Solar radiation on vertical surfaces for building application in different climate zones across China

The global concerns about energy consumption and environmental sustainability elevate the aspiration of applying solar energy to buildings. The information of solar radiation on the building envelope is important in designing the solar devices for building application. In this study, the solar radiation on the vertical surfaces in five major climate zones of China, viz. hot summer and warm winter, mild, hot summer and cold winter, cold, and severe cold, is investigated using the Klein and Theilackers model with monthly average solar radiation measurements on a horizontal surface during 1971-2000. Guangzhou, Kunming, Wuhan, Beijing, and Harbin are selected as the representative cities in the five climate zones. The results show that the peak values of the total solar radiation on the vertical surface in each month occur at different orientations with the azimuth angles during ±90°. For annual utilization, the vertical surface due south is best for the five representative cities, and the deviation in azimuth angles within 45° can assure the reduction of the solar gain will never exceed 10.