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The Effect of Direct and Diffuse Split Models on Building Energy Simulation
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 Title & Authors
The Effect of Direct and Diffuse Split Models on Building Energy Simulation
Lee, Ha-Yeong; Yoon, Seong-Hwan; Park, Cheol-Soo;
Weather data are indispensable for building energy simulation. Most weather stations measure only global solar radiation and thus, the global radiation is usually divided into direct and diffuse radiation based on solar models. The solar models being currently used are expressed in regression equations. Several studies have reported that the difference between measured direct/diffuse solar radiation and calculated direct/diffuse solar radiation out of the solar models is not negligible. This study aims to quantify the impact of the direct and diffuse split solar models on energy performance simulation. For this study, three popular solar models were chosen based on the literature review. And, a number of office buildings were simulated while changing several inputs relevant to solar load (e.g. SHGC, window-to-wall ratio, etc.). The sampling cases were made using LHS (Latin Hypercube Sampling), one of Monte Carlo techniques, and an energy simulation tool, EnergyPlus, was used. There is a significant difference between the measured weather data and the values of calculated direct and diffuse solar radiation. However, the difference between energy prediction by the measured weather data and energy prediction by solar models is not significant for large buildings. For small buildings, the difference in energy prediction is not negligible.
Building simulation;direct and diffuse split model;direct radiation;diffuse radiation;uncertainty;
 Cited by
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