Thermal and technical analyses of solar chimneys
Universität Stuttgart, Stuttgart, Baden-Württemberg, Germany Solar Energy
(Impact Factor: 3.47).
12/2003; 75(6):511-524. DOI: 10.1016/j.solener.2003.09.012
An analysis for the solar chimneys has been developed, aimed particularly at a comprehensive analytical and numerical model, which describes the performance of solar chimneys. This model was developed to estimate power output of solar chimneys as well as to examine the effect of various ambient conditions and structural dimensions on the power output. Results from the mathematical model were compared with experimental results and the model was further used to predict the performance characteristics of large-scale commercial solar chimneys. The results show that the height of chimney, the factor of pressure drop at the turbine, the diameter and the optical properties of the collector are important parameters for the design of solar chimneys.
Available from: Mehdi Ashjaee
- "Employing Computational Fluid Dynamics method and their turbine design, Ruprecht et al. presented results for a solar chimney with rated capacity of 200 MW . A computer-aided analytical study has been illustrated by Bernardes and Weinrebe to investigate thermal features of the chimney . Several researchers have shown interest in introducing models capable of predicting overall performance of the solar chimney such as Chitsomboon , Schlaich et al. , Tingzhen et al. , Zhou et al.  and Koonsrisuk and Chitsomboon . "
[Show abstract] [Hide abstract]
ABSTRACT: In this study, an improved concept design is presented to increase the thermal efficiency of the Rankine cycle of a typical steam power plant by combining a solar chimney and a dry cooling tower. The sources of the wind energy generation, include: the rejected heat from condenser to the air entering dry cooling tower, solar radiation and the airlift pumping effect on the air flow created by the stack hot flue gas which is injected into the hybrid tower as a novel change. This research primarily focuses on the Shahid Rajaee 250 MW steam power plant to determine the velocity of generated flow at the turbine inlet; a numerical finite volume code was employed for a dry cooling tower having a base diameter and a chimney height of 250 and 200 m, respectively. Calculations have been iterated for different angles of chimney walls, slopes of collectors and the base ground to find their effects on the output power. A range of 360 kW to more than 4.4 MW power is captured by the wind turbine by changing the hybrid tower geometrical parameters. Obtained results reveal a maximum of 0.538% increase for the thermal efficiency of the fossil fuel power plant.
Available from: Ayad T. Mustafa
- "The turbulent mathematical model need to be selected to describe fluid flow within the SUPPS because of Rayleigh number is found higher than10 10 . Bernardes et al.  developed an analysis for the solar chimney power plant, aimed particularly at a comprehensive analytical and numerical model, which describes the performance of the system. The collector is considered as a cavity between two parallel plates, moreover the analysis of the temperature rise in the collector section is determined by employing iterative techniques. "
[Show abstract] [Hide abstract]
ABSTRACT: In this study, mathematical and experimental models were implemented for circular solar air collector. Modeling methodology with conservation equations of continuity, momentum and energy were presented, and model solution is obtained by utilizing a developed code in MATLAB program. An experimental model of concentric circles with outer and inner diameters of 8.8 m and 1.0, respectively, was designed and fabricated in order to perform measurements for the thermal and flow processes in the system. The canopy was inclined by 8.5°. The results showed that, at same solar irradiation, the temperatures of air flow, canopy and ground are increasing by decreasing the radius. When the canopy slope increases, air flow temperature decreases and canopy temperature increases for a constant solar radiation. When the solar radiation increases, air flow, canopy and ground temperatures increases for the same collector radius. The validations of the model predictive and therefore comparisons with results of experimental model of this study and Manzanares prototype data have been done. The model results agree with the experimental results. Further investigations are recommended after installation of the vortex generation engine where the residence time of the air particles will be changed, and consequently the air stream temperature and velocity are expected to change, as well.
Available from: Liang Zhao
- "Mathematical models were built to analyze the system performance (Haaf et al., 1983; Pasumarthi and Sherif, 1998a; Pretorius and Krö ger, 2006b), the solar collector performance (Gannon and von Backstrom , 2000), the chimney performance (Ming et al., 2011; von Backströ m et al., 2003; Zhou et al., 2009d), the turbine characteristics (Denantes and Bilgen, 2006; Fluri and von Backström, 2008a,b; Gannon and von Backströ m, 2003), and the airflow compressibility (von Backstrom, 2003; von Backstrom and Gannon, 2000). Further advanced mathematical models were established for the parameters sensitivity analysis (Petela, 2009; Pretorius and Krö ger, 2007), the heat transfer coefficients (Bernardes et al., 2009, 2003), the configuration dimensionless similarity (Koonsrisuk and Chitsomboon, 2007, 2009; Koonsrisuk et al., 2010; Onyango and Ochieng, 2006) and the environmental and atmospheric effects (Harte and van Zijl, 2007; Ninic, 2006; VanReken and Nenes, 2009; Zhou et al., 2012, 2009a, 2008). Numerical analyses were carried out to simulate the inner performance, such as the pressure, velocity and temperature fields and the turbine performance (Chergui et al., 2010; Ming et al., 2008a, 2006, 2008b; Onyango and Ochieng, 2006; Pastohr et al., 2004; Zhou et al., 2009e), and to optimize the structure and system operation strategy (Bernardes and von Backstrom, 2010; Kirstein and von Backstrom, 2006; Maia et al., 2009, 2011; Pretorius and Krö ger, 2006a). "
[Show abstract] [Hide abstract]
ABSTRACT: The solar chimney power plant (SCPP) is dominated by the solar radiation, and therefore its discontinuous operation is an unavoidable problem. In this paper, low temperature geothermal water is introduced into the SCPP for overcoming this problem. Based on a developed transient model, theoretical analyses are carried out to investigate the performance of the geothermal–solar chimney power plant (GSCPP) with main dimensions the same as the Manzanares prototype in Spain. Three operation models, viz. the full solar model, the full geothermal model and the geothermal–solar combined model are compared in typical summer and winter days and throughout the year. It is found that the GSCPP can attractively run in the GSM to deliver power continuously. Due to the ambient-dependant geothermal water outlet temperature, introducing the geothermal water makes greater contribution in winter days than in summer days, in the night than in the daytime. Power generation under GSM is larger than the sum of FSM and FGM. GSM is not the simple superposition of FSM and FGM, but makes better utilization of solar and geothermal energy. In addition, introducing high temperature and mass flow rate geothermal water can doubled and redoubled improve the GSCPP’s power capacity.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.