Building energy simulation using measured and modeled hourly solar radiation data

Building energy simulation has proved useful in the development of building energy codes (especially performance-based) and subsequent code compliance checking. A weather year is required for the hourly computation of heating/cooling loads and corresponding energy consumption. Many locations have measured daily solar radiation data, but not hourly. Attempts were made to model hourly global solar radiation (GSR) data from measured daily values using the Liu and Jordan method for Harbin, Beijing, Shanghai, Kunming and Hong Kong. These cities are in the five major climate zones of China, namely, severe cold, cold, hot summer and cold winter, mild, and hot summer and warm winter. Statistical analysis of the measured and modeled hourly solar radiation was carried out. The root-mean-squared error ranges from 7 to 13%. Two weather years - one with measured hourly solar radiation and the other modeled data were developed for each city. Generic office buildings were also developed based on the local energy codes. Hourly simulations were conducted to assess the impact of using modeled solar radiation data on the heating/cooling loads. Building heating and cooling loads using modeled hourly GSR tend to be slight higher (on average, 2 to 3%) than those with the measured data.