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R744 냉매를 적용한 상용탑차용 냉동기 성능에 대한 해석적 연구
명치욱(Chiwook Myung),김상훈(Sanghun Kim),조홍현(Honghyun Cho) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
The global warming is accelerated due to the destruction of ozone layer by using CFCs and HCFCs refrigerant in commercial refrigerator truck, therefore the natural refrigerant has lively studied in order to apply into HVAC system. In this study, the refrigerating system of commercial refrigerator truck was modeled by using R744 which was environment-friendly natural refrigerant to replace the R404A refrigerant. As a result, the performance of R744 refrigerant system showed the sensitive variation with operating conditions. Besides, the COP was decreased by 30% when outdoor temperature increased from 25℃ to 35℃, and it was decreased by 41% as compressor RPM increased 1000 to 3000.
성능향상을 위해 이젝터를 적용한 CO₂ 냉동기의 성능비교
강변(Byun Kang),명치욱(Chiwook Myung),조홍현(Honghyun Cho) 대한설비공학회 2010 대한설비공학회 학술발표대회논문집 Vol.2010 No.11
Refrigerating system using an ejector is proposed in order to increase performance and system reliability in a CO₂ cycle. In this study, the analytical study on the performance characteristics of CO₂cycle with an ejector carried out with a variation of outdoor temperature, gascooler inlet air velocity, evaporator inlet air velocity, and evaporator inlet air temperature. As a result, the system performance improved by using an ejector for various operating condition because of the decrease compressor work. Besides, the high performance of an ejector system could be maintained for wide operating conditions compared to that of a basic system.
냉동탑차용 냉장시스템의 착상 및 무착상 상태에서의 성능변화에 관한 해석적 연구
김상훈(Sanghun Kim),명치욱(Chiwook Myung),조홍현(Honghyun Cho) 대한설비공학회 2011 설비공학 논문집 Vol.23 No.11
To analyze the cooling performance in the refrigerator truck according to frost growth, the analytical model of refrigeration system was developed under frost and non-frost condition using EES. The system performance was analyzed with outdoor temperature, storage temperature, outdoor front air velocity and compressor speed in order to investigate the system performance characteristics with operating conditions. Besides, the system performance under frost condition was compared with that under non-frost condition. As a result, the frost thickness was 0.9 mm when the refrigerating capacity of frost condition was decreased by 30%. The maximum of the system COP was shown at compressor speed of 1500 rpm for non-frost and frost condition, simultaneously. The performance under frost condition was more sensitive to the operating condition compared to that under non-frost condition.
김태중(Taejung Kim),명치욱(Chiwook myung),조홍현(Honghyun Cho) 한국자동차공학회 2011 한국자동차공학회 지부 학술대회 논문집 Vol.2011 No.9
The smoke is generated with the incomplete combustion because of the form of the nozzle injection and irregular spray pattern as the carbon of the injector nozzle tip is generated due to the long time use of the common rail engine injector. In order to solve this kind of problems, the injector of the common rail engine is taken out to remove the generated carbon by the disintegration and cleaning of the nozzle tip part. The result that the exhaust fumes generation amount is remarkably decreased was confirmed with the improvement of the normalization of the spray pattern of the injector and incomplete combustion compare before the carbon is removed.