• Title/Summary/Keyword: air-duct cooling

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Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

An Analysis on Thermal Performance and Economic of Heat Recovery Ventilation System Integrated with Window (창호통합형 배열회수 환기시스템의 열성능 및 경제성 평가)

  • Sung, Uk-Joo;Cho, Soo;Song, Kyoo-Dong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.8
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    • pp.646-655
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    • 2012
  • This study is intended to analyze the thermal performance and evaluate the applicability about non-duct type heat recovery ventilation system integrated with window. Eventually, economic analysis of the system is conducted according to building energy saving ratio of it. As results of the thermal performance, the U-factor of the window conducted on the basis of KS F 2278 appears to $1.8W/m^2K$, and the effective heat exchange efficiency of the ventilator conducted on the basis of KS B 6879 appears 49.95% for cooling, 66.89% for heating. In the applicability evaluated by TRNSYS 16, the caes of applying the heat recovery ventilator integrated with window is found to reduce the cooling or heating load by 2.9% or 13.5% than the non-ventilator case. The results of economic analysis taking a side of consumer is verified as the payback is 3 years, and the accumulated earning is 1,408,133 won in terms of '600,000 won/unit' for initial cost, 10 years for useful life of the system.

A Study on the Convective Heat Transfer in a Regenerative Ice Energy System by a Bundle of the Heat-pipes. (히이트파이프 다발을 이용한 냉축열시스템에서의 대류열전달에 관한 연구)

  • 권형정;김경석;김경근
    • Journal of Advanced Marine Engineering and Technology
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    • v.14 no.4
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    • pp.57-66
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    • 1990
  • In the design of an electric power plant, the capacity to meet the peak load demand is one of the important factors to be considered. This peak load usually occurs when the most of the cooling air conditioning systems are being operated during daytime in summer season, which inevitably entails the construction of an additional electric power plant. This study is aimed to carry out a basic experiment for the development of a cooling air conditioning system using the ice energy by the surplus electric power during the night-time. The experimental apparatus consists of four major parts; (1) the heating section consisting of the air duct and I.D. fan, (2) the cold section with the ice chamber, (3) the bundle of heat pipes made in a form of the staggered arrangement with ${C_y}/{d_o}$=2.0 and ${C_x}/{d_o}$=1.73, (4) the refrigerator system to cool down the ice chamber. This study involves an intensive experiment concerning the convective heat transfer of the air flow surrounding the bundle of heat pipes. This major experimental parameters are the amount of working fluid, the velocity of air and the working temperature. The major findings of the present study are as follows; (1) The optimum amount of the working fluid necessary for the horizontal heat pipes is much more than that for the vertical type. (2) The convective heat transfer coefficients of the air are coincided with the empirical equations of Grimson and ${\breve{Z}ukauskas}$. (3) The equation of the mean heat transfer coefficient obtained in the present study is ${N_um}=0.32 {Re_max^{0.63}}$.

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Pressure Recovery in a Supersonic Ejector of a High Altitude Turbofan Engine Testing Chamber (터보팬 엔진의 고고도 성능의 초음속 이젝터의 압력회복에 관한 연구)

  • Omollo, Owino George;Kong, Chang-Duk
    • Journal of the Korean Society of Propulsion Engineers
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    • v.14 no.6
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    • pp.53-59
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    • 2010
  • This research aims in finding a more optimal ejector size for evacuating engine exhaust gasses and 20% of the cell cooling air. The remaining 80% of cell cooling air pumped into the test chamber is separately exhausted from the test chamber via a discharge port fitted with flow control valves and vacuum pump. Unlike its predecessor this configuration utilizes a smaller capture area to improve pressure recovery. The modified ejector size has a diameter of 1100mm enough to evacuate 66kg/s jet engine exhaust in addition to about 20%, 24kg/s of the cell cooling air tapped from the sterling chamber. This configurations has an area ratio of the engine exit and ejector inlet of about 1.2. Simulation results of the proposed ejector configuration, indicates improved pressure recovery.

A Study on the Indoor Airflow Pattern by Changing the Location of Mechanical Terminal Unit (실내 급.배기구 위치변화에 따른 실 공기유동에 관한 연구)

  • Choi, Jeong-Min;Cho, Sung-Woo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.3
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    • pp.193-200
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    • 2009
  • The ventilation system of apartments can be divided by supply and exhaust fan, supply fan and exhaust free and supply free and exhaust fan. Recently, the individual ventilation system and central ventilation system which is combined cooling system with duct system are applied to apartment ventilation system. The airflow pattern is affected by location of supply unit and exhaust unit in indoor. This study is to investigate the proper distance between supply unit and exhaust unit using CFD. As a result of this study, the proper distance between supply unit and exhaust unit could be suggested at the interval of 3 m in supply and exhaust fan system and 2.5 m in supply fan and exhaust free.

A Study on the Flow Characteristics of Desktop Personal Computer by In-Out Fan (흡.배기 팬에 의한 Desktop Personal Computer 내부의 유동특성에 관한 연구)

  • Lee, Haeng-Nam;Park, Gil-Moon;Jung, Han-Byul
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.6
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    • pp.665-671
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    • 2007
  • The purpose of this study is to find out a flow characteristics required by the design of a computer case and to provide information about the preliminary data of cooling efficiency of CPU and a flow inside of a case. We examined a flow characteristic-suction a tracing particle occurred from a surge tand installed at an inlet into a computer case and moving it to a exit duct-experimentally by using PIV. The experimental device was consists of a fan inflowing and discharging the air into the computer case and a slot installed with a CPU cooling ran add-on, and analyzed the data of Re-stress distribution, velocity distribution, and kinetic energy distribution. This research will make a great contribution to improvement of the efficiency and performance of notebook, workstation, server, and all the design of electronic devices using large scale integrated(LSI) as well as usual computers.

Simple Design Method of the Engine Enclosure Considering Cooling and Noise Reduction (냉각과 소음을 고려한 엔진 차폐 구조의 간편한 설계 방법)

  • 최재웅;김관엽;이희준
    • Journal of KSNVE
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    • v.9 no.1
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    • pp.184-188
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    • 1999
  • Noise regulation of heavy construction machinery is getting stricter: 3 dB per every 4 year in European community. To meet this requirement many engineers have adopted the enclosing structures with thick absorbing materials and small opening, This increases internal temperature of the enclosure which have engine systems such as electric equipment that are vulnerable to heat, and engine block and muffler that can be regarded as heat sources. So noise control engineers have to consider a coupling problem: combining heat balance and noise reduction. This paper describes this approach by introducing simple heat transfer theory and SEA. The enclosing system of the loader whose enclosing structure consists of two rooms is investigated to show the validity of this method. The results represent that the simple heat transfer theory can be useful to estimate cooling performance when it is linked together by the back pressure theory in duct system. and the radiated noise can also be estimated by the SEA. Therefore a designer can use these approaches to define the opening ratio of an enclosure and the mass flow rate of air considering radiating noise.

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Sizing of Vertical Borehole Heat Exchangers using TRNOPT (TRNOPT를 이용한 수직 지중열교환기 길이 산정 방법에 관한 연구)

  • Park, Seung-Hoon;Lee, Hyun-Soo;Jang, Young-Sung;Kim, Eui-Jong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.10
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    • pp.402-407
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    • 2016
  • Ground-coupled heat pump systems have been widely used, as they are regarded as a renewable energy source and ensure a high annual efficiency. Among the system components, borehole heat exchangers (BHE) play an important role in decreasing the entering water temperature (EWT) to heat pumps in the cooling season, and consequently improve the COP. The optimal sizing of the BHEs is crucial for a successful project. Other than the existing sizing methods, a simulation-based design tool is more applicable for modern complex geothermal systems, and it may also be useful since design and engineering works operate on the same platform. A simulation-based sizing method is proposed in this study using the well-known Duct STorage (DST) model in Trnsys. TRNOPT, the Trnsys optimization tool, is used to search for an optimal value of the length of BHEs under given ground loads and ground properties. The result shows that a maximum EWT of BHEs during a design period (10 years) successfully approaches the design EWT while providing an optimal BHE length. Compared to the existing design tool, very similar lengths are calculated by both methods with a small error of 1.07%.

The Development of A.C. Induction Motor for Electric Railway Rolling Stock (철도차량용 전동기의 과제)

  • Yun, S.J.;Lee, I.W.;Sung, G.D.;Ha, H.S.;Noh, C.W.
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.24-26
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    • 1995
  • The Development of A.C. Induction Motor for Railway Rolling Stock. The traction motor is designed as 4-pole induction motor with self ventilation. The winding insulation is throughout of materials of class C. The rotor is designed as a squrrel rotor with copper bar and casting. The rotor speed is detected by means of a pulse generator. The newer tection motor have no casting(frame). Punched-in holes make up the air duct and transfer the heat losses in complete. Maximim motor rpm is higher due to rotor construction. New is the entry of water-cooled traction motors in urban, However the water cooling design in - unfortunately - not applicable in traction motor.

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Study on the Application Possibility of Heating-cooling system with Smoke ventilation duct to Standard Apartment (공동주택의 제연겸용 덕트형 냉난방 공급시스템의 적용가능성에 관한 연구)

  • Chun, Jung-Gil;Park, Jung-Han;Son, Won-Tug
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.468-473
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    • 2008
  • Currently, most of the buildings have been the high-rise buildings and not only the damage for people but also loose of property have been increased significantly. Furthermore, the damage for residents in indoor is increased significantly, the law related to fire protection is not established yet. We discussed safety of evacuation according to unitary system in standard apartment. At a result, when installing the smoke ventilation system, the RSET has been achieved and delay effect for reaching time of CO and smoke area has been obtained.

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