• Title/Summary/Keyword: Energy Estimating

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A Study on the Estimating Solar Radiation Using Hours of Bright Sunshine for the Installation of Photovoltaic System in Korea (국내 태양광시스템 설치지역을 위한 일조시간에 의한 일사예측에 관한 연구)

  • Jo, Dok-Ki;Yun, Chang-Yeol;Kim, Kwang-Deuk;Kang, Young-Heac
    • Journal of the Korean Solar Energy Society
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    • v.31 no.4
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    • pp.72-79
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    • 2011
  • Solar radiation data are the best source of information for estimating average incident radiation. Lacking this or data from nearby locations of similar climate, it is possible to use empirical relationships to estimate radiation from days of hours of bright sunshine. It is necessary to estimate the regression coefficients in order to predict the daily global radiation on a horizontal surface. Therefore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for 16 different areas over Korea by estimating the regression coefficients taking into account hours of bright sunshine. Particularly, the proposed straight line regression model shows reliable results for estimating the global radiation on a horizontal surface with monthly average deviation of -0.2 to +0.5% and each station annual average deviation of -1.6 to +1.7% from measured values.

The Basic Study on Wave Energy Conversion System(II) -Estimation on Extracted Wave Power of Wave Energy Conversion Device- (파력발전시스템에 관한 기초연구(II) -파력발전기의 흡수파력 추정-)

  • 김성근;박노식
    • Journal of Ocean Engineering and Technology
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    • v.4 no.1
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    • pp.43-48
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    • 1990
  • The results of previous works on the wave energy conversion do not seem to be satisfactory due to irregularity, and the non-linear hydrodynamic effect which is inevitably featured due to the structural complexity of the ocean wave energy conversion device. These may cause the difficulty estimating the extracted wave power. In this paper a study on estimating the extracted wave power and its ratio. The present authors have developed another method estimating the extracted wave power using the three dimensional source distribution method, which was turned out to be an improved one. It has been observed that the present results may be used for the control of the wave energy conversion device and the optimal design has been derived from the several case studies.

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Estimating Solar Radiation for Arbitrary Areas Using Empirical Forecasting Models (경험적 예측모형을 통한 임의의 지점의 일사예측)

  • Jo, D.K.;Chun, I.S.;Lee, T.K.;Auh, C.M.
    • Solar Energy
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    • v.20 no.3
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    • pp.21-30
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    • 2000
  • It is necessary to estimate the regression coefficients in order to predict the monthly mean daily global radiation on a horizontal surface. Therefore many different equations have proposed to evaluate them for certain areas. In this work, a new correlation has been made to predict the solar radiation for any area over Korea by estimating the regression coefficients taking into account percentage of possible sunshine, and cloud cover. Particularly, the multiple linear regression model proposed shows reliable results for estimating the global radiation with average deviation of -1 to 3 % from the measured values.

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A Study on the Solar Radiation Estimation of 16 Areas in Korea Using Cloud Cover (운량을 고려한 국내 16개 지역의 일사량 예측방법)

  • Jo, Dok-Ki;Kang, Young-Heack
    • Journal of the Korean Solar Energy Society
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    • v.30 no.4
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    • pp.15-21
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    • 2010
  • Radiation data are the best source of information for estimating average incident radiation. Lacking this or data from nearby locations of similar climate, it is possible to use empirical relation ships to estimate radiation from days of cloudiness. It is necessary to estimate the regression coefficients in order to predict the daily global radiation on a horizontal surface. There fore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for 16 different areas over Korea by estimating the regression coefficients taking into account cloud cover. Particularly, the straight line regression model proposed shows reliable results for estimating the global radiation on a horizontal surface with monthly average deviation of -0.26 to +0.53% and each station annual average deviation of -1.61 to +1.7% from measured values.

A Study on the Estimating Solar Radiation in Korea Using Cloud Cover and Hours of Bright Sunshine (국내 운량과 일조시간에 의한 태양광에너지 예측에 관한 연구)

  • Jo, Dok-Ki;Yun, Chang-Yeol;Kim, Kwang-Deuk;Kang, Young-Heack
    • Journal of the Korean Solar Energy Society
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    • v.32 no.2
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    • pp.28-34
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    • 2012
  • It is necessary to estimate the regression coefficients in order to predict the daily global radiation on a horizontal surface. Therefore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for 16 different areas over Korea by estimating the regression coefficients taking into account cloud hours of bright sunshine. Particularly, the multiple linear regression model proposed shows reliable results for estimating the global radiation on a horizontal surface with monthly average deviation of-0.26 to +0.53% and each station annual average deviation of -1.61 to +1.7% from measured values.

THE SOC ESTIMATION OF THE LEAD-ACID BATTERY USING KALMAN FILTER

  • JEON, YONGHO
    • Journal of applied mathematics & informatics
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    • v.39 no.5_6
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    • pp.851-858
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    • 2021
  • In general, secondary batteries are widely used as an electric energy source. Among them, the state of energy storage of mobile devices is very important information. As a method of estimating a state, there is a method of estimating the state by integrating the current according to an energy storage state of a battery, and a method of designing a state estimator by measuring a voltage and estimating a charge amount based on a battery model. In this study, we designed the state estimator using an extended Kalman filter to increase the precision of the state estimation of the charge amount by including the error of the system model and having the robustness to the noise.

Solar Radiation Estimation Technique Using Cloud Cover in Korea (운량에 의한 일사예측 기법)

  • Jo, Dok-Ki;Yun, Chang-Yeol;Kim, Kwang-Deuk;Kang, Young-Heack
    • 한국태양에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.232-235
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    • 2011
  • Radiation data are the best source of information for estimating average incident radiation. Lacking this or data from nearby locations of similar climate, it is possible to use empirical relationships to estimate radiation from days of cloudiness. It is necessary to estimate the regression coefficients in order to predict the daily global radiation on a horizontal surface. There fore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for 16 different areas over Korea by estimating the regression coefficients taking into account cloud cover. Particularly, the straight line regression model proposed shows reliable results for estimating the global radiation on a horizontal surface with monthly average deviation of-0.26 to +0.53% and each station annual average deviation of -1.61 to +1.7% from measured values.

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Solar Radiation Estimation Using Cloud Cover and Hours of Bright Sunshine (운량과 일조시간에 의한 태양자원 예측)

  • Jo, Dok-Ki;Yun, Chang-Yeol;Kim, Kwang-Deuk;Kang, Young-Heack
    • 한국태양에너지학회:학술대회논문집
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    • 2012.03a
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    • pp.126-129
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    • 2012
  • In this work a new correlation has been made to predict the solar radiation for 16 different areas over Korea by estimating the regression coefficients taking into account cloud hours of bright sunshine. Particularly, the multiple linear regression model proposed shows reliable results for estimating the global radiation on a horizontal surface with monthly average deviation of -0.26 to +0.53% and each station annual average deviation of -1.61 to +1.7% from measured values.

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Approximate Method in Estimating Sensitivity Responses to Variations in Delayed Neutron Energy Spectra

  • J. Yoo;H. S. Shin;T. Y. Song;Park, W. S.
    • Proceedings of the Korean Nuclear Society Conference
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    • 1997.10a
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    • pp.85-90
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    • 1997
  • Previous our numerical results in computing point kinetics equations show a possibility in developing approximations to estimate sensitivity responses of nuclear reactor We recalculate sensitivity responses by maintaining the corrections with first order of sensitivity parameter. We present a method for computing sensitivity responses of nuclear reactor based on an approximation derived from point kinetics equations. Exploiting this approximation, we found that the first order approximation works to estimate variations in the time to reach peak power because of their linear dependence on a sensitivity parameter, and that there are errors in estimating the peak power in the first order approximation for larger sensitivity parameters. To confirm legitimacy of our approximation, these approximate results are compared with exact results obtained from our previous numerical study.

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