Solar Chimney Power Plant Research Articles

Experimental Investigation on The Effect of Divergent Tower Solar Chimney on The Theoretical Power Potential

Solar chimney power plant is a sustainable alternative for electricity generation using solar as the source of energy. In general, the main body of a solar chimney plant requires a tall structure which is costly and challenging to construct. Thus, it is important to increase the performance of the solar chimney power plant and have a better energy-cost ratio. This study aims to experimentally investigate the influence of divergent solar chimney as opposed to a cylindrical chimney on solar chimney performance. Three divergent scaled-down solar chimney model at 1-meter, 1.5-meter and 2-meter were fabricated and tested for its performance at various simulated heat loads. The test results were compared with similar heights cylindrical solar chimney. The experiments show that divergent solar chimney increases the theoretical power generation potential and improves the stalk effect and have higher outlet velocity compared to a cylindrical solar chimney. The power potential of the divergent chimney is increased up to 18 times with the maximum theoretical power obtain at 0.183W on the 2-meter divergent chimney. Higher temperature was recorded on the 2-meter divergent chimney outlet at 341.3k compared to 330.4k on the cylindrical chimney indicates better stack effect. The highest average velocities in the divergent and cylindrical chimneys were recorded under the electric heat load of 2 kW at 0.994 m/s and 0.820 m/s respectively in the 1-meter configuration. It is also observed that the air velocity in a shorter divergent chimney is higher than taller divergent chimney models while better compared to all cylindrical height. This study finds that a shorter divergent solar chimney produces greater energy compared to a higher cylindrical solar chimney. Therefore, it is possible to reduce the overall cost of solar chimney by reducing the height of the main structure without sacrificing the performance of the solar chimney.

A computational fluid dynamics study on different solar chimney designs on solar radiation

The solar chimney power plant (SCPP) is a hopeful solution to produce electrical power from solar energy. In this paper, a 2D numerical study is presented to estimate the performance of the SCPPs while varying the collector angle, chimney diverging angle, variable solar radiation and ambient temperature and some geometrical designs. Numerical models run with solar load discrete ordinates (DO) and realizable k-ɛ turbulence models. System is defined by the collector height =50 mm, the chimney diameter =160 mm, the collector diameter =2750 mm and the chimney height =3000 mm. its investigated for each case the profile of magnitude velocity, air temperature, pressure, incident radiation and turbulence characteristics were presented. The effective choice of the best geometry is based on the maximum value of the air velocity inside the SCPP. Results indicates that a negative collector-roof positively increases the air velocity, and the output power. To a specific limit, increasing the diverging angle of the chimney has a god effect on the velocity magnitude and the other parameters. also Increasing the collector diameter and chimney height and diameter has a great effect on power output as shown in results.

Assessment of solar chimney combined with phase change materials

Using solar energy as a renewable and clean source of energy is developing rapidly. Usage of heat storage facilities in different solar systems enables dispatchability in the production of electricity and building space heating demands. It can help to decrease the intermittence issue of solar energy. Heat storage facilities also help to smooth out fluctuations of energy demands during several time periods of a day. Phase change materials (PCMs) have vital roles in developing sustainable energy modules with their notable features. The thermal energy absorbed and released by these materials, over particular temperature ranges, has become an outstanding contender in solar energy systems. This paper assesses the progresses regarding the usage of these materials in solar chimney power plants. Some descriptions about the solar chimney power plants and their mechanisms and superiorities are provided. Different techniques used in thermal energy storage are discussed. Applications of phase change materials in solar chimney are also investigated. Finally, the main results of the review and some directions for future studies in this field are provided.

Investigation of Climate Effects on the Performance of Solar Chimney Power Plants Using Numerical and Analytical Models: A Case Study for Chlef, Algeria

Investigation of Climate Effects on the Performance of Solar Chimney Power Plants Using Numerical and Analytical Models: A Case Study for Chlef, Algeria

Impact of the chimney geometry on the power output of solar chimney power plant

Impact of the chimney geometry on the power output of solar chimney power plant

Numerical instability investigation of inward radial Rayleigh–Bénard–Poiseuille flow

The spatial instability of inward radial Rayleigh–Bénard–Poiseuille flow was investigated using direct numerical simulations with random and controlled inflow forcing. The simulations were carried out with a higher-order-accurate compact finite difference code in cylindrical coordinates. Inward radial Rayleigh–Bénard–Poiseuille flows can be found, for example, in the collectors of solar chimney power plants. The conditions for the present simulations were chosen such that both steady and unsteady three-dimensional waves are amplified. The spatial growth rates are attenuated significantly in the downstream direction as a result of strong streamwise acceleration. For the oblique waves, the growth rates and wave angles decrease and the phase speeds get larger with increasing frequency. As the oblique waves travel downstream, the phase speeds decrease and the wave angles increase. Overall, steady waves with a wave angle of 90 ° are the most amplified. In general, because of the finite azimuthal extent, only certain azimuthal wavenumbers are possible. As a result, the steady waves appear to merge in the streamwise direction. When the inflow is at an angle such that a spiral flow is formed, one family of oblique waves is favored over the other and the mode shapes of the left- and right-traveling oblique waves are asymmetric with respect to the radius. As the inflow angle increases, this asymmetry is aggravated and the wavenumber of the most amplified disturbances is diminished.

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.

Design and optimization of turbine for solar chimney power plant based on lifting design method of axial-flow hydraulic turbine impeller

Based on the lifting design method of the axial flow hydraulic turbine and axial-flow pump impeller, an air turbine design method considering the optimal turbine pressure drop ratio for the solar chimney power plant was presented in this paper. Numerical simulations for the Spanish prototype system incorporating the turbine impeller were conducted to investigate the feasibility of the present turbine design method on the improvement of the system output performance. Furthermore, the influence of the solar radiation on the turbine performance was investigated. The results indicates that the turbine performance can be improved by using the proposed design method. The maximum turbine power output is 53.49 kW, 30.46% higher than that of the Spanish prototype and the turbine is less sensitive to rotational speed. In addition, the turbine high-performance rotational speed range is larger under higher solar radiation.

Ambient crosswind effect on the first integrated pilot of a floating solar chimney power plant: experimental and numerical approach

Floating Solar Chimney Power Plant (FSC) proposed by Papageorgiou is regarded as a novel type of Solar Aero-Electric Power Plants with fundamental characteristics of low cost and unaffected seismic chimney. The main disadvantage of the proposed system is the tilting of the floating chimney in windy conditions compared with a conventional reinforced concrete one. In the present research, the ambient crosswind (ACW) effect is studied on an FSC with experimental and numerical approaches. An experimental floating chimney integrated with an appropriate solar collector was designed, built, and tested under real-world conditions, and the experimental results were used for validations of the numerical analysis. Three-dimensional numerical analysis was performed to study the performance of the tilted floating solar chimney exposed to the ACW and then compared with a conventional type. Numerical results show that a tilting FSC with lower apparent height can operate more efficiently than a vertical concrete chimney in windy conditions due to eliminating adverse effects of tip vortices on updraft flow in the system. The results also show that an optimum tilting angle (OTA) exists for the specified plant and critical or prevailing wind speed, making ACW adverse effects minimum. Floating solar chimney design can be enhanced significantly based on achieving optimum tilting angle in windy conditions.

Developing and Implementation of an Optimization Technique for Solar Chimney Power Plant With Machine Learning

Abstract Green energy has seen a huge surge of interest recently due to various environmental and financial reasons. To extract the most out of a renewable system and to go greener, new approaches are evolving. In this paper, the capability of Artificial Neural Network and Adaptive Neuro-Fuzzy Inference System in geometrical optimization of a solar chimney power plant (SCPP) to enhance generated power is investigated to reduce the time cost and errors when optimization is performed with numerical or experimental methods. It is seen that both properly constructed artificial neural networks (ANN) and adaptive-network-based fuzzy inference system (ANFIS) optimized geometries give higher performance than the numerical results. Also, to validate the accuracy of the ANN and ANFIS predictions, the obtained results are compared with the numerical results. Both soft computing methods over predict the power output values with MRE values of 12.36% and 7.25% for ANN and ANFIS, respectively. It is seen that by utilizing ANN and ANFIS algorithms, more power can be extracted from the SCPP system compared to conventional computational fluid dynamics (CFD) optimized geometry with trying a lot more geometries in a notably less time when it is compared with the numerical technique. It is worth mentioning that the optimization method that is developed can be implemented to all engineering problems that need geometric optimization to maximize or minimize the objective function.

Numerical simulation of the effect of chimney configuration on the performance of a solar chimney power plant

Previous studies have shown that the crosswind reduces the output power of a SCPP (solar chimney power plant) with the deflection of the plume at the exit and separation of wind flow there at the downstream. The present numerical investigation was focused on the effect of the stack configuration on the performance of a SCPP. In this paper, the SCPP of the prototype in Manzanares was simulated, where the Boussinesq approximation was used for solving the continuity, Navier–Stokes and energy equations by the standard k-epsilon turbulence model in finite volume method. Governing parameters are taken as oblique angles from 27° to 45° and wind velocity from 0 to 10 m s−1. Investigation revealed that by changing the stack configuration, the performance of the SCPP could be improved. Numerical simulation of the conventional chimney was compared with the simulation data of the proposed altered chimney geometry (outlet bevel cutting) and observed that the throttling effect on the outlet of the chimney could be reduced. It was noticed that by changing the chimney oblique angle from 27° to 45°, the efficiency of the power plant was dropped. Further, the results illustrated that the oblique angle relies on the wind velocity and it needs to increase with the increase in the wind velocity to obtain a reasonable change in power output. The present investigation was further enhanced to incorporate a comparison of solar chimney power output in two cities (Kuala Lumpur and Kerman) for a better understanding of the effect of environment on constructing the solar tower power plant. The result shows that Kuala Lumpur is appropriated for the installation of SCPP although, the Kerman is suitable too, but the wind velocity in that city is higher than that in Kuala Lumpur.

Numerical investigation and multi‐objective thermo‐economic optimization of a solar chimney power plant

This study was conducted to optimize a solar chimney power plant from the aspects of performance improvement and cost saving. Numerical simulation was performed for a Spanish prototype to investigate the parametric sensitivity of several key variables and identify a reasonable range for the variables as the constraints of the optimization. A multi-objective optimization on the prototype was conducted using orthogonal design of experiments, response surface methodology, and the non-dominated sorting genetic algorithm. The optimum chimney diameter tends to reach the upper bound of 30 m, while the optimum collector radius is almost uniformly distributed over the allowable range. The optimum range of the turbine pressure drop ratio is between 0.82 and 0.88 for the cases with a 200-m high chimney. The optimized capital cost per unit power production ranges from 0.018 to 0.026 M€/kW, which is much less than 0.054 M€/kW of the Spanish prototype. Considering the output power and construction cost comprehensively, the Pareto solution set obtained from the optimization may provide a guide to the system design and operation.

A Numerical experimentation on fluid flow and heat transfer in a SCPP

Solar chimney power plant (SCPP) is a promising unit of power generation from renewable energy source in near future. Apart from climatic conditions, the performance of the unit depends on design parameters of plant. To understand the performance of the unit, fluid flow and heat transfer study is essential throughout the unit. In present work, a numerical study has been conducted to see the effect of inlet area on the performance of the unit through fluid flow and heat transfer. Numerical solutions of the steady turbulent flow are carried out by commercial software Fluent. A finite volume method has been employed to solve the governing equations. It is revealed that the considered plant having inlet height of 5cm performs better than that of having the inlet height10cm.

Radial Turbine Design for Solar Chimney Power Plants

Solar chimney power plants (SCPPs) collect air heated over a large area on the ground and exhaust it through a turbine or turbines located near the base of a tall chimney to produce renewable electricity. SCPP design in practice is likely to be specific to the site and of variable size, both of which require a purpose-built turbine. If SCPP turbines cannot be mass produced, unlike wind turbines, for example, they should be as cheap as possible to manufacture as their design changes. It is argued that a radial inflow turbine with blades made from metal sheets, or similar material, is likely to achieve this objective. This turbine type has not previously been considered for SCPPs. This article presents the design of a radial turbine to be placed hypothetically at the bottom of the Manzanares SCPP, the only large prototype to be built. Three-dimensional computational fluid dynamics (CFD) simulations were used to assess the turbine’s performance when installed in the SCPP. Multiple reference frames with the renormalization group k-ε turbulence model, and a discrete ordinates non-gray radiation model were used in the CFD simulations. Three radial turbines were designed and simulated. The largest power output was 77.7 kW at a shaft speed of 15 rpm for a solar radiation of 850 W/m2 which exceeds by more than 40 kW the original axial turbine used in Manzanares. Further, the efficiency of this turbine matches the highest efficiency of competing turbine designs in the literature.

Performance assessment of solar chimney power plants with the impacts of divergent and convergent chimney geometry

Abstract Influence of area ratio (AR) on main performance parameters of solar chimney power plants (SCPPs) is investigated through a justified 3D axisymmetric CFD model. Geometric characteristics of Manzanares pilot plant (MPP) are taken into consideration for the numerical model. AR is varied from 0.5 to 10 to cover both concave and convex (convergent and divergent) solar chimney designs. Following the accuracy verification of the CFD results and proving mesh-independent solution, main performance oriented parameters are assessed as a function of AR such as velocity, temperature and pressure distribution within MPP, temperature rise of air in collector, mass flow rate of air around the turbine area, dynamic pressure difference across the turbine, minimum static pressure in the entire plant, power output and system efficiency. The results reveal that AR plays a vital role in performance figures of MPP. Mass flow rate of air ($\dot{m}$) is found to be 1122.1 kg/s for the reference geometry (AR = 1), whereas it is 1629.1 kg/s for the optimum AR value of 4. System efficiency (η) is determined to be 0.29% for the reference case; however, it is enhanced to 0.83% for the AR of 4.1. MPP can generate 54.3 kW electrical power in its current design while it is possible to improve this figure to 168.5 kW with the optimal AR value.

Influence of environment and aging materials on the performance of solar chimney power plants

The simplicity of solar chimney power plant (SCPP) makes it very attractive for power generation. This paper investigates the technical feasibility of using a locally-produced plastic film (Low-Density Poly-Ethylene “LDPE”) as a solar chimney power plant collector cover. The idea is to combine a very low-cost material with a simple technical solution. As LDPE is subject to deterioration, the effect of aging on the initial properties of the used material is analyzed. Natural aging was privileged over the accelerated one by exposing the studied film, for a time duration of 3 years, to environmental constraints similar to the local conditions where the SCPP collectors are installed. Various experimental tests were carried out to show the decrease of mechanical resistance and to confirm the structural degradation. Results showed that after an exposure time of 3 years, a decrease of more than 50% of the failure stress is recorded. The spectroscopic analysis confirmed the progressive degradation of the structure of the aged films. Pyranometric measurements showed that the transmittance of the film proportionally decreases with the duration of aging which has a direct impact on the SCPP collector performance. A mathematical model is developed and validated to simulate the performance of the SCPP. An increase in the initial dimension of the collector by about 23% is necessary to maintain the design-targeted production during an exploitation period of three years. The study concluded that this type of film can be used in SCPP collectors for a maximum life cycle of 3 years under the considered environmental conditions.

Testing axial flow solar chimney turbine using wind tunnel

The solar chimney power plant (SCPP) is a modernistic and promising technology, which utilizes the combination of solar heating and chimney effect for producing electricity. Solar collector, updraft tower and air turbine are the main components of a solar chimney unit, however, the turbine plays a royal role because it converts the kinetic energy of the heating air into useful mechanical energy. In this study, I measured the power, flow rate, rotational speed and pressure drop of the designed and industrial turbines within the wind tunnel, and the power coefficient of the turbines are calculated by measured values. The turbine was designed according to the blade element theory modified to consider the surrounding duct. we measured the electric power, flow rate and pressure drop of the turbine, and the power coefficient of the turbine is calculated by measured values. Testing of the designed and industrial turbine within wind tunnel shows that the highest power coefficient of the designed turbine is 0.45, while the highest power coefficient of the industrial turbine is 0.32. The designed turbine produces 28.89% higher than the industrial one.

CFD Analysis of Solar Chimney Power Plant: Finding a Relationship between Model Minimization and Its Performance Use in Urban Areas

CFD Analysis of Solar Chimney Power Plant: Finding a Relationship between Model Minimization and Its Performance Use in Urban Areas

Investigating the Integration of Solar Chimney Power Plants with Photovoltaic Thermal Systems Under Various Weather Conditions

Investigating the Integration of Solar Chimney Power Plants with Photovoltaic Thermal Systems Under Various Weather Conditions

A novel concept of integrating bell-mouth inlet in converging-diverging solar chimney power plant

As conventional sources of energy are depleting fast, solar energy based devices can only be mass adopted in future if suitable design innovations are conceptualized and investigated to improve its extremely low energy conversion efficiency. In a first, apart from two important components: a collector and chimney, a third component called bell-mount inlet is proposed, investigated and optimised to enhance system thermal performance. Results show that with suitable design changes in collector, chimney and integrating an efficient bell-mouth at the inlet can substantially increase the air velocity by about 270% and hence drastically enhance the turbine power output compared to the conventional design. Further investigations on physics behind such a high increase in air velocity revealed that total pressure potential or the static pressure recovery becomes high and uniform along the chimney height in the new design, which is entirely absent in the conventional design. The lab-scale design was further analysed by scaling to a 50 kW power plant. Results show that the proposed new system can produce electrical power up to 1738 kW for the same collector area and chimney height of the conventional design. The proposed design is compact, efficient and a step towards making the solar device more viable.