• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.274-277
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• 2011

We measured a solar irradiation of vertical and horizontal surface per azimuth in southern area of Korea using pyrheliometer. In comparison with the provided data from ASHRAE and CIBSE, the average amount of solar irradiation has much variation of 10 to 150% in reference with north direction. In the clear day, the measured value has much difference with the value of ASHRAE and there is similar trend in case of CIBSE. The reason why amount of irradiation of clear day is differ from the average value, is able to be assumed that the value of ASHRAE and CIRSE is made of assumption based on clear days. The result of analysis of ASHRAE and CIBSE values according to the amount irradiation value for vertical and horizontal surface per azimuth using the MBE, RSME, and t-Statistic show that the CIBSE value has more reliability for the MBE, RMSE, and t-Statistic values than ASHRAE value.

• Journal of the Korean Solar Energy Society
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• v.39 no.4
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• pp.11-24
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• 2019

The total solar irradiation on horizontal surfaces is separated into the beam and diffuses components. Although horizontal global irradiance is a commonly measured parameter for many sites, horizontal diffuse irradiance is not so readily obtainable. For such sites that measure global irradiation alone, a simple but reasonably accurate method is required to estimate diffuse irradiance from its global counterpart. This study investigates the applicability of correlation coefficients models correlating hourly diffuse and beam fraction and hourly clearness index in Daejeon. The three diffuse to global correlation coefficients models (Orgill and Holland model, CIBSE Guide J model, and Erbs et al. model) are selected and the three modified beam to global correlation coefficients models are generated. MBE, RMSE, r-squared of Daejeon and Daejeon boundary site-fitted models are compared with the case of original coefficients. The comparison result shows that the beam and diffuse to global solar irradiation correlation coefficients models with boundary site-fitted coefficients are best suitable for Daejeon. Further researches will be conducted to find the boundary site-fitting method using measured data of other cities and correlation coefficients models using solar altitude, cloud cover, and sunshine duration.

• Journal of the Korean Solar Energy Society
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• v.29 no.5
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• pp.81-87
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• 2009

Computer simulation of buildings and solar energy systems is being used increasingly in energy assessments and design.. Building designers often now predict the performance of buildings simulation programmes that require hourly weather data. However, not all weather stations provide hourly data. Climate prediction models such as HadCM3 also provide the daily average dry bulb temperature as well as the maximum and minimum. Hourly temperature values are available for building thermal simulations that accounts for future changes to climate. In order to make full use of these predicted future weather data in building simulation programmes, algorithms for downscaling daily values to hourly values are required. This paper describes a more accurate method for generating hourly temperature values in the South Korea that uses all three temperature parameters from climate model. All methods were evaluated for accuracy and stability in terms of coefficient of determination and cumulative error. They were compared with hourly data collected in Seoul and Ulsan, South Korea.