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This paper presents a solar chimney that acts as a heat accumulator. It is based on its alternating charging (melting of the phase change material—PCM) and discharging (solidification), which helps to save energy and ensures stable operation of the solar chimney. In this paper, special attention has been paid to the heat dissipation process (solidification of the PCM). The theoretical model of solidification has been solved in an original way. This paper presents a new simple theoretical model for the solidification of the PCM on a flat plate and presents the results of numerical tests. The theoretical model presents a method for determining the heat transfer coefficient at the solidification front of the PCM. In addition, the heat transfer coefficient from the flowing air to the outer surface of the solidifying front plate was determined experimentally in an original way. The heat transfer coefficient values resulting from the experiments may be employed in order to calculate the heat transfer coefficient for air flowing through the slot of the collector in the solar chimney. The calculated value of the heat transfer coefficient was 18.55 W/m²K. [ABSTRACT FROM AUTHOR]

Traditional solar updraft power plants work during the daytime as it is dependent on solar radiation to generate electricity. Hence, energy productivity, efficiency, and performance are limited. This work presents a novel attempt to increase the productivity of a traditional solar updraft system by combining it with a downdraft technology in one system, the Twin-Technology Solar System (TTSS). The TTSS comprises two co-centric inner and external solar towers, turbines, water sprinklers, and a collector. The inner tower works as a traditional solar updraft system, where the air is heated under the collector due to irradiance and then moved up the chimney due to the pressure column. While the external tower creates a downdraft wind by spraying water at the hot ambient air at the top of the tower. The hot air instantly absorbs the water and descends the tower to interact with the turbines at the bottom to produce electricity. This mode is independent of solar irradiance and can operate day and night. Hence, the TTSS generates electricity, daytime and night. A mathematical simulation model was developed based on the proposed system's energy and mass balance equations to assess performance. The TTSS generated 752,763 kWh of electricity annually, 2.14 folds higher than a traditional solar updraft system. Consequently, a reduction of 677 tons of CO2 was achieved with production. The design is suitable for deployment in hot and dry weather areas, such as remote villages and deserts. Future work will investigate introducing other technologies to boost the TTSS performance.

This study presents the potential of using a natural ventilation system integrated with different combinations of enhancement techniques. The focus was on the perspective of using such configurations of passive ventilation systems (PVSs) in buildings located in different European cities. This work presents the results of obtaining the level of volumetric air flow rate for considering natural ventilation systems. Furthermore, the influences of local weather conditions (temperature, solar radiation, wind speed) were analyzed. Moreover, the year-round operation of all systems was presented. Also noted was the limitation of using PVSs based on the natural draft effect, additionally assisted by wind turbine ventilators in all European localizations. However, for the cities located in the northern part of Europe, it was confirmed that such a system can still meet minimum hygienic recommendations. It was also noted that a system additionally supported by a solar chimney is a much better solution. The best system was a PVS supported by a wind turbine ventilator and solar chimney integrated with PCM accumulation mass. The system should be additionally supported by waste heat from low-temperature sources. In the presented study, a high potential to reduce CO2 emission from building stock by the recommended system is additionally highlighted. However, there is still a need to analyze the proposed solutions by additional field tests and experimental investigations. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Solar chimneys are among the most common methods for natural ventilation of buildings. Computational Fluid Dynamics (CFD) has been widely applied in research and design of solar chimneys. Most of the previous studies are based on 2D CFD models which ignore the effects of the width (the third dimension) of the air channel. In addition, the applicability of 2D models for the solar chimneys with a low width-to-gap ratio is still questionable. This study investigates both 2D and 3D CFD models for window-sized vertical solar chimneys. The 2D model is applied to the domain comprising the central plane of the channel gap (G) and height (H) while the 3D model is applied to the domain consisting of the channel gap, height, and width (W). The flow fields, flow rates and thermal efficiencies computed with the 2D and 3D models at different heights, gaps, and widths are compared. The results show that W / G is the most crucial factor. The effects of the side walls are significant at a low W / G but gradually diminishes as W / G increases. At W / G = 15, the side wall effects are confined to a region of about 2.6% W. Particularly, for W / G >8, the differences between the 2D and 3D flow rates and thermal efficiencies are within ±5%. These findings offer a reference for researchers and engineers to select between 2D and 3D CFD models for a specific solar chimney. [ABSTRACT FROM AUTHOR]

Population growth, increase in energy demand, and environmental problems of fossil fuels have led to the use of renewable energies. One of the applications of solar energy is the solar chimney thermal power plant. Building a solar chimney is not cost-effective due to its low thermal efficiency, so studies have been conducted to increase its efficiency. Among the studies conducted, few have studied the influence of absorber geometry on system performance. In this research, the solar chimney was designed in small dimensions and effect of changing the geometry of the absorbent surface was investigated. The numerical model has been validated with experimental data of Manzanares pilot plant. The geometry was numerically simulated in Ansys Fluent software. Realizable k-ε model for turbulence and DO irradiation model for radiation has been used. The solar radiation 1000 W / m 2 is selected. The coupled arithmetic was used as the pressure–velocity coupling scheme. Besides, the discretization method for the pressure term was PRESTO! Algorithm while other terms were second-order. The criterion of convergence in solving all equations is 10 - 6 . The results showed that the maximum velocity for height 0.1 and 0.2 m has increased by 6.945% and 8.048%, respectively, compared to the smooth absorber surface. By increasing the height in the center of the solar chimney, the maximum power is obtained at a height of 0.2 m with a value of 2.338 w. Therefore, changing the geometry of the absorber affects the performance of the chimney and can strengthen it. [ABSTRACT FROM AUTHOR]

A solar tower system is a nonpolluting solar thermal power plant that utilizes a combination of a wind turbine and generator to convert thermal energy generated from a solar collector into electrical energy. The study focuses on a system comprising a solar collector that transforms solar energy into thermal energy, a chimney that converts thermal energy into kinetic energy, and a wind turbine that further converts kinetic energy into electrical energy. The system's performance is evaluated through the implementation of a numerical model, which is validated by comparing it with experimental data. Four different types of meshes are tested to determine the most suitable mesh for the system. The discrete ordinate radiation model is used to solve the radiative transfer equation, and the RNG k‐휀 turbulence model is implemented to calculate turbulence. In a subsequent study, the effect of absorber configuration on the system's performance is investigated. Three different absorber configurations—sinusoidal, square, and triangular—are proposed, and the numerical results showed that the system's performance is affected by the absorber configuration. The velocity in the chimney inlet increases for all proposed configurations compared to the standard configuration, with the triangular configuration showing the highest velocity increase. Additionally, the newly proposed configurations enhance the thermal efficiency of the system, leading to a thermal efficiency of 12.18%, 12.2%, and 13.65% for the sinusoidal, triangular, and square configurations, respectively. Overall, the solar tower system demonstrates its potential as a clean and efficient source of electrical power. [ABSTRACT FROM AUTHOR]

This work investigates integrating vegetation into solar chimney power plants (SCPPs) using numerical simulations of an SCPP prototype in Spain. A 2D axisymmetric computational fluid dynamics model with radiation heat transfer was employed to evaluate the impact of vegetation beneath the solar collector roof on system performance. Different SCPP configurations were analyzed: a standard design, one with a secondary collector roof, and another with secondary and tertiary collector roofs. Results indicate the secondary and tertiary roof configuration exhibited the highest annual electricity generation capacity of 34-80 kW. While introducing vegetation under the collector appears feasible, it is likely to reduce the overall energy output. In summary, simulations suggest that vegetation influences SCPP operation, decreasing power production, while incorporating multiple collector roofs enhances the generation capacity. [ABSTRACT FROM AUTHOR]

The development of modern life requires new energy sources, and one of this energy is renewable solar energy uses in solar chimney for natural ventilation, but at the present time it is not greatly invested, taking into account the weather conditions of the region and the physical characteristics of solar radiation and air in the area in which the study will be conducted. The current study was carried out in Basrah city- Iraq, at longitude 47.749° and latitude 30.568°, where the solar chimney was facing south. The investigation was conducted using both theoretical and experimental studied. In the theoretical study, the solar chimney with the room in the presence and absence of PCM was simulated numerically using the finite volume method using the soft package ANSYS-Fluent/2021/R2. The effect of different tilt angles (α = 30°, 45°, and 60°), solar chimney air gap (gab = 10 cm, 15 cm, and 20 cm), and PCM basin thickness (tPCM = 3 cm, 4 cm, and 5 cm) were investigated. The results were presented in the form of contours of the distribution of streamlines, velocity, temperature, and liquid fraction of the solar chimney with the room, rate of temperature of the absorber plate with time and the rate of temperature of the PCM (TPCM) with time, rate of air change per hour (ACH). As for the experimental side, the device was built, and the intensity of solar radiation was studied for several days on 30 Sep. and 15 Oct. 2023, the temperature distribution rate of the absorbent plate over time, the PCM temperature rate, and the air change per hour (ACH). The theoretical results were compared with the experimental results, where there was good agreement, and the theoretical comparison was also made with several researchers. Significant results showed that the optimal ratio of the air gap width of the solar chimney is 15 cm, the inclination angle of the solar chimney α = 30°, and the thickness of the PCM basin (tPCM = 4 cm) to obtain the maximum ventilation rate. The thickness of the PCM basin = 4 cm gives the largest liquid fraction along time and maximum average temperature of the absorber plate. On the experimental, it was found that PCM convert into the liquid phase after its melting point, which is 340 K, after 12 noon, and the highest value of ACH reached 37 on September 30/2023 at midday.

One of the disadvantages of solar systems is their low efficiency due to weather conditions such as dust and clouds that reduce their performance. Therefore, this article examines the impact of cloudy weather on the performance of the PV/solar chimney to demonstrate the performance of these solar systems under overcast weather conditions. The PV/solar chimney system was designed and built, and two days in December were chosen for testing: 27 December with clear weather without clouds and 28 December with cloudy weather.The results showed that cloudy weather has a clear effect on the performance of the PV/solar chimney where the intensity of solar radiation is low. Clouds act as a barrier preventing access to sunlight, as the electrical power generated on a clear weather day reached 341.92 W, while on a cloudy weather day, 187.88 Watts at noon. The kinetic energy on a clear weather day reached 17.212 mW, while on a cloudy weather day, it reached 9.47 mW at noon. The electrical efficiency on a clear weather day reached 15.96 %. In contrast, on a cloudy weather day, it reached 13.2 % when the test started at 9 a.m., after which the efficiency decreased with the increase in the intensity of solar radiation to become 13.574 % in clear weather while 12.12 % in cloudy weather at noon, and the thermal efficiency on a clear weather day reached 56.06 %. In contrast, on a cloudy weather day, 42 % at noon. The total efficiency in clear weather reached 69.65 %, while on a clear weather day cloudy by 54.12 % at noon.

Abstract This study explores the potential of repurposing mosque minarets as solar chimneys in hot arid regions to facilitate natural ventilation and diminish the reliance on energy-intensive cooling systems. Originating as a means to call the faithful to prayer, minarets have become iconic landmarks within Islamic cities. This research focuses on Cairo, Egypt, as a representative hot arid environment. The paper traces the evolution of the minaret, underscoring the variations in form that influence the experimental design. The investigation proceeded in two stages: the construction of physical mosque models with variably positioned minarets for laboratory testing, ensuring standardized measurements, followed by computational fluid dynamics (CFD) simulations for comparison. Findings indicate that mosque minarets can be effectively adapted for passive ventilation, with their performance significantly influenced by orientation and placement. This study concludes that traditional mosque minarets offer a viable, sustainable option for passive cooling in hot climates.

A solar chimney has been studied in this research to increase the efficacy of still convection currents. The usage of a condenser also improved the condensation process. Solar still condensers are typically made up of tubes through which salt water is pumped. But in the set-up shown, water vapour was channeled through a series of pipes submerged in the ocean. Solar still is built and tested in real-world situations with solar as a standard. Evaporator (basin) area-based efficiency comparisons reveal that the still-equipped solar chimneys and condensers yielded 9.1% superior results. The mainstream of the yielded (61%) condensed in the solar still condensers, resulting in a production rate of 5.3 L per m 2 day for the simple solar still and 6.2 L per m 2 per day for the modified still. This demonstrates that the evaporation efficiency of solar still and, by extension, its distillation efficiency improved by increasing convection and condensation. [ABSTRACT FROM AUTHOR]

This study explores the potential of repurposing mosque minarets as solar chimneys in hot arid regions to facilitate natural ventilation and diminish the reliance on energy-intensive cooling systems. Originating as a means to call the faithful to prayer, minarets have become iconic landmarks within Islamic cities. This research focuses on Cairo, Egypt, as a representative hot arid environment. The paper traces the evolution of the minaret, underscoring the variations in form that influence the experimental design. The investigation proceeded in two stages: the construction of physical mosque models with variably positioned minarets for laboratory testing, ensuring standardized measurements, followed by computational fluid dynamics (CFD) simulations for comparison. Findings indicate that mosque minarets can be effectively adapted for passive ventilation, with their performance significantly influenced by orientation and placement. This study concludes that traditional mosque minarets offer a viable, sustainable option for passive cooling in hot climates. [ABSTRACT FROM AUTHOR]

Urban air pollution has become a pressing challenge in recent times, demanding innovative solutions. This review delves into the potential of Solar Chimney Power Plants (SCPPs) as a sustainable approach to mitigating air pollution. The idea of mitigation of pollution may be an added advantage to the use of SCPPs in practice. Recent advancements, such as the integration of photocatalytic reactors (PCRs) for the elimination of greenhouse gases (GHGs), emphasizing the importance of addressing non-CO2 GHGs like CH4 and N2O are analyzed. The novelty of this review is that it not only focuses on the shifting and removal of particulate matter but also on the removal of greenhouse gases. Numerous case studies, ranging from filter-equipped SCPPs to Solar-Assisted Large-Scale Cleaning Systems (SALSCSs), are reviewed, providing a comprehensive understanding of their design, performance, and potential benefits. This review serves as a guide for researchers and policymakers, emphasizing the need for multifaceted approaches to address the intricate nexus of air pollution, renewable energy generation, and climate change mitigation. [ABSTRACT FROM AUTHOR]

Solar energy is one of the most feasible options to produce energy in countries where unexploited desert areas or solar radiation are abundant. An energy tower is an effective system for electrical power generation that can perform more efficiently along with solar radiation. As the primary aim of the present study, effects of different environmental parameters on total efficacy of energy tower were investigated. In this study, the efficiency of the energy tower system is investigated experimentally by an indoor fully adjustable apparatus. In this regard, a comprehensive set of influencing parameters like air velocity, humidity, and temperature and the effects of tower height on the performance of the energy tower are individually assessed. It is demonstrated that there is a direct relationship between an increase in humidity percentage of the surrounding and performance of energy tower, meaning that a 274% increase in humidification rate led to 43% elevation in airflow velocity. The kinetic energy increases in the direction of airflow from top to bottom, and as the height of the tower lengthens, the kinetic energy enhances and subsequently increases the overall efficiency of the tower. An elevation about 2.7% in airflow velocity was seen due to an increase from 180 to 250 cm in chimney height. Although the energy tower performs efficiently in the nighttime, airflow velocity increases averagely about 8% during the daytime and at the peak of the solar radiation, the airflow velocity enhances by 58% compared to nighttime. [ABSTRACT FROM AUTHOR]

The solar vortex engine (SVE) aims to replace the tall and expensive chimney structure in solar updraft power plants by a shorter less expensive structure named the vortex generator. In this study, the entire SVE system is simulated by CFD to determine the appropriate location for the turbine unit as well as prove the capability of the vortex generator in replacing the chimney. Three different cases for the SVE are considered and compared to corresponding cases of the solar chimney power plant (SCPP). Results revealed that the optimum turbine location is at the outlet hole of the vortex generator. An updraft air velocity of 1.82 m/s was achieved at the outlet hole, compared to 1.56 m/s at the base of a solar chimney with the same diameter as the upper hole. The consideration of the turbine pressure drop did not affect the formation and preservation of the air vortex. So, the 1 m high vortex generator successfully replaced the 8.6 m chimney component in solar updraft power plants, greatly reducing the cost and construction complexity of the plant. The vortex generator accelerated the air delivered from the solar collector, increasing its velocity by 14 times. The SVE’s power output is directly proportional to the static pressure drop across the turbine. The mean difference values along the air vortex field between the cases with and without a turbine are 0.67 Pa and 0.026 m/s for the static pressure drop and velocity magnitude, respectively.

This paper presents a solar chimney that acts as a heat accumulator. It is based on its alternating charging (melting of the phase change material—PCM) and discharging (solidification), which helps to save energy and ensures stable operation of the solar chimney. In this paper, special attention has been paid to the heat dissipation process (solidification of the PCM). The theoretical model of solidification has been solved in an original way. This paper presents a new simple theoretical model for the solidification of the PCM on a flat plate and presents the results of numerical tests. The theoretical model presents a method for determining the heat transfer coefficient at the solidification front of the PCM. In addition, the heat transfer coefficient from the flowing air to the outer surface of the solidifying front plate was determined experimentally in an original way. The heat transfer coefficient values resulting from the experiments may be employed in order to calculate the heat transfer coefficient for air flowing through the slot of the collector in the solar chimney. The calculated value of the heat transfer coefficient was 18.55 W/m²K.

Numerous studies have recently focused on enhancing the efficiency of solar chimney power plants (SCPP) and increasing their output power during periods of limited solar radiation. One such study proposes a novel solution: combining an SCPP with a gas power plant to create a hybrid power plant that generates power consistently, day and night. The system involves burying pipes underground and channeling the hot gas from the gas power plant through them, rather than releasing it into the atmosphere. This process increases the temperature of the soil beneath the canopy, which in turn raises the air temperature and the velocity of the air. The resulting decrease in air density leads to an increase in output power. Our results show that the performance of solar chimney of soil ground with buried pipe is about 30% higher than sand domain. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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 H 2 and O 2 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, H 2 , O 2 , 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. [Display omitted] • Solar-electrolysis system combing solar chimney & electrolysis station is proposed. • The system produces green hydrogen, oxygen, desalinated water, and electricity. • The solar-electrolysis system was modeled using MATLAB mathematical modeling. • The system produced 380 MW h, 13 ton H 2 , 173.3 ton O 2 , and 139,443 ton water per year. [ABSTRACT FROM AUTHOR]

This work presents a novel sustainable approach to producing desalinated water (W des), green hydrogen (G H 2 ) and electrical energy (E elc) using Hybrid Solar Chimney Power Plant (HSCPP) coupled with a water-splitting (Wat Sp) process. The HSCPP consists of a collector, absorber, chimney, bidirectional turbine outfitted with a seawater pool, and water electrolysis (Wat elc) cell. The HSCPP harnesses solar energy to heat the air under the collector creating air movement within the structure, passing the bidirectional turbine, and producing E elc. Sprinklers were fitted within the structure to operate the HSCPP as a cooling tower (CT) in the absence of solar radiation (Sol irr). The Wat elc cell directly uses the produced E elc for the production of Hydrogen (P H 2 ) and oxygen (P O 2 ), while the condensed water at the chimney's inner walls was also collected as W des. Results revealed that the continuous operation of the HSCPP has an average annual E elc of 633 ± 10 MWh that could be efficiently used to generate 21,653 kg of G R H 2 , 173,244 kg of O 2 as well as 190,863 tons of W des. The overall efficiency of the HSCPP for the P H 2 was found to be 18.5 % , which is higher than Solar PV (max∼ 6%) and geothermal Rankine (max∼ 15%). These high efficiencies rank this technology as competitive with other renewable hydrogen production technologies. In conclusion, HSCPP has a promising future as a novel and sustainable solar tower technology to produce hydrogen. [Display omitted] • A novel solar-driven system for the production of green Hydrogen is proposed. • The proposed system generates hydrogen, electricity and desalinated water. • The integrated system achieved a solar-to-hydrogen conversion efficiency of 18.5%. • The HSCPP produced of 633 MWh, 21,653 k g H 2 , 173,244 k g O 2 and 190,863 tons H 2 O. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The solar vortex engine (SVE) aims to replace the tall and expensive chimney structure in solar updraft power plants by a shorter less expensive structure named the vortex generator. In this study, the entire SVE system is simulated by CFD to determine the appropriate location for the turbine unit as well as prove the capability of the vortex generator in replacing the chimney. Three different cases for the SVE are considered and compared to corresponding cases of the solar chimney power plant (SCPP). Results revealed that the optimum turbine location is at the outlet hole of the vortex generator. An updraft air velocity of 1.82 m/s was achieved at the outlet hole, compared to 1.56 m/s at the base of a solar chimney with the same diameter as the upper hole. The consideration of the turbine pressure drop did not affect the formation and preservation of the air vortex. So, the 1 m high vortex generator successfully replaced the 8.6 m chimney component in solar updraft power plants, greatly reducing the cost and construction complexity of the plant. The vortex generator accelerated the air delivered from the solar collector, increasing its velocity by 14 times. The SVE's power output is directly proportional to the static pressure drop across the turbine. The mean difference values along the air vortex field between the cases with and without a turbine are 0.67 Pa and 0.026 m/s for the static pressure drop and velocity magnitude, respectively. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper presents a numerical study of natural convection in a solar chimney with a sloped roof designed for renewable energy production. Numerical analysis was carried out by using the Fluent 6.3.26 with a Reynolds-Averaged Navier-Stokes approach. Different turbulence models and Boussinesq approximation for buoyancy-driven flow are used. A parametric study on the performance power output of the solar chimney at various geometric parameters and different insolation levels was carried out to investigate the relationship between them. The numerical results obtained highlight the influence of these parameters. [ABSTRACT FROM AUTHOR]

This article presents an annual performance evaluation of single- and double-air-channel solar chimneys for natural ventilation induction under weather conditions in Mexico. The global energy balance method modeled both types of solar chimneys in an unsteady state. The case study evaluated five cities in Mexico. Experimental data of a single-air-channel chimney prototype evaluated under controlled conditions were used to validate the GEB numerical solution. Model validation considers climatic parameters to increase the accuracy of ventilation calculations, e.g., solar radiation, ambient temperature, wind speed, relative humidity, and atmospheric pressure. Experimental evaluation was performed considering the warmest and coldest days in each month of 2018. The modeling time to achieve the initial condition independence for each configuration was 72 h of the physical phenomenon. Results show that double-air-channel solar chimney tested configurations induced at least 70% more airflow than single-air-channel solar chimneys. Both solar chimney airflows were higher than the dwelling-unit ventilation for a space of 54 m 3 , and volumetric flows up to 120 m 3 h − 1 were identified for two studied cities. [ABSTRACT FROM AUTHOR]

The use of fossil fuels for generating power has leaded to the reduction of fossil fuel resources and many adverse influences involving climate change and environmental pollution. Solar energy has a potential to provide eco-friendly energy with a great energy supply for producing heat and electricity. Basic parts of the system are the collector, chimney and turbine. The collector is a vital component of the system and its geometrical features noticeably influence the power plant efficiency. In the current work, a three dimensional computational fluid dynamics (CFD) simulation of a SCPP based on the Manzanares prototype is performed to scrutinize the impact of collector entrance height (He) ranging from 0.75 m to 2 m on the solar chimney power output. Computational model is developed by employing RNG k-ε turbulence and discrete ordinates (DO) coupled with solar ray tracing models through ANSYS Fluent software. The model is validated using measured data published in the literature. The numerical results reveal that reducing He improves maximum velocity (Vmax), power output and pressure difference in the turbine at the expense of decreasing air mass flow rate. The highest velocity of 19.45 m/s is achieved with He = 0.75 m and Vmax enhances by 36.20% compared to base model with He = 1.85 m at 1000 W/m2. Besides this configuration provides the maximum power output of 66.51 kW and augments power output to 31.74% compared to the base case at 1000 W/m2. [ABSTRACT FROM AUTHOR]

The improvement in solar chimneys' thermal performance and thermal behavior that can be achieved by adding metal foam has been tested in computational work. The flow and heat transfer governing equations for solar chimney models were solved using computational fluid dynamics (CFD). It was solved using the control volume numerical method in ANSYS FLUENT 14.5. It is used to construct a finite volume modeling technique for solving the governing equations and the radiation heat transfer equations. With standard flat absorber plates, the results showed that heat transmission was increased by the inclusion of metal foam (10 PPI), leading to an increase in air velocity at the solar chimney of around 13.3%. The highest average air velocity with 10 PPI drops by 54.4% as the height of the absorber plate changes from 5 cm to 25 cm respectively.

This study presents the potential of using a natural ventilation system integrated with different combinations of enhancement techniques. The focus was on the perspective of using such configurations of passive ventilation systems (PVSs) in buildings located in different European cities. This work presents the results of obtaining the level of volumetric air flow rate for considering natural ventilation systems. Furthermore, the influences of local weather conditions (temperature, solar radiation, wind speed) were analyzed. Moreover, the year-round operation of all systems was presented. Also noted was the limitation of using PVSs based on the natural draft effect, additionally assisted by wind turbine ventilators in all European localizations. However, for the cities located in the northern part of Europe, it was confirmed that such a system can still meet minimum hygienic recommendations. It was also noted that a system additionally supported by a solar chimney is a much better solution. The best system was a PVS supported by a wind turbine ventilator and solar chimney integrated with PCM accumulation mass. The system should be additionally supported by waste heat from low-temperature sources. In the presented study, a high potential to reduce CO2 emission from building stock by the recommended system is additionally highlighted. However, there is still a need to analyze the proposed solutions by additional field tests and experimental investigations.

In order to build a composite application scenario for the synergistic development of clean energy generation and agricultural production, this research designs a solar chimney equipped with a rectangular collection system according to the structural characteristics of agricultural greenhouses. With collector efficiency as the primary objective and theoretical power as the secondary objective, the infusion angle is designed for the connecting section between the collection system and the chimney from the perspective of reducing the local resistance loss, and the transition factor ζ is introduced to define it accurately. Response surface methodology was then used to analyze the effect of the level of key system characteristics on collector efficiency and static pressure, and a regression model was developed to determine the best combination within the target optimization range. Results show that the infusion angle prevents too much solar energy from being lost in the vortex by reducing the local resistance loss, which increases the collector efficiency of the system. And when the transition factor is 0, the divergence angle is 2.86°, and the inlet height is 0.05 m, the collector efficiency and static pressure reach 48.75 % and −6.1 pa, respectively, which are 213 % and 563 % higher than the original model.

This study explores the performance of a solar chimney for enhancing passive ventilation and thermal comfort in the northeast of Colombia. A theoretical model and a quasi-steady computational fluid dynamics model were employed to analyse the airflow generated by the solar chimney and optimize its design. Then, the computational fluid dynamics model was used to investigate thermal comfort in the test section. The numerical model results were validated against a scaled experimental test bench. Results evidenced that solar chimneys could improve the indoor environment in the northeast of Colombia. A chimney with a length of 4 m and an angle of inclination of 55°, connected to a single room of 27 cubic meters in Bucaramanga, could improve natural ventilation and provide thermal comfort during January, March, April, August, November, and December as per the guidelines set in ASHRAE Standard 55. During the other months, it could provide partial comfort during specific hours, with being September the most critical month. This study provides valuable insights for future research dealing with the development of sustainable low-income homes in this Colombian region.

Climate change represents a vital public health challenge, resulting in serious impacts that require passive strategies in the built environment sector to mitigate such impacts. Such strategies are associated with the Sustainable Development Goals (SDGs), which present a vital need. Consequently, the solar chimney (SC) can be considered as an effective passive strategy to provide energy, thermal comfort, and air ventilation performance. Therefore, this study focused on SC performance and its related significance on air ventilation. This study aimed to bridge the gap in previous studies and indicates the hotspot topics to conduct a conceptual framework with three phases that can integrate various configurations of a SC with various buildings by considering the recent tools of numerical analysis. Thus, a bibliometric analysis based on the Biblioshiny and VOSviewer tools within the scope of the SC and air ventilation promotion was accomplished. Then, various configuration parameters related to SC performance-driven air ventilation are provided. The results indicate that further studies are required to develop themes like the "building design" of SC and its associated effects such as air quality and ventilation, in addition to "numerical analysis" and "optimization" in terms of hotspot topics and the potential for future consequences. Additionally, limited configurations of previous studies provide promising investigations resulting in several applications including many zones and floors that can be achieved by the proposed conceptual framework. Various insights and possibilities can promote numerous configuration parameters related to SC performance-driven air ventilation promotion, which serves as research guidance for designers and specialists toward the mitigation of climate change impacts and attaining the SDGs. [ABSTRACT FROM AUTHOR]

Low/medium temperature solar thermal applications are more economically feasible for seawater desalination. In this way, the current research presents a novel combined process in a solar chimney, wherein a multi-effect desalination and a polymer electrolyte membrane electrolyzer are established, producing electric power, fresh water, and high-purity hydrogen simultaneously. This model is simulated under the steady-state conditions by the engineering equation solver environment, then a comprehensive assessment is accomplished from the viewpoints of thermodynamics and cost. The results exhibit that the higher chimney's diameters and the higher pressure drops across the turbine lead to higher thermodynamic efficiencies as well as lower costs. The base design conditions show that this arrangement results in energetic and exergetic efficiencies of 31.08% and 7.08%, individually. From the cost facet, the sum unit cost of products is computed as 16.86 $/GJ, so the payback period (PP) of 3.47 years is available. The potential of the configured system is investigated using a regional application method, for which four different countries are regarded. The selected areas include Alice Springs, Madrid, Riyadh, and Tehran. Considering the case study, the proposed arrangement is more efficient when applied to the climatic conditions in Tehran. • Designing a novel combined arrangement into a solar chimney using MED and PEME unit. • Multi-aspect appraisal from the viewpoint of thermodynamics, economics, and NPV. • Defining a regional application technique for four climatic conditions in the world. • Design conditions show exergetic efficiency and products' cost of 7.08% and 16.86 $/GJ. [ABSTRACT FROM AUTHOR]

The improvement in solar chimneys' thermal performance and thermal behavior that can be achieved by adding metal foam has been tested in computational work. The flow and heat transfer governing equations for solar chimney models were solved using computational fluid dynamics (CFD). It was solved using the control volume numerical method in ANSYS FLUENT 14.5. It is used to construct a finite volume modeling technique for solving the governing equations and the radiation heat transfer equations. With standard flat absorber plates, the results showed that heat transmission was increased by the inclusion of metal foam (10 PPI), leading to an increase in air velocity at the solar chimney of around 13.3%. The highest average air velocity with 10 PPI drops by 54.4% as the height of the absorber plate changes from 5 cm to 25 cm respectively. [ABSTRACT FROM AUTHOR]

This work presents a novel triple-renewable energy system (TRES) that is based on integrating the photovoltaic panels (PVPs), conventional solar chimney (CSC), and cooling tower (CT) in one structure. The ultimate objective of the proposed TRES system is to produce electrical power (Pelc), desalinated water (Dw), and if required cooling utilities. The components of the system include a chimney tower, collector, base, PVPs, water pool, bi-directional turbine, and water sprinklers. The TRES system can be operated as CSC during the daytime and CT at night providing 24-h operation. The PVPs were integrated within the structure to increase the Pelc production and enhance the process performance by heating the air inside the system. The TRES structure increased the efficiency to 0.860% in comparison with the CSC (0.313%). The annual Pelc production from the TRES system was found to be 792 MWh compared with only 380 MWh generated by the CSC achieving 2.1 folds overall improvement. The CSC-PV and CT contributed to 47% (494 MWh) and 24% (253 MWh) of the Pelc production, respectively. The annual Dw production was found to be 1.2-fold higher (163,142 tons) higher than the CSC (139,443 tons). The newly developed TRES system offers a great potential to produce Pelc and Dw and save fossil fuel consumption while reducing the emissions of greenhouse gasses (GHGs) to the atmosphere. [ABSTRACT FROM AUTHOR]

The work represents a unique methodology for control of frequency in three area independent and interconnected hybrid microgrid systems. The proposed hybrid microgrids consist of solar chimney (SC), combined solar gas turbine (CSGT), bio‐diesel operated generator (BDOG), DC link, energy storage units such as battery energy storage unit (BESU), super‐magnetic energy storage unit (SMESU), and redox flow battery (RFB) based. Integration of generating units such as SC, CSGT, BDOG, SMESU, RFB, and DC link in three area hybrid microgrid is also a unique work. A newly developed chaotic butterfly optimization algorithm (CBOA) is applied so as to obtain the optimized standards of the cascaded PI‐TID controller employed with dispatchable generating units. Comparative analysis of different algorithms and controllers is achieved to establish the dominance of the anticipated control strategy. The impact of each component on the system is examined while taking into account various real‐time scenarios. Finally, the efficacy of cascaded PI‐TID controller tuned using CBOA is established by sensitivity analysis with significant changes in source and load circumstances. [ABSTRACT FROM AUTHOR]

Solar chimney systems which consist of three main parts (collector, chimney, turbine) are one of the main thermal methods that produce electricity using solar energy. In a solar chimney, the high-power generation that can be obtained by increasing the design dimensions can also cause ineffective high investment costs. In this study, differing from the traditional design approach, a heuristic optimization method based on the Bees Algorithm is present to obtain the optimum design parameters (the chimney and collector dimensions) that are provided the more effective solutions. It is made for 3 configurations in order to prove the accuracy of the optimization study using different algorithm parameters. By using the obtained mathematical equations and the defined non-currency investment cost unit for a traditional solar chimney, the optimum design parameters that can provide more power output with acceptable costs are investigated. Two main objectives are taken into consideration namely maximizing efficiency of solar chimney system and minimizing investment cost. In the optimization process, within the ranges determined for the decision variables, the maximum and minimum dimensions are determined as 1293.05–1330.47 m for the collector diameter, 94–99 m for the chimney diameter and 783–792 m for the chimney height. The obtained results showed that this open to develop approach proposed within the scope of the study can be useful in the optimal design of solar chimney systems. [ABSTRACT FROM AUTHOR]

Abstract A solar chimney power plant (SCPP) is suitable to be deployed in desert areas, but there are few studies on the impact of desert wind and sand. In this paper, numerical simulations for the Spanish prototype SCPP were conducted to investigate desert environmental parameters, including sand movement, crosswind, and sand deposition, on the output performance of SCPP. The results indicate that the main erosion area of the turbine blade in the SCPP is the leading edge of the blade pressure surface. The erosion area of the suction surface is much less than that of the pressure surface, mainly concentrated on the leading edge. The output power of SCPP is reduced by 73.3% because of the crosswind and it decreases by 16.9% after the windbreak wall is installed. The sand and dust deposition would affect the transmissivity of the solar radiation through the collector cover. In a dusty environment for 1 month, the system output power decreased by 12.9%, and the collector efficiency decreased from 34% to 23% due to the sand deposition. These results show that the sand has a considerable negative effect on the performance of SCPP in ways of sand erosion and deposition. Sand removal is necessary for SCPP.

The numerical and experimental study was carried out under Iraqi weather conditions to verify the improvement of the performance of the solar updraft tower system SUTS by introducing porous metal foam as a heat-absorbent plate. a semicircular basin of the solar collector was divided into two equal identical quarters. A porous foam material was fixed on one of the basins while the other basin was fixed on a traditional copper plate. The positions of the metal foam absorber plate are changed with two inclination angles (0֯ and 18֯) and the optimum position is achieved when it gives the highest thermal performance. A finite volume modeling technique is used to solve the governing equations and radiation heat transfer equations by using ANSYS Fluent. The experimental part was conducted in Baghdad / Iraq at latitude 33.3°. The presence of the metal foam absorber plate caused a significant decrease in the average temperatures of the heat-absorbent plate. The maximum airflow temperature was recorded with an inclined angle of 18◦. The metal foam as a heat-absorbent plate enhanced the efficiency and the output power of the SUTS to about 51.9% and 47.2% respectively compared to the traditional plate.

Solar Chimney Power Plant (SCPP) is a renewable energy system that indirectly converts solar energy to electricity. However, the efficiency of SCPP is not sufficient for practical applications. Integrating SCPPs with Photovoltaic-Thermal systems (PVT) could enhance their performance to levels acceptable for industrial adoption. This study investigates the combined SCPP-PVT performance for the weather conditions of Austin (Texas), San Diego (California), and Phoenix (Arizona), all on a similar latitude. Various configurations of this combined system are numerically simulated, and their efficiencies are compared with a conventional SCPP, SCPP-Photovoltaic (PV), and stand-alone PV modules. Moreover, to predict and optimize the performance of these systems, the Support Vector Regression with Linear (LSVR), Polynomial (PSVR), Gaussian (GSVR), and Hybrid (HSVR) kernels are implemented. In order to optimize the hyperparameters of the Machine Learning (ML) models, the Grey Wolf Optimizer (GWO) is implemented. Also, the optimum performance of the SCPP-PVT system is obtained using the Multi-objective Grasshopper Optimization Algorithm (MOGOA). The results show that the HSVR ML model has the highest accuracy, followed by PSVR, GSVR, and LSVR models. It is shown that the SCPP-PVT system outperforms both SCPP-PV and stand-alone PV modules, respectively. Finally, the SCPP-PVT is shown to outperform the PV modulus by up to 4.8%. [Display omitted] [ABSTRACT FROM AUTHOR]