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운전조건에 따른 R404A와 R134a를 적용한 냉동탑차용 냉장시스템의 엑서지 비교
신윤찬(Yunchan Shin),김태중(Taejung Kim),조홍현(Honghyun Cho) 대한설비공학회 2014 설비공학 논문집 Vol.26 No.11
The performances of refrigeration truck systems using R404A and R134a were investigated by experimental testing, and compared. The optimal COPs of the R404A and R134a systems were 2.96 and 3.42, when the refrigerant charge amount was 1.3 kg and 1.4 kg, respectively. When the indoor side air temperature increased from 5℃ to 9℃, the total exergy destruction rate of the R404A system was on average 39.1% higher than that of the R134a system. In addition, the exergy efficiency of the R404A system was 12.9% higher than that of R134a system, for various indoor air temperatures. When the outdoor side air temperature increased from 25℃ to 35℃, the total exergy destruction rate of the R404A and R134a systems decreased by 18.9% and 19.5%, respectively. In addition, the exergy efficiency of the R404A and R134a systems increased by 25.2% and 30.7%, respectively. As the compressor rotating speed increased, the COP of the R404A and R134a systems decreased by 23.6% and 18.4%. The total exergy destruction rate and exergy efficiency of the R404A system were 27.2% and 15.7% higher than those of R134a system, respectively. Compared to the R404A system, the R134a system showed a higher COP and a lower exergy destruction rate; thus it can be concluded that the R134a system has the better performance.
R134a와 R1234yf 냉매 적용에 따른 냉동탑차 냉장시스템의 성능비교
신윤찬 ( Yunchan Shin ),김진현 ( Jinhyun Kim ),조홍현 ( Honghyun Cho ) 조선대학교 공학기술연구원 2017 공학기술논문지 Vol.10 No.2
Recently, the importance of delivery system has being developed according to the growth of online and mobile shopping market. Especially, transportation of frozen food by online and home shopping is increasing significantly. Therefore, the demand of refrigeration truck is also increasing. In this study, performance characteristics of refrigeration system using R134a and R1234yf in a refrigeration truck were compared by experimental method. When the refrigerant charging amounts increased from 1.1 to 1.4 kg, COP of R134a system was increased and the maximum COP was 2.63 at the charge amount of 1.4 kg. And that of R1234yf system was 2.49 at the optimal charge amount of 1.3 kg. The optimal EEV opening of R134a and R1234yf system was 60% and 50%, respectively. Besides, the COP was 2.69 and 2.49 for R134a and R1234yf at the optimal EEV opening. When the outdoor air temperature increased from 25℃ to 35℃, the system COP of R134a and R1234yf decreased by 15.0% and 11.6%, respectively. Besides, When the compressor rotating speed increased from 1000 to 2000 rpm, the system COP of R134a and R1234yf decreased by 37.5% and 35.9%, respectively. The R134a system showed a higher performance than R1234yf system, but the R134a system showed the larger reduction in the performance according to compressor rotating speed.
착상조건에서 R134a와 R1234yf를 적용한 핀-관 형태의 증발기 성능 비교
신윤찬(Shin, Yunchan),김진현(Kim, Jin-Hyun),조홍현(Cho, Hong-Hyun) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.9
식생활의 향상 및 다양화로 신선한 제품에 대한 요구가 증가하고 있으며, 이에 따라 냉장 및 냉동식품의 저온유통 또한 점차 증가되고 있다. 현재 냉동산업에는 주로 R134a 냉매가 사용되고 있으며 GWP(Global Warming Potential)가 1300으 로써 매우 높아 지구온난화에 영향을 미친다. 이를 대체하기 위한 냉매로써 R1234yf 냉매가 있으며, GWP는 4로써 매우 낮 다. 냉동탑차 냉장시스템에 사용되는 증발기는 저온조건에서 작동되기 때문에 서리가 형성되어 시스템의 성능을 급격히 감 소시킨다. 따라서, 본 연구에서 R134a와 R1234yf 냉매를 작동유체로 사용한 증발기의 성능을 착상조건 하에서 다양한 운전 조건으로 분석하였다. 해석결과, 서리성장 조건에서 공기측 입구온도, 상대습도, 증발온도 변화에 대하여 R134a 증발기의 성능이 R1234yf 증발기보다 더욱 민감하게 나타났으며 서리의 성장 또한 R134a 증발기가 더 크게 나타났다. The low temperature distribution of the refrigerated and frozen food has been increased gradually. Refrigeration industry is using R134a refrigerant, which GWP is 1300. R1234yf is an alternative refrigerant of R134a because GWP of R1234yf refrigerant is just 4. Evaporator used in refrigeration truck refrigeration system is operated on low temperature condition. Accordingly, evaporator is formed frost and the formation of frost is rapidly decreased performance of evaporator. In this study, the performance of evaporator using R134a and R1234yf refrigerant was analyzed with operating conditions under frost condition. As a result, the performance of R134a evaporator according to air inlet temperature, relative humidity and evaporating temperature was more sensitive than R1234yf evaporator. Besides, the frost growth of R134a evaporator is steeper than that of R1234yf one.