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Solar energy 2012 Part 8

Tham khảo tài liệu 'solar energy 2012 part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Floating Solar Chimney Technology 203 The exit temperature of the first sector is the inlet temperature for the second etc. and finally the exit temperature of the final Mth sector is the To3 i.e. the inlet stagnation temperature to the air turbines. The solar chimney heat transfer analysis during a daily 24 hours cycle is too complicated to be presented analytically in this text however we can use the results of this analysis in order to have a clear picture of the operational characteristics of the SAEPs. Using the code of the heat transfer analysis for moving mass flow mM the daily variation of the exit temperature T B can be calculated. Using these calculated daily values of the T03 and by the thermodynamic cycle analysis for the optimal mass flow mM the daily power profile of the electricity generation can be calculated. With this procedure the 24 hour electricity generation power profile of a SAEP with a solar collector of surface area Ac 106m2 and a FSC of H 800m height and d 40m internal diameter for an average day of the year has been calculated. The SAEP is installed in a place with annual horizontal solar irradiation Wy 1700 KWh m2. In the following figure three electric power profiles are shown with or without artificial thermal storage. SAEP of H 800m d 40m Ac 1.0 sqrKm Wy 2000KWh sqm solar time in hours Fig. 13. The average daily SAEP s electricity generating profiles The relatively smooth profile shows the electric power generation when only the ground acts as a thermal storage means. While the smoother profiles are achieved when the greenhouse is partly covered 10 or 25 of its area by plastic black tubes of 35cm of diameter filled with water i.e. there is also additional thermal storage of an equivalent water sheet of 35-n 4 27.5 cm on a small part of the solar collector. The daily profiles show that the SAEP operates 24hours day due to the greenhouse ground and artificial thermal storage. That is a considerable benefit of the FSC technology .