Predicting CIE Standard General Sky Based on Meteorological Data and Assessing Daylight Performance of Buildings for Subtropical Hong Kong (415711) (1 Jan 12 - 31 Dec 13)
• Researchers: NG Yan Yung, CHAN Pak Wai, TREGENZA Peter
• Funding Amount: HK$620,000
• Funding source: Research Grants Council - General Research Fund

The Commission Internationale de l'Eclairage (CIE) General Sky can be defined by sky scans from ground stations. However, it is resource intensive to run and maintain. And it can only cover one location at certain time. To test out the feasibility of utilizing weather observation data for daylight and sky type prediction, we have developed a method to predict daylight availability dynamically based on forecasts of weather observatory for Hong Kong(Ng, Gadi et al., 2007) which indicates a way forward. To improve accuracy and application, this study will further investigate the relationship between more different types of meteorological data from HKO weather statistics and CIE Standard General Sky under subtropical climate conditions. This investigation is based on the sky scans from June 2003 to May 2005 collected by CIE International Daylight Measurement Programme (IDMP) station in The Chinese University of Hong Kong. Simultaneous meteorological data such as solar irradiance, sunshine duration and cloud cover from Hong Kong Observatory (HKO) will be correlated to the measured sky scans. Such work is seen by the CIE as an essential follow-up of the IDMP(CIE, 2010). Other countries are making this type of analysis so international comparisons will be made. This study will conduct an experimental study for cross-comparing the vertical sky component (VSC) and interior daylight performance of modelled and calculation data. A study of daylight performance in typical residential buildings of Hong Kong will also be conducted to investigate the improvement of prediction under the real sky types predicted by meteorological data against that under the CIE overcast sky. (CU11157)