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대체 냉매를 적용한 친환경 냉동탑차 성능 특성에 관한 해석적 연구
박차식 한국산학기술학회 2024 한국산학기술학회논문지 Vol.25 No.7
냉동탑차용 냉동시스템은 트럭 탑차에 장착되어 목적지까지 운반되는 수송과정에서 적재물의 일정한 온도를 유지하며 콜드체인 시스템에서 중요한 역할을 한다. 냉동 및 냉장 식품은 냉동탑차를 이용해 수송하고 있으며 현재 대부분의 냉동탑차는 엔진의 동력으로 냉동기를 구동하는 엔진 구동방식인데, 최근 전기상용차 보급의 확대로 냉동탑차의 전기차 전환을 위한 냉동시스템 개발에 대한 관심이 증대되고 있다. 본 연구에서 적용하는 R404A와 R454C 냉매의 냉동사이클 기본 성능 특성을 비교하기 위하여 냉동탑차의 증발온도 운전 조건에 따른 냉동사이클 시뮬레이션을 실시하였다. 기존의 엔진구동 방식의 압축기를 적용한 R404A 시스템과 대체 시스템인 전기구동 방식의 압축기를 적용한 R454C 시스템에 대하여 냉동사이클 해석을 수행하였다. 증발온도가 –25~0℃까지 변화할 때 R404A 시스템의 냉방용량과 압축기 소비동력은 각각 251.9%와 72.6% 증가하였고, R454C 시스템의 냉방용량과 압축기 소비동력은 각각 148.5%와 10.5% 증가하였다. 소형 상용차용 내연기관 냉동탑차의 전환 시스템으로 전기 상용차 냉동탑차에 대체냉매 R454C를 적용할 경우 기존의 R404A 시스템보다 전반적으로 성능이 우수한 것으로 나타났다. The refrigeration system for refrigerated vehicles is installed on trucks and plays a vital role in the cold chain system by maintaining a constant cargo temperature during transportation to its destination. With the expansion of electric commercial vehicles, the interest in developing refrigeration systems for converting refrigerated trucks to electric vehicles has increased. A simulation was conducted to compare the basic performance characteristics of the refrigeration cycle of the R404A and R454C refrigerants used in this study. A refrigeration cycle analysis was performed on the R404A system using a conventional engine-driven compressor and the R454C system using an alternative system, an electric-driven compressor. When the evaporation temperature changed from -25 to 0°C, the cooling capacity and compressor power consumption of the R404A system increased by 251.9% and 72.6%, respectively, and the cooling capacity and compressor power consumption of the R454C system increased by 148.5% and 10.5%, respectively. When applying the alternative refrigerant R454C to electric commercial vehicle refrigerated trucks as a conversion system for internal combustion engine refrigerated trucks for small commercial vehicles, the overall performance was better than the existing R404A system.
R22를 적용한 전자팽창밸브의냉매유량 특성 및 유량예측 모델링
박차식,이선일,김용찬,이영수 대한설비공학회 2006 설비공학 논문집 Vol.18 No.11
The objective of this study are to analyze the flow characteristics of R22 flowing through EEVs and to develop an empirical correlation to predict the refrigerant flow rate. The mass flow rates of EEVs with different geometries were measured at various condensing temperatures, subcoolings, and EEV openings. Based on the experimental data, an empirical correlation for mass flow predictions in EEVs was developed by modifying the orifice equation. The correlation showed good agreement with the measured data for R22 with average and standard deviations of 1.4% and 6.1%, respectively. Approximately 90% of the measured data were within ±10% of the predictions.
열병합시스템 경제성 평가 프로그램의 개발 및 적용에 관한 연구
박차식,김용찬,Park, Chasik,Kim, Yongchan 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.11
The object of this study was to develop an economic assessment program for the optimal design of the cogeneration systems composed of combining engine, generator, waste heat recovery exchanger, absorption chiller, and boiler, etc. The energy demand categorized by electric power, heating, cooling and water supply was determined by statistical data of the existing cogeneration systems. An economic assessment was performed by comparing the total cost of cogeneration system with that of non-cogeneration system. The total cost was evaluated by adding initial investment to operational cost considering efficiency of equipment, cost of equipment, fuel and electricity. To confirm the validity of the developed program, a hotel building with an area of $127,960m^2$ was selected, and the simulated results were compared with the measured data. The difference between the simulated and the measured values for the selected hotel building was approximately 12% for annual electric consumption.
박차식,안태길,박경우,김도형,차귀수,서정식,Park, C.S.,Ahn, T.K.,Park, K.W.,Kim, D.H.,Cha, G.S.,Seo, J.S. 한국초전도저온학회 2009 한국초전도저온공학회논문지 Vol.11 No.3
The thermal characteristics of quench propagation is a crucial problem for the stability of the superconductor. The objective of this study is to simulate the quench propagation with the variation of disturbance energy in Bi-2223/Ag HTS pancake coil. In this analysis, the temperature-time trace of a point away from heater was calculated under conditions of different quench energy. The critical disturbance energy between quench propagation and quench recovering was calculated, In addition, the minimum quench energy with different transport currents was obtained through the present simulation. These results are significant to the application of HTS.
하천수열원을 이용한 2단압축 열펌프의 난방성능 시뮬레이션
박차식,김보현,김용찬,이영수,방기영 대한설비공학회 2005 설비공학 논문집 Vol.17 No.11
The use of river water as a heat source of a heat pump has the advantage in the performance compared to the use of atmospheric air because the temperature variation of river water over the year is relatively small. In this study, the performance of the heat pump system using river water as a heat source was numerically investigated. A simulation model for the 2-stage compression heat pump system was developed with each component model composed of compressors, heat exchangers, a flash tank and electronic expansion devices. The performance of the heat pump system using river water was improved by 50% compared to that using atmospheric air in winter conditions.