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.

Heat Storage Performance Analysis of Solar Chimney Power Plant System

2014 ◽  
Vol 472 ◽  
pp. 276-285 ◽  
Author(s):  
Hong Jing Guo ◽  
Jian Lan Li ◽  
Shu Hong Huang
Keyword(s):  
Heat Transfer ◽  
Power Generation ◽  
Power Plant ◽  
Heat Storage ◽  
Storage System ◽  
Solar Chimney ◽  
Unsteady Temperature ◽  
Heat Transfer Theory ◽  
Solar Chimney Power Plant ◽  
Continuous Power

Solar chimney power plant which can realize continuous power generation is a potential power generation technology. Based on the heat transfer theory and hydrodynamics theory, a comprehensive heat transfer and flow model of solar chimney power plant was proposed, and the characteristics of unsteady temperature field and flow field of the system were analyzed. With Manzanares solar chimney power plant as the geometric prototype, the performance of plant generation output and generation stability were studied in condition of different thickness of heat storage layer, different specific heat capacity and thermal conductivity of heat storage medium. The numerical stimulation results showed that above three factors significantly affected the power generation output and generation stability. Thus, the optimization of the three factors was achieved in this paper, which provides the basis for the solar chimney heat storage system design.

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.

Parametric Analysis of a Bayonet Tube With a Special Type of Extended Surface

2010 ◽  
Author(s):  
L. Almanza-Huerta ◽  
A. Hernandez-Guerrero ◽  
M. Krarti ◽  
J. M. Luna
Keyword(s):  
Heat Transfer ◽  
Parametric Analysis ◽  
Numerical Study ◽  
Systematic Investigation ◽  
Heat Transfer Characteristics ◽  
Maximum Heat ◽  
Turbulent Transition ◽  
Maximum Heat Transfer ◽  
Internal Fluid ◽  
Extended Surface

The present paper provides a numerical study of a parametric analysis of a bayonet tube with a special type of extended surface during the laminar-turbulent transition. The working internal fluid is air. Attention is focused on the heat transfer characteristics of the tube. The results constitute a systematic investigation of the effect of the extended surface located along the annulus of the bayonet on the overall heat transfer rate. The effects of the variation of some parameters related to the extended surface aiming to attain the maximum heat transfer with the minimum pressure drop are discussed. Comparisons between designs with and without extended surface are also made.

Study of the Heat Storage Device Characteristic in the Solar Chimney Power Plant System with Vertical Collector

2011 ◽  
Vol 221 ◽  
pp. 356-363 ◽  
Author(s):  
Yan Zhou ◽  
Wen Juan Zheng ◽  
Xiao Hui Liu ◽  
Qing Ling Li
Keyword(s):  
Power Plant ◽  
Heat Storage ◽  
Storage Device ◽  
Solar Chimney ◽  
Storage Devices ◽  
Plant System ◽  
Heat Storage Materials ◽  
Solar Chimney Power Plant ◽  
Storage Ability ◽  
Better Than

The three difference structural heat storage devices are designed used paraffin as phase change heat storage materials for the chimney power plant system with vertical collector, and the FLUENT software is used to study the heat storing and releasing capacity of four different structural heat storage devices. The results are shown that: in the same case, The heat storage and heat release abilities of the devices with different surfaces are studied through numerical simulation, the results show that: the heat storage ability of the device with fins is much better than that of flat-plate device, and the heat storage ability of the device with longitudinal fins is a little better than that of the device with lateral fins. So for the solar chimney power plant system with vertical collector, the heat storage device with longitudinal fins can be chosen in consideration of the flow resistance and heat transfer ability. These results are the theoretical basis for the actual construction of the solar chimney power plant system with vertical collector.

scholarly journals Thermophysical Characterization and Numerical Investigation of Three Paraffin Waxes as Latent Heat Storage Materials

2019 ◽  
Author(s):  
Manel Kraiem ◽  
Mustapha Karkri ◽  
Sassi Ben Nasrallah ◽  
patrick sobolciak ◽  
Magali Fois ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Heat Storage ◽  
Numerical Study ◽  
Melting Process ◽  
Heat Transfer Mode ◽  
Transfer Mode ◽  
Paraffin Waxes ◽  
Thermophysical Characterization

Thermophysical characterization of three paraffin waxes (RT27, RT21 and RT35HC) is carried out in this study using DSC, TGA and transient plane source technics. Then, a numerical study of their melting in a rectangular enclosure is examined. The enthalpy-porosity approach is used to formulate this problem in order to understand the heat transfer mechanism during the melting process. The analysis of the solid-liquid interface shape, the temperature field shows that the conduction is the dominant heat transfer mode in the beginning of the melting process. It is followed by a transition regime and the natural convection becomes the dominant heat transfer mode. The effects of the Rayleigh number and the aspect ratio of the enclosure on the melting phenomenon are studied and it is found that the intensity of the natural convection increases as the Rayleigh number is higher and the aspect ratio is smaller. In the second part of the numerical study, a comparison of the performance of paraffins waxes during the melting process is conducted. Results reveals that from a kinetically RT21 is the most performant but in term of heat storage capacity, it was inferred that RT35HC is the most efficient PCM.

Effect of the ground heat storage on solar chimney power plant performance in the South of Tunisia: Case of Tozeur

Solar Energy ◽  
2019 ◽  
Vol 193 ◽  
pp. 545-555 ◽  
Author(s):  
Faten Attig-Bahar ◽  
Melik Sahraoui ◽  
Mohamed Sadok Guellouz ◽  
Slim Kaddeche
Keyword(s):  
Power Plant ◽  
Heat Storage ◽  
Plant Performance ◽  
The South ◽  
Solar Chimney ◽  
Solar Chimney Power Plant

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.

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