Numerical study of the influence of geometric form of chimney on the performance of a solar updraft tower power plant

2018 ◽  
Vol 30 (4) ◽  
pp. 685-706 ◽  
Author(s):  
A Jameei ◽  
P Akbarzadeh ◽  
H Zolfagharzadeh ◽  
SR Eghbali
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Numerical Study ◽  
Geometric Form ◽  
Air Velocity ◽  
Hot Air ◽  
Step Procedure ◽  
Parabolic Form ◽  
Tower Height ◽  
Solar Updraft Tower

Today, solar radiation is known as an important renewable energy which can be exploited in several ways such as solar updraft tower power plants, photovoltaic power plants, etc. In a solar updraft tower power plant, sunshine heats the air beneath a wide collector surrounding a tall tower and causes a hot air updraft in the tower by the chimney effect. This airflow drives wind turbines, placed almost in the chimney base, to produce electricity. In this study, the effect of the geometric form of the chimney on the performance of one solar updraft tower power plant is numerically investigated. Regarding the importance of the kinetic power of the hot air on power generation, it is intended to increase the air velocity by varying the forms of the chimney without changing the main dimensions of solar updraft tower power plant such as tower height and collector geometries. This approach may decrease the financial costs of the solar updraft tower power plant. For the numerical simulations, a finite volume computational fluid dynamics code solves the governing equations on an axisymmetric pi-shape domain (15° of whole geometry). To validate the results, the Manzanares solar updraft tower power plant experimental data are utilized. In this study, 15 forms of chimney based on a logical three-step procedure (from a basic cylindrical to a parabolic form) are examined. So, an appropriate/final form with a parabolic curve of chimney wall with divergence angle is obtained. Results indicate that the final form has the highest updraft air velocity. In fact, the average updraft air velocity increases from 15.66 m/s for the basic form to the value of 23.36 m/s (around 49.17% increments) for the final form.

Model-Based Analysis of the Start-Up Improvement of a CCPP due to Steam Turbine Warm-Keeping With Air

2019 ◽  
Author(s):  
Dennis Toebben ◽  
Tobias Burgard ◽  
Sebastian Berg ◽  
Manfred Wirsum ◽  
Liu Pei ◽  
...  
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Power Plants ◽  
Cold Start ◽  
Nox Emissions ◽  
Data Set ◽  
Water Steam ◽  
Hot Air ◽  
Start Up ◽  
Low Load

Abstract Combined cycle power plants (CCPP) have many advantages compared to other fossil power plants: high efficiency, flexible operation, compact design, high potential for combined heat and power (CHP) applications and fewer emissions. However, fuel costs are relatively high compared to coal. Nevertheless, major qualities such as high operation flexibility and low emissions distinctly increase in relevance in the future, due to rising power generation from renewable energy sources. An accelerated start-up procedure of CCPPs increases the flexibility and reduces the NOx-emissions, which are relatively high in gas turbine low load operation. Such low load operation is required during a cold start of a CCPP in order to heat up the steam turbine. Thus, a warm-keeping of the thermal-limiting steam turbine results in an accelerated start-up times as well as reduced NOx-emissions and lifetime consumption. This paper presents a theoretical analysis of the potential of steam turbine warm-keeping by means of hot air for a typical CCPP, located in China. In this method, the hot air passes through the steam turbine while the power plant is shut off which enables hot start conditions at any time. In order to investigate an improved start-up procedure, a physical based simplified model of the water-steam cycle is developed on the basis of an operation data set. This model is used to simulate an improved power plant start-up, in which the steam turbine remains hot after at least 120 hours outage. The results show a start-up time reduction of approximately two-thirds in comparison to a conventional cold start. Furthermore, the potential of steam turbine warm-keeping is discussed with regards to the power output, NOx-emissions, start-up costs and lifetime consumption.

Design and Implementation of an Efficient Biomass Drier System for a Wood Gasification Based Power Plant

2011 ◽  
Vol 110-116 ◽  
pp. 4772-4779
Author(s):  
Kumar Ashlesh ◽  
Rohit Vadera ◽  
K. Ramachandra
Keyword(s):  
Power Plant ◽  
Rural Areas ◽  
Power Plants ◽  
Fossil Fuels ◽  
Waste Heat ◽  
Optimum Level ◽  
Design Development ◽  
Engine Exhaust ◽  
Energy Demands ◽  
Hot Air

The use of woody biomass gasification based power plants to generate electricity is on the rise with the fast depletion of fossil fuels and ever increasing energy demands. An important sub-system of such a plant is the drier which is used to reduce the moisture content of biomass to an optimum level for trouble free and optimum performance of the gasification system. This work concerns with the design, development and implementation of a drier system which utilizes waste heat available from the power plant to dry biomass. The drier designed is simple yet effective in capturing the waste heat from the engine exhaust as well as the radiator hot air. The drier is also easy to implement in rural areas.

Numerical Study of Discharged Heat Water Effect on Aquatic Environment From Coastal Thermal Power Plant by Using Two Water Discharged Pipes

2018 ◽  
Vol 7 (2) ◽  
pp. 97-116
Author(s):  
Alibek Issakhov
Keyword(s):  
Power Plant ◽  
Aquatic Environment ◽  
Thermal Power Plant ◽  
Power Plants ◽  
Numerical Study ◽  
Water Discharge ◽  
Thermal Power ◽  
Numerical Results ◽  
Stratified Medium ◽  
Discharge System

The article presents a numerical study of the thermal load on the aquatic environment by using two water discharge pipes under various operational capacities of thermal power plant. It is solved by the Navier-Stokes and temperature transport equations for an incompressible fluid in a stratified medium. The aim of this article is to improve the existing water discharge system for reduce the heat load on the reservoir-cooler of the thermal power plants operation (Ekibastuz SDPP-1). In this article, thermal pollution using only two water discharge pipes, using the existing one and building only one additional in the eastern part of the reservoir-cooler is numerically simulated. The numerical method is based on the projection method, which was approximated by the finite volume method. The obtained numerical results of three-dimensional stratified turbulent flow for two water discharge pipes under various operational capacities of the thermal power plant were compared with experimental data and with the numerical results for one water discharge pipe.

scholarly journals Use of LNG Cold Potential in the Cogeneration Cycle of Ship Power Plants

2020 ◽  
Vol 8 (9) ◽  
pp. 720
Author(s):  
Zhongcheng Wang ◽  
Sergejus Lebedevas ◽  
Paulius Rapalis ◽  
Justas Zaglinskis ◽  
Rima Mickeviciene ◽  
...  
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Numerical Study ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Model And Simulation ◽  
Excess Power ◽  
Liquid Natural Gas ◽  
Cogeneration Cycle ◽  
Regenerative Cycle

This paper presents the results of a numerical study on the parameters that affect the efficiency of the cogeneration cycle of a ship’s power plant. The efficiency was assessed based on the excess power (Ngen.) of a free turbine, operated with the inflow of gaseous nitrogen, which was used to generate electricity. A mathematical model and simulation of the regenerative cycle were created and adjusted to operate with a dual-fuel (diesel-liquid natural gas (LNG)) six-cylinder four-stroke engine, where the energy of the exhaust gas was converted into mechanical work of the regenerative cycle turbine. The most significant factors for Ngen. were identified by parametrical analysis of the cogeneration cycle: in the presence of an ‘external’ unlimited cold potential of the LNG, Ngen. determines an exhaust gas temperature Teg of power plant; the pressure of the turbo unit and nitrogen flow are directly proportional to Ngen. When selecting the technological units for cycle realization, it is rational to use high flow and average πT pressure (~3.0–3.5 units) turbo unit with a high adiabatic efficiency turbine. The effect of the selected heat exchangers with an efficiency of 0.9–1.0 on Ngen. did not exceed 10%. With LNG for ‘internal’ use in a ship as a fuel, the lowest possible temperature of N2 is necessary, because each 10 K increment in N2 entering the compressor decreases Ngen. by 5–8 kW, i.e., 5–6%.

Numerical Study of the Flow Inside a Modular Bag Filter From a Biomass Power Plant

2020 ◽  
Author(s):  
Maria Inês Vinha ◽  
João Silva ◽  
Senhorinha Teixeira ◽  
Ana Gomes ◽  
José Carlos Teixeira
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Numerical Study ◽  
Operating Conditions ◽  
Solid Particles ◽  
Biomass Combustion ◽  
Bag Filter ◽  
First Case ◽  
Vertical Baffle ◽  
Biomass Power Plant

Abstract Nowadays, one of the most important issues in modern industrial power plants is air pollution. Solid particles are harmful to human health and are one of the main pollutants released through the combustion of biomass. The main goal of this paper was to study the flow in a modular bag filter of a dedusting system implemented in a Biomass Power Plant, in order to improve the filtration of the solid particles coming from the biomass combustion. For this purpose, a numerical model using the ANSYS Fluent software was developed. Initially, it was necessary to model the dedusting system in the software SolidWorks. Once this system had 10 modules and to facilitate the simulation in Fluent, only one module was modeled with proper simplifications. Once the geometry was modeled, it was exported to Fluent where the mesh was made, with special care in the inlet of the module, as it is the most critical zone for the simulation. It was simulated 4 cases, where the action of each individual filter was considered. The first case study considered the nominal operating conditions of a biomass power plant. Thereafter, two cases with different mass flow rates were simulated to assess if there were any differences in the flow inside the bag filter. Lastly, it was studied the influence of the vertical baffle size that is in the inlet of the module. Comparing the four simulations, it was concluded that in the first three cases, the flow is very similar, with only a slight increase in the velocity in the study with higher flow, as expected. Furthermore, it was concluded that using a smaller vertical baffle, the flow would be improved, once the filters close to the inlet would be more used.

Demonstration of ORC System Powered by Waste Heat From the Heuksando Island Internal Combustion Diesel Power Plant

2018 ◽  
Author(s):  
Sanghyup Lee ◽  
Hoon Jung
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Heat Source ◽  
Power Plants ◽  
Waste Heat ◽  
Numerical Study ◽  
Cooling Water ◽  
Organic Rankine Cycle ◽  
Operating Conditions ◽  
Source Analysis

Geographical characteristics give the island of Heuksando no choice but to use diesel power generation. This option is not economical, and more than half of the generated energy is released through exhaust gas, cooling water, and other sources of energy loss. In order to reduce these losses and improve power generation efficiency, this research studied Organic Rankine Cycle systems that use waste heat from diesel power plants as a heat source. Unlike previous Rankine cycles, electric power generation and operation are possible because of low heat source and capacity. Cycle design and demonstration-operation logic are required to set the range of waste heat temperature and capacity. In addition, as the overall efficiency may change substantially depending on the efficiency of each component, the operating conditions of various BOPs should be optimized. It is necessary to obtain the optimization and operating conditions of each element of the system through modeling and numerical study of the whole system. In this research, heat source analysis and BOP design were conducted in order to apply the 20kW/30kW ORC systems to the Heuksando Island 1MW diesel power plant. A heat-connecting technique that thermally connects the heat exhaust end piping and the evaporator of the ORC system was developed in this study. The demonstration experiment was conducted sharing the waste heat source with the 20kW and 30kW ORC systems. This paper presents the waste heat analysis and the demonstration operation results of the Heuksando island power plant.

Electricity Generating from Small Scale Solar Updraft Tower for Remote Area

2011 ◽  
Vol 121-126 ◽  
pp. 2011-2015
Author(s):  
Yuttachai Keawsuntia ◽  
Cheevin Limsiri ◽  
Thamrong Prempridi ◽  
Sanguan Patamatamkul
Keyword(s):  
Fluid Dynamics ◽  
Solar Collector ◽  
Remote Area ◽  
Small Scale ◽  
Small Community ◽  
Air Velocity ◽  
Computation Fluid Dynamics ◽  
Air Inlet ◽  
Hot Air ◽  
Solar Updraft Tower

Solar updraft tower is an alternative technology for electricity generating from solar energy. It’s suitable for use in remote area, where there is high potential of solar radiation, because the constructions are cheap and the technologies involved are conventional. From the study of small scale solar updraft tower by using the computation fluid dynamics program and experimental, show that the hot air velocity in the solar updraft tower from the computation fluid dynamics program similarly with the experimental data. From this study, the small-scale solar updraft tower with 72 m length in each side of solar collector, air inlet height of 0.5 m above the ground, an updraft tower of 30 meter high with 1.2 m length of each side was studied to determine the performance. It was found that the electricity generating from this model was 6893 W/day, enough to supply electricity for up to 13 families of small community in the rural area.

A Modified SSLPS Algorithm with Logistic Pseudo-Random Sequence Generator for Improving the Performance of Neka Power Plant

2015 ◽  
Vol 6 (1) ◽  
pp. 1-29
Author(s):  
Ahmad Mozaffari ◽  
Mehdi Emami ◽  
Nasser L. Azad ◽  
Alireza Fathi
Keyword(s):  
Mathematical Model ◽  
Power Plant ◽  
Power Systems ◽  
Power Plants ◽  
Large Scale ◽  
Numerical Study ◽  
Random Sequence ◽  
Chaotic Map ◽  
Logistic Map ◽  
Energetic Efficiency

Metaheuristic techniques have successfully contributed to the development and optimization of large-scale distributed power systems. The archived literature demonstrate that the modification or tuning of the parameters of specific metaheuristics can provide powerful tools suited for optimization of power plants with different types of constraints. In spite of the high potential of metaheuristics in dealing with such systems, most of the conducted researches only address the optimization of the electrical aspects of power systems. In this research, the authors intend to attest the applicability of metaheuristics for optimizing the mechanical aspects of a real-world large-scale power plant, i.e. Neka power plant sited in Mazandaran, Iran. To do so, firstly, based on the laws of thermodynamics and the physics of the problem at hand, the authors implement a mathematical model to calculate the values of exergetic efficiency, energetic efficiency, and total cost of the Neka power plant as three main objective functions. Besides, a memetic supervised neural network and Bahadori's mathematical model are used to calculate the dynamic values of specific heat over the operating procedure of the power plant. At the second stage, a modified version of a recent spotlighted Pareto based multiobjective metaheuristic called synchronous self-learning Pareto strategy (SSLPS) is proposed. The proposed technique is based on embedding logistic chaotic map into the algorithmic architecture of SSLPS. In this context, the resulting optimizer, i.e. chaos-enhanced SSLPS (C-SSLPS), uses the response of time-discrete nonlinear logistic map to update the positions of heuristic agents over the optimization procedure. For the sake of comparison, strength Pareto evolutionary algorithm (SPEA 2), non-dominated sorting genetic algorithm (NSGA-II) and standard SSLPS are taken into account. The results of the numerical study confirm the superiority of the proposed technique as compared to the other rival optimizers. Besides, it is observed that metaheuristics can be successfully used for optimizing the mechanical/energetic parameters of Neka power plant.

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