Numerical evaluation of a solar chimney geometry for different ground temperatures by means of constructal design

Vieira, Rodrigo Spotorno; Petry, Adriane Prisco; Rocha, Luíz Alberto Oliveira; Isoldi, Liércio André; Santos, Elizaldo Domingues dos

doi:10.1016/j.renene.2017.03.007

Cited by 49 publications

(14 citation statements)

References 32 publications

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“…Our computational models assumed steady-state turbulent flow for which the standard k-ε model was used because of its proven accuracy in predicting the temperature profile of the SUT collectors in earlier studies [35][36][37][38]. In addition, the enhanced wall treatment was applied to resolve the laminar sublayer near the wall [39].…”

Section: Methodsmentioning

confidence: 99%

Numerical Investigation on the Effects of Baffles with Various Thermal and Geometrical Conditions on Thermo-Fluid Dynamics and Kinetic Power of a Solar Updraft Tower

2018

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Solar updraft towers (SUTs) are used for renewable power generation, taking advantage of the thermal updraft air flow caused by solar energy. Aerodynamic devices have been applied to SUTs to improve their performance and the baffle is one such device. Here, we investigate the effect of baffle installation on the thermo-fluid dynamic phenomena in the collector of an SUT and how it enhances the overall SUT performance using computational fluid dynamics analysis. Two geometric parameters (height and width of baffle) and two thermal boundary conditions of the baffle (adiabatic condition and heat flux condition) were tested through simulations with 10 different models. The vortex generated by the baffle has a positive effect on the delivery of heat energy from the ground to the main flow; however, one disadvantage is that the baffle inherently increases the resistance of the main flow. Over 3% higher kinetic power was achieved with some of the simulated baffle models. Therefore, an optimum design for baffle installation can be achieved by considering the positive and negative thermo-fluid dynamics of baffles.

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Section: Methodsmentioning

confidence: 99%

Numerical Investigation on the Effects of Baffles with Various Thermal and Geometrical Conditions on Thermo-Fluid Dynamics and Kinetic Power of a Solar Updraft Tower

2018

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“…[13] employed Constructal Design to evaluate analytically the effect the ratio between height of chimney and radius of collector over the power production for a reference plant. In spite of application of the same method for geometrical evaluation, the work brings different findings than [14] results.…”

Section: Introductionmentioning

confidence: 96%

On the Influence of Collector Size on the Solar Chimneys Performance

2017

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Abstract. Performance of solar chimney power plant system is highly influenced by the design geometries. The collector size is logically enhances the solar chimney performance, but the trend of enhancement is not yet investigated. In the present work, experimental and numerical investigations have been carried out to ascertain, in terms of qualitative and quantitative evaluation, the effect of the collector diameter. Daily thermal efficiency has been determined at four different collector diameter. Two different collector diameters, 3.0 and 6.0 m, have been investigated experimentally, and then scaled up, to 9.0 and 12.0 m, by numerical simulation using ANSYS-FLUENT®15 software. Results demonstrated that collector diameter has effectively influenced the system performance. Larger collector diameter imposed increase in the velocity, temperature and the daily average thermal efficiency of the system. From the experimental results, increasing the collector diameter from 3.0 to 6.0 m has increased the daily average thermal efficiency of the collector from 9.81 to 12.8. Simulation results at 800 W/m 2 irradiation revealed that the velocity in the chimney have increased from 1.66 m/s at 3.0 m collector diameter to 2.34, 2.47 and 2.63 m/s for 6.0, 9.0 and 12.0 m collector diameters, respectively.

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“…Since the first proposal of solar chimney in 1980, several studies were carried out in order to know and optimize the main features of this technology [1][2]. Such as: Vieira et al [3] carried out a numerical analysis to investigate the influence of geometry and different soil temperatures on the power of the plant. Shirvan et al [4] studied a two-dimensional axial symmetric model of a solar chimney in Zanjan (Iran), identifying collector and chimney geometry values for maximum power.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on a Solar Chimney in a Building Façade under Different Climatic Condition

Capasso¹,

Diana²,

Manca³

et al. 2019

IJES

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Solar chimney is a technology used to regulate the heat flow between indoor and outdoor of a building. It employs solar radiation to increase the temperature of the air for optimize its circulation and by improving its quality. In this paper, a numerical investigation on a prototypal solar chimney system integrated in a south facade of a building is presented. The chimney is 4.0 m high, 1.5 m wide whereas the thickness at the inlet the channel has a gap equal to 0.34 m and at the outlet it is 0.20 m. The chimney consists of a converging channel with one vertical wall and one inclined of 2°. The analysis is carried out on a threedimensional model in airflow and the governing equations are given in terms of k-ε turbulence model. The problem is solved by means of the commercial code Ansys-Fluent. The simulations are carried out considering the solar irradiance for assigned geographical location and for a daily distribution in four different days, one for each climatic season. Further, comparison between the different results obtained by operating in quasisteady state regimes is examined and discussed. Results are given in terms of wall temperature distributions, air velocity and temperature fields and transversal profiles in order to evaluate the differences between the different configurations and thermal and fluid dynamic behaviors.

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Numerical evaluation of a solar chimney geometry for different ground temperatures by means of constructal design

Cited by 49 publications

References 32 publications

Numerical Investigation on the Effects of Baffles with Various Thermal and Geometrical Conditions on Thermo-Fluid Dynamics and Kinetic Power of a Solar Updraft Tower

Numerical Investigation on the Effects of Baffles with Various Thermal and Geometrical Conditions on Thermo-Fluid Dynamics and Kinetic Power of a Solar Updraft Tower

On the Influence of Collector Size on the Solar Chimneys Performance

Numerical Investigation on a Solar Chimney in a Building Façade under Different Climatic Condition

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