Solar Chimney Power Plant Research Articles

Energy Generation Intensity (EGI) of Solar Updraft Tower (SUT) Power Plants Relative to CSP Plants and PV Power Plants Using the New Energy Simulator “Aladdin”

The current investigation provides information about solar updraft tower power plants, SUTPPs (also called solar chimney power plants, SCPPs), which form a unique method of solar-powered electricity production through a ducted wind turbine driven by induced airflow as a result of solar heating. The investigation is conducted using numerical modeling via the system-level simulation tool Aladdin (developed and released freely by the Institute for Future Intelligence, IFI) for solar energy systems, wind energy systems, or the built environment. The Aladdin energy simulator is first evaluated here by comparison with published experimental and numerical results corresponding to the historical 50 kW prototype SUTPP that was successfully tested in Manzanares (Spain) between 1982 and 1989. This prototype has a height of about 195 m for the chimney (the updraft tower) and a radius of about 122 m for the solar heat absorber (the solar air collector or the greenhouse). Next, various climate and performance characteristics are investigated and contrasted for nine different locations around the world with a similar latitude of 24°, which is within the sunbelt, assuming that the same Manzanares SUTPP prototype geometry is employed in these locations. These nine locations are Muscat (Oman), Al Jawf (Libya), Riyadh (Saudi Arabia), Karachi (Pakistan), Ahmedabad (India), Havana (Cuba), Culiacán (Mexico), Dhaka (Bangladesh), and Baise (China). The energy generation intensity (EGI) for the Manzanares-type solar updraft tower power plant in these nine examined locations was between 0.93 kWh/m2 per year (in Baise) and 2.28 kWh/m2 per year (in Muscat). Also, Muscat had the smallest seasonality index (maximum-to-minimum monthly electric output) of 1.90, while Baise had the largest seasonality index of 4.48. It was found that the main limitation of the overall SUTPP energy conversion efficiency is the chimney efficiency (the process of accelerating the air after entering the chimney). This study concludes that solar updraft towers (SUTs) cannot compete with existing mature and modular renewable energy alternatives, particularly photovoltaic (PV) panels, if the aimed use is commercial utility-scale electricity generation. Instead, SUTs may become attractive and achievable if viewed as hybrid-use projects by serving primarily as a large-scale greenhouse area for agricultural applications while secondarily allowing energy harvesting by generating clean (emissions-free) electricity from the incoming solar radiation heat.

Experimental evaluation of the performance and power output enhancement of a divergent solar chimney power plant by increasing the chimney height

Solar energy is an attractive renewable energy option for countries located in the tropical region. Harvesting this energy using simple yet innovative technologies such as solar chimney power plants (SCPP) will help the developing countries in meeting their sustainable development goals. In an SCPP, air is heated under a greenhouse collector and the hot air is passed to a chimney, where it drives a turbine while rising up. Research efforts have been directed in the past at improving the performance and power output of an SCPP by varying its geometric parameters. The chimney height of a previously optimized solar chimney power plant, having a divergent chimney, was increased from 4 to 6 m and then to 8 m in this first experimental work of this kind. The temperature variations inside the collector, along the chimney height, the velocity at the turbine section, the power available and the output power of an air turbine, estimated by applying mechanical load, are compared for the three chimney heights. The temperature rise of the air inside the collector was the highest for the 4 m tall SCPP and reduced as the chimney height was increased to 6 and 8 m due to the lower time of stay of air in the collector for greater chimney heights. Along the height of the divergent chimney, the temperature dropped with the maximum drop occurring for the 8 m tall SCPP indicating a lower enthalpy loss at the chimney exit. The air velocity at the turbine section was found to increase with chimney height for given solar insolation/time of the day due to the higher driving force which is the buoyancy effect produced by the hot air. The maximum turbine output power for the 8 m tall SCPP increased by 252% compared to the 4 m tall SCPP indicating that significant improvement in the power output can be achieved by increasing the height of a divergent chimney SCPP. An average power of about 40 kW will be available for a chimney height of 100 m which will be extremely beneficial for the sustainable development of small islands.

Thermal and energy analysis of a novel solar updraft tower design with divergent chimney and convergent collector concept: CFD analysis with experimental validation

Abstract The fact that energy sources are heavily dependent on fossil fuels increases the need for alternative energy day by day. Solar energy is the most popular alternative energy source with massive potential. Solar chimney power plants (SCPP) are one of the systems of interest based on solar energy. SCPP systems are rare systems that can provide 24-hour power output. Their performance has been the subject of constant research since the first pilot plant in Manzanares. Design is crucial for performance figures of SCPPs, and the limitation of climatic parameters causes the system to be approached with different designs. This study makes a 3D CFD model by combining the divergent chimney and convergent collector structure based on the first pilot plant. The solar ray tracing algorithm and the RNG k-e turbulence model are applied and the model equations are solved under dynamic conditions with the reliable software ANSYS FLUENT. After the mesh-independent solution of the model is complete, it is validated with experimental data. The two cases are compared for solar radiation of 1000 W/m2 and environmental temperature of 293 K. A power output of 50.51 kW is achieved for standard pilot sizing. With the new model, the power output rises to 146.34 kW. It is seen that the divergent chimney and convergent collector affect the airflow in the system, increasing the maximum air velocity to 19.363 m/s. In parallel with the experimental data, it is seen that the temperature on the ground exceeds 360 K in the CFD results.

A case study of an integrated solar chimney power plant and water desalination plant in Qatar

The study proposes a novel solution of integrating a solar chimney power plant (SCPP) with a water desalination pilot plant (WDPP) to enhance generating energy and fresh water. The integration was accomplished by coupling the excess heat from the WDPP to the collector of the SCPP. Hence, enhance the temperature profile within the structure for better energy production. Hourly weather data (temperature, humidity, wind speed, and solar irradiance) were gathered during the entire year and their impacts on the efficiency of the SCPP were analyzed. The performance of SCPP+WDPP was assessed in terms of the production of electrical power and desalinated water. The temperature differences between the inside and exterior of the SCPP had a significant impact on the airflow pattern within the chimney and the resulting energy production. The results emphasized the superior performance of SCPP+WDPP, especially in terms of continuous 24-h electrical and water production. The proposed system increased water production from 139,443.4 tons to 224,513.7 tons and energy production from 633,125.9 kWh to 1,103,435 kWh compared with SCPP. The SCPP+WDPP could reduce the annual CO2 emissions by 993,091.5 kg and increased power efficiency by 98 %. Performing further techno-economic assessments is advised to enhance the system efficiency.

Critical interpretation and analysis to correlate the canopy height to collector diameter ratio for optimized design of solar chimney power plants

The collector's periphery height determines the entrance size to the solar chimney power plant. There is inconsistency in the published experimental and numerical results on the optimum collector inlet height for different collector diameters. This paper aims to analyze the available data to identify the best collector inlet height-to-diameter ratio and to introduce a design guide for an optimized performance of solar chimney power plants. The experimental data reported in previous works have been clustered and manipulated to produce a comparative argument on the collector inlet height-to-diameter. In addition, a numerical model is developed to support the literature conclusions and to produce further data to decide the optimum collector inlet height-to-diameter ratio. For a 6.6-m collector diameter, four different inlets have been investigated, namely, 0.05, 0.1, 0.15, and 0.2 m. The best performance in terms of air velocity and temperature rise is obtained with the 0.05-m inlet height, where it shows an improvement of up to 35.35% compared to the larger inlet heights. The lower collector inlet height allows a more effective heat transfer from the ground and the collector to the air. It is concluded that the optimum collector inlet height-to-diameter design ratio for solar chimneys with collector diameters larger than 3 m is 0.0075±0.0005. For small-scale solar chimney models with less than 3 m collector diameter, the best collector inlet height-to-diameter ratio ranges between 0.015 and 0.03.

Impact of the chimney junction radius on the air-flow characteristics inside a solar Chimney Power Plant

The chimney junction of solar chimney power plant was the main element coupled the solar collector to the chimney. It presents an important impact on the SCPP design, which is change the air-flow direction. The numerical code ANSYS Fluent was used in this study to investigate how the chimney Junction radius affected the local air-flow characteristics and the turbine site. Using test results from an experimental prototype constructed in Sfax, Tunisia, the numerical method was validated and verified. For four set-ups with various chimney connection radii, thermodynamic variables such as distributions of the total pressure, static temperature, static pressure, and magnitude velocity were examined. Also, the influence of these parameters on the air turbulence was analyzed through the transition zone. The results showed that the local air-flow characteristics and therefore, the SCPP efficiency were significantly impacted by changes in junction radius. Besides, the maximum velocity inside the chimney was varied and changes its location when the junction radius changed. These facts affect directly the overall turbine expenditure, which represented in terms of structure and power capacity.

Advancements in solar updraft towers: A comprehensive review

The desire for a carbon-free planet has prompted a few experts to advocate for the most abundant energy known to us i.e Solar Energy. There are lots of solar powered energy systems in which the solar chimney power plant has been significant among passive methods in generating carbon free power. There are many attempts taken both experimentally as well as theoretically in developing efficient solar chimneys. This article reviews the major activities carried out in the various topographical regions covering significant research articles. In addition, the survey focuses on experimental research, understanding and recreational works, applications, and analogous work references, all of which are based on a broad range reference. Further, discussion on the research gap in each of the section is included with recommendations for future enhancement of this technology.

EFFICIENCY DETERMINATION OF SOLAR CHIMNEY POWER PLANT RETROFITTED WITH NOVEL FINNED COLLECTOR UNDER REAL-TIME SOLAR IRRADIANCE

This paper discusses the three-dimensional numerical study of a new finned collector integrated into the solar chimney power plant. Manzanares pilot's details, which are tower height 194.6 m, rooftop height 1.85 m, rooftop diameter 244 m, tower diameter 10.16 m, and pilot mean temperature 20°C with air speed 15 m/s, are implemented in this work to check the suitability of the finned collector as a way of improvement. In order to assess the unique idea, a parametric study is done with different number of fins: 46, 33, and 25; different fin widths: 0.5, 0.25, and 0.1 m, and different fin heights: 1.2, 0.925, and 0.6 m. Therefore, optimal outputs could be obtained by the novel rooftop that is proposed in this study, where the efficient case is specified dimensionally by 46 fins, a fin width of 0.1 m, and a fin height of 1.2 m, which gives 1.674% as the station performance, 700.597 kW as the resulted power of the plant, 1790.3 as the Nusselt number, and 1.96E+14 as the Rayleigh number.

Building and Experimenting Solar Chimney Power Plant

Recently several resources of sustainable and clean energy have been developed, such as solar panels, wind turbines, and others. The Solar Chimney Power Plant (SCPP), which is among those harnessing solar power where a stream of air is induced by adding heat through solar irradiation using the greenhouse effect, is rarely utilized for generating power. The hot air flows through the chimney under the effect of buoyancy force which in turn drives a vertical axis wind turbine. Although this technique is investigated by many reports, unfortunately, it is still in the laboratory phase. However, it might be an optimal solution for zones where operating other techniques is not efficient for various reasons. In this project, an SCPP prototype was built and tested in Anbar, a central province in Iraq. The impact of various design parameters on power generation was assessed. The experimental results prove the feasibility of SCPPs for generating electricity at low costs and the suitability of building SCPPs in countries technologically less developed with specific weather conditions and scarcity in water resources that are normally needed for cleaning solar panels, for example.

Performance Enhancement of the Basic Solar Chimney Power Plant Integrated with an Adsorption Cooling System with Heat Recovery from the Condenser

In a previous work, a solar chimney power plant integrated with a solid sorption cooling system for power and cold cogeneration was developed. This prior work showed that reusing the heat released from the adsorption bed enhances the system’s utilization of solar energy and increases the turbine’s output power. In the present paper, a subsequent modification to the arrangement and operation of the preceding system is introduced. The primary objective of the modification is to enhance performance and increase the plant’s capacity to effectively harness the available solar radiation. The method involves placing the condenser tubes at the solar collector entrance. Therefore, the airflow captures the condenser-released heat before it enters the collector. The modified configuration and operation of the system are discussed. A dynamic mathematical model is established to simulate the hybrid system’s operation and evaluate its parameters. The obtained results show that a 5.95% increase in output power can be achieved by recovering the heat of condensation. Furthermore, the modified system attains a 6% increase in solar-to-electricity conversion efficiency compared with the basic system. The findings suggest that the modified system, which recycles condenser heat, provides noticeable enhanced performance compared with the basic system.

Influence of Inclination Angle at the Chimney Inlet on the Power Generation in Solar Chimney Power Plants through 3D CFD Model

The sun is an abundantly available and clean renewable energy source. Therefore, solar energy offers significant potential for mitigating climate change and reducing emissions from burning fossil fuels in the future. Solar chimney power plants (SCPPs) have a technical capability for meeting the massive sustainable power production. Basic parts of SCPP system are the chimney, turbine, and collector. The geometric dimensions of the components are the crucial factors for improving the solar chimney efficiency. The goal of this work is to analyse the influences of the inclination angle (θ) at chimney inlet on performance characteristics of the system by employing RNG k−ε turbulence model coupled with discrete ordinate (DO) solar ray tracing method via ANSYS Fluent CFD software. The model is built by taking into consideration geometric parameters of Manzanares plant and verified with its measurements. The innovative chimney entrance configurations are produced by altering the chimney entrance slope (θ=50°–80°) with the geometrical dimensions of the chimney, collector, and fillet keeping constant. The computational results display that the new chimney configurations improve the maximum velocity, system power output, and turbine pressure drop. The peak velocity of 18.1 m/s is gained for the configuration with θ=80° compared to that of 14.3 m/s obtained for the base model having θ=45° at 1000 W/m2. Besides, this configuration enhances power output to 61.5 kW with a rise of 24.5% compared to the base model with a power output of 49.1 kW at 1000 W/m2.

Comparative Analysis of Solar Chimney Power Plant Chimney Design: Performance Evaluation and Material Cost Comparison

Abstract: This paper investigates different configurations of solar chimney design in a solar chimney power plant system. Mathematical analysis of the system has been done in Ansys software. The results of the maximum (inlet) velocity, pressure, efficiency, and temperature of the air are obtained for base type, convergent, divergent, sudden contraction, and sudden expansion types of chimneys. Furthermore, the electrical power output of Solar Chimney Power Plants has been determined for different chimney types. In this analysis, one Solar Chimney Power Plant (SCPP) with a solar collector diameter of 258 m and a chimney height of 197 meters and outlet diameter of 10 m has been taken as the basis. It has been found that sudden expansion and divergent types of chimneys give higher output power than the other types of chimneys. Also, while calculating the cost of materials of the different types of chimneys, it has been found that the sudden expansion type of chimneys is costing less than other types of chimneys. When power output was compared, it was found that the sudden expansion type of chimney gives higher output than other chimneys. Detailed simulation, testing, and analysis are necessary to consolidate the results.

A comprehensive analysis of time-dependent performance of a solar chimney power plant equipped with a thermal energy storage system

Solar Chimney Power Plants (SCPP) are among the promising solar thermal electricity generation technologies. Equipped with a Thermal Energy Storage (TES) system, such technologies can overcome variations in the main driving factors such as solar radiation and ambient air temperature. This article presents a comprehensive semi-analytical model of a TES to predict the time-dependent performance of an SCPP. By introducing a Quality Factor of power generation (QF) that includes energy conversion efficiency and capacity factor, the effects of 15 TES materials have been studied on the plant performance. Results indicate no significant difference between water TES and clay or soil type, and water-filled bags or tubes are relatively ineffective in improving performance compared to them. Among the various TES materials analyzed, a type of wet soil, i.e., the specific wet mixture of clay, sand, and silt in closed and dark-colored bags, show excellent performance in both QF enhancement and having low Heat Penetration Depth (HPD) simultaneously. The QF and HPD are directly affected by thermal effusivity and thermal diffusivity, respectively. Implementing wet soil TES for the studied power plant (Manzanares) enhances the QF from 7.46 % (for limestone soil) to 10.95 %. Water-filled bags demonstrate a heat penetration depth of 0.4 m, while wet soil exhibits a slightly greater depth of 0.5 m. Furthermore, water-filled bags experience a broader temperature range of 40 °C, whereas wet soil undergoes a comparatively smaller temperature variation of 26 °C. Furthermore, the capacity factor raises from 41.18 % to 61.07 % when utilizing wet soil TES compared to water-filled bags.

A novel design of a twin-chimney solar power plant for power and distilled water production

This work suggests an innovative and distinctive solar twin-chimney power plant (STCPP) design. The proposed unique design consists of a solar chimney power plant, upgraded with a secondary low-cost chimney. Unlike other solar chimney power plants, the proposed design attaches the secondary chimney directly to the collector to maximize water output while having a high energy density and utilization. Several solar chimney power plants designed with water desalination have been proposed in the literature. However, in all the proposed designs, the water desalination occurs mainly at the primary (inner) chimney. In contrast, water desalination occurs at the secondary chimney of the STCPP. The secondary chimney provides a larger surface area than the primary one, hence more water desalination and higher utilization.According to the findings, the novel method produced 1,111,754 kWh of energy annually, 2.9 times more than a conventional solar chimney power plant (384,092 kWh). The findings also revealed that the new design generated 209,165 tons of distilled water instead of nothing with the traditional solar chimney. Additionally, the results showed that the proposed design could reduce CO2 emissions by 658318.5 kg annually, with a 0.650 utilization factor. Furthermore, the comparative study with similar designs showed that the proposed design outperformed all other methods regarding utilization, energy production, water production, and CO2 reduction.

A genetic programming approach for the prediction of solar chimney power plant power

This study empirically examines the effectiveness of the solar chimney power plants (SCPP), which is an innovative method for the use of solar energy, in the middle latitude region (37.88° N) in the northern hemisphere. Experimental measurement parameters of temperature, velocity, and radiation obtained from four cardinal directions (north, south, east, and west) and from 26 different locations were recorded throughout the day (08:00 am-07:30 pm). These measurements were used to calculate and estimate the power values used to measure the energy efficiency of the solar chimney. In the study, the genetic programming method was used to estimate the power value. In the five different forecast models developed, 15 different parameters were used diagonally. The obtained power estimation equations were cross-checked using statistical methods. Determination coefficient value is higher than >0.90 in all equations and is close to the ideal. In the comparison of all statistical models, the Global Performance Indicator (GPI) was used, with the best result obtained from Model 2. The results of this model are MAPE:6.5233, MBE: −0.0124, RMSE:1.1036 ve t-stat:0.0374, which is quite close to zero. In addition, the power values obtained from both the calculated and developed models were dimensioned and compared over the power-time factor of eight different studies in the literature. The mean relative error value nof the values calculated as a result of this comparison varies between 2.3% and 21.3%. This study provides a model for the different geometries of solar chimney prototypes and provides an example for measuring the design and performance of solar chimney systems to be installed in the middle latitudes and in regions with “Csa” climate characteristics, and is recommended for academic and industrial users. The mathematical models developed can be considered as a step to increase the efficiency of the solar chimney power plants.

Experimental and 3D numerical analysis of the impact of a tower shape on the performances of a solar chimney power plant

AbstractThis article presents both numerical and experimental analyses investigating the impact of tower shape on the performance of a solar chimney power plant (SCPP). The study explores several cases through experiments and computational fluid dynamics (CFD) modeling. Specifically, variations in the tower's outlet section and overall shape were examined under different solar radiation conditions. The shape of the tower was found to have a significant influence on various performance parameters of the studied SCPP. These include the mass flow rate, velocity, temperature rise in the collector, pressure in the tower, as well as power production, and overall efficiency. The obtained results indicate that when the tower's outlet section is twice the size of the inlet section, all of these parameters experience substantial improvements. For a configuration similar to that of the Manzanares prototype, the generated power increased from 50 to 56 kW, representing an enhancement of about 12%. The findings underscore the importance of considering the tower shape when designing SCPPs. Optimizing the tower's geometry can lead to significant improvements in key performance metrics, resulting in enhanced power generation and overall efficiency.

The potential of employing a novel hybrid solar chimney power plant in the Arabian Gulf: A case study

Many countries worldwide are setting energy strategies to meet the future NetZero goal, including the states in the Arabian Gulf. Hence, this work assesses deploying a hybrid solar chimney power plant (HSCPP) in the Arabian Gulf countries to meet this goal. The proposed HSCPP not only produces clean energy but also produces distilled water and reduces CO2 emissions to the atmosphere. Hourly actual weather conditions (solar irradiation, temperature, wind speed, and meteorological factors) for one full year were incorporated with the HSCPP mathematical simulation to evaluate its performance in fourteen locations (Bahrain, Iraq, Kuwait, Oman, Qatar, UAE, Saudi Arabia, and Yemen), spanning the entire Arabian Gulf. The results showed varying HSCPP performance regarding electricity and water production, depending on the geographical and meteorological conditions. Shahrua City in the Kingdom of Saudia Arabia showed the highest electricity production and CO2 emissions reduction. Conversely, Sanaa in Yamen showed the most minor electricity production and the least CO2 emission reduction. Furthermore, Jal Aliyah produced the freshest water in Kuwait, while Sanaa had the least. This study showed that the HSCPP can meet the Arabian Gulf region's power and water demand while lowering carbon emissions.

Rating and sizing analysis of the solar chimney power plant considering uncertainty in solar radiation and under different load conditions

ABSTRACT The main focus of this research is on modeling and analyzing an industrial-scale solar chimney power plant (SCPP) under actual or realistic conditions. While most of earlier studies considered the steady state kind of solar radiation, this study is based on the assumption of the diffuse and erratic nature of solar energy in calculating the sizing rating of SCPP. Moreover, the use of uncertainties in solar radiations is time-consuming and difficult, and hence a theoretical approach is used to get the required results. Statistics and probability theory concerning solar radiation and weather data of Mumbai, India region are used for said analysis. The best generator rating and daily energy output are determined by taking into consideration variables like chimney height, collector radius, and storage thickness below the absorber plate of SCPP. Based on the aforementioned characteristics, one may construct SCPP sizing curves to yield 136, 435, and 945 kWh energy generation in 24 h period. It is essential to consider the full load and part load operations of the generator in order to prevent the unused kinetic energy linked to low velocity and increased velocity. While the majority of the past research by various researchers was carried out under full-load conditions, this study also addresses half-load situations. The current effort will help manufacturers and the scientific community develop sizing and rating taking into account different sun radiation statistics.

Integrating solar chimney power plant with electrolysis station for green hydrogen production: A promising technique

This paper explores the use of Solar Chimney Power Plants (SCPPs) for the production of green hydrogen as a means to store excess electrical energy generated from renewable energy resources (RESs). The proposed structure produces electrical energy and distilled water by heating the air under the SCPP. The electrolyzer is integrated into the seawater pool and installed at the solar chimney's base. The weather conditions at the proposed location of the SCPP including solar radiation, temperature, humidity, and wind speed, are analyzed to assess their impact on the performance of the SCPP. The potential applications and economic feasibility of the SCPP are discussed, considering its contribution to renewable energy generation and the benefits of hydrogen as a clean energy carrier. The results show that solar radiation levels and favorable temperature profiles play an important role in the performance of the SCPP. The SCPP could produce 380,263 kW h of electrical energy and 139,443 tons of distilled water annually. The results also showed that the SCPP could produce 13,000 kg of green hydrogen and 173,224 kg of oxygen annually. The revenue generated from the production of H2 and O2 has improved the levelized cost of energy (LCOE) for the SCPP to 0.51 $/kWh and made it compete with other energy production facilities. Monthly variations in electrical energy, H2, O2, and distilled water production, highlight the dependence of hydrogen production on solar intensity and temperature. Overall, the research demonstrates the potential of SCPPs and hydrogen production as a sustainable and efficient solution for storing and utilizing excess renewable energy.

Computational Investigation of Under Expanded Solar Chimney Power Plant

Computational Investigation of Under Expanded Solar Chimney Power Plant