Calculation of Pressure and Density in Solar Power Plant Chimneys

2003 ◽  
Vol 125 (1) ◽  
pp. 127-129 ◽  
Author(s):  
Theodor W. von Backstro¨m
Keyword(s):  
Power Plants ◽  
Average Density ◽  
Wall Friction ◽  
Solar Power Plant ◽  
Calculation Methods ◽  
Solar Chimney ◽  
Flow Area ◽  
Density Distributions ◽  
Internal Bracing ◽  
Mach Numbers

This technical brief develops calculation methods for the pressure drop in very tall chimneys, as in solar chimney power plants. The methods allow for density and flow area change with height, for wall friction and internal bracing drag. It presents equations for the vertical pressure and density distributions in terms of Mach number. One of these is a generalization of the adiabatic pressure lapse ratio equation to include flow at small Mach numbers. The other is analogous to the hydrostatic relationship between pressure, density, and height, but extends it to small Mach numbers. Its integration leads to an accurate value of the average density in the chimney.

Effect of Flow Area to Fluid Power and Turbine Pressure Drop Factor of Solar Chimney Power Plants

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Xinping Zhou ◽  
Yangyang Xu ◽  
Yaxiong Hou
Keyword(s):  
Heat Flux ◽  
Pressure Drop ◽  
Solar Collector ◽  
Power Plants ◽  
Real Life ◽  
Ideal Gas ◽  
Fluid Power ◽  
Solar Chimney ◽  
Flow Area ◽  
Ideal Gas Law

In this paper, a theoretical model of solar chimney power plants (SCPPs) is presented based on compressible ideal gas law assumptions. The theoretical optimal turbine pressure drop factors (TPDFs) for constant and nonconstant densities (CD and NCD) are studied, and the effects of flow area parameters examined. Results show that the theoretical optimal TPDF for CD is equal to 2/3 and is independent of the flow area parameters. Results also show that the theoretical optimal TPDF for NCD is close to 1 and is affected by the flow area parameters. However, the theoretical maximum fluid power (MFP) obtained for NCD is never attained in real life. For the actual states, the theoretical optimal TPDF for NCD is still effectively high enough. The TPDF and the fluid power for NCD increase with the reduction of the collector inlet area, and more precisely with the reduction of the chimney inlet area. The TPDF and the fluid power definitely increase with larger chimney flow area. The increase in the fluid power due to shape optimization of the SCPP is limited compared to that due to higher input heat flux of collector. Divergent-top and upward slanting roof shapes are recommended for the solar chimney and the solar collector, respectively, for better SCPP performance. Additionally, locations exposed to strong solar radiation are preferred for SCPPs.

Pressure Drop in Solar Power Plant Chimneys

2003 ◽  
Vol 125 (2) ◽  
pp. 165-169 ◽  
Author(s):  
Theodor W. von Backstro¨m ◽  
Andreas Bernhardt ◽  
Anthony J. Gannon
Keyword(s):  
Pressure Drop ◽  
Kinetic Energy ◽  
Separated Flow ◽  
Wall Friction ◽  
Solar Chimney ◽  
Rectangular Section ◽  
Frictional Pressure Drop ◽  
Internal Bracing ◽  
Flow Through ◽  
Kinetic Energy Loss

The paper investigates flow through a representative tall solar chimney with internal bracing wheels. It presents experimental data measured in a 0.63-m-dia model chimney with and without seven bracing wheels. The bracing wheels each had a rim protruding into the chimney and 12 spokes, each spoke consisting of a pair of rectangular section bars. The investigation determined coefficients of wall friction, bracing wheel loss, and exit kinetic energy in a model chimney, for both ideal non-swirling uniform flow and for swirling distorted flow. A fan at one end of the chimney model either sucked or blew the flow through it. The flow entering the chimney through the fan and its diffuser simulated the flow leaving the turbine at the bottom of the chimney. The swirling distorted flow increased the total pressure drop by about 28%, representing 4.7% of the turbine pressure drop. The pressure drop across the bracing wheels exceeded the frictional pressure drop by far. Designers of tall, thin-walled chimneys should take care to minimize the number of bracing wheels, reduce their rim width as much as possible, and investigate the feasibility of streamlining their spoke sections. If at all structurally possible, the top bracing wheel should be far enough from the chimney exit to allow the spoke wakes to decay and the separated flow to re-attach to the chimney wall downstream of the rims before the flow leaves the chimney, to reduce the exit kinetic energy loss.

Effects of flow area changes on the potential of solar chimney power plants

Energy ◽  
2013 ◽  
Vol 51 ◽  
pp. 400-406 ◽  
Author(s):  
Atit Koonsrisuk ◽  
Tawit Chitsomboon
Keyword(s):  
Power Plants ◽  
Solar Chimney ◽  
Flow Area

scholarly journals Radial Turbine Design for Solar Chimney Power Plants

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 674
Author(s):  
Paul Caicedo ◽  
David Wood ◽  
Craig Johansen
Keyword(s):  
Power Plants ◽  
Reference Frames ◽  
Three Dimensional ◽  
Discrete Ordinates ◽  
Large Area ◽  
Solar Chimney ◽  
Cfd Simulations ◽  
Radial Turbine ◽  
Design Changes ◽  
Turbine Design

Solar chimney power plants (SCPPs) collect air heated over a large area on the ground and exhaust it through a turbine or turbines located near the base of a tall chimney to produce renewable electricity. SCPP design in practice is likely to be specific to the site and of variable size, both of which require a purpose-built turbine. If SCPP turbines cannot be mass produced, unlike wind turbines, for example, they should be as cheap as possible to manufacture as their design changes. It is argued that a radial inflow turbine with blades made from metal sheets, or similar material, is likely to achieve this objective. This turbine type has not previously been considered for SCPPs. This article presents the design of a radial turbine to be placed hypothetically at the bottom of the Manzanares SCPP, the only large prototype to be built. Three-dimensional computational fluid dynamics (CFD) simulations were used to assess the turbine’s performance when installed in the SCPP. Multiple reference frames with the renormalization group k-ε turbulence model, and a discrete ordinates non-gray radiation model were used in the CFD simulations. Three radial turbines were designed and simulated. The largest power output was 77.7 kW at a shaft speed of 15 rpm for a solar radiation of 850 W/m2 which exceeds by more than 40 kW the original axial turbine used in Manzanares. Further, the efficiency of this turbine matches the highest efficiency of competing turbine designs in the literature.

Economic Assessment of Concrete and Floating Based Solar Chimney Power Plants in Bangladesh

2020 ◽  
Author(s):  
Md. Abdul Aziz Bhuiyan ◽  
Md Abdul Aziz Bhuiyan ◽  
Mehedi Hasan Bhuiyan ◽  
Mehedi Hasan Bhuiyan ◽  
Md Ashiqur Rahman ◽  
...  
Keyword(s):  
Power Plants ◽  
Economic Assessment ◽  
Solar Chimney

Constructal Distribution of Solar Chimney Power Plants: Few Large and Many Small

2010 ◽  
Vol 7 (6) ◽  
pp. 577-592 ◽  
Author(s):  
S. Lorente ◽  
A. Koonsrisuk ◽  
A. Bejan
Keyword(s):  
Power Plants ◽  
Solar Chimney

Analysis of the Variable Cross-Section Duct and Straightening Device Geometry Effects on the Hydrogen Combustion Process

2021 ◽  
pp. 62-71
Author(s):  
O.V. Guskov ◽  
V.S. Zakharov ◽  
Minko
Keyword(s):  
Combustion Chamber ◽  
Cross Section ◽  
High Speed ◽  
Power Plants ◽  
Combustion Process ◽  
Variable Cross Section ◽  
Hydrogen Combustion ◽  
Variable Cross ◽  
Calculation Methods ◽  
Transition Channel

The development and research of high-speed aircrafts and their individual parts is an urgent scientific task. In the scientific literature there is information about the integral characteristics of aircrafts of this type, but there is no detailed consideration of such an important part as the transition channel between the air intake and the combustion chamber. The article considers several flow path configurations. The numerical simulation results of hydrogen combustion in the channels of variable cross section using a detailed kinetic mechanism are presented. Based on the analysis of the data obtained, the models of the transition channel and the combustion chamber showing the best characteristics were selected. The impulse and the fuel combustion efficiency are used as criteria for comparing the flow paths. The difference in the application of two calculation methods is described. The presented results and calculation methods can be used at the stage of computational research of the working processes in advanced power plants.

scholarly journals Enclosed Solar Chimney Power Plants with Thermal Storage

OALib ◽  
2016 ◽  
Vol 03 (05) ◽  
pp. 1-18
Author(s):  
Christos D. Papageorgiou
Keyword(s):  
Power Plants ◽  
Thermal Storage ◽  
Solar Chimney

scholarly journals Improving the Efficiency of Solar Power Plants

2020 ◽  
Vol 30 (3) ◽  
pp. 480-497
Author(s):  
Dmitriy S. Strebkov ◽  
Yuriy Kh. Shogenov ◽  
Nikolay Yu. Bobovnikov
Keyword(s):  
Power Plant ◽  
Solar Radiation ◽  
Solar Energy ◽  
Power Plants ◽  
Solar Power ◽  
Horizontal Surface ◽  
Solar Power Plant ◽  
Utilization Factor ◽  
Working Surface ◽  
Solar Power Plants

Introduction. An urgent scientific problem is to increase the efficiency of using solar energy in solar power plants (SES). The purpose of the article is to study methods for increasing the efficiency of solar power plants. Materials and Methods. Solar power plants based on modules with a two-sided working surface are considered. Most modern solar power plants use solar modules. The reflection of solar radiation from the earth’s surface provides an increase in the production of electrical energy by 20% compared with modules with a working surface on one side. It is possible to increase the efficiency of using solar energy by increasing the annual production of electric energy through the creation of equal conditions for the use of solar energy by the front and back surfaces of bilateral solar modules. Results. The article presents a solar power plant on a horizontal surface with a vertical arrangement of bilateral solar modules, a solar power station with a deviation of bilateral solar modules from a vertical position, and a solar power plant on the southern slope of the hill with an angle β of the slope to the horizon. The formulas for calculating the sizes of the solar energy reflectors in the meridian direction, the width of the solar energy reflectors, and the angle of inclination of the solar modules to the horizontal surface are given. The results of computer simulation of the parameters of a solar power plant operating in the vicinity of Luxor (Egypt) are presented. Discussion and Conclusion. It is shown that the power generation within the power range of 1 kW takes a peak value for vertically oriented two-sided solar modules with horizontal reflectors of sunlight at the installed capacity utilization factor of 0.45. At the same time, when the solar radiation becomes parallel to the plane of vertical solar modules, there is a decrease in the output of electricity. The proposed design allows equalizing and increasing the output of electricity during the maximum period of solar radiation. Vertically oriented modules are reliable and easy to use while saving space between modules.

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