• 제목/요약/키워드: heat system

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온수 급탕 및 난방을 위한 히트 펌프 태양열 시스템의 성능 분석 (Performance Analysis of Solar Thermal System with Heat Pump for Domestic Hot Water and Space Heating)

  • 손진국
    • 한국태양에너지학회 논문집
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    • 제38권5호
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    • pp.49-62
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    • 2018
  • This study aims to analyze the performance of solar thermal system with heat pump for domestic hot water and heat supply. There are four types of system. Systems are categorized based on the existence of a heat pump and the ways of controlling the working fluid circulating from the collector. Working fluid is controlled by either temperature level (categorized as system 1 and 2) or sequential flow (system 3 and 4). Heat balance of the system, the solar fraction, hot water and heating supply rates, and performance of heat pump are analyzed using TRNSYS and TESS component programs. Technical specifications of the main facilities are as follow; the area of the collector to $25m^2$, the volumes of the main tank and the buffer tank to $0.5m^3$ and $0.8m^3$, respectively. Heating capacity of the heat pump in the heating mode is set to 30,000 kJ / hr. Hot water supply set 65 liters per person each day, total heat transfer coefficient of the building to 1,500 kJ / kg.K. Indoor temperature is kept steadily around $22^{\circ}C$. The results are as follows; 6 months average solar fraction of system 1 turns out to be 39%, which is 6.7% higher than system 2 without the heat pump, indicating a 25% increase of solar fraction compared to that of system 2. In addition, the solar fraction of system 1 is 2% higher than that of system 3. Hot water and heating supply rate of system 1 are 93% and 35%, respectively. Considering the heat balance of the system, higher heat efficiency, and solar fraction, as whole, it can be concluded that system 1 is the most suitable system for hot water and heat supply.

지열원 열펌프 시스템의 에너지 생산량 모니터링 신뢰도 향상 방안 연구 (A Study on the Monitoring Methods for Energy Production in Ground Source Heat Pump System)

  • 강신형;이광호;도성록;최종민
    • 한국지열·수열에너지학회논문집
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    • 제15권2호
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    • pp.10-16
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    • 2019
  • In this study, the present regulation of heat metering for the ground source heat pump was investigated. The ground source heat pump has been adopting the heat metering system used in the district heating system for estimating the heating and cooling energy production amount. The accuracy of the present heat metering systems for a water to water ground source heat pump is low, because the system for district heating has a relatively high temperature range comparing with the ground source heat pump operating conditions. Even though the heat amount for the building side should be measured, the heat absorption and extraction amount from or to the ground was measured for the water to air ground source heat pump due to the difficulty of estimating the air side heating and cooling capacity in the present regulation. It is highly recommended to validate the heat metering system to have reliability for the ground source heat pump and develop the system to be applicable water to air ground source heat pump.

스택 폐열을 이용한 연료전지 자동차용 열펌프 시스템의 성능 특성에 관한 연구 (A Study on the Performance Characteristics of a Heat Pump System using Stack Wast Heat in Fuel Cell Vehicles)

  • 전병용;고원빈;박윤철
    • 설비공학논문집
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    • 제28권8호
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    • pp.325-330
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    • 2016
  • This study was conducted to develop a heating system for a fuel cell-driven electric vehicle. The system consists of a compressor, an expansion device and three heat exchangers. A conventional air source heat exchanger is used as primary heat exchanger of the system, and an additional water source heat exchanger is used as a pre-heater to supply heat to the upstream air of the primary heat exchanger. On the other hand, the third heat exchanger consists of a water-to-refrigerant heat exchanger. The heat source of the pre-heater and the water-refrigerant heat exchanger is the waste heat from the fuel cell's stack. In the experiment, the indoor and the outdoor air temperature were fixed, and the compressor speed, EEV opening and waste heat temperature were varied. The results indicate that the $COP_h$ of the proposed system is 3.01 when the system is operating at a 1,200 rpm compressor speed, 50% EEV opening, and $50^{\circ}C$ waste heat source temperature in air pre-heater operation. However, when the system uses a water-refrigerant heat exchanger, the $COP_h$ increases to up to 9.42 at the same compressor speed and waste heat source temperature with 75% EEV openings.

공기열원 및 수열원을 이용한 열펌프 시스템의 성능특성에 관한 연구 (A study on the comparison of the performance of a heat pump system with air and water heat sources)

  • 고원빈;박윤철
    • Journal of Advanced Marine Engineering and Technology
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    • 제40권7호
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    • pp.563-568
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    • 2016
  • 본 연구는 연료전지 자동차용 공기조화기의 난방성능평가를 위하여 기존의 전반적인 히트펌프 시스템 중 공기열원 히트펌프 시스템의 증발기를 판형열교환기로 교체하여 시스템에 흐르는 냉매와 연료전지 스택 폐열을 직접 열교환이 가능한 수열원 이용이 가능한 난방시스템의 성능실험을 수행하였다. 실험결과에서 압축기의 회전수가 높을수록 소비동력이 증가하였다. 공기열원 이용방식의 경우 압축기 회전수가 1,200rpm이고 EEV개도가 25%인 경우 $COP_h$가 2.03으로 가장 높게 나타났고, 같은 압축기의 회전수에서 수열원 시스템은 EEV개도가 75% 및 스택 폐열의 온도가 $50^{\circ}C$인 경우 $COP_h$가 9.42로 가장 높게 나타났다.

지중열원 열펌프 시스템의 난방성능 해석 (A Study on the Heating Performance of Ground Source Heat Pump System)

  • 우정선;김대기;이세균
    • 설비공학논문집
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    • 제16권12호
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    • pp.1175-1182
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    • 2004
  • Installations of vertical boreholes for the ground source heat pump system are expensive to install. One way to reduce the initial cost is to increase the specific heat extraction rate of borehole system. However, as the specific heat extraction rate increases the temperature of borehole fluid decreases with the resultant lower Coefficient Of Performance in Heating(COPH) of heat pump system. The purpose of this study is to provide the basic informations about the performance of heat pump system with the specific heat extraction rate and soil thermal properties such as thermal conductivity and temperature. It is shown that the specific heat extraction rate is the most important parameter for the ground source heat pump system. To obtain the reasonable COPH value (COPH > 3) the heat extraction rate should be about 25 W/m or less. Accurate measurements of soil thermal properties are also very important to design the system properly. The effects of borehole thermal resistances are also examined in this study.

Heat source control intelligent system for heat treatment process

  • Lee, JeongHoon;Cho, InHee
    • International journal of advanced smart convergence
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    • 제11권4호
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    • pp.28-40
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    • 2022
  • Although precise temperature control in the heat treatment process is a key factor in process reliability, there are many cases where there is no separate heat source control optimization system in the field. To solve this problem, the program monitors the temperature data according to the heat source change through sensor communication in a recursive method based on multiple variables that affect the process, and the target heat source value and the actual heat treatment heat source to match the internal air temperature and material temperature. A control optimization system was constructed. Through this study, the error rate between the target temperature and the atmosphere (material surface) temperature of around 10.7% with the existing heat source control method was improved to an improved result of around 0.1% using a process optimization algorithm and system.

지중열 이동 시뮬레이션을 이용한 수평형 지열시스템의 채열성능 예측 (Prediction of the Heat Exchange Rate for a Horizontal Ground Heat Pump System Using a Ground Heat Transfer Simulation)

  • 남유진;채호병
    • 설비공학논문집
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    • 제25권6호
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    • pp.297-302
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    • 2013
  • The ground source heat pump (GSHP) system has attracted attention, because of its stability of heat production, and the high efficiency of the system. However, there are few studies on the prediction method of the heat exchange rate for a horizontal GSHP system. In this research, in order to predict the performance of a horizontal GSHP system, coupled simulation with a ground heat transfer model and a heat exchanger circulation model was developed, and calculation of heat exchange rate was conducted by the developed tool. In order to optimally design the horizontal GSHP system, the flow rate of circulation water, and the depth and buried spaces of heat exchangers were considered by the case study. As a result, the temperature of circulation water and the heat exchange rate of the system were calculated in each case.

액-가스 열교환기를 이용한 R170(에탄)용 냉동시스템의 성능 특성 (Performance Characteristics of Refrigerant R170(Ethane) Refrigeration System Using Liquid-gas Heat Exchanger)

  • 구학근
    • 동력기계공학회지
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    • 제20권5호
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    • pp.78-85
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    • 2016
  • This paper considers the influence of internal heat exchangers to the efficiency of a refrigerating system using R170. These liquid-gas heat exchangers(internal or suction-line heat exchangers) can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analysis the performance characteristics of refrigeration system with internal heat exchanger. The influence of operating conditions, such as the mass flowrate of R170, inner diameter tube and length of internal heat exchanger, to optimal dimensions of the heat exchanger is also analyzed in the paper. The main results were summarized as follows : the mass flowrate of R170, inner diameter tube and length of internal heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative Capacity Index) of this system. Exception for the effect of inner diameter, the RCI of R170 with respect to refrigerant mass flowrate, the length and effectiveness of internal heat exchanger is about 2.1~3.3% higher than that of R13 at the same experimental conditions. With a thorough grasp of these effect, it is necessary to design the R170 compression refrigeration cycle using internal heat exchanger.

수치 시뮬레이션을 이용한 수직밀폐형 지열시스템의 채열특성에 관한 연구 (Study on the characteristic of heat exchange for vertical geothermal system using the numerical simulation)

  • 남유진;오진환
    • 한국태양에너지학회 논문집
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    • 제34권2호
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    • pp.66-72
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    • 2014
  • Ground source heat pump system can achieve high efficiency of performance by utilizing annually constant underground temperature to provide heat source for space heating and cooling. Generally, the depth of constant-temperature zone under the ground depends on surface heat flux and soil properties. The deeper the ground heat exchanger is installed, the higher the heat exchange rate can be acquired. However, in order to optimally design the system, it is necessary to consider both the installation cost and the system performance. In this study, performance analysis of ground source heat pump system according to the depth has been conducted through the case study.

내부 열교환기를 이용한 R744용 초임계 냉동사이클의 성능 분석 (Performance Analysis of R744 (Carbon Dioxide) Transcritical Refrigeration System Using Internal Heat Exchanger)

  • 손창효;오후규
    • Journal of Advanced Marine Engineering and Technology
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    • 제33권4호
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    • pp.459-465
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    • 2009
  • This paper considers the influence of internal heat exchangers to the efficiency of a refrigerating system. These internal heat exchangers(liquid-suction or suction-line heat exchangers) can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analysis the performance characteristics of refrigeration system with internal heat exchanger. The influence of operating conditions, such as gas cooler pressure and evaporation temperatures, superheat in the evaporator and temperature of gas cooler outlet, to optimal dimensions of the heat exchanger is also analyzed in the paper. The main results were summarized as follows : the mass flowrate of R744, inner diameter tube and length of internal heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative capacity index) of this system. With a thorough grasp of these effect, it is necessary to design the R744 compression refrigeration cycle using internal heat exchanger.