Sloped Solar Chimney Power Plant Research Articles

Numerical investigation of a sloped solar chimney power plant: a three-dimensional study

Sloped solar chimney power plant (SSCPP) is a solar energy technology to generate solar electrical energy. Compared to the conventional solar chimney power plant (SCPP), this system has a sloped collector that operates as a chimney. This study using computational fluid dynamics (CFD) is provided a 3 D numerical simulation of the SSCPP along with a heat storage layer. The effects of pressure drop during turbine operation and solar irradiances on system parameters and the distribution of velocity and temperature are investigated. Based on results on the no-load condition, the maximum velocity of the system can be reached around 17 m/s at solar irradiance of 1000 W/m2. On the load condition, the airflow temperature increased while the velocity decreased, compared to the no-load condition. Furthermore, the power output of the SSCPP was 50 kW when the turbine pressure drop and solar irradiances were 120 Pa and 1000 W/m2, respectively. Also, it indicated that at a specific solar irradiance, there is an optimum pressure drop across the turbine. According to found results, the sloped solar chimney power plant is competitive with a conventional SCPP and has the same functionality under the same conditions.

Experimental study of a micro-scale sloped solar chimney power plant

Experimental study of a micro-scale sloped solar chimney power plant

Numerical investigation of a small scale sloped solar chimney power plant

The solar chimney power plant has been admitted as one of the feasible methods for utilizing solar energy. However, the reason why the height of the chimney is limited for conventional solar chimney power plants, in terms of construction and harnessing the solar energy in mountainous and impassable areas, is offered the sloped solar chimney power plant as one of the novel techniques. In this paper, we analyzed velocity and temperature distributions of a prototype of a sloped solar chimney power plant by using a three-dimensional simulation. Furthermore, the simulation was validated by experimental data from the literature. Simulation results indicate that steady state flow was an applicable assumption, for solar radiations above 600 W/m2 from morning to noon in a day. Further, the maximum air velocity in a sloped solar chimney power plant where is the entrance of the chimney was reported 2.73 m/s for solar radiation of 800 W/m2. Last but not least, geometrically, the studies showed by reduction of the height of the chimney by 25% (from 9 to 2.25 m), the maximum air velocity was decreased considerably from 2.73 to 2.07 m/s, and average air temperature at the chimney entrance was went up moderately nearly 1%.

The fuzzy logic-based modeling of a micro-scale sloped solar chimney power plant

The energy demand of world is increasing worldwide because of increasing population and developing technology. The use of environmentally friendly renewable resources is very important in providing the increasing energy needs. In the renewable energy sources, the solar energy has a strategic importance because of its huge potential and unlimited. The production of electrical energy by solar chimney power plants is one of the reliable and profitable methods. Fuzzy logic-based approaches are commonly used for modeling different systems in many fields. Also, a renewable energy system can be modelled by fuzzy definitions. In this way, it can provide efficiently and quickly theoretical estimates of systems with productive simulations. In this study, using the experimental data obtained from the micro-scale sloped solar chimney power plant in carried on scientific research project by authors, the obtaining and verifying a fuzzy logic-based model (FLBM) that can calculate the change in air velocity at turbine according to the change of radiation and temperature is presented. The air velocity at the turbine inlet is the considerable variable determining the electricity generation in a solar chimney. Thus, the output of the model is determined as this air velocity. In changes in the radiation and temperature values are defined as inputs. A two input-one output fuzzy model is obtained, in which the inference method is designed in the form of Mamdani and the membership functions in the form of the triangle, making inferences according to the rule base determined by the experience achieved from the experimentally studies. In order to investigate the accuracy of the FLBM, the simulation results and the data get from experimental setup in April 2019 are compared and evaluated. The validation of the FLBM compared to the experimental system is investigated using different error evaluation criteria. It is proved that the results of FLBM and experimental data are realized at a high rate (95.95 %) close to each other and similarly.

Mathematical evaluation of sloped solar chimney power plant for power generation in different regions of Nepal

Abstract Sloped solar chimney power plant (SSCPP) could be one of the appropriate technologies for powering Nepalese communities. The main components of the plant are chimney, collector and power-generating unit. In this study, the mathematical evaluation of the SSCPP has been conducted for the estimation of the power generation in Nepalese context. For the analysis, the mathematical models have been developed from the governing equations. The parameters such as chimney height and radius, collector radius, ambient temperature and solar insolation have been taken as inputs for simulation of the overall system. The output parameters such as overall system efficiency, chimney efficiency, air velocity, power output from the turbine and electrical power from the proposed system have been evaluated. The results showed that power developed by air, turbine power and electrical power is 120, 66 and 44 kW, respectively. The developed power is estimated when the height and the radius of the chimney were 190 and 5 m, respectively. It is seen that ambient temperature and velocity of air also play an important role in the power generation. The performance influencing the power output based on turbine pressure ratio, thermal conductivity and specific heat capacity of soil and the mass flow rate have also been estimated. Besides, the solar insolation data were taken for five different regions of Nepal to find the power generation and collector efficiency.

Comparative Energetic and Exergetic Analysis of Conventional and Sloped Solar Chimney Power Plants

A CFD analysis using ANSYS Fluent software was conducted to study the effects of collector slope on solar chimney's performances. Three solar chimney configurations, named A, B, and C, which correspond, respectively, to an inclination angle of the collector roof of 0°, 2.5°, and 5°, were investigated. The results show that the thermodynamic performances of the solar chimney were improved by increasing the inclination angle of the collector roof. In fact, the power extracted from the sloped solar chimney power plants increases with increasing the inclination angle and the solar radiation intensity, while it achieves a maximum at 800 W/m2 for configuration A. The energetic and the exergetic analysis show that configure B has the best performance in terms of conventional, effective, and total efficiencies of the collector and in terms of exergy destruction ratios in both the collector and the transition section. Whereas, configuration C has the highest amount of power extracted and the best overall energetic efficiency.

Full-year simulation of solar chimney power plants in Northwest China

Abstract The solar chimney power plant is one method of large-scale solar energy utilization. Transient performances of the conventional solar chimney power plant (CSCPP) and sloped solar chimney power plant (SSCPP) have not been well discussed in the literature. In the present study, the full-year power capacity of the CSCPP and the SSCPPs with maximum solar radiation (MSR) angle and maximum power generation (MPG) angle were first simulated. The accumulated power generation of SSCPPs with different solar collector angles were then compared. The major factors influencing the accumulated power generation were finally discussed. It is found from the study that the SSCPP with MSR angle generates steadier power than the CSCPP and SSCPP with MPG angle throughout the year. The SSCPP with MPG angle generates higher power in the winter. The airflow temperature rise in the solar collector and the system height are the two major factors those influence the SCPP's power capacity and accumulated power generation.

Design and simulation of a solar double-chimney power plant

The solar chimney power plant (SCPP) is one method of solar thermal utilization with high/super-high chimney. There are few methods to decrease the solar chimney height. One possible method is the sloped solar chimney power plant (SSCPP), which depends on the special geographical condition. In the present paper, another system is proposed to overcome this problem, which is named solar double-chimney power plant (SDCPP). Mathematical models of the SDCPP are established and its performances are analyzed. It is found that, for an SDCPP with 5 MW configuration size, the average temperature rises of the horizontal and tilted solar collectors are 5.64 K and 7.87 K respectively. The highest wind speeds in the inner chimney and in the interlayer of the inner and outer chimney are 15.28 m/s and 19.41 m/s respectively. The annually average SDCPP power productivity and power efficiency are 4.72 MW and 1.2% respectively. The power productivity of the SDCPP is 1.59 times larger than that of the CSCPP and 2.77 times larger than that of the SSCPP. Through comparing with the CSCPPs in the literature, the SDCPPs can increase their power productivities by 21%–55%. The SDCPP is a promising method for non-concentrating solar thermal power generation.

Performance analysis of sloped solar chimney power plants in the southwestern region of Iran

The sloped solar chimney power plant (SSCPP) has significant capability to fulfil a part of the forthcoming energy requirements of villages located in the southwestern region of Iran. This paper presents the performance analysis of SSCPP which was expected to fulfil the urgent need for electric power in the southwestern region of Iran. However, to investigate the SSCPP performance and power generation throughout the southwestern region of Iran, five different regions across the Persian Gulf were considered. A mathematical model was developed to estimate the power output of solar chimneys. The performances, such as rate of air mass flow, system efficiency and solar collector efficiency, of the SSCPP were studied. The obtained results show that SSCPPs can produce from 2.98 to 5.91 MW of electricity power in the selected regions during different months of the year.

Comparison of conventional solar chimney power plants and sloped solar chimney power plants using second law analysis

In the present paper the performance of solar chimney power plants based on second law analysis is investigated for various configurations. A comparison is made between the conventional solar chimney power plant (CSCPP) and the sloped solar chimney power plant (SSCPP). The appropriate entropy generation number and second-law efficiency for solar chimney power plants are proposed in this study. Results show that there is the optimum collector size that provides the minimum entropy generation and the maximum second-law efficiency. The second-law efficiency of both systems increases with the increasing of the system height. The study reveals the influence of various effects that change pressure and temperature of the systems. It was found that SSCPP is thermodynamically better than CSCPP for some configurations. The results obtained here are expected to provide information that will assist in improving the overall efficiency of the solar chimney power plant.

Economic analysis of solar chimney power plants in Northwest China

Solar chimney power plant (SCPP) with a long life span is a promising large-scale solar thermal utilization technology. This paper performs an economic analysis for the conventional solar chimney power plant (CSCPP) and the sloped solar chimney power plant (SSCPP) in Northwest China. Cash flows are influenced by many factors including the investment, the payback period, the inflation rate, and the sale price of solar electricity. The techno-economic analyses of the CSCPPs and SSCPPs are performed taking Lanzhou, China as a case study. The results show that the SCPP investment is influenced by both its configuration and the material price, and the SSCPP is more cost-effective than the CSCPP during the system life span. In addition, the SCPP with large power capacity holds good competitiveness with the conventional fossil fuel combustion plants. The economic evaluation of building SCPPs in Northwest China is of high significance considering the local abundant solar radiation, favorable government policy, and under-developing economics.

Numerical Simulation and Comparison of Conventional and Sloped Solar Chimney Power Plants: The Case for Lanzhou

The solar chimney power plant (SCPP) generates updraft wind through the green house effect. In this paper, the performances of two SCPP styles, that is, the conventional solar chimney power plant (CSCPP) and the sloped solar chimney power plant (SSCPP), are compared through a numerical simulation. A simplified Computational Fluid Dynamics (CFD) model is built to predict the performances of the SCPP. The model is validated through a comparison with the reported results from the Manzanares prototype. The annual performances of the CSCPP and the SSCPP are compared by taking Lanzhou as a case study. Numerical results indicate that the SSCPP holds a higher efficiency and generates smoother power than those of the CSCPP, and the effective pressure in the SSCPP is relevant to both the chimney and the collector heights.

Mathematical modeling of sloped solar chimney power plants

Sloped solar chimney system is a solar chimney power plant with a sloped collector. Practically, the sloped collector can function as a chimney, then the chimney height can be reduced and the construction cost would be reduced also. A mathematical model based on the continuity, momentum, energy, and state equations is developed for the sloped solar chimney system in this study. The flow details inside a collector are included in the model. The mathematical model was solved numerically using an iterative technique. Then, the numerical simulation was performed using the commercial CFD package. The consistency of the predictions of the mathematical model and that of the CFD package justifies the validity of the proposed mathematical model. A detailed study of the plant characteristics is done. Results show that using a near-unity ratio of the collector inlet flow area and the collector exit flow area might cause some problems. In addition, the assumption that the density differences in the collector and that in the chimney are approximately equal is investigated. The study shows that this assumption provides a large overprediction of the results. The effects of the chimney height and the collector area on the plant performance are also illustrated.

Performance analysis of conventional and sloped solar chimney power plants in China

The solar chimney power plant (SCPP) has been accepted as one of the most promising approaches for future large-scale solar energy applications. This paper reports on a heat transfer model that is used to compare the performance of a conventional solar chimney power plant (CSCPP) and two sloped solar chimney power plants (SSCPPs) with the collector oriented at 30° and 60°, respectively. The power generation from SCPPs at different latitudes in China is also analyzed. Results indicate that the larger solar collector angle leads to improved performance in winter but results in lower performance in summer. It is found that the optimal collector angle to achieve the maximum power in Lanzhou, China, is around 60°. Main factors that influence the performance of SCPPs also include the system height and the air thermophysical characteristics. The ground energy loss, reflected solar radiation, and kinetic loss at the chimney outlet are the main energy losses in SCPPs. The studies also show SSCPPs are more suitable for high latitude regions in Northwest China, but CSCPPs are suggested to be built in southeastern and eastern parts of China with the combination to the local agriculture.

Simulation of a sloped solar chimney power plant in Lanzhou

Solar chimney power system is one large-scale utilization style of solar energy, which has drawn high attentions worldwide. Though scholars all over the world have made many researches on the solar chimney power system, reports of sloped solar chimney power system are still few. A sloped solar chimney power plant, which is expected to provide electric power for remote villages in Northwest China, has been designed for Lanzhou City in this paper. The designed plant, in which the height and radius of the chimney are 252.2 m and 14 m respectively, the radius and angle of the solar collector are 607.2 m and 31° respectively, is designed to produce 5 MW electric power on a monthly average all year. The performances, such as the airflow temperature increase, pressure, the airflow speed, system efficiency and solar collector efficiency, of the built sloped solar chimney power plant are simulated and presented. Simulation results show that parameters of the sloped solar chimney power plant are symmetrical and stable; the power plant has better performances in spring and autumn days; the overall efficiency of the power plant is low. Considering the abundant solar radiation, environmental friendliness, easy management and low population density, the sloped solar chimney power system is of high value to Northwest China.