• Title/Summary/Keyword: Absorption efficiency

Search Result 1,053, Processing Time 0.028 seconds

Characteristic of Electromagnetic Wave Shielding Coatings by Thermal Spray (용사에 의한 페라이트 자성재료 코팅의 .전자파 차폐특성)

  • 정태식;박경채
    • Proceedings of the KWS Conference
    • /
    • 2000.10a
    • /
    • pp.240-242
    • /
    • 2000
  • This study was investigated absorption properties of electromagnetic wave in thermal sprayed Sr-ferrite coatings. The experiment of this study was ; manufactured thermal spraying powder for improving absorption-efficiency, processed for increasing strength of thermal spray coatings, and measured the electromagnetic wave shielding efficiency. This study was obtained excellent absorption-efficiency by thermal sprayed Sr-ferrite coatings.

  • PDF

A Study on CO2 Removal by Chemical Absorption Using Structured Packing (규칙충전물을 적용한 화학흡수법에 의한 이산화탄소 제거에 관한 연구)

  • K?m, Jae-Hong;K?m, Hyoung-Ho;Kim, Jang-ho
    • Clean Technology
    • /
    • v.9 no.1
    • /
    • pp.43-48
    • /
    • 2003
  • As a result of study on factor affecting absorption efficiency using the structured packing, Mellapak N. 250Y for the chemical absorption of $CO_2$ that cause global warming due to development of industry, it is shown that Mellapak N. 250Y has lower pressure drop and superior efficiency of mass transfer than 25mm Pall ring. Also, in the absorption process, it produces high efficiency in the increase of load and concentration of absorption liquid and produces low efficiency in the increase of temperature. In the effect of overall mass transfer coefficient for 15% MEA on the temperature variation of absorbent, when absorbent temperature for 15% MEA varied as 25, 50, $80^{\circ}C$, overall mass transfer coefficients were shown as 0.83, 1.00, $0.90kmol/m^3-h-kPa$.

  • PDF

Effect of Sunlight Polarization on the Absorption Efficiency of V-shaped Organic Solar Cells

  • Kang, Kyungnam;Kim, Jungho
    • Journal of the Optical Society of Korea
    • /
    • v.18 no.1
    • /
    • pp.9-14
    • /
    • 2014
  • We numerically investigate the effect of sunlight polarization on the absorption efficiency of V-shaped organic solar cells (VOSCs) using the finite element method (FEM). The spectral distribution of absorbance and the spatial distribution of power dissipation are calculated as a function of the folding angle for s-and p-polarized light. The absorption enhancement caused by the light-trapping effect was more pronounced for s-polarized light at folding angles smaller than $20^{\circ}$, where s-polarized light has a relatively larger reflectance than p-polarized light. On the other hand, the absorption efficiency for p-polarized light is relatively larger for folding angles larger than $20^{\circ}$, where the smaller reflectance at the interface of the VOSC is more important in obtaining high absorption efficiency.

Development of High Efficiency Cycle by Combining Double-Effect with Single-Effect Absorption Chiller Systems (이중 효용과 일중 효용을 복합한 다단 재생 고효율 흡수식 냉동 사이클 개발)

  • Yun, Sang Kook
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.29 no.7
    • /
    • pp.360-365
    • /
    • 2017
  • Recently, development efforts of triple-effect absorption chiller have been increased in order to improve the efficiency of double-effect absorption chiller. However, triple-effect absorption chiller has some disadvantages, including high corrosion characteristic of LiBr solution at high temperature of $200^{\circ}C$. Moreover, it is necessary to develop new components for operation under high pressure of 2 bars even though COP is increased to 1.6 or 1.7. The objective of this study was to introduce a new system by combining double effect absorption chiller with single effect absorption chiller with multi-generators using bypass flow of LiBr dilute solution to $3^{rd}$ generator to overcome the disadvantages of triple-effect chiller and improve energy efficiency. Results indicate that the new absorption cycle had a much higher efficiency than double-effect chiller system, showing significant improvement when bypass solution flow rate of 25% was applied to the $3^{rd}$ generator using the main dilute solution of the absorber. The COP of the new chiller system was found to be 1.438, which was 21.7% higher than that (1.18) of the present double-effect system. The COP was decreased when solution by-pass rate to the $3^{rd}$ generator was increased. In addition, lower cooling water temperature caused higher COP. Therefore, the multi-generator system with by-pass solution might be an excellent chiller alternative to triple-effect absorption chiller with higher efficiency.

A Study on the Noise Absorption of Textiles for Interiors (실내장식용 섬유소재의 흡음성에 관한 연구)

  • Choi, In-Ryu;Bang, Hey-Kyong
    • The Research Journal of the Costume Culture
    • /
    • v.20 no.4
    • /
    • pp.475-484
    • /
    • 2012
  • The purpose of this study is to help to prevent daily noises by measuring the noise absorption coefficient of the non-woven fabrics and wallpapers which are commonly used in lining and noise absorption coefficient of lining curtain. Seven types of fiber materials for the interior decoration, one non-woven fabric for the wallpaper linings, and two types of textiles for curtain linings are used as the experimental materials in this study. The noise absorption coefficient of the noise absorbents were measured by using impedance tube. And the thermal transmittance were measured by using thermal transmittance tester. The results of this study are as follows; Observing the noise absorption efficiency of each experimental materials, the combination of fiber materials and linings, the noise absorption efficiency of cotton, polyester and silk were similar and for the experimental materials of flax, rayon, acrylic and nylon were resulted the similar noise absorption efficiency. The result of combination of fiber material and black fabric was highest among the combined linings. For the combination of fiber material and non-woven fabric, double layers of non-woven fabric resulted slightly higher noise absorption coefficient result than single layer of non-woven fabric. The thermal transmittance and the sound absorbents of experimental materials were affected by the thickness, density and layer of air of the experimental materials.

A Study on the Characteristics of Dye Sensitized Solar Cells with Cell Area and Dye Absorption Time (셀 면적 및 흡착시간에 따른 염료감응형 태양전지 특성에 관한 연구)

  • Lee, Don-Kyu;Song, Young-Joo
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.61 no.4
    • /
    • pp.595-600
    • /
    • 2012
  • In this paper, it is investigated the characteristics of DSSC(Dye Sensitized Solar Cell) with cell area(0.25, 1, 2.25 $cm^2$) and dye absorption time(12, 24, 36 h). Thus, we obtain the following results by using the EIS, UV-VIS, I-V measurement. When the cell area increases, the efficiency decreases to 21~32 percent because of the increase about 40~$60{\Omega}$ of internal impedance regardless of dye absorption time. When the absorption time increases up to 24 hours, the efficiency increases to over 40 percent cause of the reduction of internal impedance regardless of cell area. When the dye absorption time becomes 36 hours, the internal impedance increases and at the same time, in the range of 600~700 nm, as the optical absorption reduces. Therefore, the efficiency decreases to 19~31 percent. When it is absorbed the dye for 24 hours in the smallest cell area which is 0.25 $cm^2$, the DSSC has the best efficiency (7.11 %).

Efficiency Analysis of a Wave Power Generation System by Using Multibody Dynamics (다물체동역학을 이용한 다자유도 파력발전시스템의 흡수 효율 분석)

  • Kim, Min Soo;Sohn, Jeong Hyun;Kim, Jung Hee;Sung, Yong Jun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.40 no.6
    • /
    • pp.557-563
    • /
    • 2016
  • The energy absorption efficiency of a wave power generation system is calculated as the ratio of the wave power to the power of the system. Because absorption efficiency depends on the dynamic behavior of the wave power generation system, a dynamic analysis of the wave power generation system is required to estimate the energy absorption efficiency of the system. In this study, a dynamic analysis of the wave power generation system under wave loads is performed to estimate the energy absorption efficiency. RecurDyn is employed to carry out the dynamic analysis of the system, and the Morison equation is used for the wave load model. According to the results, the lower the wave height and the shorter the period, the higher is the absorption efficiency of the system.

Energy Absorption Efficiency of Structural Steel System (강구조 시스템의 에너지 흡수효율)

  • 김장훈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
    • /
    • 2003.03a
    • /
    • pp.294-301
    • /
    • 2003
  • The energy concept has been applied to the reported experimental results of six different structural steel connections to investigate the characteristics of system-dependent energy curve and energy absorption efficiency. For this the concept o( static and kinematic energy absorption efficiency has been defined. The present paper closes with the implication of the necessity of further investigation to extend the energy concept to reach the engineering practice.

  • PDF

Modeling of Mixed Phosphors in White Light Emitting Diode (백색 발광다이오드에서의 혼합 형광체 모델링)

  • Kim, Dowoo;Gong, Dayeong;Gong, Myeongkook
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.26 no.7
    • /
    • pp.567-574
    • /
    • 2013
  • An optical model is proposed in the white LED using phosphor and LED chip. In this paper a new model that describes the absorption rate and quantum efficiency with increasing the mixing ratio of phosphor in silicone, and the allotment of the phosphor absorption optical power in the several phosphor mixing in the silicone. Single phosphor in silicone from the optical measurement data before and after molding, the solution to get the blue optical power and the phosphor emission optical power is proposed. By these solution the absorption rate and the quantum efficiency was obtained. The model with single phosphor mixing in the silicone the validity was confirmed.

Effect of an emitting-layer height on a photon extraction efficiency in LED (LED에서 발광층의 높이가 광추출 효율에 미치는 영향)

  • Kwon, Keeyoung
    • The Journal of the Convergence on Culture Technology
    • /
    • v.7 no.1
    • /
    • pp.564-569
    • /
    • 2021
  • In this paper, for the typical LED and the tilted LED, when there is no electrode, when 20% absorption (80% reflection) occurs at the electrode, and when 60% absorption (40% reflection) occurs at the electrode, the effect of the absorption at the electrode and the height of the active region on the photon extraction efficiency and the mean photon path length was investigated, and an appropriate height of the active region was proposed. In a typical LED, as the absorption of the electrode increases, the photon extraction efficiency decreases from 18% to 15% and 13%, and the photon extraction efficiency is highest when the height of the active area is located in the center between the two electrodes. In the tilted LED, as the absorption of the electrode increases, the photon extraction efficiency decreases from 38% to 33% and 25%, and the photon extraction efficiency is highest when the height of the active area is located in the center between the two electrodes. The tilted LED can increase the photon extraction efficiency more than twice than that of a typical LED, where photons are trapped inside the chip due to total reflection.