• Title/Summary/Keyword: Air stack effect

Search Result 106, Processing Time 0.025 seconds

Analysis on Energy Demand Resulting From the Change in Window Area & Installation of Interior Exterior Blinds (기존 노후건축물의 최적 리모델링 개선안 연구)

  • Kim, Dae-Won;Chung, Kwang-Seop;Kim, Young-Il;Nam, Ariasae;Oh, Se Min
    • Journal of Energy Engineering
    • /
    • v.23 no.2
    • /
    • pp.207-216
    • /
    • 2014
  • The energy loss can be divided into the loss caused by heat transfer and the loss caused by air flow. Heat transfer is the loss resulting from the heat transmittance of external wall, roof, and floor, and represents one of the most vulnerable elements of existing buildings. To prevent such loss, it is necessary to increase the mean heat transmittance of entire external wall, including the window, to a level above the standard regional value and ensure the air-tightness of window. The old buildings have the structure which is prone to the loss of greater air flow due to the air infiltration through the exit/entrance door upward along the stairway by the stack effect and simultaneous suction of air from each floor, and becomes even vulnerable to the loss of heat insulation for each floor, although the external wall and windows are the most vulnerable parts. The improvement plans for each floor need to be submitted in tandem with the diagnosis of whole building, regarding the diagnosis plan and energy improvement measures based on the survey of site, rather than adhering to the misconception that the replacement of window alone will result in energy-savings.

Effect of Secondary Air on Flow and Combustion Characteristics in a Pyrolysis Melting Incinerator (열분해 용융소각로 연소실의 2차공기 주입 영향에 관한 전산해석 및 실험)

  • Jeon, Byoung-Il;Park, Sang-Uk;Shin, Dong-Hoon;Ryu, Tae-Woo;Jeon, Kum-Ha;Hwang, Jung-Ho;Lee, Jin-Ho
    • 한국연소학회:학술대회논문집
    • /
    • 2004.06a
    • /
    • pp.149-157
    • /
    • 2004
  • In the present paper we studied experimentally fundamental optimization of oxygen enriched pyrolysis melting incinerator, Characteristics of this system was confirmed dealing with the gas flow and combustion properties for the inside secondary air injection. The experiment setup has a disposal rate of 30kg/hr which was measured by the inside temperature and gas. Along with above experiments, the three-dimensional computation was employed to analyse the combustion fluid dynamics and gas residence time. Equations for turbulence and heat - transmission as well as chemical reactions were solved by using common codes. The experimental combustion chamber was composed of staged combustion types structure for reducing NOx. Finally, it was verified that the control of the secondary air and air ratio of thermo stack were important. In the computational analysis, it showed reasonable agreement with the experimental results regarding the temperature and discharged gas concentration.

  • PDF

A Study on the Analysis of the Performance and Efficiency of a Low-pressure Operating PEMFC System for Vehicle Applications Using MATLAB/Simulink (MATLAB/Simulink를 이용한 자동차용 상압형 PEM 연료전지 시스템의 성능 및 효율 분석 연구)

  • Park, Raehyeok;Kim, Han-Sang
    • Journal of Hydrogen and New Energy
    • /
    • v.24 no.5
    • /
    • pp.393-400
    • /
    • 2013
  • The air supply system has a significant effect on the efficiency of polymer electrolyte membrane fuel cell (PEMFC) systems. The performance and efficiency of automotive PEMFC systems are greatly influenced by their air supply system configurations. This study deals with the system simulation of automotive PEMFC systems using MATLAB/Simulink framework. In this study, a low-pressure operating PEMFC system adopting blower sub-module (turbo-blower) is modeled to investigate the effects of stack operating temperature and air stoichiometry on the parasitic power and efficiency of automotive PEMFC systems. In addition, the PEMFC net system efficiency and parasitic power of air supply system are mainly compared for the two types (low-pressure operating and high-pressure operating) of automotive PEMFC systems under the same net power conditions. It is suggested that the obtained results from this system approach can be applied for establishing the novel operating strategies for FC vehicles.

A Study on Application of Shaft-box Type Double Skin to Apartment Building (공동주택에 대한 Shaft Box형 이중외피의 적용에 관한 연구)

  • Roh, Ji Wooung
    • KIEAE Journal
    • /
    • v.13 no.1
    • /
    • pp.75-81
    • /
    • 2013
  • The balcony of our apartment building consists of unique construction similar to double skin. It is announced broadly that double skin is very effective system in improvement of natural ventilation and indoor thermal environment, and outdoor sound protection. So, for the improvement of indoor climate and energy saving, many peoples studied about environmental performance of our balcony construction. This study focus on shaft box facade, special form of box window construction. It consists of a system of box window with continuous vertical shafts that extend over a number of stories to create a stack effect. Proto-type was decided by analyzing various types of exiting apartments. Shaft box type balcony was created by setting up shaft space at a part of balcony. Air flow and contribution of air temperature were simulated, performance of shaft box type balcony was compared with existing balcony. Finally, we confirmed that shaft box type balcony has many possibility for improvement of indoor environment.

A Study on Natural Ventilation by the Caloric Values of HLW in the Deep Geological Repository (지하처분장내 고준위 방사성 폐기물 발열량에 따른 자연환기력 연구)

  • Roh, Jang-Hoon;Choi, Heui-Joo;Yu, Yeong-Seok;Yoon, Chan-Hoon;Kim, Jin
    • Tunnel and Underground Space
    • /
    • v.21 no.6
    • /
    • pp.518-525
    • /
    • 2011
  • In this study, the natural ventilation pressure resulting from the large altitude difference which is a characteristic of high radioactive waste repository and the caloric value of the heat emitted by wastes was calculated and based on the results, natural ventilation quantities were calculated. A high radioactive waste repository can be considered as being operated through closed cycle thermodynamic processes similar to those of thermal engines. The heat produced by the heating of high radioactive wastes in the underground repository is added to the surrounding air, and the air goes up through the upcast vertical shaft due to the added heat while working on its surroundings. Part of the heat added by the work done by the air can be temporarily changed into mechanical energy to promote the air flow. Therefore, if a sustained and powerful heat source exists in the repository, the heat source will naturally enable continued cyclic flows of air. Based on this assumption, the quantity of natural ventilation made during the disposal of high radioactive wastes in a deep geological layer was mathematically calculated and based on the results, natural ventilation pressure of $74{\sim}183$Pa made by the stack effect was identified along with the resultant natural ventilation quantity of $92.5{\sim}147.7m^3/s$. The result of an analysis by CFD was $82{\sim}143m^3/s$ which was very similar to the results obtained by the mathematical method.

Study on Co-incineration of Municipal Solid Waste and Organic Sludges (도시쓰레기와 유기성 하수 슬러지 혼합소각에 관한 연구)

  • Jurng, Jong-Soo;Chin, Sung-Min
    • 한국연소학회:학술대회논문집
    • /
    • 2005.10a
    • /
    • pp.238-244
    • /
    • 2005
  • This study performs the pilot-plant experiments to evaluate the effect of the oxygen enrichment on the co-incineration of municipal solid waste and organic sludge from a wastewater treatment facility. The design capacity of the stoker-type incinerator pilot-plant is 150 kg/h. Combustion chamber temperatures were measured as well as the stack gas concentrations, i.e., NOx, CO, and the residual oxygen. The maximum ratio of organic sludge waste to the total waste input is 30%. Also the oxygen-enriched air with 23% of oxygen in supplied air is used for stable combustion. As the co-incineration ratio of the sludge increased up to 30% of the total waste input, the primary and the secondary combustion chamber temperature was decreased $to900^{\circ}C$ (primary combustion chamber), $750^{\circ}C$(secondary combustion chamber), respectively, approximately $200^{\circ}C$ below the incineration temperature of the domestic waste only (primary: $1,100^{\circ}C$, secondary: $950^{\circ}C$). However, if the supplied air was enriched to 22% oxygen content in air, the incinerator temperature was high enough to burn the waste mixture with 30% sludge, which has the heating value of 1,600 kcal/kg.

  • PDF

Numerical Analysis of Electromagnetic Radiation Characteristics by High Voltage and General Cables for Fuel Cell Electric Vehicle (FCEV) (수소 연료전지 차량용 고전압 케이블과 일반 케이블에 의한 차량 전자파 방사 특성 수치해석 연구)

  • Lee, Soon-Yong;Seo, Won-Bum;Lim, Ji-Seon;Choi, Jae-Hoon
    • Journal of Hydrogen and New Energy
    • /
    • v.22 no.2
    • /
    • pp.152-160
    • /
    • 2011
  • The electromagnetic characteristics of FCEVs (fuel cell electric vehicles) are much different from the existing combustion engine cars as well as hybrid, plug-in-hybrid, and pure electric vehicles due to the high voltage/current generated by a fuel cell stack which uses a compressed hydrogen gas reacted with oxygen. To operate fuel cell stack efficiently, BOP (Balance of Plant) which is consisted of many motors in water pump, air blower, and hydrogen recycling pump as well as inverters for these motors is essential. Furthermore, there are also electric systems for entertainment, information, and vehicle control such as navigation, broadcasting, vehicle dynamic control systems, and so on. Since these systems are connected by high voltage or general cables, EMC (Electromagnetic compatibility) analysis for high voltage and general cable of FCEV is the most important element to prevent the possible electric functional safety errors. In this paper, electromagnetic fields by high voltage and general cables for FCEVs is studied. From numerical analysis results, total time harmonic electromagnetic field strength from high voltage and general cables have difference of 13~16 dB due to ground effect by impedance matching. The EMI results of FECV at 10 m distance shows difference of 41 dB at 30 MHz and 54 dB at 230 MHz compared with only general cable routing.

Coolant Leak Effect on Polymer Electrolyte Membrane Fuel Cell (고분자전해질연료전지의 냉각수 누설에 대한 연구)

  • Song, Hyun-Do;Kang, Jung-Tak;Kim, Jun-Bom
    • Journal of the Korean Electrochemical Society
    • /
    • v.10 no.4
    • /
    • pp.301-305
    • /
    • 2007
  • The performance of polymer electrolyte membrane fuel cell could be decreased due to coolant leaked from connection part. Micro pump was used to put small amount of coolant and investigate the effect on fuel cell. The stoichiometric ratio of hydrogen/air was 1.5/2.0, both side of gas was fully humidified, and current density of $400mA/cm^2$ was used as standard condition in this experiment. Constant current method was used to check performance recovery from coolant effect in 3 cell stack. The performance was recovered when coolant was injected in cathode side. On the other hand, the performance was not recovered when coolant was injected in anode side. Ethylene glycol could be converted to CO in oxidation process and cause poisoning effect on platinum catalyst or be adhered on GDL and cause gas diffusion block effect resulting performance decrease. Water with nitrogen gas was supplied in anode side to check performance recovery. Polarization curve, cyclic voltammetry, electrochemical impedance spectroscopy was used to check performance, and gas chromatography was used to check coolant concentration. Constant current method was not enough in full recovery of performance. However, water injection method was proved good method in full recovery of performance.

Study on Application of Shaft Box type Balcony for Improvement of Ventilation Performance in Apartment (공동주택의 환기성능 개선을 위한 Shaft Box형 발코니의 적용성 검토)

  • Roh, Ji-Woong;Kim, Gon
    • KIEAE Journal
    • /
    • v.7 no.6
    • /
    • pp.3-8
    • /
    • 2007
  • Recently, because of the continuous rise of international oil price, energy saving is strongly demanding. So, Ecological technics of architecture such as use of natural energy have been actively explored in the field of building. In the method of utilizing natural energy, the key point is to saving energy effectively as not lowering the comfort of indoor environment, various systems investigated. Many papers about double skin facade system have been reported, it is announced broadly that the system is very effective in improvement of natural ventilation and indoor thermal environment, and also protecting outdoor sound. The shaft box facade is a special form of box window construction. It consists of a system of box windows with continuous vertical shafts that extend over a number of stories to create a stack effect. The facade layout consists of an alternation of box windows and vertical shaft segments. This research investigated the natural ventilation performance of shaft box type balcony which conform the shaft box type double skin to the exiting balcony construction. First, analyzed various types of exiting apartments, proto-type was decided. By using virtual environment Program, modeling the proto-type, compared the contribution of air temperature and the effect of outdoor air cooling. by this research, we confirmed that shaft box type balcony had many possibility for improvement of indoor environment.

A Study on Block from Spread of Fire of the Exteriors Installation Space (외장재 설치 공간의 화재확산 차단에 관한 연구)

  • Min, Se-Hong;Yun, Jung-Eun;Kim, Mi-Suk
    • Journal of the Korea Safety Management & Science
    • /
    • v.14 no.2
    • /
    • pp.83-89
    • /
    • 2012
  • In this study, FDS fire simulation experiments and measured wind speed by applying the exterior installation portion for blocking the spread of the fire was investigated. As a result, aluminum composite panels installed in the lower and the upper part of the panel to remove all the lower side, and then the maximum wind speed 0.24 m/s and the upper side 0.58 m/s were measured. In the FDS, the measured wind speed difference air currents are approximately 3.7 times in 12 seconds, the occurrence of 17 seconds early moment wind 2.2 m/s was measured from. Before and after the fire occurred in early of the air velocity about 39 seconds was 3.5 times difference. Such air currents caused by the temperature of the building but also by the building height was found. Turbulent flame of fire by expanding the vertical extent of damage become greatly important factor. Therefore, through the exterior installation portion of the block that can delay the spread of fire is expected that this should be taken.