• Title/Summary/Keyword: Heating value

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The Heat Management of PEM Fuel Cell Stack (운전 조건에 따른 PEMFC 스택 열 관리)

  • Son, Ik-Jae;Lee, Jong-Hyun;Nam, Gi-Young;Ko, Jae-Jun;Ahn, Byung-Ki
    • Transactions of the Korean hydrogen and new energy society
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    • v.21 no.3
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    • pp.184-192
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    • 2010
  • PEM fuel cell produces electric power, water and heat by the electrochemical reaction of hydrogen and oxygen. The heating value is dependent on the molar enthalpy of vaporization of product water and the performance loss. In this paper, the heating value of fuel cell stack has been studied under various stack operating temperatures to achieve more efficient heat management. A technology using the molar enthalpy of vaporization of product water is suggested to reduce heat-up time during start-up of a fuel cell vehicle.

Thermal Characteristics and Simulation Model Development for Greenhouse Heating System with Heat Pump (열펌프에 의한 그린하우스 난방시스템의 열특성과 시뮬레이션 모델개발)

  • 노정근;송현갑
    • Journal of Biosystems Engineering
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    • v.26 no.2
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    • pp.155-162
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    • 2001
  • The greenhouse heating system with heat pump was built for development of simulation model and validation. The computer simulation model for the system to predict temperature of air and soil and moisture content of soil in the greenhouse were developed, and its validity was justified by actual data. From the analysis of experimentally measured data and the simulation output, following results were obtained. 1. The expected values of inside air temperature for the heating system with heat pump were very much close to the experimental values. 2. In the heating system with heat pump, the expected values of day time surface temperature of soil by computer simulation were very much similar to the measured values, but those of night time were higher than the measured value by at most 2.0$\^{C}$. 3. The simulation model predicted temperature of greenhouse film as of 1$\^{C}$ below than the mean value of ambient air and greenhouse air temperature. 4. Heat loss value of daytime was found to be larger than that of nigh as much as 1.3 to 2.3 times for the heating system with heat pump. 5. In the heating system with heat pump, when the lowest ambient temperature was -8$\^{C}$∼-7$\^{C}$ the air temperature of greenhouse was 5$\^{C}$∼6$\^{C}$, thus the heat pump heating system contributed in greenhouse heating by 13$\^{C}$.

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Performance Test and Flue Gas Characteristics of a 350 kW Wood Pellet Boiler (350 kW(300,000 kcal/h)급 우드 펠렛 보일러 운전 특성 및 성능 평가)

  • Kim, Jong-Jin;Kang, Sae-Byul
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.167-171
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    • 2009
  • We conducted performance test of a 350 kW class wood pellet boiler installed at a dormitory whose total area is $1,354\;m^2$. The maximum heating capacity of the boiler is 350 kW(300,000 kcal/kg). The wood pellet boiler consists of 3 parts; boiler, hot water storage tank and wood pellet storage tank. In testing the boiler, we shut off hot water utility supply and open up floor heating water system in order to measure exact value of the heating output of the wood pellet boiler. To determine the efficiency and heating output of the wood pellet boiler, we measured mass flow rate of wood pellet, the lower heating value(LHV) of the wood pellet, mass flow rate and temperature of water for floor heating and so on. We measured the mass flow rate of fuel, wood pellet with respect to rotational speed of auger, wood pellet feeding screw. We also measured the flue gas concentration of the wood pellet boiler by using a gas analyser. The result shows that the efficiency of the wood pellet boiler is 80.6% based on lower heating value at 124 kW of heating output. At this condition, O2 concentration of the flue gas is 6.0%, CO and NOx concentrations are 85 and 102 ppm.

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Change of Organoleptic Properties with Heating Concentration of Oriental Melon Juice (참외주스 가열농축에 따른 관능적 특성 변화)

  • 이기동;권승혁;이명희;김숙경;주길재;권중호
    • Food Science and Preservation
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    • v.11 no.1
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    • pp.130-133
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    • 2004
  • This study was carried out to observe the change of organoleptic properties of the juice prepared with various heating temperature and heating time. Organoleptic color showed maximum value at 94.95$^{\circ}C$ and 21.63 min and organoleptic aroma showed maximum value at 63.14$^{\circ}C$ and 20.38 min. Organoleptic taste showed maximum value at 96.63$^{\circ}C$ and 14.31 min and overall palatability showed maximum value at 97.18$^{\circ}C$ and 14.55 min. The best condition was 98$^{\circ}C$(heating temperature) and 13 min(heating time) at organoleptic evaluation of oriental melon juice.

The Characteristics and Heating Values Analysis of Municipal Solid Wastes according (쓰레기종량제에 따른 쓰레기의 특성 및 발열양 분석)

  • 문추조;정순형;이태호
    • Journal of environmental and Sanitary engineering
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    • v.10 no.3
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    • pp.29-34
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    • 1995
  • This study was on the characteristics and heating values analysis of municipal solid wastes according to the volume- rate garbage collection system in Busan. Each waste sample was analyzed to obtain physical composition, proximate analysis, heating value, chemical composition. And the heating value were compared with those of the past waste collection system. The average physical composition of A.P.T. area was food waste 54.0~65.7% , while that of common residence was food waste 57.9~61.2% . The density of solid waste were largely different for site and the highest densities of waste was $399.6kg/m^{3}$ from Market. The low heating value of waste from residence site was 996.9kca1/kg~1, 238.1 kcal/kg which was lower than 1, 000kcal/kg~1, 800kca1/kg of the past wastes. These difference was mainly due to the difference of moisture content and the amount of vegetables.

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Characteristics of the Water Soluble Browning Reaction of Korean Red Ginseng as Affected by Heating Treatment (열처리에 따른 고려홍삼의 수용성 갈변물질의 특성)

  • 이종원;이성계
    • Journal of Ginseng Research
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    • v.22 no.3
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    • pp.193-199
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    • 1998
  • The purpose of this study was to Investigate characteristics of the water soluble browning reaction products (WS-BRPs) from Korean red ginseng by heat treatment. Absorbance of WS- BRPs was increased with increases of heating temperature and time, but pH value were decreased In Muter color value L and b value were decreased, while a value was increased. and absorbance at 280 nm in spectrum of the WS-BRPs was increased according to the increase of heating temperature. When the WS-BRPs were applied on Bio-Gel P-30 column after heating and pH treatment, two majors browning products increased according to the progress on time. And pH 3.0 increased in quantity of high molecular fractions and pH 8.0 increased in quantity of low molecular fractions.

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Study on Deterioration of Domestic Edible Oils Upon Heating at High Temperatures (시판식용유(市販食用油)의 고온연속가열(高溫連續加熱)에 따르는 경시적(經時的) 변화(變化)에 관(關)한 연구(硏究))

  • Oh, Young-Bok;Kim, Kwang-Ho
    • Journal of Nutrition and Health
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    • v.11 no.3
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    • pp.25-30
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    • 1978
  • A study was planned to evaluate the influence of continual heating at $150{\pm}5^{\circ}C$ and $170{\pm}5^{\circ}C$ respectively upon edible oils for frying the several food. Two kinds of domestic edible oils (Sample A and B) were collected by random sampling from market and in order to estimate deterioration degrees at both temperatures previously mentioned, thiobarbituric acid (TBA) value, acid value (AV), peroxide value (POV) and carbonyl value (CV) were measured at intervals due to its optical density. Those values were examined and compared according to the temperatures and times, and it was concluded as follows: 1) TBA value was rapidly increased until 24 hours in both temperatures and after 1 day its value have shown a slower increase as compared with initial rapid reaction. 2) Acid value and peroxide value of both oils (A & B) used for frying were increased continuously during heating and the changes in these values were dependent on the thermal oxidation, and moreover at low temperature $(150{\pm}5^{\circ}C)$ these values were found to be increased more readily than at high temperature $(170{\pm}5^{\circ}C)$. 3) Carbonyl value of both sample A and B show almost the same increasing rate at either $150{\pm}5^{\circ}C$ or $170{\pm}5^{\circ}C$ in proportion to the heating time. 4) It was found that there were differences between the chemical changes caused by heating sample A and B at high and low temperature.

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Physico-Chemical Characteristics Evaluation of White Pork Rind and Black Pork Rind (백돈피와 흑돈피의 이화학적 품질특성 평가)

  • Jeon, Ki-Hong;Hwang, Yoon-Seon;Kim, Young-Boong;Choi, Yun-Sang;Kim, Byoung-Mok;Kim, Dong-Wook;Jang, Aera
    • The Korean Journal of Food And Nutrition
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    • v.28 no.4
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    • pp.544-550
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    • 2015
  • In order to determine the material characteristics of pork rinds according to the breeds, the chemical composition, color, pH, collagen contents, shear force, fatty acid and amino acid contents of pork rinds were investigated. White pork rinds (WPR) and black pork rinds (BPR) were evaluated before and after heating to compare the differences between breeds and the effects of heating treatment. In the chemical composition test, the respective moisture contents for WPR and BPR before heating were 49.90% and 53.75% but increased to 60.75% and 61.09% after heating. The test for crude protein and crude fat contents showed lower values after heating but WPR was higher than BPR. In the color test, the L value decreased rapidly with heating, dropping from 68.75 to 45.11 in WPR and from 67.22 to 49.64 in BPR. WPR had a higher L value and a lower a value than BPR before heating but had a higher L value and a lower a value than WPR after heating. pH was significantly higher in WPR than BPR regardless of heating (p<0.05). The collagen content for WPR and BPR was 10.38 g/100 g and 11.54 g/100 g but increased to 12.00 g/100 g in WPR and decreased to 11.40 g/100 g in BPR after heating. The shear force of 26.14 kgf in WPR was significantly higher than 12.89 kgf in BPR before heating (p<0.05), but the values decreased significantly after heating in both WPR and BPR. Linoleic acid in WPR was 17.29%, which was higher than 15.13% in BPR. The USFA for BPR was also higher than WPR. In amino acid composition, the EAA contents in WPR was 7,190 mg%, which was higher than 5,520 mg% in BPR.

The physicochemical characteristics of manufactured RPF by industrial combustibility waste (사업장 가연성폐기물로 제조된 RPF의 물리화학적 특성)

  • Ryu, Young-Bok;Kim, Yang-Do;Kang, Min-Su;Lee, Gang-Woo;Shon, Byung-Hyun;Lee, Man-Sig
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.234-241
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    • 2010
  • Industrial combustible waste is very valuable source for refuse derived solid fuel since its heating value is usually over 3,000kcal/kg. Especially, synthetic high molecular compound which is high of productivity and heating value is used as raw material in many cases. Film type plastic has been widely used for producing RPF because their shaping is easy and they has high heating value. On the other hand, the possibility of various type of waste as a source for RPF in this study. It has been found that resin compound drived and tire derived solid fuel showed more than 6,000kcal/kg of heating value. But the heating value decreased by adding paper and wood waste.

Effects of CNG Heating Value on Combustion Characteristics of a Diesel-CNG Dual-Fuel Engine (디젤-CNG 혼소엔진에서 CNG 발열량 변화가 연소 특성에 미치는 영향)

  • Kim, Yongrae;Jang, Hyeongjun;Lee, Janghee;Kim, Changgi
    • Journal of the Korean Institute of Gas
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    • v.19 no.6
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    • pp.28-33
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    • 2015
  • In this study, a dual fuel engine fueled with natural gas and diesel was tested to investigate the effects of heating value variation of CNG fuel. CNG substitution rate which is defined as the ratio of CNG and diesel supplied in a heating value basis was fixed at 80%. The higher heating value was varied from $10,400kcal/Nm^3$ to $9,400kcal/Nm^3$ by mixing nitrogen gas with pure CNG and diesel fuel was injected at a fixed injection timing. The engine test results showed that thermal efficiency and power output were decreased as the heating value of mixed CNG fuel was decreased. And the peak cylinder pressure was also decreased but the ignition delay time and the combustion duration and timing were almost same.