• 제목/요약/키워드: Multi air-conditioner

검색결과 47건 처리시간 0.023초

유동제어를 통한 자동차 부품의 복합 성형기술 (The Technology of Complex Forming for Automobile Part with Flow Control)

  • 이동주;김동진;김병민
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1999년도 단조 심포지엄
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    • pp.185-194
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    • 1999
  • This paper suggests the new techmology to control metal flow in order to reduce the number of preforming and machining for the cold forged product with complex geometry. This technology can be summarized the complex forming, which consists of bulk forming and sheet forming, and multi-action forging, which be preformed double action dies. To analyze the process, finite element simulation has been performed. The proposed technology is applied to hub which is part of air conditioner clutch. According to the result of this study, the relative velocity of mandrel and punch is primary process variable.

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환기시스템이 적용된 히트펌프의 난방시 급기효율 평가에 관한 연구 (A Study on the Evaluation of Air Change Efficiency of Multi-Air-Conditioner with Ventilation System for Heating Season)

  • 권용일;한화택;김경환;정백영;이감규
    • 설비공학논문집
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    • 제17권1호
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    • pp.56-61
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    • 2005
  • Indoor air quality becomes of a concern recently in view of human health. This study investigates the air diffusion performance and the air change efficiency of a classroom, when outdoor air is introduced in addition to the heating/cooling operation of a ceiling-mounted heat pump. A CFD analysis has been performed to investigate the effect of the discharge angle of the air jets from the heat pump for both parallel and series types of outdoor air system. It is observed that the series type creates more uniform indoor environment compared to the parallel type in general. It can be concluded the discharge angle should not be larger than 40o for the parallel type, in order not to generate thermal stratification in the room.

라지스케일 칼로리미터에 의한 멀티시스템형 에어컨실외기의 연소실험에 관한 연구 (A Study on Combustion Experiments of Multi Type Air-Conditioner Outdoor Units by Large Scale Calorimeter)

  • 민세홍;배연준
    • 한국화재소방학회논문지
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    • 제25권6호
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    • pp.168-177
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    • 2011
  • 본 연구에서는 현재 상업용으로 가장 많이 사용되고 있는 멀티시스템형 에어컨실외기의 화재 위험성을 평가하기 위하여 에어컨실외기의 실물 연소실험을 수행하였다. 그 결과 에어컨실외기는 내부 폭발과 상부 배출 그릴을 통한 급격한 화염분출 및 화재확산을 보였으며, 이는 실외기 내부에 내장된 전선, 전자 제어판, 열교환용 동판 및 합성수지류 등의 가연물이 연소하고 냉매가스가 충전된 배관이 가열로 인해 파괴되어 냉매가스가 분출되면서 화재폭발과 외부로 화염분출을 가속시켜 일어난 것이다. 본 실험에서 에어컨실외기의 최고 열방출율은 5,830 kW로 나타났으며, 열화상 카메라 및 열전대에 의해 측정된 실외기의 내부 온도는 최고 $1,201^{\circ}C$이고, 외부온도는 최고 $881^{\circ}C$ 이상, 화염의 길이는 약 5 m 이상 상승하였다. 그러므로 에어컨실외기의 화재는 주변 가연물을 발화시키는 원인으로 작용하여 건축물에 2차 화재를 발생시킴으로써 큰 피해를 줄 수 있을 것으로 판단된다. 이러한 실물실험에서 얻어낸 결과는 향후 컴퓨터시뮬레이션에서 에어컨실외기의 화재구현 및 주변 가연물로의 화재 확산 예측에 적용될 수 있을 것이다.

회전 변형 파워항을 고려한 진동 절연계 해석 : 컴프레서 마운트 계에의 응용 (Vibrational Power Analysis of Multi-dimensional Vibration System with Rotational Terms Included and Its Application to Compressor System)

  • 이호정;김광준;이병찬;진심원;정인화
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집B
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    • pp.618-623
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    • 2001
  • In a practical vibration isolation system, vibration is transmitted from the source to the receiver through several paths such as more than one inter-connected point and multi-degree of freedom at each connection point. Therefore, the major path investigation for vibration transmission among them is often required in a point of view of isolation. For the path analysis of multi-dimensional vibration isolation system, it is useful to employ the concept of vibration power in high frequency range where radiation of noise from the receiver structure is concerned. The idea is simple to understand and formulate but rather complicated to apply in practice. For an accurate estimation of power flow especially over a high frequency range, it is well known in theory that rotational motions should be taken into consideration together with translational motions at inter-connected points. In reality, however, power transmissions related to rotational terms are often neglected mainly due to difficulties in the instrumentation. In this paper, necessary formula and measurable mechanical quantities for vibration power analysis will be reviewed and experimental results with rotational terms included for compressor system in a commercial air conditioner will be shown.

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유동 저항에 따른 원심홴의 선정 (Selection of Centrifugal Fan for Flows with Down-Stream Resistance)

  • 김재원;장동희;안은영
    • 한국유체기계학회 논문집
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    • 제9권3호
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    • pp.44-48
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    • 2006
  • Comprehensive experimental works are carried out for the optimal design of a centrifugal blower adopted in an indoor unit of an air-conditioner. The models for consideration are typical multi-blade turbo blower and limit loaded one, respectively. The main interest lies on the fluid dynamics performance when the blower Is installed in the practical system. The methodologies are an experimental estimations with a wind tunnel for blower performance and PIV measurement for the detail flow information. A centrifugal blower with limit loaded fan shows pronounced performances in terms of the flow rate and static pressure rise and the reason is explained by the precise measurement of the flows between blades using PIV. Consequently, it is found that the blower is proper for the flows with a resistance in down stream such as a heat exchanger.

Multi-scale simulation of wall film condensation in the presence of non-condensable gases using heat structure-coupled CFD and system analysis codes

  • Lee, Chang Won;Yoo, Jin-Seong;Cho, Hyoung Kyu
    • Nuclear Engineering and Technology
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    • 제53권8호
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    • pp.2488-2498
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    • 2021
  • The wall film-wise condensation plays an important role in the heat transfer processes of heat exchangers, refrigerators, and air conditioner. In the field of nuclear engineering, steam condensation is often utilized in safety systems to remove the core decay heat under both transient and accident conditions. In particular, passive containment cooling system (PCCS), are designed to ensure containment safety under severe accident conditions. A computational fluid dynamics (CFD) scale analysis has been conducted to calculate the heat transfer rate of the PCCS. However, despite the increase in computing power, there are challenges in the long-term transient simulation of containment using CFD scale codes. In this study, a heat structure coupling between the CFD and system analysis codes was performed to efficiently analyze PCCS. In addition, the component unstructured program for interfacial dynamics (CUPID) was improved to analyze the condensation behavior of ternary gas mixtures. Thereafter, the condensation heat transfer on the primary side was calculated using the improved CUPID and CFD code, whereas that on the secondary side was simulated using MARS. Both the coupled codes were validated against the CONAN facility database. Finally, conjugate heat transfer simulations with wall condensation in the presence of non-condensable gases were appropriately performed.

태양에너지 분야의 최근 연구동향- 2000년$\sim$2002년 학회지 논문에 대한 종합적 고찰 - (Recent Progress in Solar Energy Research - A review of Papers Published in the Korean Journal of Solar Energy between 2000 and 2002 -)

  • 유호천;장문석
    • 한국태양에너지학회 논문집
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    • 제22권4호
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    • pp.107-119
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    • 2002
  • A review on the papers published in the Korean Journal of Solar Energy between 2000 and 2002 has been done. Focus has been put on current status of research in the aspect of Insolation. Solar Collector and Storage System, Solar Heating and Cooling System, Solar Cell and Lighting System, Active and Passive Solar Building, Heat Transfer in Solar Energy and Natural Energy. The conclusions are as follows. 1) Many studies on Insolation were conducted to optimize the usage of Solar Energy. 2) A review of the recent studies on solar thermal shows that there were many papers on solar collector and storage system. However, studies on the HVAC system using solar energy were relatively insufficient. 3) To produce high efficient solar cell. various experimental and numerical papers were published. However studies on control system, solar cell and lighting were seemed to be insufficient. 4) Studies on using solar energy in passive solar buildings were widely carried out, however, studies based on synthetic analysis of buildings and BIPV were insufficient. 5) Studies on heat transfer were mainly about heat exchanger, performance of heat pipe and multi air conditioner. 6) Studies on energy resources except for solar energy, such as hydraulic power and wind power etc. were very few.

설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제26권12호
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. 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 fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are 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 general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, 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 is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

도시철도 역사 스크린 도어 개폐에 따른 냉방 기류 해석 및 효율 비교 분석 (Analysis of Cooling Air Current and Efficiency of Air Conditioning in the Underground Subway Station with Screen-Door Opening and Closing)

  • 장용준;류지민;정호성
    • 한국철도학회논문집
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    • 제17권5호
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    • pp.328-335
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    • 2014
  • 도시철도 지하역사 냉방 기류 및 냉방 효율을 조사하기 위하여 수치해법을 이용하여 해석하고 현장 실험 결과와 비교하여 분석하였다. 해석 대상 역사로는 지하 8층의 깊이 43.6m인 서울 5호선 신금호 역사를 선정하였다. 전체 역사를 해석 영역으로 하였으며, 공조기 모드는 평상시 모드로 고정시켰다. 냉방 공조를 위하여 대합실 천정에 총 94개의 정사각형($0.6m{\times}0.6m$) 환기구를 모델하였으며, 승강장은 총 222개의 환기구가 승강장 천정에 모델되었다. 대합실에서 급기되는 공기는 $47,316m^3/h$, 배기되는 공기량은 $33,980m^3/h$이며, 승강장에서 급기되는 공기는 $33,968m^3/h$, 배기되는 공기량은 $76,190m^3/h$로 현장의 풍량을 반영하였다. 승강장에서 스크린도어(PSD)는 닫힌 경우와 열린 경우 각각을 조사하였다. 총 750만개의 격자가 사용되었으며, 전체 영역을 22개의 다중 블록으로 나누어서 계산하고, MPI를 이용하여 각각의 블록에서 계산된 결과를 교환하였다. LES 기법을 이용하여 운동량 방정식 및 에너지 방정식을 계산하였다.

공동주택에서 지열 냉난방 시스템 적용시 경제성 분석 (Economic Analsys of Cooling-Heating System Using Ground Source Heat in Multi Family Apartment)

  • 박용부;박종배;임해식;백성권
    • 한국지반환경공학회 논문집
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    • 제8권3호
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    • pp.11-18
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    • 2007
  • 본 연구에서는 파급효과가 큰 공동주택에서 지열 냉난방 시스템의 경제성을 아파트 분양평형, 운전시간, 냉난방 및 급탕 설치형태별로 구분하여 초기 공사비 증가, 운전비 절감액, 초기 투자비 회수기간등을 산정하였다. 냉난방 및 급탕 운전시간이 많을수록 초기 공사비 증가액에 비해 운전비용 절감액이 커 초기 투자비 회수기간이 단축되었다. 전용면적이 클수록 투자회수 기간이 길었으며 냉난방 및 급탕 설치형태에서는 냉난방을 지열원, 급탕을 폐열회수한 경우가 초기 투자 회수기간이 가장 짧았다. 기존 시스템(패키지 에어콘, LNG 난방 및 급탕)에 비해 냉난방, 급탕을 모두 지열로 이용하는 경우, 냉난방은 지열, 급탕은 폐열을 이용하는 경우, 냉난방은 지열, 급탕은 LNG인 경우에 공사비가 $m^2$당 각각 약 72,000원, 66,900원, 62,300원 정도 증가하였다.

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