Pressure Losses in Solar Chimney Power Plant

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Xinping Zhou ◽  
Yangyang Xu

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.

Author(s):  
Carl F. Kirstein ◽  
Theodor W. von Backstro¨m ◽  
Detlev G. Kro¨ger

A solar chimney power plant consists of a large greenhouse type collector surrounding a tall chimney. The air, heated within the collector, passes through an inlet guide vane (IGV) cascade and then through a transition section to a turbine that powers a generator. The transition section contains the turbine inlet guide vanes that support the whole chimney and guides the flow entering the turbine. The primary objective of the study was to determine the loss coefficient of this section as dependent on IGV stagger angle and collector roof height. Very good agreement was found between experimental values measured in a scaled model and commercial CFD code predictions of flow angles, velocity components and internal and wall static pressures. The agreement between measured and predicted total pressure loss coefficient was reasonable. The CFD code served to extend the predictions to a proposed full-scale geometry.


Author(s):  
Nima Fathi ◽  
Seyed Sobhan Aleyasin ◽  
Patrick Wayne ◽  
Peter Vorobieff

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.


2018 ◽  
Author(s):  
Yan Zhou ◽  
Chen Yang ◽  
Kai Hao ◽  
Liang-Heng Zhang

Author(s):  
Sellami Ali ◽  
Benlahcene Djaouida ◽  
Abdelmoumène Hakim Benmachiche ◽  
Zeroual Aouachria

Author(s):  
Sreelekha Arun

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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