• 제목/요약/키워드: Solution heat exchanger

검색결과 131건 처리시간 0.03초

용접형 판형 열교환기의 열전달 및 압력강하 특성에 관한 실험적 연구 (Experimental study of Heat Transfer and Pressure Drop Characteristics for the Welded Plate Heat Exchanger)

  • 정종윤;김성수;강용태
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2008년도 하계학술발표대회 논문집
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    • pp.419-424
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    • 2008
  • Heat transfer and pressure drop characteristics of welded plate heat exchanger are studied to apply it for the solution heat exchanger of 210RT absorption system. This study quantifies the effect of mass flow rate and strong solution concentration on the heat transfer coefficient and pressure drop in the plate heat exchanger. The concentration of weak solution is fixed at 55% and the strong solution varies 55%, 57%, and 59% in mass. The results show that the overall heat transfer coefficient and pressure drop increase linearly with increasing Reynolds number. It is also found that the heat transfer coefficient of hot side increases with increasing the concentration of strong solution while the strong solution concentration has no effect on heat transfer coefficient of cold side.

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부동액 도포에 의한 핀-튜브 열교환기 착상방지 (Frost Prevention of Fin-Tube Heat Exchanger by Spreading Antifreezing Solution)

  • 오상엽;장영수
    • 설비공학논문집
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    • 제18권6호
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    • pp.477-485
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    • 2006
  • A study on frost prevention of fin-tube heat exchanger is experimently performed by spreading antifreezing solution on heat exchanger surface. It is desirable that the antifreezing solution spreads completely on the surface forming thin liquid film to prevent frost nucleation and crystal growth and to reduce the thermal resistance across the liquid film. A small amount of antifreezing solution falls in drops on heat exchanger surface using two types of supplying devices, and a porous layer coating technique is adopted to enhance the wettedness of antifreezing solution on the surface. It is observed that the antifreezing solution liquid film prevents fin-tube heat exchanger from frosting, and heat transfer performance does not degrade through the frosting tests. The concentration of supplied antifreezing solution can be determined by heat transfer analysis of the first row of heat exchanger to avoid antifreezing solution freezing due to dilution by moisture absorption.

흡수식 냉동기 고효율화를 위한 사이클 설계 (The study of High Efficiency Cycle Characteristics of the absorption Chiller)

  • 박찬우
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2007년도 동계학술발표대회 논문집
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    • pp.534-539
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    • 2007
  • The objectives of the present work is to investigate the influence of the solution cooled absorber(SCA), refrigerant drain heat exchanger(RSX), exhaust gas/solution heat exchanger(ESX) and high efficiency solution heat exchanger on COP for a double-effect series-flow absorption chiller. A simulation program has been prepared for the cycle analysis of absorption chillers. As a result, Solution heat exchangers(LSX, HSX) are a most effective element for the COP than the others. In spite of the poor contribution to COP, SCA make a rule to reduce the crystallization phenomena of LiBr solution at solution heat exchanger. And the optimum solution split ratio are varied with the relative size of RSX and LSX.

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흡수식 냉동기 고효율화를 위한 사이클 설계 (The Study on High Efficiency Cycle Characteristics of the Absorption Chiller)

  • 박찬우
    • 설비공학논문집
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    • 제20권10호
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    • pp.662-668
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    • 2008
  • The objectives of the present work are to investigate the influence of the solution cooled absorber(SCA), refrigerant drain heat exchanger(RSX), exhaust gas/solution heat exchanger(ESX) and high efficiency solution heat exchanger on COP for a double-effect series-flow absorption chiller. A simulation program has been prepared for the cycle analysis of absorption chillers. As a result, solution heat exchangers(LSX, HSX) are the most effective element for the COP than the others. In spite of the poor contribution to COP, SCA plays an important role to reduce the crystallization phenomena of LiBr solution at solution heat exchanger. And the optimum solution split ratio varies with the relative size of RSX and LSX.

An Experimental Study on the Frost Prevention using Micro Liquid Film of an Antifreeze Solution

  • Chang Young-Soo;Yun Won-Nam
    • International Journal of Air-Conditioning and Refrigeration
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    • 제14권2호
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    • pp.66-75
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    • 2006
  • The effect of antifreeze solution liquid film on the frost prevention is experimentally investigated. It is desirable that the antifreeze solution spreads widely on the heat exchanger surface forming thin liquid film to prevent frost nucleation while having small thermal resistance across the film. A porous layer coating technique is adopted to improve the wettability of the antifreeze solution on a parallel plate heat exchanger. The antifreeze solution spreads widely on the heat exchanger surface with $100{\mu}m$ thickness by the capillary force resulted from the porous structure. It is observed that the antifreeze solution liquid film prevents a parallel plate heat exchanger from frosting. The reductions of heat and mass transfer rate caused by the thin liquid film are only $1{\sim}2%$ compared with those for non-liquid film surface.

판형 열교환기식 제습기에서 LiCl 수용액의 열 및 물질전달 특성 (Heat and Mass Transfer Characteristics of LiCl Aqueous Solution for a Plate Heat Exchanger Type Dehumidifier)

  • 전동순;이해승;김선창;김영률
    • 설비공학논문집
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    • 제24권1호
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    • pp.16-22
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    • 2012
  • Experimental investigations were carried out to examine the heat and mass transfer characteristics of LiCl aqueous solution for a plate heat exchanger type dehumidifier. Cooling dehumidification was adopted vertical type heat exchanger. Also non woven fabric is attached surface of the heat exchanger for spreadability of LiCl aqueous solution. Mass flow-rate of LiCl aqueous solution and concentration were selected as experimental conditions. Also, In this study, the effects of relative humidity of process air and velocity were investigated experimentally. As a result of heat transfer coefficient and mass transfer coefficient of were increased film reynolds number increased. heat transfer coefficient and mass transfer coefficient of LiCl aqueous solution were 0.14~0.24 kW/$m2^{\circ}C$ and $1.3{\times}10-63{\sim}6.2{\times}10-6$ m/s respectively.

용접형 판형열교환기의 열전달 및 압력강하특성에 관한 수치해석 (A Numerical Analysis on the Heat Transfer and Pressure Drop Characteristics of Welding Type Plate Heat Exchangers)

  • 정종윤;남상철;강용태
    • 대한기계학회논문집B
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    • 제32권9호
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    • pp.676-682
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    • 2008
  • Numerical analysis was carried out to examine the heat transfer and pressure drop characteristics of plate heat exchangers for absorption application using Computational Fluid Dynamics(CFD) technique. A commercial CFD software package, FLUENT was used to predict the characteristics of heat transfer, pressure drop and flow distribution within plate heat exchangers. In this paper, a welded plate heat exchanger with the plate of chevron embossing type was numerically analyzed by controlling mass flow rate, solution concentration, and inlet temperatures. The working fluid is $H_2O$/LiBr solution with the LiBr concentration of 50-60% in mass. The numerical simulation shows reasonably good agreement with the experimental results. Also, the numerical results show that plate of the chevron shape gives better results than plate of the elliptical shape from the view points of heat transfer and pressure drop. These results provide a guideline to apply the welded PHE for the solution heat exchanger of absorption systems.

마이크로 부동액막을 이용한 착상방지에 관한 실험적 연구 (An Experimental Study on the Frost Prevention using Micro Liquid Film of an Antifreezing Solution)

  • 장영수;윤원남
    • 설비공학논문집
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    • 제17권5호
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    • pp.459-467
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    • 2005
  • The effect of anti freezing solution liquid film on the frost prevention is experimentally investigated. It is desirable that the antifreezing solution spreads widely on the heat exchanger surface forming thin liquid film to prevent frost nucleation and reduce the thermal resistance across the film. A porous layer coating technique is adopted to improve the wettedness of the anti freezing solution on a parallel plate heat exchanger. The antifreezing solution spreads widely on the heat exchanger surface with 100 $\mu$m thickness by the capillary force resulting from the porous structure. It is observed that the antifreezing solution liquid film prevents a parallel plate heat exchanger from frosting. The reductions of heat and mass transfer rate caused by thin liquid film are only $1\~2\%$ compared with those for non-liquid film surface.

지하수를 이용한 양액냉각시스템 개발에 관한 기초연구 (A Fundamental Study on the Nutrient Solution Cooling System Utilizing Ground Water)

  • 남상운;손정익;김문기
    • 생물환경조절학회지
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    • 제2권1호
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    • pp.1-8
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    • 1993
  • Experimental and theoretical analyses were carried out to investigate the heat exchange characteristics of the nutrient solution cooling system utilizing ground water. The material of heat exchanger used in the experiment was polyethylene and the cross-flow type was adapted in which nutrient solution was mixed and ground water unmixed. For the exchanger surface area of 0.33$m^2$ and flow rates of ground water of 1-6$\ell$/min, NTU(number of transfer units) and effectiveness of experimental heat exchanger were 0.1-0.45 and 10-35%, respectively. Therefore these results showed that the hydroponic greenhouse of 1,000$m^2$(300 pyong) with the ground water of 10$m^2$/day could cover about 55-70% of maximum cooling load in summer.

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냉매 열교환기 구성방법에 따른 제 2종 흡수식 히트펌프의 성능 특성 변화에 관한 연구 (Performance Characteristics of Type II LiBr-H2O Absorption Heat Pump in Accordance with the Refrigerant Heat Exchanger Configuration)

  • 이창현;윤준성;김인관;권오경;차동안;배경진;김민수;박찬우
    • 설비공학논문집
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    • 제29권7호
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    • pp.373-384
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    • 2017
  • The objective of this study was to determine the effect of refrigerant heat exchanger on the performance of type II absorption heat pump performance using numerical analysis. Two heat exchange installation methods were used: solution to refrigerant and waste hot water to refrigerant. These methods were compared to the standard model of hot water flow without using refrigerant heat exchanger. When waste hot waters were bypassed to refrigerant heat exchanger, COP was not affected. However, steam mass generation rates were increased compared to those of the standard model. When solutions were bypassed to the refrigerant heat exchanger, results were different depending on the place where the solution rejoined. COP and steam mass generation rates were lower compared to those when waste heat water was passed to refrigerant heat exchanger. Thus, it is possible to obtain higher steam mass generation rates by using waste water and installing refrigerant heat exchanger.