Computational Assessment of Double-Inlet Collector in Solar Chimney Power Plant Systems

2017 ◽  
Author(s):  
Nima Fathi ◽  
Seyed Sobhan Aleyasin ◽  
Patrick Wayne ◽  
Peter Vorobieff
Keyword(s):  
Power Plant ◽  
Mass Flow ◽  
Flow Rate ◽  
Scale Model ◽  
Solar Chimney ◽  
Rate Improvement ◽  
Mass Flow Rates ◽  
Limited Mass ◽  
Solar Chimney Power Plant ◽  
Volume Method

Solar chimney power plant systems (SCPPS) offer a simple and reliable way to generate electricity using solar radiation to drive a flow of buoyant air. A typical SCPP setup includes a collector, a tower, and a turbine or several turbines. Current SCPP designs have low thermal efficiency: only between 0.5% and 5% of the incident solar energy is converted into electricity. Inefficiencies result partially from limited mass flow rates through the tower. It is therefore desirable to provide a new design for the collector to increase the inlet air mass flow rate. In this paper, we present a double-inlet collector concept and results of numerical analysis to evaluate this design in terms of flow rate improvement. Computational fluid dynamics (CFD) was utilized to perform the numerical modeling and simulation (M&S) by using a finite volume method package. The Manzanares prototype (the only operational solar tower power plant with available published reports) is selected to implement the double-inlet collector design and study its effect on the power plant. Beside this case, we fabricated a 1/1000 scale model of the Manzanares prototype which enables us to measure the filed variables experimentally. Validation analysis was performed to quantify the reliability of our numerical model with respect to the available experimental data. We obtained a significant increase (14%) in the available output power by using the double-inlet collector.

Pressure Losses in Solar Chimney Power Plant

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Xinping Zhou ◽  
Yangyang Xu
Keyword(s):  
Power Plant ◽  
Mass Flow ◽  
Pressure Loss ◽  
Dynamic Pressure ◽  
Low Flow ◽  
Solar Chimney ◽  
Flow Rates ◽  
Pressure Losses ◽  
Pressure Loss Coefficient ◽  
Solar Chimney Power Plant

This technical brief develops a theoretical model of all the pressure losses in the solar chimney power plant (SCPP, also called solar updraft power plant) and analyzes the pressure losses for different chimney internal stiffening appurtenance (SA) structures, different roof heights, and different collector support parameters. Results show that the exit dynamic pressure drop (EDPD) accounts for the majority of the total pressure loss (TPL), while other losses constitute only small proportions of the TPL, and the collector inlet loss is negligible. Pressure losses are strongly related to the mass flow rate, while reasonable mass flow rates excluding too low flow rates have little influence on the pressure loss ratios (PLRs, defined as the ratios of the pressure losses to the TPL) and the total effective pressure loss coefficient (TEPLC). Designing of the SA structure in view of reducing the drag, for example, using the ring stiffeners without wire spoked instead of the spoked bracing wheels (SBWs), reducing the width of the chimney internal rims of SAs, or reducing the number of SAs results in large reduction of the SA PLR and the TPL. Lower roof leading to higher velocity inside the collector, larger supports, or shorter intersupport distance leads to the increase in the support PLR. This technical brief lays a solid foundation for optimization of SCPPs in future.

Performance analysis of a solar chimney power plant system in two Algeria regions

2021 ◽  
pp. 1-26
Author(s):  
Sellami Ali ◽  
Benlahcene Djaouida ◽  
Abdelmoumène Hakim Benmachiche ◽  
Zeroual Aouachria
Keyword(s):  
Power Plant ◽  
Performance Analysis ◽  
Solar Chimney ◽  
Plant System ◽  
Solar Chimney Power Plant

scholarly journals Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Tobias Blanke ◽  
Markus Hagenkamp ◽  
Bernd Döring ◽  
Joachim Göttsche ◽  
Vitali Reger ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Circular Ring ◽  
Flow Conditions ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Pipe Radius

AbstractPrevious studies optimized the dimensions of coaxial heat exchangers using constant mass flow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar flow types. In contrast, in this study, flow conditions in the circular ring are kept constant (a set of fixed Reynolds numbers) during optimization. This approach ensures fixed flow conditions and prevents inappropriately high or low mass flow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic effort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass flow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellström’s borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefficients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy difference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy flux and hydraulic effort. The Reynolds number in the circular ring is instead of the mass flow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54% of the outer pipe radius for laminar flow and 60% for turbulent flow scenarios. Net-exergetic optimization shows a predominant influence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth’s thermal properties and the flow type. Conclusively, coaxial geothermal probes’ design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.

scholarly journals Off-Design Dynamic Performance Analysis of a Solar Aided Coal-Fired Power Plant

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2950
Author(s):  
Vinod Kumar ◽  
Liqiang Duan
Keyword(s):  
Power Plant ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Dynamic Performance ◽  
Feed Water ◽  
Saving Rate ◽  
Coal Consumption ◽  
Dynamic Performance Analysis

Coal consumption and CO2 emissions are the major concerns of the 21st century. Solar aided (coal-fired) power generation (SAPG) is paid more and more attention globally, due to the lesser coal rate and initial cost than the original coal-fired power plant and CSP technology respectively. In this paper, the off-design dynamic performance simulation model of a solar aided coal-fired power plant is established. A 330 MW subcritical coal-fired power plant is taken as a case study. On a typical day, three various collector area solar fields are integrated into the coal-fired power plant. By introducing the solar heat, the variations of system performances are analyzed at design load, 75% load, and 50% load. Analyzed parameters with the change of DNI include the thermal oil mass flow rate, the mass flow rate of feed water heated by the solar energy, steam extraction mass flow rate, coal consumption, and the plant thermal efficiency. The research results show that, as DNI increases over a day, the coal saving rate will also increase, the maximum coal saving rate reaches up to 5%, and plant thermal efficiency reaches 40%. It is analyzed that the SAPG system gives the best performance at a lower load and a large aperture area.

Solar Chimney Power Plant - A Review on Latest Technological Advances for Performance Enhancement

2021 ◽  
Vol 9 (VI) ◽  
pp. 2434-2443
Author(s):  
Sreelekha Arun
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Performance Enhancement ◽  
Mechanical Energy ◽  
Technological Advancement ◽  
Solar Chimney ◽  
Air Turbine ◽  
Power Generation Technology ◽  
Solar Chimney Power Plant ◽  
Generation Technology

The energy consumption on global scale is continuously increasing, resulting in rapid use of energy resources available. Solar chimney power generation technology hence began to get growing attention as its basic model needs no depleting resources like fossil fuels for its functioning but only uses sunlight and air as a medium. It takes the advantage of the chimney effect and the temperature difference in the collector that produces negative pressure to cause the airflow in the system, converting solar energy into mechanical energy in order to drive the air turbine generator situated at the base of the chimney. Solar Chimney Power Plant (SCPP) brings together the solar thermal technology, thermal storage technology, chimney technology and air turbine power generation technology. However, studies have shown that even if the chimney is as high as 1000 m, the efficiency achievable is only around 3%. Hence, this review paper intents to put together the new technological advancement that aims to improve the efficiency of SCPP.

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