| The growing demand for energy and the increasing serious environmental problems force people to adjust the current energy structure and to reduce the dependence of the nonrenewable energy such as coal, oil, and nature gas. Solar chimney power generation system, as a kind of clean and renewable energy sources, has attracted attention in researchers. It has the advantages of simple structure and low heat storage cost, but at the same time, its high initial investment and low conversion efficiency restricts the promotion of the power generation technology. Therefore, considering the characteristics of solar chimney power plant, to optimize the system performance, improve its efficiency and reduce the investment cost, this paper is divided into the following two aspects.In the first part, an unsteady comprehensive model of solar chimney power plant is proposed to analyze the power generation performance and optimize the system structure based on the heat transfer and flow characteristics analysis of the solar collector, the chimney, the turbine, and the heat storage layer. Moreover, a new power generation quality factor is defined to evaluate and optimize the overall power generation performance of a solar chimney power plant, which combines two key factors, the economic efficiency and the power generation stability. The simulation results indicate that the power generation performance improves with the increasing of chimney height and the decreasing of solar collector radius. Meanwhile, there are optimal values of chimney diameter, solar collector height and storage layer thickness to make the system achieving maximum performance. For the SUPP system with a certain power, there exist an optimal values of chimney height and collector radius that make the system achieving optimal economical performance.In the second part, based on the study of the SUPP system, the analysis and modeling of the flow and heat transfer of the solar updraft tower cooling and power generation system(SUTCPS) is conducted in this thesis. And the performance and economic optimization of this system is also studied. The optimization results show that the power generation power of the SUTCPS system is related with the configuration of turbine pressure drop, the solar collector radius and solar radiation. For the SUTCPS cooperate with the 660 MW coal-fired power station, the optimization of its solar collector radius is 150.7m, and its power generation efficiency is up to 2.95%, while the same size SUPP system efficiency is only 0.17%. The stability of the SUTCPS without heat storage system can reach 0.98, which is better than that of the SUPP system under the condition of ideal heat storage. The SUTCPS system and coal fired power plant co-generation system has higher energy efficiency compared with the coal-fired power plants with forced air cooling system and SUPP independent power generation system. It can save 2.14 g coal consumption for 1k Wh electricity production. The power generation cost of the SUTCPS system can be as low as 0.18 yuan /k Wh, which has a good engineering significance. |
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