• 제목/요약/키워드: Refrigeration Effect

검색결과 849건 처리시간 0.029초

온도변화가 실린더 주위 열전달계수에 미치는 영향에 관한 실험적 연구 (Effect of Temperature Variations on Heat Transfer Coefficient in Crossflow over a Circular Cylinder)

  • 고상근
    • 설비공학논문집
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    • 제4권2호
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    • pp.137-145
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    • 1992
  • coefficient precisely, experiments were carried out in three categories which contain the regime of (1) constant wire temperature (2) constant fluid temperature (3) constant temperature difference between wire and fluid. Measurements were made with electrically heated circular tungsten wire placed normal to air stream at the exit of jet. Heat transfer coefficient was increased with wire temperature increasing and decreased by fluid temperaure increasing and was not changed with varying both temperature if their difference were kept constant.

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단순 급수관로계내의 에어챔버 및 어레스터의 수격방지효과에 관한 실험적 연구 (An Experimental Study on the Effect of Water Hammer Arresters and Air Chambers in a Simple Water Piping System)

  • 한화택;김종만
    • 설비공학논문집
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    • 제8권1호
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    • pp.37-44
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    • 1996
  • Water hammer pressure waves were measured in a simplified water piping system with and without arresters and air chambers by the operations of the solenoid valve. Experiments were performed to investigate the effects of the location of the arresters and the effects of the volume of the air chambers on maximum and minimum water hammer pressures and wave frequency for various flow rates.

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온도차 마랑고니 대류에 의한 열전달 촉진에 관한 연구 (A study of Heat Transfer Enhancement by Temperature Driven Marangoni Convection)

  • 김종윤;이동호;박종화;최국광
    • 설비공학논문집
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    • 제15권10호
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    • pp.795-801
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    • 2003
  • The primary object of this study is to obtain a basic knowledge of heat transfer enhancement mechanism as affected by temperature driven Marangoni convection. Experiments is achieved to visualize the enhanced heat transfer phenomena by the effect of Marangoni convection through the laser holographic interferometry. Also Nusselt Number is introduced for the relation of Marangoni Number.

온도 성층축열조 가시화 및 실증분석에 관한 고찰 (Effect on Stratification due to Diffuser Shape in a Thermal Storage Tank)

  • 이영수;이상남;김종률
    • 설비공학논문집
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    • 제17권11호
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    • pp.990-997
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    • 2005
  • The stratified effect was investigated with three different types of diffuser shape in a thermal storage tank with variation of diffuser diameter, velocity, Froude number etc. Its effect was estimated by the degree of stratification. No matter of diffuser diameter and shape, the degree of stratification was the best as the Froude number gets closer to 1. In the case of a curved diffuser, when its diameter is a quarter of tank diameter and ejection velocity in a diffuser is approximately 0.2 m/s, the Froude number was almost 1. In the case of a flatted diffuser, when ejection velocity was 0.05 m/s, the Froude number was 1.5. Both cases which Froude number were nearer 1, showed the good degree of stratification.

실내수영장의 에너지 소비요소별 에너지 절약효과에 관한 연구 (A Study on the Energy Conservation Effect of Each Energy Consumption Component In Indoor Swimming Pools)

  • 김영돈;권규동;여명석;김광우
    • 설비공학논문집
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    • 제14권12호
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    • pp.1092-1101
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    • 2002
  • The objective of this study is to develop energy saving strategies for indoor swimming pools and to estimate the effect of each energy saving strategy. For this purpose, field measurements regarding pool water heating energy, domestic hot water heating energy are conducted and a base energy consumption model is implemented using the DOE-2.1E program. The results of the study reveal that 25% of the total pool water heating energy may be saved by using night time pool covers, 27% of the total domestic hot water heating energy may be saved by using a waste water heat recovery system (effic. 60%), and of the total ventilation energy may be saved using an exhaust air heat recovery system (effic. 60%).

이산화탄소/프로판 혼합냉매의 냉방성능 특성 (Cooling Performance of Several $CO_2/propane$ Mixtures in an Air-Conditioning System)

  • 김주혁;김민수
    • 설비공학논문집
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    • 제18권1호
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    • pp.47-54
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    • 2006
  • [ $CO_2$ ] and propane mixtures were chosen as promising alternative refrigerants and their performance potentials were evaluated experimentally in an air-conditioning system. Pure $CO_2$ and 85/15, 75/25 and 60/40 binary blends by the charged mass percentage of $CO_2/propane$ were selected as working fluids. The effect of the inlet temperature of the secondary fluids and degree of superheat on the cooling performance was tested and discussed. The charging amounts of refrigerants were adjusted to make the system show the maximum COP. Comparisons among different refrigerants were carried out on the same compressor speed basis for a given operating condition. In addition, the temperature gliding effect of zeotropic mixtures on the system performance were analyzed based on the drop-in test results.

The Effects of Nitrite Treatment on the Lipid Composition, Fatty Acid Composition, and Susceptibility to Oxidation of Pork Biceps Femoris Muscle

  • Han, S.K.;Yamauchi, K.
    • Asian-Australasian Journal of Animal Sciences
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    • 제13권12호
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    • pp.1764-1769
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    • 2000
  • The purpose of this experiment was to investigate the antioxidant effect of nitrite on total, neutral, and polar lipids and fatty acid composition in laboratory-cooked ground pork. Muscle samples (Biceps femoris) were analyzed using Iatroscan, gas chromatography, phosphorus content, and TBARS value. The total and neutral lipid contents of muscle were higher in nitrite-untreated meat (0 ppm) than in nitrite-treated meat (100 ppm) but the reverse was observed for polar lipid contents. The results for neutral lipids showed a similar trend when compared with total lipids. Polyunsaturated fatty acids contents of total, neutral and polar lipid in 100 ppm treated meat were higher than that of 0 ppm. The phosphorus content was higher in 100 ppm meat than in 0 ppm but the reverse was observed for TBARS value. These results showed that the addition of 100 ppm nitrite to ground pork resulted in a remarkable antioxidant effect during refrigeration storage.

저온재생기2열원2중효용(低溫再生器2熱源2重效用) Parallel Flow Cycle의 특성(特性) 해석(解析) (Simulation of the performance characteristics of the double effect Parallel flow cycle with secondary heat at the low temperature qenerator)

  • 최국광;이동호
    • 태양에너지
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    • 제17권3호
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    • pp.43-49
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    • 1997
  • 본 연구는 저온재생기에서 용액 재생 열원으로 저온열을 보조열원으로 이용가능한 2열원 2중효용 흡수 사이클특성을 규명하기 위한 방법으로 병렬 용액 순환형 2중 효용 흡수 사이클 해석을 수행한다. 본 해석은 저온 재생기에서 필요한 재생열의 일부를 태양열 또는 배열 등과 같은 저온 보조 가열원을 이용하여 열의 유용성 검증을 위한 기초 수단으로 가열원 입구 온도, 용액 순환량을 변화시켜 2중효용 parallel flow cycle 의 특성을 규명한다.

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