• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 춘계학술대회 논문집
• /
• pp.53-54
• /
• 2006

The main purpose of tunnel ventilation system is to maintain CO pollutant and VI (visibility index) under an adequate level to provide drivers with safe driving condition. Moreover, it is necessary to minimize power consumption used to operate ventilation system. To achieve the objectives, the control algorithm used in this research is reinforcement teaming (RL) method. RL is a goal-directed teaming of a mapping from situations to actions. The goal of RL is to maximize a reward which is an evaluative feedback from the environment. Constructing the reward of the tunnel ventilation system, two objectives listed above are included. RL algorithm based on actor-critic architecture and natural gradient method is adopted to the system. Also, the recursive least-squares (RLS) is employed to the learning process to improve the efficiency of the use of data. The simulation results performed with real data collected from existing tunnel are provided in this paper. It is confirmed that with the suggested controller, the pollutant level inside the tunnel was well maintained under allowable limit and the performance of energy consumption was improved compared to conventional control scheme.

• 한국태양에너지학회 논문집
• /
• 제31권4호
• /
• pp.57-65
• /
• 2011

This study proposes a Passive Solar Chamber System (PSCS) as a passive method for reduction of building energy consumption. Through numerical analysis, the study quantitatively analyzes system performance and aims to provide foundational data for system design. For this purpose, the study configures different system operation modes seasonally and also computes thermal and ventilation performance of the system in accordance with design factors(solar radiation, air channel height and distance). System and ventilation efficiency increases along with increase in solar radiation and air channel distance; however, as the air channel height increases, the efficiencies showed a tendency to decrease. Upon installation of PSCS, an average of $98.23W/m^2$ of heat flux was introduced in the daytime for the month of January in comparison to walls with no PSCS installed. For the month of August, natural ventilation of $56.68m^3/h$ was shown to be supplied to the room.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2006년도 동계학술발표대회 논문집
• /
• pp.68-68
• /
• 2006

• 토지주택연구
• /
• 제3권1호
• /
• pp.89-96
• /
• 2012

본 연구는 공동주택에서 하이브리드 환기시스템의 적용성을 검토하고, 하이브리드 환기시스템의 성능을 향상하기 위해 CFD시뮬레이션을 이용하여 설계방안을 제시하고자 하였다. 연구대상으로는 전용 $51m^2$, $84m^2$의 공동주택을 선정하였으며, 하이브리드 환기시스템은 창틀자연급기와 각실을 덕트로 연결하여 배기하는 시스템(Hybrid 1)과 창틀자연급기와 욕실 거실배기가 혼합된 시스템(Hybrid 2)을 적용하였다. 이때 각 시스템별 배기구의 위치를 변수로 하여 CFD를 수행하였다. $51m^2$, $84m^2$ 모두 Hybrid 2가 Hybrid 1보다 환기효율이 우수한 것으로 나타났으며, 평균공기연령 또한 낮은 것으로 나타났다. Hybrid 1의 경우, 덕트 배기구의 위치가 각 실 입구에 설치하는 것보다 실 안쪽 모서리에 설치하여 기류이동을 많이 유발할 수 있는 유형이 효과적인 것으로 나타났다. Hybrid 2의 경우, 욕실 고정압팬에 덕트를 연결하여 거실중심에 배기구를 설치하는 시스템이 환기효율이 가장 우수한 것으로 나타났다. 그러나 $51m^2$의 경우 Hybrid 2가 Hybrid 1보다 20%의 향상된 환기효율을 나타낸 반면, $84m^2$의 경우는 14%의 향상된 환기효율을 나타내 공동주택 규모에 따른 적정한 하이브리드 환기시스템에 대한 검토가 필요하다.

• 한국터널지하공간학회 논문집
• /
• 제11권4호
• /
• pp.395-401
• /
• 2009

장대터널의 환기 및 방재시스템 설계시 주요한 요소설계인자 중 하나인 자연환기력은 그 중요성에도 불구하고 관련 영향변수들의 상호관계는 정량화가 매우 복잡하여, 자연환기력에 의한 유입 자연풍에 관한 설계기준을 정량적 근거하에서 제시하고 있지 못하다. 최근 발생한 터널화재에 의한 문제 및 터널 이용자에 의한 보다 나은 공기질에 대한 요구 등으로 터널 환기시스템의 최적화가 시급히 필요하며, 따라서 최적화의 주요 설계인자인 자연환기력에 대한 연구가 절실히 요구된다. 본 연구에서는 국내 최장대 도로터널로 계획된 인제터널(연장 10.9 km)을 대상으로 자연환기력의 예측을 목적으로 하였다. 지형적 요인에 의한 외부풍의 풍압에 기인하는 자연환기력의 최대 가능수준을 예측할 수 있는 기압장벽고의 개념을 적용하여 외부풍에 의한 자연환기력을 추정하고 터널내외부 공기 밀도차로 인한 굴뚝효과에 따른 자연환기력을 동시에 분석하였다.

• 설비공학논문집
• /
• 제27권12호
• /
• pp.639-644
• /
• 2015

This study reviews the discharge coefficient for thermal buoyancy natural ventilation through experimentation. We measure the air velocity at the outlet, which is needed to derive the discharge coefficient and to compare with the theoretical value. When a temperature difference exists between the inside and outside of the building, the measured discharge coefficient differs from the theoretical value with a maximum difference of 12%. The size and position of the openings have little effect on the discharge coefficient. For practical application, the theoretical discharge coefficient can be used with little modification.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2010년 춘계학술대회논문집
• /
• pp.10-13
• /
• 2010

The flow field in road tunnel is influenced by some facts such as piston effect of vehicle's move, operation of ventilation facilities, natural wind and buoyancy effect of fire plume. Among those, jet fan is one of main ventilation facilities especially in longitudinal ventilation system of tunnel. In this study to analyze tunnel flow induced by operation of jet fan, numerical simulation has been carried out. The velocity distributions and streamlines in tunnel are examined to consider the three-dimensional characteristics of tunnel flow caused by jet fan.

• 한국안전학회지
• /
• 제15권1호
• /
• pp.72-79
• /
• 2000

In recent, occupational diseases in harmful working places become a social issue. It is the well-known fact that a respiration in polluted working places exert a serious effect on health of workers. Accordingly, the cutting off contaminants air originally is the best way to improve working environments. In these cases, ventilation systems should be essentially installed to dilute or exhaust the contaminated indoor air. In this study, we investigated the characteristics of ventilation system of the noxious gas in working indoor places with natural ventilation by using COMET. The numerical simulations were carried out the natural ventilation with two phase(air, dust). For turbulent flow, Reynolds stresses were closed by the standard $\kappa$-$\varepsilon$ model. The results are as follows ; 1) In the natural exhaust in the working place, the flows of the central region have a more rapid velocity vector than the right and left one. 2) Numerical results show that the distribution of contaminants concentration have greater influence on convection than the case of diffusion by government of velocity vectors. 3) To observe the velocity variation with distance, three location of distance are considered. As results, it shows that the velocity are 0.075(m/s) at y=5(m), 10(m) and mean concentration are raised 10.6% at y=5(m), 10(m). 4) We have presented the useful data for the adequate counterplan in the harmful working places by carrying out the various investigation of the natural ventilation.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2007년도 동계학술발표대회 논문집
• /
• pp.113-118
• /
• 2007

As the economic living standards are higher, the demands for more comfortable living space are also larger. In the response of this requirements, studies for improving indoor air environment have been conducted. In case of newly-built apartment buildings, the standard for the minimum ventilation to improve their indoor air quality was made. This study analysed the experimental results from the mock-up test of the hybrid ventilation system which is composed of natural and mechanical ventilation.

• Structural Engineering and Mechanics
• /
• 제88권6호
• /
• pp.521-533
• /
• 2023

In the present study, the finite volume method is applied for the thermal performance prediction of the natural ventilation system using vertical solar chimney whereas, design parameters are optimized through the response surface methodology (RSM). The computational simulations are performed for various parameters of the solar chimney such as absorber temperature (40≤T_abs≤70℃), inlet temperature (20≤T₀≤30℃), inlet height of (0.1≤h≤0.2 m) and chimney width (0.1≤d≤0.2 m). Analysis of variance (ANOVA) was carried out to identify the design parameters that influence the average Nusselt number (Nu) and mass flow rate (ṁ). Then, quadratic polynomial regression models were developed to predict of all the response parameters. Consequently, numerical and graphical optimizations were performed to achieve multi-objective optimization for the desired criteria. According to the desirability function approach, it can be seen that the optimum objective functions are Nu=25.67 and ṁ=24.68 kg/h·m, corresponding to design parameters h=0.18 m, d=0.2 m, T_abs=46.81℃ and T₀=20℃. The optimal ventilation flow rate is enhanced by about 96.65% compared to the minimum ventilation rate, while solar energy consumption is reduced by 49.54% compared to the maximum ventilation rate.