Relationship between the total solar radiation on tilted surfaces and the sunshine hours in Hong Kong

Solar energy technologies can play an important role in meeting the ultimate goal of replacing fossil fuels to generate inexhaustible, clean and safe energy. The availability of more comprehensive solar radiation data is invaluable for the design and evaluation of solar-based conversion systems. In many places of the world, particularly the developing countries, the basic solar radiation data for the surfaces of interests are not readily obtainable. This paper presents an approach to estimate the annual global solar radiation on various inclined planes facing different orientations based on measured sunshine hours. Solar radiation and sunshine hours data recorded in 2004 were used for the model development. The performance of the proposed model was assessed against data measured in 2005. It is shown that the solar radiations estimated by the proposed method are in good agreements with the measured data and the peak difference was found less than 5.2%. The predictive ability and the simplicity nature of the model provide a reliable and convenient alternative for estimating inclined solar radiation.