Jung-Yup Kim

Study on Induction Capability of Chilled Beam HVAC System

Since a chilled beam system can reduce the conveyance energy for air conditioning and has many advantages in terms of constructability and indoor environment, its supply has been rapidly expanding mainly in Europe. For this chilled beam system to be effectively available in Korea, a product suitable for the domestic climatic environment and HVAC system operating conditions needs to be developed. Also, domestic products need to have an edge in cost competitiveness compared to overseas products. In this study, the induction structure of a chilled beam is deduced and an analysis on the induction performance is carried out while the chilled beam system that meets domestic situations is in the process of development.

Study on Numerical Model of Leakage Flow at Gap between Compartments in a Building

Abstract 1D-numerical analysis of the network algorithm with the orifice equation for the relationship between pressure difference and flowrate has been mostly used to analyse leakage flow at the gap. In this study, a 3D-numerical methodapplying momentum loss model to the gap region in the computational domain is represented to reflect effectively the effectof leakage flow by determining the proportion of pressure difference to air passage velocity. While the 3D-numerical method is verified through the computation of the two compartments model, the numerical analysis of the stack effect in a building stairwayis performed. As the temperature of air outside drops, the pressure in the upper stairway and leakage flowrate through the gap in the door rise. The change of gap area does not have an effect on pressure in the stairway for the analysis conditions. Key words Gap(틈새), Leakage flow(누설유동), Pressure difference(압력차), Momentum loss model(운동량 손실 모델), Numerical analysis(수치해석)†Corresponding author, E-mail:

Study on Field Experiment of Stack Effect Reduction in Stairwell of Building

Abstract The winter stack effect that occurs in vertical construction passages such as the stairwell or elevator shaft of a high-rise building negatively affects living environments, energy usage, and personal safety; therefore, a mitigation of thestack effect is required to improve building conditions. Recently, circulation-type facilities that comprise the usage of air blowers and vertical ducts were proposed as part of a mechanical approach to quantitatively control the stack effect. Inthis study, these circulation-type facilities were installed in a building stairwell and the performance of the device was evaluatedduring its operation. A numerical-analysis result was obtained under the test conditions using a network-model-based, numerical-analysis method, and the result was then used for a comparison with the test result. Key words Stack effect(연돌효과), High-rise building(고층건물), Pressure difference(압력차), Field experiment(현장실험), Numerical analysis(수치해석)†Corresponding author, E-mail:

Study on 3D Numerical Analysis of Stack Effect Reduction in Stairwell of Building

Abstract Stack effect on high-rise building have negative effect on living environment, energy and life-safety aspect. Thus,it’s necessary to find the measure to reduce the stack effect. As a result of field test on a 31-story building, a circulatingtype stack effect reduction technology was developed, which supplies air in the low stairs and discharges air in the highstairs. To evaluate the performance of this circulating type stack effect reduction technology on building stairs, a 3D numericalanalysis was carried out by using Momentum Loss Model for analyzing leakage flow between compartments in a building. Consequently, numerical analysis proved that the stack effect on building stairs was reduced by a circulating type stackeffect reduction technology. Key words Stack effect(연돌효과), High-rise building(고층건물), Pressure difference(압력차), Momentum loss model(운동량 손실 모델), Numerical analysis(수치해석)†Corresponding author, E-mail: jykim1@kict.re.kr 1. 서 론 도시가 고도화 ․ 집적화되면서 건물의 고층화 ․ 대형화 및 복합화가 급격히 진행됨에 따라 고층 건물이 증가하고 있다. 한국에서도 이러한 추세가 반영되고 있으며, Table 1과 같이 과거 5년간 매년 800~1,000 동의 고층 건물이 건설되고 있어 고층 건물의 에너지

A Study of Effect of the Radiative Heat Flux on the Evacuation of Agents

Recently, the safety assessments with using the various evacuation programs are performed for improving the performance of fire and evacuation safety in the building. Generally, the evacuation programs can simulate the human behavior in fire situation by applying the variation of the movement speed and Fractional Effective Dose (FED) index in the smoke. However, if the simulation is performed without optional setting around the fire, the agents do not avoid the fire and they move through the fire. Therefore in this study, we define the radiative repulsion force which exists between the fire and the agents. Moreover, we modify the Helbing`s movement model by adding the radiative repulsion force. As a result of the modified movement model, all agents move around the fire and they do not enter the upper bound area of radiative heat flux, . From these results, we verified the reliability of the modified movement model.

Study on Suggestion of Smoke-proof System Using a Restroom for a Refuge Space

In restroom on high-rise building, exhaust system comprising the blower and duct is installed to discharge the odor and the water is suppled. Thus the restroom with fire and flame protection system may be used as refuge area in a fire situation. The study presents the smoke-proof system which operates such that the exhaust system to discharge the odor is converted to air supply system and appropriate pressure difference between the restroom and the accommodation is maintained. Also real-scale test facilities of smoke-proof system for refuge space using a restroom are installed on 5-story smoke control test building and experiments for evaluating the operational performance of smoke-proof system are carried out.

A Study on Improvement of Smoke Control System to Prevent Smoke from Spreading to Emergency Stair

Extended Abstract Emergency stair needs to be maintained safe by preventing the smoke from penetrating into the stair which serves the primary vertical evacuation route so as to allow the occupants to escape from the building when fire occurs in high-rise building. In recent study, the review to improve the performance of smoke control system on emergency stair is underway in a way of conducting the full-scale experiment and numerical analysis [1-4]. The measure commonly used in Korea for such purpose is the pressure differential system which raises the air pressure in lobby located between the accommodation and the stair, making use of the air blower for smoke control, air duct and control damper. In this study, a field test which is intended to evaluate the performance of the pressurization smoke control system installed on emergency stair of the building was conducted in two high-rise buildings and the result from the performance test was analyzed and as a result, the separate air supply system which feeds the air for leakage and supplement separately through different channels was proposed as the enhanced alternative that will replace the existing pressurization smoke control system for emergency stair. The parts of the result from the field test are highlighted as follows. That is, after starting operation of the pressurization system while all doors of lobby remain closed, the pressure difference between the lobby and the accommodation on the 2nd floor reached to 97 Pa. And on the 11th and 18th floor, the difference in pressure was 112 Pa and 124 Pa, respectively, which far exceeded the design requirement, 40 Pa. When the pressure difference between the lobby and the accommodation is so high, the problem with open force appears to be inevitable. But when the doors of lobby are open, pressure difference between the lobby and the accommodation on the 3rd floor was reduced to 23 Pa and on the 30th floor, it was reduced to 46 Pa. As seen above, with the existing smoke control system, the pressure in the lobby on each floor would possibly be reduced when the doors of the lobby are open. In this study, the separate air supply system which feeds the air for leakage and supplement separately through different channels is proposed. In smoke control system with separate air supply system, it feeds the air for leakage and supplement which are independent each other in terms of function and role separately to the lobby on each floor through different channels. It feeds the air to the lobby on each floor using own air blower, air duct and damper for leakage purpose and also it feeds the air to the lobby on each floor using own air blower, air duct and damper for supplement purpose. When introducing such separate air supply approach, appropriate air supply depending on door status could be achieved. That is, when the door of lobby is closed, the air as much as the leakage is supplied and appropriate pressure difference is maintained accordingly, avoiding excessive pressure difference between the lobby and the accommodation. And when the doors are open, the air is supplied as much as for supplement purpose so as to create the airflow for smoke control while preventing the air from leaking though the doors open. Separate air supply system for smoke control developed in this study is expected to avoid excessive pressure between the compartments or falling-pressure which occurs with existing system as well as to effectively secure the smoke control performance necessary for safe evacuation.

A Study for Estimation of Ventilation Capacity of Large Enclosure Considering Real Fire Load

In this study, we reviewed the performance of smoke control system by national fire safety code to secure evacuation time of occupants in case of a fire in large enclosure structures. Towards this end, we performed numerical analysis modeling of the existing large underground shopping mall and investigated types of business and combustibles loaded inside the stores situated at the shopping mall to fulfill the same configuration requirements with actual fire load conditions. To compare effects of smoke control system by national fire safety code, we created 11 smoke control scenarios of large enclosure shopping malls according to the ventilation capacity and conducted numerical analysis of evacuation behavior of occupants and the spread of fire against each scenario. In addition, to compare the results of the numerical analysis, we analyzed total heat release amount, flash-over occurrence time, residual amount of soot indoors and the number of evacuation failures and the dead, thereby deducing the optimal ventilation capacity.

Development of Smoke Control System Ensuring Safe Evacuation Through Stairwell for High-Rise Building in Korea

In general, the pressure differential smoke control system has been used as a smoke control system on the emergency stairs of high-rise buildings, but it can fail to achieve the purpose of pressure differential system due to high possibility of overpressure between the lobby and the accommodation or pressure drop in the lobby in case the leakage and supplementary air flow is supplied at the same time through one air supply path. In connection with improvement of this problem, we suggested device configuration and methods to conduct supply of leakage and supplementary air flow through different flow passages, thereby providing safe evacuation environment in case of a fire in high-rise buildings.

FIELD EXPERIMENT OF TRAIN-INDUCED WIND PRESSURE ON PLATFORM SCREEN DOOR AT SUBWAY STATION

In a bid to evaluate the train wind pressure on platform screen door installed on the platform of the subway station, the field test was conducted in existing Seoul Metropolitan Subway Line 2 in operation now. Variations in wind pressure on platform screen door, which were caused by the running train were measured depending on four different train operation patterns. The highest pressure of 28.1 kgf/m2 was indicated on platform screen doors while two trains were passing the platform in different directions at a speed of 60 km/h.