Study On The Characteristics Of Concentration Of Tower - Type Thermal Power Station

As the shortage of energy, increasing demand for energy of human beings and worsening global climate, solar energy has been paid more and more attention with its incomparable advantages of infinite, clean and cheap. Due to higher focusing temperature and energy collection efficiency, solar tower power is the primary choice among solar thermal power technologies. This thesis mainly focuses on the researches of sun motion, dynamic drift characteristics of heliostat spots, solar flux of heliostat field, the best design of heliostat field. The main work presented as following:First, the sun motion model is established to calculate sun angles throughout vernal equinox day, summer solstice, autumnal equinox and winter solstice. Variation rules of the sun angles are summarized.Second, method of the solar facular position formed by reflected rays projected on the aim point of the central receiver is proposed on the basis of optical reflection principle. Furthermore, this thesis researches on the correlation among height of tower, heliostat geometric position, time and dynamic drift characteristics of heliostat spots. Then, analysis of the impact of heliostat tracking error on dynamic drift characteristics of heliostat spots is done. Based on the whole rectangular heliostat field, simulations of dynamic drift characteristics of heliostat spots are performed at different periods of Spring Equinox.Third, the solar flux model of heliostat field is established. Analysis of impact of sun position, distance between adjacent heliostat and height of tower on shadow efficiency is done. The solar flux distribution in different time is simulated. At the same time, relationships among heliostat spacing, height of tower and average solar energy are obtained.Forth, design principles of heliostat filed are presented. Based on these principles, three kinds of heliostat filed design are proposed. Furthermore, through analysis and comparison of cosine efficiency, spot drift characteristics, shadow efficiency, solar flux distribution and ground coverage of three kinds of heliostat field, the best design solution can be got.These methods are confirmed to be feasible and high precision through simulations and experiments. The conclusions of this thesis lay a theoretical basis for research on solar tower power technology.