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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.
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.
토출유량변화에 따른 배수용 수중펌프 성능 특성에 대한 해석적 연구
신윤찬(Yunchan Shin),유지호(Jiho Ryu),김태중(Tae-Jung Kim) 한국산업기술융합학회(구. 산업기술교육훈련학회) 2023 산업기술연구논문지 (JITR) Vol.28 No.4
기후변화에 따른 이상기후가 일상화되며 매년 크고 작은 홍수가 꾸준히 발생하고 있어 농경지 침수로 인한 피해가 증가하고 있다. 최근에는 집중호우로 인해 농경지의 침수를 막아주는 빗물펌프장이 충남 청양군 일대에서 설치된 4곳중 3곳이 제대로 가동되지 않아 농작물과 시설하우스만 여러 동이 침수되는 피해가 발생하였다. 본 연구에서는 토출유량 변화에 따른 배수용 수중펌프의 성능 특성에 대한 해석적 연구를 수행하였으며, 토출유량에 따라 실험과 해석에 대한 수중펌프의 효율은 ±3.4%이내임을 확인하였다. Abnormal weather owing to climate change has become commonplace. Large and small floods have steadily occurred annually, increasing damage owing to flooding of agricultural land. Recently, owing to torrential rain, three of four rainwater pumping stations installed in Cheongyang-gun, Chungcheongnam-do, had failed to operate properly, thereby flooding several buildings and facility houses. In this study, an analytical study was conducted on the performance characteristics of centrifugal submersible pumps according to changes in the discharge flow rate. The results confirmed that the efficiency of the submersible pump for the experiment and analysis was within ±3.4% with the discharge flow rate.
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.
뇌졸중 환자의 운동기능에 원격재활이 미치는 효과: 체계적 문헌고찰
신윤찬(Shin Yun-Chan),박지혁(Park Ji-Hyuk) 대한신경계작업치료학회 2018 재활치료과학 Vol.7 No.4
목적: 뇌졸중 환자에게 원격재활을 적용하고 운동기능의 변화를 알아본 연구들을 체계적으로 고찰하여 원격재활에서 사용한 원격감독 방법과 원격으로 제공된 중재의 효과를 알아보아 국내에서의 적용을 위한 기초자료를 제공하려 한다. 연구방법: 2000년부터 2018년 4월까지의 국외 문헌들을 PubMed, Embase 그리고 Cochrane을 통해 수집하였고 RISS를 통해 국내 문헌을 검색, 수집하였다. 국외 논문 검색어로는 Telerehabilitation, Telemedicine, Stroke을 사용하였고 국내 문헌은 원격재활, 뇌졸중, stroke, CVA, 뇌혈관질환 검색어를 사용하였다. 총 406개의 국외 문헌과 15개의 국내 문헌이 검색되었으며 결과적으로 총 7개의 문헌이 분석대상 문헌으로 선정되었다. 결과: 7편의 문헌 모두 원격재활을 적용받는 그룹에게 중재를 원격에서만 제공하였으며 전, 후 비교를 통해 운동기능에서 유의미한 효과를 확인하였다. 또한 원격재활 중재의 유의미한 효과를 전, 후 비교(n=7) 및 그룹간의 비교(n=4)를 통해 분석하여 운동기능에서의 긍정적인 효과를 확인하였다. 사용된 원격감독은 목적에 따라 중재로써의 감독(n=4)과 확인을 위한 감독(n=3)으로 분류할 수 있었다. 결론: 본 연구를 통해 전통적인 재활 서비스를 제공받는 것에 제한이 있는 뇌졸중 환자들에게 원격재활의 적용이 잠재적인 대체 방법이 될 수 있음을 제한적으로 확인하였다. 원격재활의 실질적인 국내적용을 위해서는 국내 실정에 맞는 비용효과에 대한 연구가 필요하며, 원격재활을 통해 제공되는 가장 효율적인 중재별 원격감독 방법을 확인해 볼 수 있는 연구가 이루어져야 할 것이다. Objective: The purpose of this study was to investigate the effects of telerehabilitation on stroke patients through remotely operated intervention and monitoring. Methods: Literature from 2000 to April 2018 was collected through PubMed, Embase, Cochrane, and RISS. We used telerehabilitation, telemedicine, and stroke as the search terms in regard to foreign literature, and the terms telerehabilitation, stroke, and CVA in regard to Korean literature. A total of 406 foreign and 15 Korean published studies were found. As a result, a total of seven documents was selected for the analysis. Results: As a result of the analysis, all the interventions applied through telerehabilitation were provided remotely, and significant effects were reported between pre-post assessments. In addition, the significant effects of telerehabilitation were reported through analyzing pre-post(n=7) and between groups(n=4) assessments. The monitoring used could be categorized according to purpose, that is, for checking (n=3) and as an intervention (n=4). Conclusions: This study confirmed, within limits, that the application of telerehabilitation could be a potential alternative for stroke patients with limited rehabilitation services. In order to apply telerehabilitation in Korea, it is necessary to study the cost effectiveness, according to the current domestic situation, and confirm the most effective monitoring method based on the intervention.