• 제목/요약/키워드: Hot water heating exchanger system

검색결과 38건 처리시간 0.024초

Empirical Modeling of Fouling Rate of Milk Pasteurization Process : A case study

  • Budiati, Titik;Wahyono, Nanang Dwi;Hefni, Muh.
    • International journal of advanced smart convergence
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    • 제4권1호
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    • pp.11-17
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    • 2015
  • Fouling in heat exchanger becomes a major problem of dairy industry and it increases the production cost. These are lost productivity, additional energy, additional equipment, chemical, manpower, and environmental impact. Fouling also introduces the risk of food safety due to the improper heating temperature which allow the survival of pathogenic bacteria in milk, introducing biofilm formation of pathogenic bacteria in equipments and spreading the pathogenic bacteria to milk. The aim of this study is to determine the fouling rate during pasteurization process in heat exchanger of pasteurized milk produced by Village Cooperative Society (KUD) "X" in Malang, East Java Indonesia by using empirical modeling. The fouling rate is found as $0.3945^{\circ}C/h$ with the heating process time ranged from 0 to 2 hours and temperature difference (hot water inlet temperature and milk outlet temperature) ranged from 0.654 to $1.636^{\circ}C$. The fouling rate depends on type and characteristics of heat exchangers, time and temperature of process, milk type, age of milk, seasonal variations, the presence of microorganism and more. This results will be used to plan Cleaning In Place (CIP) and to design the control system of pasteurization process in order to maintain the milk outlet temperature as standard of pasteurization.

지열-태양열원 복합시스템의 부하추종특성에 관한 실험 연구 (An Experimental Study on the Load Delivery Characteristics of Hybrid Energy System with Geothermal and Solar Heat Sources)

  • 황인주;우남섭
    • 한국지열·수열에너지학회논문집
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    • 제2권2호
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    • pp.1-8
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    • 2006
  • The objective of the present study is to investigate the load delivery characteristics of a hybrid-renewable energy system with geothermal and solar heat sources for hot water, heating and cooling of a residential house in Korea. The hybrid energy system consists of ground source heat pump of 2 RT for cooling with a 150 m vertical U-bend ground heat exchanger, solar collectors of 4.8 m2 and gas fired backup boiler. The averaged coefficient of performance of geothermal module during cooling and heating seasons are evaluated as about 4.5 and 3.8, respectively.

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인공신경망 모델을 활용한 저심도 모듈러 지중열교환기의 난방성능 예측에 관한 연구 (Heating Performance Prediction of Low-depth Modular Ground Heat Exchanger based on Artificial Neural Network Model)

  • 오진환;조정흠;배상무;채호병;남유진
    • 한국지열·수열에너지학회논문집
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    • 제18권3호
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    • pp.1-6
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    • 2022
  • Ground source heat pump (GSHP) system is highly efficient and environment-friendly and supplies heating, cooling and hot water to buildings. For an optimal design of the GSHP system, the ground thermal properties should be determined to estimate the heat exchange rate between ground and borehole heat exchangers (BHE) and the system performance during long-term operating periods. However, the process increases the initial cost and construction period, which causes the system to be hindered in distribution. On the other hand, much research has been applied to the artificial neural network (ANN) to solve problems based on data efficiently and stably. This research proposes the predictive performance model utilizing ANN considering local characteristics and weather data for the predictive performance model. The ANN model predicts the entering water temperature (EWT) from the GHEs to the heat pump for the modular GHEs, which were developed to reduce the cost and spatial disadvantages of the vertical-type GHEs. As a result, the temperature error between the data and predicted results was 3.52%. The proposed approach was validated to predict the system performance and EWT of the GSHP system.

응축형 가스보일러시스템의 제어 알고리즘 개발을 위한 효과적인 동적모델 (Effective Dynamic Models for the Development of Control Algorithms of a Condensing Gas Boiler System)

  • 한도영;김성학
    • 설비공학논문집
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    • 제20권6호
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    • pp.365-371
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    • 2008
  • Condensing gas boiler units may make a big role for the reduction of energy consumption in heating industries. In order to decrease the energy consumption of a condensing gas boiler unit, effective operations of the system are necessary. In this study, mathematical models of a condensing gas boiler system were developed in order to develop control algorithms of the system. These include dynamic models of a blower, a gas valve, a pump, a burner, a boiler heat exchanger, and a hot water heat exchanger. Control algorithms of a blower, a gas valve, and a pump were also assumed. Simulation results showed good predictions of dynamic behaviors of a boiler system. Therefore, the simulation program developed for this study may be effectively used for the development of control algorithms of a boiler system.

지역난방 적용 태양열시스템의 장기 열성능 분석 (Analysis of Long-term Thermal Performance of Solar Thermal System Connected to District Heating System)

  • 백남춘;신우철
    • 한국태양에너지학회 논문집
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    • 제27권4호
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    • pp.167-173
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    • 2007
  • This study analyzed by simulation using TRNSYS as well as by experiment on the solar district heating system installed for the first time for the district heating system in Bundang. Simulation analysis using TRNSYS focused on the thermal behavior and long-term thermal efficiency of solar system. Experiment carried out for the reliability of simulation system. This solar system where the circuits of two different collectors, flat plate and vacuum tube collector, are connected in series by a collector heat exchanger, and the collection characteristics of each circuit varies. Therefore, these differences must be considered for the system's control. This system uses variable flow rate control in order to obtain always setting temperature of hot water by solar system. Specifically, this is a system that heats returning district heating water (DHW) at approximately $60^{\circ}C$ using a solar collector without a storage tank, up to the setting temperature of approximately $85{\sim}95^{\circ}C$ To realize this, a flat plate collector and a vacuum tube collector are used as separate collector loops. The first heating is performed by a flat plate collector loop and the second by a vacuum tube collector loop. In a gross collector area basis, the mean system efficiency, for 4 years, of a flat plate collector is 33.4% and a vacuum tube collector is 41.2%. The yearly total collection energy is 2,342GJ and really collection energy per unit area ($m^2$) is 1.92GJ and 2.37GJ respectively for the flat plate vacuum tube collector. This result is very important on the share of each collector area in this type of solar district heating system.

저에너지주택의 지열히트펌프시스템 냉·난방 성능분석 (Heating and Cooling Performance Analysis of Ground Source Heat Pump System in Low Energy House)

  • 백남춘;김성범;신우철
    • 설비공학논문집
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    • 제28권10호
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    • pp.387-393
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    • 2016
  • A ground source heat pump system maintains a constant efficiency due to its stable heat source and radiant heat temperature which provide a more effective thermal performance than that of the air source heat pump system. As an eco-friendly renewable energy source, it can reduce electric power and carbon dioxide. In this study, we analyzed one year of data from a web based remote monitoring system to estimate the thermal performance of GSHP with the capacity of 3RT, which is installed in a low energy house located in Daejeon, Korea. This GSHP system is a hybrid system connected to a solar hot water system. Cold and hot water stored in a buffer tank is supplied to six ceiling cassette type fan coil units and a floor panel heating system installed in each room. The results are as follows. First, the GSHP system was operated for ten minutes intermittently in summer in order to decrease the heat load caused by super-insulation. Second, the energy consumption in winter where the system was operated throughout the entire day was 7.5 times higher than that in summer. Moreover, the annual COP of the heating and cooling system was 4.1 in summer and 4.2 in winter, showing little difference. Third, the outlet temperature of the ground heat exchanger in winter decreased from $13^{\circ}C$ in November to $9^{\circ}C$ in February, while that in summer increased from $14^{\circ}C$ to $17^{\circ}C$ showing that the temperature change in winter is greater than that in summer.

온수, 증기 동시 발생형 가스엔진 열병합발전의 배열회수 특성: 100 kW급 모형 실험 (Heat Recovery from a 1 MW Class Gas Engine CHP System: 100 kW Class Model Test)

  • 안준;김혁주;최규성;송대석
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2008년도 동계학술발표대회 논문집
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    • pp.345-350
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    • 2008
  • The present study has been conducted to develop a heat recovery system for a 1 MW class gas engine based cogeneration system. In the cogeneration system, heat is recovered from two parts, which are jacket water and exhaust gas. The heat from the jacket water is recovered by a plate type heat exchanger and used for the room heating and/or hot water supply. The heat from the exhaust gas is used to generate steam. For both of the heat recovery devices, 1/5 scaled tests are performed and the data are compared to the conventional correlations for the design.

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자연대류형 태양열 온수 급탕 시스템의 열성능 및 실증실험 (An Experimental and Field Study on Thermal Performance of Thermosyphon Solar Hot Water System)

  • 강용혁;곽희열;전홍석
    • 태양에너지
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    • 제11권1호
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    • pp.16-26
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    • 1991
  • 주거용 온수급탕에 소비되는 에너지를 절약하기 위하여 국내기후와 생활환경에 적합한 자연대류형 태양열 온수 급탕 시스템의 개발에 관한 연구이다. 비교분석을 위해 집열기와 열교환 형태에 따른 여러형태의 축열조를 제작하여 실험을 수행하였다. 또한, 열성능 분석결과를 토대로 시스템 최적화를 통한 모범도면을 작성하였고, 지역별, 기후별 실증실험을 위하여 전국7개도시(서올, 부산, 대구, 광주, 대전, 강릉, 제주)에 시범 설치하여 열성능 및 실용화 가능성을 검토하였다.

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설비공학 분야의 최근 연구 동향 : 2016년 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 2016)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제29권6호
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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.

고분자전해질 연료전지의 중저온 열원을 건물난방에 이용하기 위한 온도 제어장치 개발 (Development of Temperature Control System to use in Building Heating of low Temperature Heat of PEMFC)

  • 차광석;김회서
    • 플랜트 저널
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    • 제10권3호
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    • pp.45-51
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    • 2014
  • 본 연구에서는 기존 가정용연료전지에서 활용이 미약한 중저온의 배열을 건물난방부하에 적용할 수 있도록 온도 안정화 장치를 개발하였으며 이 장치가 기존 난방설비와 연계가 가능하도록 제어시스템을 구축하였다. 연료전지 시스템의 정상작동을 위해서는 연료전지로부터 배출되는 온수의 공급온도가 $60^{\circ}C$이어야 하고 다시 연료전지로 회수되는 작동 유체의 환수온도는 항상 $55^{\circ}C$로 유지하여야 한다. 본고에서는 먼저 스택배열 활용을 극대화하기 위해 CFD 분석을 통해 소형열교환기와 기존 난방설비배관과의 최적 연계장치시스템을 구성하였다. 또한 계절별 난방 수온의 불규칙한 온도변화에 대응하기 위해서 연료전지 스택의 열원과 아파트세대 난방용 환수관을 연결한 온도자동조절 밸브를 사용하여 온도안정화 장치를 개발하였다. 소형열교환기와 통합 활용할 수 있도록 설정된 온수의 온도가 편차 ${\pm}0.5^{\circ}C$ 이내에서 유지되도록 하였다. 이 연구결과를 통해 연료전지인 PEMFC의 배열을 건물난방부하에 활용이 추후 가능할 것으로 예상된다.

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