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Design and Performance Analysis of Conical Solar Concentrator
Na, Mun Soo,Hwang, Joon Yeal,Hwang, Seong Geun,Lee, Joo Hee,Lee, Gwi Hyun Korean Society for Agricultural Machinery 2018 바이오시스템공학 Vol.43 No.1
Purpose: The objective of this study is to evaluate the performance of the conical solar concentrator (CSC) system, whose design is focused on increasing its collecting efficiency by determining the optimal conical angle through a theoretical study. Methods: The design and thermal performance analysis of a solar concentrator system based on a $45^{\circ}$ conical concentrator were conducted utilizing different mass flow rates. For an accurate comparison of these flow rates, three equivalent systems were tested under the same operating conditions, such as the incident direct solar radiation, and ambient and inlet temperatures. In order to minimize heat loss, the optimal double tube absorber length was selected by considering the law of reflection. A series of experiments utilizing water as operating fluid and two-axis solar tracking systems were performed under a clear or cloudless sky. Results: The analysis results of the CSC system according to varying mass flow rates showed that the collecting efficiency tended to increase as the flow rate increased. However, the collecting efficiency decreased as the flow rate increased beyond the optimal value. In order to optimize the collecting efficiency, the conical angle, which is a design factor of CSC, was selected to be $45^{\circ}$ because its use theoretically yielded a low heat loss. The collecting efficiency was observed to be lowest at 0.03 kg/s and highest at 0.06 kg/s. All efficiencies were reduced over time because of variations in ambient and inlet temperatures throughout the day. The maximum efficiency calculated at an optimum flow rate of 0.06 kg/s was 85%, which is higher than those of the other flow rates. Conclusions: It was reasonable to set the conical angle and mass flow rate to achieve the maximum CSC system efficiency in this study at $45^{\circ}$ and 0.06 kg/s, respectively.
Design and Performance Analysis of Conical Solar Concentrator
( Mun Soo Na ),( Joon Yeal Hwang ),( Seong Geun Hwang ),( Joo Hee Lee ),( Gwi Hyun Lee ) 한국농업기계학회 2018 바이오시스템공학 Vol.43 No.1
Purpose: The objective of this study is to evaluate the performance of the conical solar concentrator (CSC) system, whose design is focused on increasing its collecting efficiency by determining the optimal conical angle through a theoretical study. Methods: The design and thermal performance analysis of a solar concentrator system based on a 45° conical concentrator were conducted utilizing different mass flow rates. For an accurate comparison of these flow rates, three equivalent systems were tested under the same operating conditions, such as the incident direct solar radiation, and ambient and inlet temperatures. In order to minimize heat loss, the optimal double tube absorber length was selected by considering the law of reflection. A series of experiments utilizing water as operating fluid and two-axis solar tracking systems were performed under a clear or cloudless sky. Results: The analysis results of the CSC system according to varying mass flow rates showed that the collecting efficiency tended to increase as the flow rate increased. However, the collecting efficiency decreased as the flow rate increased beyond the optimal value. In order to optimize the collecting efficiency, the conical angle, which is a design factor of CSC, was selected to be 45° because its use theoretically yielded a low heat loss. The collecting efficiency was observed to be lowest at 0.03 kg/s and highest at 0.06 kg/s. All efficiencies were reduced over time because of variations in ambient and inlet temperatures throughout the day. The maximum efficiency calculated at an optimum flow rate of 0.06 kg/s was 85%, which is higher than those of the other flow rates. Conclusions: It was reasonable to set the conical angle and mass flow rate to achieve the maximum CSC system efficiency in this study at 45° and 0.06 kg/s, respectively.
나문수 ( Mun Soo Na ),황성근 ( Seong Geun Hwang ),이귀현 ( Gwi Hyun Lee ) 한국농업기계학회 2017 한국농업기계학회 학술발표논문집 Vol.22 No.2
현재 대기오염이나 온실가스로 인한 환경파괴를 막기 위해 신재생에너지의 사용과 에너지 절약형 설비 등을 다각적으로 연구하고 있다. 신재생에너지로서 이용가치가 높은 태양에너지는 우리나라의 지리적인 위치와 계절적 기후조건으로 인해 에너지 이용에 유리하다. 하지만 일조시간 동안만 공급되어 지속적인 에너지이용에 제약이 있다. 본 연구에서는 태양에너지를 집열하여 열에너지를 생산하는 원추형 태양열 집광시스템과 일조시간에 제약을 받지 않고 지속적인 에너지 이용을 위한 축열시스템으로 구성된 농산물건조장치의 설계 및 제작과정을 다룬다. 4개의 원추형 집광기로 구성된 원추형 태양열 집광시스템은 태양의 위치에 따라 고도각과 방위각을 추적하여 효율적으로 집광할 수 있도록 2축 태양추적장치에 설비되었다. 농산물 건조를 위한 에너지는 태양에너지와 보조 열원을위한 전기에너지를 복합적으로 사용함으로 에너지 절약이 크게 기대되며, 건조 대상 농산물의 적정 건조온도에 따라 제어할 수 있도록 설계하였다. 특히, 원추형 태양열 집광시스템의 태양에너지 이용 면에서 볼 때 대체로 중·저온의 건조온도를 요하는 농산물 건조에 특화될 수 있을 것으로 사료된다.
유량 변화에 따른 원추형 태양열 집광기의 집열효율 분석
나문수 ( Mun Soo Na ),황준열 ( Joon Yeal Hwang ),이귀현 ( Gwi Hyun Lee ) 한국농업기계학회 2016 한국농업기계학회 학술발표논문집 Vol.21 No.2
원추형 집광기의 성능 향상을 위해 다양한 원추각도에 따른 집광비 분석 통하여 최고의 집열효율을 갖는 원추 각은 45도로 판단하였다. 따라서 45도의 원추각을 갖는 원추형 집광기를 설계 및 제작하여 성능분석을 수행하였다. 원추형 집광 시스템은 태양에너지를 집열하는 집광기, 열매체축열을 위한 축열조, 유량 측정을 위한 유량계, 열매체의 강제순환을 위한 펌프로 구성되어있다. 또한 원추형 집광기는 태양의 위치에 따라 고도각과 방위각을 추적하여 태양 복사열을 효율적으로 집광할 수 있도록 2축 태양추적장치 위에 설비하였다. 원추형 집광기의 중심부에는 집열된 태양 복사에너지를 흡수하는 흡수관이 설비되어 있으며, 흡수관은 열매체의 순환을 위해 이중열교환기 구조로 제작하였다. 또한, 흡수관의 열손실을 최소화하기 위해 흡수관의 길이를 집광기의 높이와 동일하게 설계 및 설비하였으며, 태양 복사열의 흡수율을 높이기 위하여 흡수관 표면을 검은색으로 도색하였다. 원추형 태양광 집광시스템의 최적 순환유량을 분석하기 위해 청명한 날, 유량을 2, 4, 6L/min으로 변화시켜 3회 반복 성능실험을 수행하여 유량변화에 따른 집열효율을 분석하였다. 실험결과 4L/min의 유량에서 원추형 집광시스템 효율이 약 74%∼85%으로 가장 우수한 것으로 나타났다. 본 연구를 통해 유량이 증가함에 따라 집열효율이 상승하지만 임계유량 이상이 되면 집열효율이 감소한다는 것을 알 수 있었다.
원추형 집광기를 이용한 태양광-열(CPV/T) 복합시스템 개발
나문수 ( Mun Soo Na ),이귀현 ( Gwi Hyun Lee ) 한국농업기계학회 2017 한국농업기계학회 학술발표논문집 Vol.22 No.1
본 연구에서 원추형 집광기와 CPV셀을 기반으로 한 태양광-열(CPV/T) 복합시스템의 설계 및 제작과정을 다룬다. 원추형 집광기의 경우, 이론적 해석을 통하여 최고의 집열효율을 갖는 원추각 45도의 집광기 4개를 결합하여 사용하였다. 원추형 복합시스템은 태양에너지를 집열하여 열에너지를 생산하는 집광기와 작동유체의 순환을 위해 이중 구조로 제작된 흡수기, 집광된 태양으로부터 전기에너지를 생산하는 CPV셀 등으로 구성되어 있다. 효율적인 태양복사열 집광을 위해 태양 위치에 따라 고도각과 방위각을 추적할 수 있는 2축 태양추적장치를 설비하였다. CPV셀은 원추형 집광기의 중심부에 위치한 이중 흡수관의 고집광부인 상단부에 위치하였으며, CPV셀의 결함을 방지하고, 부가적 태양광 집광을 위해 2차 보조 집광기를 부착하였다. 본 논문에서 소개하는 원추형 CPV/T 복합 시스템은 기존 원추형 시스템에 CPV셀을 부착하여 전기와 열을 동시에 생산 할 수 있으며, 생산된 전기에너지와 열에너지를 이용하여 온실재배의 난방 문제, 운영비용 절약 등 다양하게 농업 분야에 적용가능하다. 특히, 원추형 복합시스템은 설계 및 제작에 있어 쉽고 간결하며, 제작 단가가 낮다는 점에서 보급에 이점이 있을 것으로 사료된다.
Mun, Se Hwan,Kim, Hyuk Soon,Kim, Jie Wan,Ko, Na Young,Kim, Do Kyun,Lee, Beob Yi,Kim, Bokyung,Won, Hyung Sik,Shin, Hwa-Sup,Han, Jeung-Whan,Lee, Hoi Young,Kim, Young Mi,Choi, Wahn Soo The Japanese Pharmacological Society 2009 Journal of pharmacological sciences Vol.111 No.1
<P>We investigated whether oral administration of curcumin suppressed type II collagen–induced arthritis (CIA) in mice and its effect and mechanism on matrix metalloproteinase (MMP)-1 and MMP-3 production in CIA mice, RA fibroblast-like synoviocytes (FLS), and chondrocytes. CIA in mice was suppressed by oral administration of curcumin in a dose-dependent manner. Macroscopic observations were confirmed by histological examinations. Histological changes including infiltration of immune cells, synovial hyperplasia, cartilage destruction, and bone erosion in the hind paw sections were extensively suppressed by curcumin. The histological scores were consistent with clinical arthritis indexes. Production of MMP-1 and MMP-3 were inhibited by curcumin in CIA hind paw sections and tumor necrosis factor (TNF)-α–stimulated FLS and chondrocytes in a dose-dependent manner. As for the mechanism, curcumin inhibited activating phosphorylation of protein kinase Cδ (PKCδ) in CIA, FLS, and chondrocytes. Curcumin also suppressed the JNK and c-Jun activation in those cells. This study suggests that the suppression of MMP-1 and MMP-3 production by curcumin in CIA is mediated through the inhibition of PKCδ and the JNK/c-Jun signaling pathway.</P>
Mun, Se Hwan,Kim, Jie Wan,Nah, Seong Su,Ko, Na Young,Lee, Jun Ho,Kim, Ju Dong,Kim, Do Kyun,Kim, Hyuk Soon,Choi, Ji Da,Kim, Soo Hyun,Lee, Chang Keun,Park, Seung Hwa,Kim, Bo Kyung,Kim, Hyung Sik,Kim, Yo Wiley Subscription Services, Inc., A Wiley Company 2009 Vol.60 No.3
<B>Objective</B><P>Interleukin-32 (IL-32) is a recently discovered cytokine that appears to play a critical role in human rheumatoid arthritis (RA). It is highly expressed in synovium and fibroblast-like synoviocytes (FLS) from RA patients, but not in patients with osteoarthritis (OA). This study was undertaken to assess IL-32 levels in RA synovial fluid (SF) and to investigate the secretion and regulation of IL-32 in RA FLS.</P><B>Methods</B><P>FLS and SF were obtained from the joints of RA patients. The secretion and expression of IL-32 and activation of signaling molecules were examined by enzyme-linked immunosorbent assay, immunoblotting, immunoprecipitation, reverse transcriptase–polymerase chain reaction, and small interfering RNA (siRNA) transfection.</P><B>Results</B><P>IL-32 levels were high in RA SF compared with OA SF. Furthermore, RA FLS expressed and secreted IL-32 when stimulated with tumor necrosis factor α (TNFα). TNFα-induced expression of IL-32 was significantly suppressed, in a dose-dependent manner, by inhibitors of Syk, protein kinase Cδ (PKCδ), and JNK and by knockdown of these kinases and c-Jun with siRNA. We also observed that PKCδ mediated the activation of JNK and c-Jun, and experiments using specific inhibitors and siRNA demonstrated that Syk was the upstream kinase for the activation of PKCδ.</P><B>Conclusion</B><P>The present findings suggest that IL-32 may be a newly identified prognostic biomarker in RA, thereby adding valuable knowledge to the understanding of this disease. The results also demonstrate that the production of IL-32 in RA FLS is regulated by Syk/PKCδ-mediated signaling events.</P>