large-size FOV (field of view). Under real recirculation ventilation condition, the spatial distributions of stream-wise turbulence intensity and mean velocity were measured in the vortical panel-duct center plane under the panel ventilation mode. These experimental data would be useful for understanding the detailed flow structure of real ventilation flow and validating numerical predictions.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.115-123
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• 2010

Cool-down performance after soaking is important because it affects passenger's thermal comfort. The cooling capacity of HVAC system determines initial cool down performance in most cases, the performance is also affected by location, and shape of panel vent, indoor seat arrangement. Therefore, optimal indoor designs are required in developing a new car. In this paper, initial cool down performance is predicted by CFD(computational fluid dynamics) analysis. Experimental time-averaging temperature data are used as inlet boundary condition. For more reliable analysis, real vehicle model and human FE model are used in grid generation procedure. Thermal and aerodynamic characteristics on re-circulation cool vent mode are investigated using CFX 12.0. Thermal comfort represented by PMV(predicted mean vote) is evaluated using acquired numerical data. Temperature and velocity fields show that flow in passenger's compartment after soaking is considerably unstable at the view point of thermodynamics. Volume-averaged temperature is decreased exponentially during overall cool down process. However, temperature monitored at different 16 spots in CFX-Solver shows local variation in head, chest, knee, foot. The cooling speed at the head and chest nearby panel vent are relatively faster than at the knee and foot. Horizontal temperature contour shows asymmetric distribution because of the location of exhaust vent. By evaluating the passenger's thermal comfort, slowest cooling region is found at the driver's seat.

• Fire Science and Engineering
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• v.17 no.2
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• pp.62-69
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• 2003

The smoke control system in subway platform is not only using for smoke exhaust facility but also using ventilation system. For this reason, smoke vent effectiveness is depending on its position, ventilating volume capacity and the vent method. In this study, the passenger's evacuation time was calculated for the case of fire on sloped subway train vehicle in subway platform. In order to recommend the mechanical smoke exhaust operation mode, SES (Subway Environmental Simulation) was used to predict the airflow of the inlet and outlet tunnel for the subway station. Fire dynamics Simulator(FDS) was used the SES's velocity boundary conditions to calculate the smoke density and temperature under the condition of fire on stopped subway train vehicle at the platform. We compared smoke density and temperature distributions for each 6 types of smoke exhaust systems to clarify the characteristics of smoke and hot air exhaust effectiveness from the result of fire simulation.