• Title/Summary/Keyword: R410A

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Investment policy and trends of agri-food R&D in major overseas countries (해외 주요국가의 농·식품 R&D 투자 정책 및 동향)

  • Hong, Seok-In
    • Food Science and Industry
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    • v.53 no.4
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    • pp.410-421
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    • 2020
  • Regarding a long-term strategic plan in the food and agriculture sector, R&D policies and investment trends in major overseas countries are reviewel. The importance of efficient resource management is emphasized along with continuous government support for R&D in the agri-food industry. In response to facing social issues such as climate change, food security, food safety, health, and environment, research and innovation agenda is mainly focused on harmony between economy and environment, human nutrition and health as well as animal and plant health, and an integrated ecosystem approach. Particularly in the food sector, public investment is generally made in food safety, nutrition and health, and private investment for food processing and manufacturing. Public-private collaboration is carried out in order to enhance the efficiency of R&D innovation and development strategies in the agri-food industry.

Heat and Mass Transfer Characteristics and Performance Evaluation of a Double-Tube Condenser for an Alternative Refrigerant (대체냉매의 2중관 응축기 열 및 물질전달과 성능평가)

  • 이상무;박병덕;소산번
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.6
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    • pp.468-476
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    • 2002
  • This paper deals with heat and mass transfer characteristics and performance evaluation of a counter flow double-tube condenser for a multi-component refrigerant mixture. The local heat and mass transfer characteristics of ternary zeotropic refrigerant mixtures composed of HFC32/HFC125/HFC134a are evaluated for a counter flow double-tube condenser cooled by water. Then, the local values of vapor quality, thermodynamic states at bulk vapor, vapor-liquid interface and bulk liquid, heat flux and condensation mass flux are obtained. The heat exchange performance for ternary zeotropic refrigerant mixtures composed of HFC32/HFC125/HFC134a on the total pressure drop and the heat transfer characteristics are also compared with those for R404A, R410A, R502, R22, R32, Rl23 and R134a.

An Experimental Study on Evaporation/Condensation Heat Transfer with Flow Direction in Brazed Plate Heat Exchanger using Refrigerant 410A (R410A를 이용한 브레이징 타입 판형열교환기에서 물 측 유동방향에 따른 응축/증발 성능 평가)

  • Lee, Sung-Woo;Jeong, Young-Man;Lee, Jae-Keun;Lee, Dong-Hyuk
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.1096-1101
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    • 2009
  • The plate heat exchanger(PHE) in heat pump has two flow streams of the refrigerant and water. The flow direction of the refrigerant, unlike that of water, can be changed by a 4-way valve depending on operating condition. Therefore the flow arrangement is a parallel flow for heating and a counter flow for cooling, respectively. In this study, the effects of the flow direction of the water on the heat transfer rate are investigated experimentally. The experiments are carried out for brazed plate heat exchangers under a parallel and counter flow conditions in evaporation and condensation. The experimental parameters in this study include the mass flux of the refrigerant 410A from 3 to $14\;kg/m^2s$ and the flow patterns for the pressure of PHE fixed at 0.97 and 2.46 MPa. The results show that both the heat transfer rate and frictional pressure drop across the PHE increase with the mass flux. The heat transfer rate of the refrigerant 410A for evaporation show great sensitivity to flow direction of the water. The heat transfer rate for evaporation with a counter flow are 5-30% higher than that with a parallel flow.

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Prediction of condensation heat transfer coefficients inside horizontal tube in annular flow regime (환상유동 영역에서의 수평관내 응축 열전달계수 예측)

  • Kwak, Kyung-Min;Bae, Chul-Ho;Jung, Mo;Lee, Sang-Chun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.6
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    • pp.732-742
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    • 1998
  • Prediction method for heat transfer coefficients in a horizontal smooth tube with forced convection condensation is proposed. In this paper, the analogy between momentum and heat transfer was applied to an annular flow regime and the logarithmic velocity distribution is applied to describe the velocity profile within the liquid film. Prediction results are compared with those of experimental ones. The test refrigerants are R113, R22, R134a, R407C(R33/R125/R134a, 23/25/52 wt%), R410A(R32/R125, 50/50 wt%) and R134a+R123(R134a/R123, 85.5/14.5 wt%) which are used under operating conditions in a condenser of air-conditioner. The proposed prediction method shows good agreement with experimental data within$\pm 30%$ for pure refrigerants. For the mixture refrigerants including the ternary mixture refrigerant R407C, condensation heat transfer from this study are higher than those from experiments. By correcting the constant in two-phase frictional multiplier, the predicated heat transfer coefficients become similar to the experimental results.

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Changes of Physical Characteristics of Chubu Perilla Leaves(Penilla Frutescens var. Japonica HARA)during Different Storage Conditions (저장조건에 따른 추부 깻잎의 물리적 특성 분석)

  • Hur, Sang-Sun
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.2
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    • pp.410-417
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    • 2017
  • The physical properties of perilla leaves cultivated in Geumsan province were analyzed according storage conditions. The a/b values of perilla leaves increased with increasing storage period. Electronic nose composed of 12 different metal oxide sensors was used to differentiate flavors of perilla leaves. Sensitivities(delta $R_{gas}/R_{air}$) of sensors from electronic nose were obtained by principal compound analysis(PCA). Proportion of the first principal component was 93.07% at $25^{\circ}C$ and 97.81% at $4^{\circ}C$, respectively. In our result, flavor patterns of perilla leaves can be differentiated according to the storage temperature.

A Study on the Characteristics of Heat Exchanger in Air-Conditioning System using Alternative Retrigerants (대체냉매를 사용하는 공조기용 열교환기의 특성에 관한 연구)

  • 김남신;이은호;유재석;김기현;최윤호;김권진;김만회;황석렬
    • Journal of Energy Engineering
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    • v.9 no.3
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    • pp.192-201
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    • 2000
  • 증발기와 응축기로 폐회로 냉동 시스템을 구성하여 기존 사용 냉매인 R22와 대체냉매로써 부각되고 있는 R407C, R410A를 사용하여 여러 가지 관 직경과 휜 형상을 가지는 열교환기에 대한 열전달량, 질량유량, 열교환기를 지나가는 냉매의 온도분포 그리고 공기측 압력강하를 측정하였다. 모든 열교환기에서 냉매의 질량유량이 증가함에 따라 열전달량은 증가하였다. R22와 R407C의 경우에 증발기측에서는 거의 같은 열전달량을 나타냈고 응축기측에서는 R407C가 전체적으로 열전달량이 높게 나타났다. 그리고 열교환기의 전달량은 유로의 형상보다는 냉매의 질량유량과 전열면적에 더 많은 영향을 받는다. 공기측 압력 강하는 열수가 많은 열교환기의 경우가 작게 나타났으며 슬릿휜을 가지는 열교환기의 압력강하가 가장 크고 웨이비휜을 가지는 열교환기가 가장 작게 나타났다.

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Soft ice-cream maker operating with mixed refrigerant R290/R32 (혼합냉매 (R290/R32) 적용 소프트 아이스크림 제조기 (drop-in 시험))

  • Park, Tae-Gyun;Han, Seong-Pil;Lee, Eung-Ryeol;Kim, Nae-Hyeon;Park, Hyeong-Chae
    • Proceedings of the SAREK Conference
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    • 2005.11a
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    • pp.410-413
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    • 2005
  • Drop-in tests were conducted using R290/R32 (31:69) mixture in an ice-cream maker for possible replacement of R-502 and R-404A. Optimum refrigerant charge and TEV opening were obtained through a series of experiments. At the standard outdoor condition ($35^{\circ}C$ DT, $24^{\circ}C$ WT), the time required for initial ice-cream making was 6'22", which was approximately the same as that of R-404A. The electric energy consumed was 660 kJ, which was about 10% higher than that of R-404A. The compressor outlet temperature ($8^{\circ}C$) and pressure (2.52 MPa) were higher than those ($60^{\circ}C$ and 1.48 MPa) of R-404A. The reason could be the usage of the same R-404A compressor although the specific volume of R290/R32 is much larger.

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Development of the closed-loop Joule-Thomson cryoablation device for long area cooling

  • Lee, Cheonkyu;Park, Inmyong;Yoo, Donggyu;Jeong, Sangkwon;Park, Sang Woo
    • Progress in Superconductivity and Cryogenics
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    • v.15 no.3
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    • pp.40-48
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    • 2013
  • Cryoablation device is a surgical instrument to produce the cooling effect to destroy detrimental biological tissue by utilizing low temperature around 110 K. Usually, this device has the concentrated cooling region, so that it is suitable for concentrated and thick target. Accordingly, it is hard to apply this device for the target which is distributed and thin target. In this study, the design procedure of a closed-loop cryoablation device with multiple J-T expansion part is developed for the treatment of incompetent of great saphenous vein. The developed cyoablation device is designed with the analysis of 1-dimensional (1-D) bio-heat equation. The energy balance is considered to determine the minimum mass flow rate of refrigerant for consecutive flow boiling to develop the uniform cooling temperature. Azeotropic mixed refrigerant R410A and zeotropic mixed refrigerant (MR) of R22 ($CHClF_2$) and R23 ($CHF_3$) are utilized as operating fluids of the developed cryoablation device to form the sufficient temperature and to verify the quality of the inside of cryoablation probe. The experimental results of R410A and the zeotropic MR show the temperature non-uniformity over the range are $244.8K{\pm}2.7K$ and $239.8K{\pm}4.7K$ respectively. The experimental results demonstrate that the probe experiences the consecutive flow boiling over the target range of 200 mm.

The Pressure Drop Characteristics in Small Diameter Tubes Using HCFC Alternative Refrigerants (세관내 HCFC계 대체냉매의 압력강하에 관한 연구)

  • Son, C.H.;Lee, H.R.;Jeong, J.H.;Choi, Y.S.;Oh, H.K.
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.347-352
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    • 2000
  • The pressure drop characteristics of R-22 and R-410A(a mixture of 50wt% R-32 and 50wt% R-125) flowing in a small diameter tube with 1.77[mm] inner diameter and 3.14[mm] outer diameter was investigated experimentally. the mass fluxes of refrigerants are ranged from 450 to $1050[kg/(m^2{\cdot}s)]$ and the qualites are varied from 0.05 to 0.95. The main experimental results were summarized as follows; The single-phase liquid friction factors for small diameter tubes are higher than those predicted by the Blasius equation. In case of two-phase flow, the pressure gradient of the small diameter tube increases with increasing mass velocity and vapor quality. The experimental data are not well correlated by predictions which were proposed for the large diameter tube.

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Factors affecting clinical dental hygienist emotional intelligence on burnout (임상치과위생사의 감성지능이 소진에 영향을 미치는 요인)

  • Kim, Young-Im
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.8
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    • pp.410-416
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    • 2018
  • The purpose of this study was to investigate the factors affecting the exhaustion of emotional intelligence of clinical dental hygienist and to improve the quality of customer service and effective management of clinical dental hygienist. The results of the study were as follows: 394 clinical dental hygienists working in Jeollabukdo from February 6 to May 31, 2017. Clinical dental hygienist's emotional intelligence showed a significant negative correlation with burnout(r=-.623, p<.001). Self emotion appraisal, others' emotion appraisal, and use of emotion were found to be related factors to exhaustion of clinical dental hygienist..Based on the results of this study, it would be necessary to develop programs to improve the emotional intelligence of clinical dental hygienists, to reduce burnout and to improve the work efficiency of clinical dental hygienists.