• Title, Summary, Keyword: Fluid Absorption

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A Study on Remodeling for Solar driven $NH_3/H_2O$ absorption chiller (태양열 구동 $NH_3/H_2O$ 흡수식 냉동기 리모델링 연구)

  • Shin, You-Soo;Maeng, Ju-Sung;Kwak, Hee-Youl
    • Journal of the Korean Solar Energy Society
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    • v.23 no.4
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    • pp.37-43
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    • 2003
  • The aim of this research is to study the feasibility of the solar(hot fluid) driven $NH_3/H_2O$ absorption chiller, made by re-manufacturing of Gas fired $NH_3/H_2O$ absorption chiller. This experimental study is performed with the temperature of the inlet hot fluid of generator. In order to determine the inlet temperature of the generator, which gives maximum COP, the experimental data are obtained with various hot fluid supply temperature in range of $130\sim170^{\circ}C$. Remodeled chiller is operated with periodical cooling effect, which due to mixture subcooled pool boiling, then the COP is evaluated in average. The maximum COP$(\sim0.36)$ is at $160^{\circ}C$. The temperature is stable operation temperature range of typical vacuum collector. It offers a feasibility of solar driven $NH_3/H_2O$ absorption chiller.

Characteristic Analysis of Double Effect Absorption Refrigeration Machine using $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ ($H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$를 이용한 2중 효용 흡수식 냉동기 특성해석)

  • 문춘근
    • Journal of the Korean Society of Marine Engineering
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    • v.22 no.6
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    • pp.792-799
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    • 1998
  • Further improvement of existing $H_{2}O/LiBr$ absorption refrigeration machine is absolutely neces-sary to promote the utilization of gas-cooling system Among various methods to improve the per-formance of the absorption refrigeration machine this research has focused on the use of a new working fluid that has better properties than the existing $H_{2}O/LiBr$ working fluid. In the series of the research, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ system was selected as the most promisable candidate. The absorption refrigeration machine is water-cooled double-effect, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ sys-tem with series flow type. In this study we found out the characteristic of new working solution through the cycle simulation and compared the result with that of LiBr solution to evaluate. Theoptimum designs and operating conditions were determined based on the operating constraints and the coefficient of performance. Results demonstrate that new working fluid subsrantially increases COP by as much as 10% and has a wider working range with 8% higher crystallization limits compared to the conventional $H_{2}O/LiBr$.

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Characteristic analysis of air-cooled absorption refrigeration machine (공냉식 흡수식 냉동기의 특성 해석)

  • Kwon Oh-Kyung;Moon Choon-Geun;Yang Young-Myung;Yu Sun-Il;Yoon Jung-In
    • 한국가스학회:학술대회논문집
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    • pp.249-254
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    • 1998
  • This paper describes the study of developing air-cooled absorption system which uses a new working solution instead of LiBr solution to improve the performance of system. The absorption chiller-heater considered was an air-cooled, double-effect, $H_2O/LiBr+HO(CH_2)_3$ system of parallel flow type. In this study, we found out the characteristic of new working solution through the cycle simulation and compared the result that of LiBr solution to evaluate. The new working fluid has a wider working range with $8\%$ higher crystallization limit at the saturated refrigerant pressure of 0.8kPa. The optimum designs and operating conditions of air-cooled absorption system were suggested based on this cycle simulation analysis. It was demonstrated that new working fluid substantially improves the performance of the absorption refrigeration machine and is expected to increase the COP by as much as $5\%$.

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Glucose Prediction in the Interstitial Fluid Based on Infrared Absorption Spectroscopy Using Multi-component Analysis

  • Kim, Hye-Jeong;Noh, In-Sup;Yoon, Gil-Won
    • Journal of the Optical Society of Korea
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    • v.13 no.2
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    • pp.279-285
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    • 2009
  • Prediction of glucose concentration in the interstitial fluid (ISF) based on mid-infrared absorption spectroscopy was examined at the glucose fundamental absorption band of 1000 - 1500/cm (10 - 6.67 um) using multi-component analysis. Simulated ISF samples were prepared by including four major ISF components. Sodium lactate had absorption spectra that interfere with those of glucose. The rest NaCl, KCl and $CaCl_2$ did not have any signatures. A preliminary experiment based on Design of Experiment, an optimization method, proved that sodium lactate influenced the prediction accuracy of glucose. For the main experiment, 54 samples were prepared whose glucose and sodium lactate concentration varied independently. A partial least squares regression (PLSR) analysis was used to build calibration models. The prediction accuracy was dependent on spectrum preprocessing methods, and Mean Centering produced the best results. Depending on calibration sample sets whose sodium lactate had different concentration levels, the standard error prediction (SEP) of glucose ranged $17.19{\sim}21.02\;mg/dl$.

The Evaluation of Shock Absorption Performance of Magneto-Rheological Elastomer Through the Drop Impact Test (낙하 충격 실험을 통한 자기유변탄성체의 충격 흡수 성능 평가)

  • Joeng, Kyeong Sik;Lee, Chul Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.92-93
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    • 2013
  • In this study, Shock Absorption performance of Magneto-rheological elastomer(MRE) is identified through the drop impact test. Magneto-rheological materials are divided into two groups by MR fluid in fluid state and MR elastomer in solid state like rubber. The stiffness characteristics of Magneto-rheological material can be changed as magnetic field is applied. The impact loads in MR elastomer were measured under weight of impactor. Experiment results are shown through the experiments to confirm the effect of shock absorption of MR elastomer. Thus, the MR elastomer can be applied to shock absorber used in area that shock occurs.

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Delayed Absorption of Subretinal Fluid after Retinal Reattachment Surgery and Associated Choroidal Features

  • Kim, Jong Min;Lee, Eun Jung;Cho, Ga Eun;Bae, Kunho;Lee, Ju Yeun;Han, Gyule;Kang, Se Woong
    • Korean Journal of Ophthalmology
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    • v.31 no.5
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    • pp.402-411
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    • 2017
  • Purpose: The aim of this study was to investigate the incidence and associated clinical factors of delayed absorption of subretinal fluid (SRF) after surgery for rhegmatogenous retinal detachment. Methods: This study involved 36 eyes of 36 consecutive patients who underwent successful surgery for rhegmatogenous retinal detachment. A complete ophthalmologic evaluation, including clinical fundus examination, optical coherence tomography, and indocyanine green angiography, was conducted before and after surgery. Delayed absorption was defined as the presence of residual concave SRF or an SRF bleb at 6 months after surgery. Clinical factors and choroidal features on indocyanine green angiography were compared according to the presence and absence of delayed absorption. Results: Eighteen of 36 eyes (50%) showed delayed absorption. Macular involvement and worse preoperative visual acuity were significantly related to the presence of delayed absorption (p = 0.001 and p = 0.034, respectively). On indocyanine green angiography, preoperative choroidal vascular hyperpermeability was noted in 70% of eyes with delayed absorption and in 14% of eyes without it (p = 0.010). Conclusions: Delayed absorption of SRF after retinal reattachment surgery was not rare, with a 50% of incidence in this study. Macula-off status was significantly related to the incidence of delayed SRF absorption, and choroidal features such as choroidal vascular hyperpermeability might be responsible in part, possibly through the resultant exudative property of choroid.

A frame work for heat generation/absorption and modified homogeneous-heterogeneous reaction in flow based on non-Darcy-Forchheimer medium

  • Hayat, Tasawar;Ahmad, Salman;Khan, Muhammad I.;Khan, Muhammad I.;Alsaedi, Ahmed
    • Nuclear Engineering and Technology
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    • v.50 no.3
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    • pp.389-395
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    • 2018
  • The present work aims to report the consequences of Darcy-Forchheimer medium in flow of Cross fluid model toward a stretched surface. Flow in porous space is categorized by Darcy-Forchheimer medium. Further heat transfer characteristics are examined via thermal radiation and heat generation/absorption. Transformation procedure is used. The arising system of nonlinear ordinary differential equations is solved numerically by means of shooting method. The effects of different flow variables on velocity, temperature, concentration, skin friction, and heat transfer rate are discussed. The obtained outcomes show that velocity was enhanced with the increase in the Weissenberg number but decays with increase in the porosity parameter and Hartman number. Temperature field is boosted by thermal radiation and heat generation; however, it decays with the increase in the Prandtl number.

Design of an Absorption Heat Transformer with Methanol-Glycerine System as a Working Fluid (메탄올-글리세린 계를 작동유체로 하는 변형흡수식 열펌프 설계)

  • Chung, Chan-Kyo;Min, Byong-Hun
    • Clean Technology
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    • v.11 no.1
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    • pp.13-19
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    • 2005
  • An absorption heat transformer for energy recovery has been investigated using methanol-glycerine. The simulated calculation of theoretical thermal efficiency was performed based on the thermodynamic properties of the working fluid over various operating conditions. The thermal efficiency of higher than 0.4 was obtained by raising industrial waste heat, $70-80^{\circ}C$, by $40^{\circ}C$ in this system.

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Estimation of the Endogenous Pancreatic/Biliary Zinc Pool and the Effect of Phytate and Calcium on Zinc Homeostasis

  • Kwun, In-Sook;Donald Oberleas
    • Preventive Nutrition and Food Science
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    • v.2 no.1
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    • pp.35-41
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    • 1997
  • The pancreas is an important organ in the maintenance of zinc homeostasis. Endogenous zinc is con-tinuously secreted via pancreatic exocrine fluid or to a lesser extent in bile. Much of the endogenous secretion must be reabsorbed to sustain zinc homeostasis. The objective of this study was to estimate the relative size of the pancreatic/biliary zinc pool in comparision to the dietary zinc intake, and to study the effect of the phytate and calcium on the zinc homeostasis using a rat model. At the termination of the experiment, pan-creatic/biliary fluid was collected from the rats. Both radioactivity and total zinc were measured and the relative size of the pancreatic/biliary zinc pool was estimated. To determine the effect of phytate and calcium on zinc homeostsis, dietary zinc intake, the amount of zinc in pancreatic.biliary fluid and fecal zinc excretion were measured. The flow rate of pancreatic/biliary fluid, as corrected for tubing constriction, gives the corrected zinc concentration in the pancreatic/biliary fluid was 2.2 times higher than dietary zinc intake. To maintain zinc homeostasis, zinc absorption/reabsorption was very efficient in the current model; 76%, 88% of absorption/reabsorption for low calcium group and high calcium group 81% for phytate group and non-phytate group, respectively.

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Analysis of Three-dimensional Earthquake Responses of a Floating Offshores Structure with an Axisymmetric Floating Structure (축대칭 부유구조물을 가지는 부유식 해양구조물의 3차원 지진응답 해석기법 개발)

  • Lee, Jin Ho;Kim, Jae Kwan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.19 no.4
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    • pp.145-159
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    • 2015
  • A seismic response analysis method for three-dimensional floating offshore structures due to seaquakes is developed. The hydrodynamic pressure exerted on the structure is calculated taking into account the compressibility of the sea water, the fluid-structure interaction, the energy absorption by the seabed, and the energy radiation into infinity. To validate developed method, the hydrodynamic pressure induced by the vibration of a floating massless rigid circular disk is calculated and compared with an exact analytical solution. The developed method is applied to seismic analysis of a support structure for a floating offshore wind turbine subjected to the hydrodynamic pressures induced from a seaquake. Analysis results show that earthquake response of a floating offshore structure can be greatly influenced by the compressibility of fluid, the depth (natural frequencies) of the fluid domain, and the energy absorption capacity of the seabed.