Performance evaluation of a solar chimney power plant

[摘要] A solar chimney power plant consists of a central chimney that is surrounded by atransparent canopy located a few meters above ground level. The ground beneaththis canopy or collector as it is known is heated by the solar radiation that iseffectively trapped by the collector. This in turn heats the air in the collector, whichflows radially inwards towards the chimney. This movement is driven by thedifference between the hydrostatic pressure of the air inside- and outside the solarchimney system. The energy is extracted from the air by a turbine driven generatorsituated at the base of the chimney.The performance of such a solar chimney power plant is evaluated in this studymaking use of a detailed mathematical model. In this model the relevant discretisedenergy and draught equations are deduced and solved to determine the performanceof a specific plant referred to as the reference plant. This plant is to be located at asite near Sishen in the Northern Cape in South Africa where meteorological data isavailable.The performance characteristics of this plant are presented using values from the21 st of December as an example. These characteristics include the instantaneousand integrated power output, as well as the absorption of the solar radiation of eachof the parts of the collector. The air temperatures throughout the plant and theconvective heat transfer coefficients in the collector in the region of developing andfully developed flow are presented. The pressure of the air throughout the system ispresented as well as the pressure drop over the turbine. Temperature distributions inthe ground below the collector are also presented and discussed.

[发布机构] Stellenbosch University