• Title/Summary/Keyword: Heat exchange system

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Heating and cooling properties in cultivation room and cultural characteristics of oyster mushroom according to type of air exchange (외부공기 유입방식에 따른 느타리버섯 생육실의 온도변화 및 자실체의 생육특성)

  • Jang, Myoung-Jun;Lee, Yun-Hae;Ju, Young-Cheol
    • Journal of Mushroom
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    • v.11 no.4
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    • pp.214-218
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    • 2013
  • This study was carried out to find out suitable input method for air exchange about bottle cultivation of oyster mushroom. There was no difference of average temperature in cultivation room, but T1(direct introduction of outside air) was higher than T2(heat exchanger) and T3(air buffer) in the standard deviation. The ratio of cooling operating was the highest in August and in the descending order, T1 54%, T3 43%, T2 33%. At ratio of energy reduction, T2 and T3 were higher than T1. The operating ratio of heater was highest in January and in the descending order, T1 53%, T3 37%, T2 30%. At ratio of energy reduction(%), T2 and T3 were higher than T1 similar to result of cooling operating. Therefore there were largest in August about Cooling Degree-Hour and in January about Heating Degree-Hour. And fruitbody yields quality was excellent in T2 and T3 than T1. The suitable effective type of air exchange in oyster mushroom cultivation are heat exchange and air buffer system.

A Study on Performance Characteristics of an Evaporative Heat Exchanger with Mini-channels (환경조절장치용 미세유로형 증발열교환기의 성능특성 연구)

  • Lee, Hyung-Ju;Yoo, Young-June;Min, Seong-Ki;Hwang, Ki-Young
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.247-253
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    • 2011
  • An experimental study on performance characteristics of an evaporative heat exchanger based on tests for various operating conditions was presented. The heat exchanger maximizes the heat transfer rate per unit volume by applying mini-channels for both the air and coolant flow paths, and minimizes the amount of the coolant by using its latent heat of evaporation. The heat exchanger was manufactured by etching the flow paths, brazing the heat exchange plates, and welding the in/out ports of the media. The basic performance test has confirmed that the heat exchanger met its design requirements, and the results of the map test were analyzed to produce the performance characteristics quantitatively depending on the air inlet temperature, the air flow rate, and the coolant flow rate.

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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 2016 (설비공학 분야의 최근 연구 동향 : 2016년 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.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. 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 flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (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 of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth 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, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving 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 analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

A Study on the Application of the Radiant Floor Cooling System in Residential Building (주거 건물의 복사냉방시스템 적용에 관한 연구)

  • 임재한;여명석;김광우
    • Journal of the Korean housing association
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    • v.15 no.3
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    • pp.73-82
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    • 2004
  • The objective of this study is to demonstrate the potential of radiant cooling systems using Ondol as an alternative cooling system in residential buildings. For this purpose, computer simulation and model experiments have been performed for the system performance analysis regarding comfort, floor surface condensation, and supply water temperature. The results of this study is the following: In radiant floor cooling system, room air temperatures were maintained within the set temperature range of $\pm$1$^{\circ}C$ without any discomfort condition. And taking into account only the condensation occurrence, it was possible to achieve radiant floor cooling for a period of about 77% of the total cooling period in weather condition of Seoul. The minimum supply water temperature is about 15$^{\circ}C$, so renewable energy system such as ground heat exchange system can be used as an alternative in cooling source. Also, floor surface condensation can be prevented by integrating with the dehumidification system.

The Development of Diesel Engine Room Fault Diagnosis System Using a Correlation Analysis Method (상관분석법에 의한 선박기관실 고장진단 시스템 개발)

  • Kim, Young-Il;Oh, Hyun-Kyung;Yu, Yung-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.30 no.2
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    • pp.253-259
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    • 2006
  • There is few study which automatically diagnoses the fault from ship's monitored data. The bigger control and monitoring system is. the more important fault diagnosis and maintenance is to reduce damage caused by system fault. This paper proposes fault diagnosis system using a correlation analysis algorithm which is able to diagnose and forecast the fault from monitored data and is composed of fault detection knowledge base and fault diagnosis knowledge base. For all kinds of ship's engine room monitored data are classified with combustion subsystem, heat exchange subsystem and electric motor and pump subsystem, To verify capability of fault detection, diagnosis and prediction, FMS(Fault Management System) is developed by C++. Simulation by FMS is carried out with population data set made by the log book data of 2 months duration from a large full container ship of H shipping company.

The Development of Diesel Engine Room Fault Diagnosis SystemUsing a Correlation Analysis Method (상관분석법에 의한 선박기관실 고장진단 시스템 개발)

  • Kim, Young-Il;Oh, Hyun-Gyeong;Cheon, Hang-Chun;Yu, Yung-Ho
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.06a
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    • pp.251-256
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    • 2005
  • There is few study which automatically diagnose the fault from ship's monitored signal. The bigger control and monitoring system is, the more important fault diagnosis and maintenance is to reduce damage brought forth by system fault. This paper proposes fault diagnosis system using a correlation analysis algorithm which is able to diagnose and forecast the fault and is composed to fault detection knowledge base and fault diagnosis knowledge base. For this all kinds of ship's engine room monitored data are classified with combustion subsystem, heat exchange subsystem and electric motor and pump subsystem by analyzing ship's operation data. To verifying capability of fault detection, diagnosis and prediction, Fault Management System(FMS) is developed by C++. Simulation experiment by FMS is carried out with population data set made by log book data of 2 months duration from a large full container ship of H shipping company.

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A Study on the Actual Status of Heat Transfer oils in Industries for Process Safety Management (공정안전관리 사업장의 열매체유 사용실태에 관한 연구)

  • Lee, Keun Won;Lee, Joo Yeob
    • Journal of the Korean Institute of Gas
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    • v.18 no.5
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    • pp.33-39
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    • 2014
  • Heat transfer oils are used in applications such as chemical plant heating systems, refinery heat exchange systems, certain gas processes, injection molding systems, and pulp and paper processing. These oils are extremely stable and resistant to thermal and oxidative degradation. In the event of a spill or accidental release of heat transfer oils, it can be ignited easily when there is an ignition source. This study discusses the status of safety management through the actual status of the heat transfer oils to prevent fire and explosion accidents in industries for process safety management. The actual status of the heat transfer oils in process system of industries surveyed by a questionnaire developed. The results of this study can be used to help establishment of safety management to prevent fire and explosion accidents, such as the management of heat transfer oils, safe operation and maintenance in heat transfer oil processes.

Study on the corrosion of A/C condenser in the ship (선박용 해수 열교환방식 A/C 응축기의 부식원인)

  • Baek, S.M.;Yang, J.H.;Kim, K.J.;Moon, K.M.;Lee, M.H.
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2006.06a
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    • pp.283-284
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    • 2006
  • The ship performs heat exchange using seawater to keep main engine and auxiliary machinery at optimum temperature. In heat exchanger, refrigerant located outside of copper tube is cooled by seawater flowing through inside of copper tube. On the other hand, seawater erosion and corrosion nay occasionally cause the corrosion of the copper tube in A/C(Air Conditioner) condenser. This corrosion of copper tube makes seawater and refrigerant mixed, seriously damaging A/C system. In this study, accordingly, the exact ive mechanism of the corrosion on the condenser entailing serious problems occasional is investigated through the electrochemical polarization experiments on the condenser's component materials. According to the experiments, the corrosive procedures on the copper tube was verified by the fact that passive film of the copper tube surface which is destroyed by the pressure of sucked seawater, is damaged by the corrosive ingredients in the seawater.

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A Study on Effect of Flow Characteristics for Turbine Impeller Shape (Turbine Impeller 형상이 유동특성에 미치는 영향에 관한 연구)

  • Jeon, Eon-Chan;Youn, Gi-Ho;Kang, Chang-Hun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.4
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    • pp.36-43
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    • 2014
  • Recently, research has been conducted to develop the ORC (organic Rankine cycle), to recover waste heat from facilities such as industrial plants ultimately to create mechanical or electrical energy. The ORC system consists of a heat exchange, a condenser, a pump and a boiler. In this paper, 84 flow analyses were conducted with 21 cases and three variables, i.e., a number of large wings, a number of small wings, and RPMs. R245fa was used as a refrigerant. The flow cavitation phenomenon was investigated through a flow analysis, and a flow stream analysis was conducted.