Abstract：The overall performance of any solar energy project depends very much on the availability of solar radiation and the orientations of solar collectors. Presented in this paper is a numerical analysis of the solar irradiation received at the coastal region of South China. This region, with latitudes from 20.5N to 24N, belongs to the subtropical monsoon climatic zone.The computations were based on the typical meteorological year (TMY) weather data of Macau, compiled as a result of the ASHRAE International Weather for Energy Calculations Project. The hourly data were applied to the ESP-r building simulation program with the adoption of the Perez solar model. The analyses estimated the solar irradiation received on inclined surfaces at different orientations and slopes, and for different periods of the year. It was found that a solar collector facing the south-west direction could be most desirable for a wide range of tilt angles, and for maximizing the annual yield. The trends of variations towards other directions, tilt angles, and shorter periods of the year are also explored.

Keywords: Solar energy; Solar collector; Optimal performance