scholarly journals Numerical study for the ventilation with solar chimney under effect of different location and the shape of the section opening window

2020 ◽  
Vol 881 ◽  
pp. 012164
Author(s):  
Ahamed Q. Mohamed ◽  
Ahmed K Alshara ◽  
Hussein M. Mitlaik
Keyword(s):  
Numerical Study ◽  
Solar Chimney

The Comparison of CFD Flow Field between Slope Solar Energy Power Plant and Traditional Solar Chimney Power Generating Equipment

2013 ◽  
Vol 561 ◽  
pp. 614-619 ◽  
Author(s):  
Qing Ling Li ◽  
Xiao Qing Xie ◽  
Jun Chao ◽  
Xuan Xin ◽  
Yan Zhou
Keyword(s):  
Power Plant ◽  
Velocity Field ◽  
Solar Energy ◽  
Numerical Study ◽  
Solar Chimney ◽  
Heat Collector ◽  
Fluent Software ◽  
Generating Equipment ◽  
The Cost ◽  
Power Generating Equipment

A numerical study with FLUENT software has been carried out as to air performance in the slope solar energy power plant. The velocity field, temperature and pressure fields in the solar chimney, and the simulated result were compared with the simulated result of traditional solar chimney power generating equipment. The simulation results show that distribution of the temperature field and the velocity field in slope solar energy power plant and traditional solar chimney power generating equipment. In the case of the same height, the velocity of traditional is slightly larger than the slope style's, but there is little difference. In order to achieve the same power generation effect, the overall height of slope style is more than the traditional style, but the vertical chimney height of traditional style is greater than the slope style. The cost of construction of vertical chimney is expensive, and many problems have been considered, like radix saposhnikoviae and earthquake prevention, the heat collector also need to be cleaned on time. The slope style can take full advantage of land, the height of vertical chimney will be reduced, so the construction of the chimney will be relatively easy. Rainwater can clean the heat collector when it runs down from it. All things considered. The slope solar energy power plant has more development prospects.

Applying CFD for Studying the Dynamic and Thermal Behavior of Solar Chimney Drying System with Reversed Absorber

2017 ◽  
Vol 13 (11) ◽  
Author(s):  
Souheyla Khaldi ◽  
A. Nabil Korti ◽  
Said Abboudi
Keyword(s):  
Thermal Behavior ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Numerical Study ◽  
Packed Bed ◽  
Maximum Temperature ◽  
Storage Material ◽  
Solar Chimney ◽  
Solar Dryer

AbstractThis article provides numerical study of the solar chimney (SC) assembled with a reversed absorber and packed bed for the indirect-mode solar dryer. The present study was designed to determine the effects of using the SC in three configuration and physical proprieties of the packed (thickness and porosity) on the dynamic and thermal behavior of airflow. The results reveal that (1) using SC without storage material can increase the maximum mass flow rate up to 5%. However, integrating a storage material in the SC can improve the mass flow rate up to 32% during nighttime; (2) the use of a packed bed can decrease the crops temperature fluctuation until about 76% and increase the operating time of the solar dryer up to 12.5 hours rather than 10 hours in the case without packed bed; (3) increasing the porosity from 0.1 to 0.8 can increase the maximum temperature by about 10°C.

Virtual Height Aided Solar Chimney: A New Design

2011 ◽  
Author(s):  
Khaled I. E. Ahmed ◽  
Ali K. Abdel-Rahman ◽  
Mahmoud Ahmed ◽  
Wael M. Khairaldien
Keyword(s):  
Electric Power ◽  
Co2 Emissions ◽  
Conversion Efficiency ◽  
Numerical Study ◽  
Air Flow ◽  
Flow Speed ◽  
Numerical Results ◽  
Solar Chimney ◽  
Virtual Height ◽  
Wide Range

Renewable energy source deployment is growing rapidly as it reduces CO2 emissions and increases diversity and security of supply. Solar chimney (SC) is a promising large-scale power technology, which absorbs solar radiation and converts parts of solar energy into electric power free of CO2 emissions. A major problem of Solar Chimney Power Plant (SCPP) is its low conversion efficiency as determined by the thermal performance of the system. However, the conversion efficiency of SCPP significantly increases with the SC height increase. The current paper proposes a new design of a virtual height aided solar chimney. In this new system the solar chimney is aided with a passive cooling system at the top of the chimney and a passive solar heater at its base to virtually mimic larger heights of the chimney. The new design has been simulated numerically for development and optimization. The numerical study is done in two stages to examine this concept. In the first stage, numerical results are obtained for the effect of the chimney height on the inside air flow speed. Then, in the second stage, the effect of decreasing the temperature at the chimney exit and the effect of increasing the temperature at the chimney base on the air flow speed are examined separately for small chimney heights. Then the combined effect of the two actions is investigated at a wide range of chimney heights. The numerical results have shown that the localized base heating and exit cooling have significantly enhanced the chimney performance for chimney heights up to 500m. A chimney with height of 300m gains an increase in the air velocity more than 25% due to the heating and cooling actions. Virtual height aided Chimney with original height of 300m acts similarly to a conventional chimney with height of 500m due to the effect of base heating and exit cooling actions. This air flow velocity increase reflects 100% increase in the expected generated electric power. Further detailed results are presented and discussed.

A Parametric Study of Conjugate Heat Transfer of Solar Chimney

2009 ◽  
Author(s):  
J. Arce ◽  
J. P. Xaman ◽  
G. Alvarez ◽  
M. J. Jime´nez ◽  
M. R. Heras
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Parametric Study ◽  
Solar Irradiance ◽  
Natural Ventilation ◽  
Numerical Study ◽  
Ambient Air ◽  
Computer Code ◽  
Solar Chimney ◽  
Conservation Equations

Recently, new buildings are being designed considering natural sources such as natural ventilation as a passive technique. Solar chimneys are among those techniques of passive ventilation systems in buildings, to enhance the air quality and some times the thermal comfort. In this work, a numerical study of a solar chimney for forced ventilation is carried out. Also a parametric study varying the ambient air temperature, the solar irradiance and Reynolds number is considered. The dimensions of the solar chimney are 4.0 m high, and 0.35 m deep, the absorber surface of the solar chimney was 0.15 m thick of reinforced concrete. The conservation equations of mass, momentum, energy and two turbulence equations are solved under some simplifications such as: 2-D, incompressible, steady state turbulent air flow and conjugated heat transfer (conduction, forced convection and radiation). k-ω turbulent model was implemented and finite volume technique was applied to solve the conservation equations. In order to guarantee the right performance of the computer code, it was reduced to cases reported in the literature and verified; also, it was validated with an experiment. The variation of ambient temperature, solar irradiance and Reynolds number are analyzed in the parametric study. The heat transfer correlations for total Nusselt number (convective plus radiative) are introduced. From the results, it was found that the heat transfer increases as the Reynolds number increases for the hot surface of the solar chimney.

Numerical Study on Enhanced Paraffin/Air Heat Transfer with Extended Surface

2012 ◽  
Vol 501 ◽  
pp. 376-381
Author(s):  
Yan Zhou ◽  
Wen Juan Zheng ◽  
Xi Yan Fan ◽  
Jun Chao ◽  
Qing Ling Li
Keyword(s):  
Heat Transfer ◽  
Heat Storage ◽  
Numerical Study ◽  
Solar Chimney ◽  
Release Capacity ◽  
Vertical Heat ◽  
Heat Collector ◽  
Extended Surface ◽  
Solar Chimney Power Plant ◽  
Air Flow Velocity

The extended surface is used to enhance paraffin/air heat transfer because of the paraffin’s poor thermal conductivity, and the heat storing and releasing capacity of paraffin heat storage layer with variety of extended surface are compared by numerical simulation. The results show that: the heat storage layer with vertical rectangular fin extended surface has stronger ability on the heat storage and release, and can more effectively improve the air flow velocity in the solar chimney power plant system with vertical heat collector. Due to the restrictions of manufacturing, the heat storage and release capacity is stronger when the heat storage layer surface area with vertical rectangular fin is from 3.4 times to 5.8 times compare to the flat-plate heat storage layer.

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