Scientific Publications Year 2008 for Solar Updraft ChimneysCOPYRIGHT:
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Scientific Publications in English
Title - Author – Reference - Abstract
Analysis and feasibility of implementing solar chimney power plants in the Mediterranean region
Energy, Volume 33, Issue 11, November 2008, Pages 1680-1690
S. Nizetic, N. Ninic, B. Klarin
This paper analyzes the feasibility of solar chimney power plants as an environmentally acceptable energy source for small settlements and islands of countries in the Mediterranean region. For the purpose of these analyses, two characteristic geographic locations (Split and Dubrovnik) in Croatia were chosen and simplified model for calculation of produced electric power output is also developed. These locations possess typical characteristics of the Mediterranean climate. The solar characteristics of the chosen geographic locations are shown along with characteristic meteorological data. A solar chimney (SC) power plant with a chimney height of 550 m and a collector roof diameter of 1250 m would produce 2.8–6.2 MW of power. The average annual electric power production of this SC power plant would range between 4.9 and 8.9 GWh/year, but in reality from 5.0 to 6.0 GWh/year in average. An approximate costs analysis, which included a total investment estimate, was performed. The levelized electricity cost was also calculated. It is found that the price of produced electric energy by solar chimney power plant in Mediterranean region is considerably higher compared to the other power sources.
Performance analysis of the power conversion unit of a solar chimney power plant
Solar Energy, Volume 82, Issue 11, November 2008, Pages 999-1008
T.P. Fluri, T.W. Von Backström
The power conversion unit (PCU) of a large solar chimney power plant consists of one or several turbogenerators, power electronics, a grid interface and the flow passage from collector exit to chimney inlet. The main goals of this paper are to analyze the performance of the PCU and its interaction with the plant as well as to compare three configurations from an efficiency and energy yield point of view.
First, a reference plant is defined and the plant performance data taken from simulations with a model found in the literature are analyzed, and the matching of the turbine(s) to the characteristic of the plant is discussed. It was found that a well designed turbine can be run at high efficiency over the entire operating range, as the plant performance data can be fitted using the ellipse law of Stodola.
Loss models for all components of the power conversion unit are then defined, and the impact of the various losses on the overall performance is assessed. Three configurations of the PCU are compared, i.e. the single vertical axis, the multiple vertical axis and the multiple horizontal axis turbine configuration. It is found that the single vertical axis turbine has a slight advantage with regards to efficiency and energy yield because certain loss mechanisms are not present. But its output torque is tremendous, making its feasibility questionable. It is shown that with designing the flow passage in an appropriate manner the aerodynamic losses can be kept low. The assumption made by many other researchers that the total-to-total efficiency of the PCU is 80 % has been confirmed with the present model. Further, it has been shown that the PCU efficiency deteriorates significantly with increasing diffuser area ratio but improves only slightly with reducing the diffuser area ratio below unity.
Solar chimney power generation project - The case for Botswana
Renewable and Sustainable Energy Reviews, Volume 12, Issue 7, September 2008, Pages 2005-2012
Clever Ketlogetswe, Jerzy K. Fiszdon, Omphemetse O. Seabe
Import of a huge proportion of electrical energy from the Southern African Power Pool, and the geographical location and population distribution of Botswana stimulated the need to consider renewable energy as an alternative to imported power. The paper describes a systematic experimental study on a mini-solar chimney system. Particular attention is given to measurements of air velocity, temperature and solar radiation. The results for the selected 5 and 6 clear days of October and November, respectively, are presented. These results enable the relationship between average insolation, temperature difference and velocity for selected clear days to be discussed.
The solar cyclone: A solar chimney for harvesting atmospheric water
Energy, Volume 33, Issue 2, February 2008, Pages 331-339
B.A. Kashiwa, Corey B. Kashiwa
The Solar Cyclone has been introduced as a means of extracting fresh water from Earth's atmosphere. The conceptual device operates in the fashion of a Solar Chimney; it is composed of a greenhouse for collecting and storing solar energy as heat, with a central chimney that channels an updraft of surface air heated in the greenhouse. An expansion cyclone separator for condensing and removing atmospheric water is placed at the base of the chimney. The separator consists of a strongly rotating vortex in which the central temperature is well below the dew point for the greenhouse air. Power consumed in the expansion and separation is furnished by the motive potential of the chimney updraft. Turbulent flow conditions are established in the expansion cyclone separator to enhance the centrifugal separation. Excess updraft power is used to generate electricity, as is done in the Solar Chimney. The article furnishes a theoretical basis for the feasibility of the Solar Cyclone, suggesting that an experimental study of the separation device would be worthwhile.
Comparison of modelling approaches and layouts for solar chimney turbines
Solar Energy, Volume 82, Issue 3, March 2008, Pages 239-246
T.P. Fluri, T.W. von Backström
The turbogenerator is a core component of any solar chimney power plant. Various layouts for the turbogenerator have been proposed in the literature. In this paper the performance of these layouts is compared using analytical models and optimization techniques, and the important design parameters are discussed. The turbine layouts under consideration are single rotor and counter rotating turbines, both with or without inlet guide vanes.
In contrast to similar investigations found in the literature, various radial sections along the blades are analysed in the turbine model. This approach is more appropriate than using a simple mean line analysis when dealing with turbines with high blade aspect ratio and low hub to tip ratio. Furthermore, a limit to the degree of reaction of the turbine has been introduced to avoid diffusion at the hub.
It is shown in this paper that these slight changes in modelling approach have a significant impact on the performance prediction. Further it can be concluded that the single rotor layout without guide vanes performs very poorly; the efficiency of the other three layouts is much better and lies in a narrow band. The counter rotating layouts provide the highest peak efficiencies, but at relatively low speeds, which leads to an undesirable higher torque for the same power output.
2. Turbine modelling
2.1. Structure of the program
2.2. Mathematical turbine models
2.2.1. Velocity diagram
2.2.2. Losses and efficiency
2.2.3. Torque evaluation
2.2.4. Solidity and number of blades
2.2.6. Models for layouts two, three and four
3. Comparison of layouts
3.3. Solidity and number of blades
4. Comparison of various modelling approaches
Modeling of the optimum tilt of a solar chimney for maximum air flow
Solar Energy, Volume 82, Issue 1, January 2008, Pages 80-94
E.P. Sakonidou, T.D. Karapantsios, A.I. Balouktsis, D. Chassapis
The aim of this work is to develop a mathematical model to determine the tilt that maximizes natural air flow inside a solar chimney using daily solar irradiance data on a horizontal plane at a site. The model starts by calculating the hourly solar irradiation components (direct, diffuse, ground-reflected) absorbed by the solar chimney of varying tilt and height for a given time (day of the year, hour) and place (latitude). In doing so it computes the transmittance and absorbance of the glazing for the various solar irradiation components and for various tilts. The model predicts the temperature and velocity of the air inside the chimney as well as the temperatures of the glazing and the black painted absorber. Comparisons of the model predictions with CFD calculations delineate the usefulness of the model. In addition, there is a good agreement between theoretical predictions and experiments performed with a 1 m long solar chimney at different tilt positions.
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Scientific Publications in Chinese
Study on Solar Chimney Thermal Power Technology and Its Application in Western China
【导师】 杨家宽； 肖波；
【作者基本信息】 华中科技大学， 环境工程， 2008， 博士
【摘要】 太阳能烟囱发电技术是一种适宜大规模发电的热气流发电技术。我国特别是人烟稀少的西部地区具有发展大规模太阳能发电系统的优势:广袤的荒地、巨大的山体高差、丰富的太阳能资源和日较差资源。太阳能烟囱热气流利用系统在西部地区有极大的应用潜力。然而,太阳能烟囱发电技术能量转换效率低、投资大、安全可靠性难以保证,至今仍未建成商业性电站,其基础研究及应用模式都有待深入研究。因此,研究和开发综合成本低、运行维护方便、适合西部地域特征的太阳能热气流发电系统服务于西部能源与生态环境的改造具有巨大潜力和现实意义。本文主要研究了基于西部特征的太阳能烟囱发电技术,重点开展了以下两方面的研究。(1)建造了国内第一套小型太阳能烟囱发电实验原型,并展开了相应的实验及数值模拟的基础研究。设计并建造了一套集热棚直径10 m,烟囱高8 m的小型太阳能烟囱发电实验原型,并开展了实验研究。实验结果表明:在集热棚内,从入口向中部汇集过程中,空气温度逐渐升高,速度先减后增,在烟囱内,随着高度增加,空气温度略有降低;不同天气条件下,棚内空气温度较高,晴天、阴天温升可达到20 K和10 K以上,集热棚有较好的温室效应;在早上,烟囱口附近出现逆温层,而且逆温层持续时间随太阳辐射增强而变短,逆温层的出现将使得太阳能烟囱发电系统运行较为困难。太阳能烟囱热气流发电系统中的流动和换热模型解析以及模型应用尚待明确的问题主要集中在空气可压缩性问题、集热棚内对流换热系数确定、涡轮处压降因子确定、涡轮发电机组模拟及效率问题、商业化CFD软件自带浮升力模型模拟问题等。针对以上问题,本论文开展了三类太阳能烟囱发电系统的数值模拟方法。编写了SIMPLE类算法三维数值模型,用于对发电系统进行三维模拟,方便研究者自行调节。通过编写UDF定义流体密度和精确的浮升力项,对Fluent软件进行了二次开发,构建一套三维可压缩流浮升力模型,成功地克服了因商业化CFD软件自带浮升力模型假设过多的缺点而引起解的偏差较大的问题。编写了“1+1”维可压缩流数值模型,通过联合热网方程求解。该模型包括了主要的流动阻力、涡轮处的压降和温降、随高度而变的大气压力和温度、集热棚内空气的混合流(自然对流和强迫对流)等。该模型假设较少,基本上解决了现有模型应用中尚需明确的问题。通过将以上模型模拟的结果与实验数据或权威模型的计算结果比较,分别验证了以上模型。这些模型为后续的研究创造了条件。讨论了采用商业化CFD软件自带的浮升力模型——Boussinesq近似浮升力模型和全浮升力模型模拟大规模太阳能烟囱发电系统的准确性。结果表明:以高1500 m、直径160 m的大型烟囱为例,全浮升力模型和Boussinesq近似浮升力模型造成的发电量的偏差分别达到42%倍和33%倍。通过利用“1+1”维可压缩流数值模型进行计算,探讨了太阳辐射强度、结构参数对太阳能烟囱系统性能的影响规律。结果表明:太阳能烟囱系统的发电功率随太阳辐射强度、烟囱高度或棚直径的增加而增加。(2)基于分析西部地域特征,提出了几种不同的太阳能烟囱热气流利用模式,并对大规模漂浮烟囱的经济性进行了分析,探讨了大型太阳能烟囱对局部气候的影响。结合我国西部地域特点,提出了不同的太阳能热气流利用模式。首次提出了太阳能烟囱直接抽取地下水的概念,设计了太阳能烟囱直接抽取地下水模型,分析了在我国西北边远地区,利用中小规模太阳能烟囱热气流系统抽取地下水提供生活用水和农业灌溉用水的可行性和经济性,结果表明:中小规模太阳能烟囱热气流系统在电网输入困难且风力资源贫乏的偏远山区有很大的应用潜力。讨论了太阳能烟囱热气流抽水装置的额定驱动功率与服务人口规模和地下水源的关系。介绍了三类结合山体的复合式太阳能烟囱发电系统的特性,从效率、建造难度、成本、安全等方面研究和评价了这三类山体复合式烟囱发电系统。和同纬度的传统竖直烟囱系统相比,斜坡集热棚式系统的效率最高,45°倾角的斜坡集热棚式系统的效率提高了近40%,建造在15°倾角山脚上斜烟囱式和山洞烟囱式系统的效率提高了近20%。与高大山体结合的三类复合式发电系统可行性大、“烟囱”高、安全性好、投资较低,有效地解决了超高竖直烟囱带来的安全问题以及投资太大等问题。对大气风力作用下的漂浮烟囱进行了受力平衡分析,讨论了大气风力和净浮力对发电功率的影响规律。结果表明:大气风力越大或净浮力越小,烟囱偏角将越大,发电功率将越小。漂浮烟囱更适用于大风不频繁的地区,地面主风均速在3.5 m/s以下是比较适宜的条件。构建了一套经济学模型,估算了大规模漂浮烟囱发电系统的最低销售价格,表明了在考虑温室气体的减排效益且获得低利率贷款情况下, 200 MW以上大规模漂浮烟囱发电系统的电力最低销售价格低于0.58元/kW•h,可与火力发电水平相当。对大型太阳能烟囱出口暖湿气流在高空冷大气中的对流和换热过程进行了数值模拟研究。首次提出了大型太阳能烟囱可能影响局部气候。进一步探讨了降水的可能性和降水强度随着烟囱结构参数、气象条件的变化规律,并讨论了降水机会增加而产生的环境、经济效益。结果表明:烟囱越高,相对湿度越大,或大气风速越小,降水的可能性和降水强度越大;水汽冷凝过程中释放出的潜热促进来流继续上升,从而增大降水面积。本论文的研究成果为太阳能烟囱电站在我国西部地区的实际建立和优化设计提供了一定的理论上的依据和指导。 更多还原
Solar chimney power system (SCPS) is a thermal system that is suitable for large-scale power generation. There are vast desertified regions, high-fall mountains, abundant available solar radiation, and large diurnal temperature in Western China where SCPS has large potential of application. However, the energy conversation efficiency of SCPS is low, its investment is large, and its safety is not good. By now, any commercial power plant has been not built up. Further study on fundamental problems and application of SCPS can be performed. It is significant to develop cost-effectiveness SCPS adapting to the local topography in Western China to supply energy.The dissertation is studying SCPS and its application in Western China and divided into the following two sections.The first section: A testing prototype of SCPS is built and the experimental and theoretical investigations of SCPS are performed.A testing prototype of SCPS is designed and built in China, which has a collector 10 m in diameter and a chimney 8 m high. Experimental investigation of SCPS is performed. The results show that the temperature of air increases along a radius from the inlet to the outlet, the velocity of air firstly decreases and then increases, the temperature of air decreases with heights in the chimney, the temperature rise in the collector reaches more than 20 K in a sunny day and 10 K in a cloudy day, a temperature inversion occurs around the chimney outlet in the morning and its duration decreases with higher solar radiation, and temperature inversion will block the operation of SCPS.The problems of the models modeling the flow and heat transfer in SCPS include compressibility, convective heat transfer between the flow and the ground, pressure drop coefficient, turbine efficiency, simulation using commercial computational fluid dynamics (CFD) software. As for the above problems, three numerical simulation models are developed to simulate the flow and heat transfer in SCPS. A 3D code is written in C based on SIMPLE algorithm. This code written can be free adjusted by the researcher. The CFD programme Fluent is re-developed by introducing functions of accurate density and buoyancy, which improves the inaccuracy of simulation using the buoyancy models automatically included in CFD programmes where some crucial assumptions are made. A‘1+1’dimensional compressible flow code is written by Matlab. In the model, natural and forced convection effects is considered for convection between the air flow and the ground and that between the air flow and the collector roof, flow resistance in the collector and chimney, and the pressure drop and temperature drop at the turbines are included, the ambient pressure and temperature changes with heights. This model has few assumptions and is more realistic, which solves the above problems of other models modeling the flow and heat transfer in SCPS.All the modes are validated by the comparisons of the simulation and the measurements or the calculation using the authoritative model. The deviation of the simulated results using the re-developed buoyancy model and the results using the buoyancy models (i.e. Full buoyancy model and Boussinesq model) automatically included in CFD programmes in a proposed 1500 m high solar chimney is estimated. The results show that Full buoyancy model and Boussinesq model give 42% and 33% times more power respectively than our model. Then, the influence of different solar radiations and dimensions on the power output are analyzed by using the‘1+1’dimensional compressible flow code, respectively. The results show that the power capacity of SCPS increases with the increase in solar radiation, chimney height, or collector diameter.The second section: Adapting to the special topography in Western China, various solar chimney thermal systems are proposed, economic analysis of large scale SCPS and its influence on local climate are performed, respectively.A concept of solar chimney groundwater pumping is first proposed and the solar chimney groundwater pumping system (SCGPS) is designed. The feasibility and economics of the use of small and mediumsmall scale SCGPS for driving to pump groundwater for drinking and agricultural use are discussed. The results show that the small and mediumsmall scale SCGPS has large potential at the remote villages where grid electricity is not reached and wind is plain. The relation of driving power capacity of SCGPS and its service scope and the depth of groundwater is investigated. The performances of three combined power systems with mountains are investigated. The performances of the three combined power systems with high mountains are analyzed by comparing their efficiency, building difficulty, investment, safety and the likes. The efficiency of the sloped collector system is the highest. The efficiency of the sloped collector system with 45°inclination mountain-side is about 40% more than, and the efficiencies of the sloped chimney system and tunnel chimney system with 15°inclination mountain foot are about 20% more than the classical system at the same latitude. It’s concluded that compared to the classical reinforced concrete SCPS, the three combined power systems with high mountains are more available and has potential of reaching high height for‘chimney’, good safety and low investment..Force equilibrium of floating solar chimney is established. The influence of wind velocity and net buoyancy of chimney on the power capacity of large scale floating solar chimney power system (FSCPS) are discussed. The analyses show that the optimal condition for floating solar chimney power system is that annual wind velocity is below 3.5 m/s at the ground level. Economic analyses of FSCPS are performed by using the developed economic model including the carbon credits. The results show that the minimum electricity price of more than 200 MW FSCPS under financial incentive of soft loan is less than 0.58 yuan/kWh, which is competitive with coal-fired plant. Flow and heat transfer of the plume from the gigantic chimney in the cross-section atmosphere are simulated. Viewpoint that the gigantic solar chimney is likely to affect the local climate is presented. The influences of chimney height, relative humidity, and wind velocity on the potential precipitation area and precipitation strength are analyzed. Environmental and economic benefits of increasing chance of precipitation around the large scale FSCPS are analyzed. It is concluded that higher chimney, bigger relative humidity of atmosphere, bigger velocity of wind increased the potential precipitation area and precipitation strength. In addition, latent heat produced in condensation process helps rise of plume by heating the plume. The investigation in this dissertation would provide the theoretical basis for the design and construction of solar chimney power plant in Western China, to some extent.
【关键词】 太阳能热气流发电； 漂浮烟囱； 集热棚； 西部地域； 山体复合式； 数值模拟； 可压缩流；
【Key words】 Solar thermal power generation； Floating chimney； Collector； Western China； Combined power systems with mountains； Numerical simulation； Compressible flow；
Wind-induced Response of the Solar Chimney
Xiaodong Lv, Xingfei Yuan and Lian Zhou
Space Structures Research Center, Zhejiang University, Hangzhou 310058, China
Keywords: Solar chimney, Wind-induced response, Time-history simulation, Wind vibration coefficient.
Wind-induced response was investigated on the chimney of a 100MW solar thermal power station. Firstly, dynamic characteristic of the chimney was analyzed and the first eight vibration mode shapes and frequencies were obtained. Wind velocity time-history simulation was then conducted utilizing harmonic superposition method with Fast Fourier Transformation. Followed that, transient dynamic analysis was carried out to obtain the wind-induced response and the wind vibration displacement coefficient calculated. Numerical results indicate that the maximal displacement and acceleration of the chimney appear on the top with a value of 0.5593m and 0.1933m/s2 respectively. Wind vibration displacement coefficient on the chimney increases with height with an average value of 2.303.
Numerical simulation of the solar chimney power plant systems coupled with turbine
Renewable Energy, Volume 33, Issue 5, May 2008, Pages 897-905
, Liu Wei, Xu Guoling, Xiong Yanbin, Guan Xuhu, Pan Yuan
Numerical simulations have been carried out on the solar chimney power plant systems coupled with turbine. The whole system has been divided into three regions: the collector, the chimney and the turbine, and the mathematical models of heat transfer and flow have been set up for these regions. Using the Spanish prototype as a practical example, numerical simulation results for the prototype with a 3-blade turbine show that the maximum power output of the system is a little higher than 50 kW. Furthermore, the effect of the turbine rotational speed on the chimney outlet parameters has been analyzed which shows the validity of the numerical method advanced by the author. Thereafter, design and simulation of a MW-graded solar chimney power plant system with a 5-blade turbine have been presented, and the numerical simulation results show that the power output and turbine efficiency are 10 MW and 50%, respectively, which presents a reference to the design of large-scale solar chimney power plant systems.
2. Numerical models
3. Mathematical models
3.1. In the collector and chimney regions
3.2. In the turbine region
4. Near-wall treatments for turbulent flows
5. Numerical simulation method
6. Results and discussions
6.1. Validity of the method for the Spanish prototype
6.2. Characteristic of 3-blade turbine for the Spanish prototype
6.3. Results for MW-graded solar chimney
NUMERICAL SIMULATION OF UNSTABLE STATE IN POWER GENERATION SYSTEM WITH HOT AIR FLOW PROVIDED FROM SOLAR ENERGY
【作者】 明廷臻； 刘伟； 熊宴斌； 管绪虎； 许国良； 潘垣；
【Author】 MING Ting-zhen
, LIU Wei, XUN Yan-bin, GUAN Xu-hu, PAN Yuan
Middle China University of Science & Technology, Wuhan 430074, Hubei Province, PRC
【机构】 华中科技大学； 华中科技大学 湖北武汉430074； 湖北武汉430074；
【摘要】 对太阳能热气流发电系统及蓄热层中的传热与流动特性进行了数值模拟。建立了集热棚、烟囱以及蓄热层内部的传热流动数学模型,分析了太阳辐射对蓄热层蓄热性能的影响。计算结果表明:土壤具有热惯性和较强的蓄热作用;蓄热层表面平均温度和烟囱出口平均温度随时间有一个较大的波动,且蓄热层表面平均温度的波动幅度更显著;蓄热介质的平均温度及系统散热量随时间波动,采用双层玻璃或薄膜材料可减小集热棚顶棚能量损失。 更多还原
The numerical simulation of heat transfer and flow characters in power generation system with hot air flow provided from solar energy and in the heat-accumulating layer has been carried out. The mathematical model of heat transfer and flow in heat-collecting shed, chimney, and inside the heat-accumulating layer has been established, the influence of solar radiation upon the heat-accumulating performance of said layer being analysed. Result of calculation shows that the soil has thermal inertia and stronger heat-accumulating effect; there is a large fluctuation of average temperature at the surface of heat-accumulating layer and at the outlet of chimney along with the elapse of time; and the fluctuation of average temperature at surface of the heat-accumulating layer is more remarkable; the average temperature of heat-accumulating medium and the heat-dissipating amount of said system are also fluctuating along with the elapse of time. The energy loss from ceiling of the heat-collecting shed can be decreased by using double-layer glass or membrane materials.
【关键词】 太阳能； 热气流发电系统； 集热棚； 蓄热层； 烟囱； 传热； 非稳态数值摸拟；
【Key words】 solar energy； power generation system with hot air flow； heat-collecting shed； heat-accumulating layer； heat transfer； numerical simulation of unstable state；
【文献出处】 热力发电, Thermal Power Generation, 编辑部邮箱 , 2008年01期
Unsteady Conjugate Numerical Simulation of the Solar Chimney Power Plant System
【作者】 明廷臻； 刘伟； 许国良； 黄素逸； 潘垣；
【Author】 MING Ting-zhen
, LIU Wei, XU Guo-liang, HUANG Su-yi, PAN Yuan
(Huazhong University of Science and Technology,Wuhan 430074, Hubei Province, China)
【机构】 华中科技大学； 华中科技大学 湖北省武汉市430074； 湖北省武汉市430074；
【摘要】 太阳能热气流发电技术是目前国际太阳能研究领域的热点之一,但对带有蓄热层的太阳能热气流发电系统的研究并不多。该文分别建立了集热棚、烟囱和蓄热层的流动与传热数学模型。以西班牙试验电站模型为例进行的非稳态耦合数值计算结果表明:土壤具有较强的蓄热作用且能很好调整系统昼夜发电峰谷差;太阳辐射强度对系统散热损失的影响相当显著,太阳辐射越强,散热量越大;集热棚的顶棚是系统散热损失的主要部件,散热热流密度约为太阳辐射的10%。 更多还原
The solar chimney power generation system is one of the hotspots in the world solar energy research at the current time, but there is few study on the solar chimney power plant systems coupled with energy storage layer. Different mathematical models of flow and heat transfer for the the collector, the chimney and the energy storage layer were developed. Unsteady conjugate numerical simulation results for the solar chimney prototype in Spain show that the soil has the effect of energy storage and can modulate the difference of output power of the solar chimney power plant system between day and night, and that the solar radiation intensity has a significant effect on the energy loss from the system which will increase with the increasing of the solar radiation, and that the canopy of the collector is the main part of energy loss through the system, with a heat-transfer rate per unit area about 10% the amount of the solar radiation.
【关键词】 太阳能热气流发电系统； 自然对流； 蓄热层； 集热棚； 烟囱；
【Key words】 solar chimney power plant system； natural convection； energy storage layer； collector； chimney；
【文献出处】 中国电机工程学报, Proceedings of the CSEE, 编辑部邮箱 , 2008年05期
NUMERICAL ANALYSIS OF HEAT TRANSFER AND FLOW IN THE SOLAR CHIMNEY POWER GENERATION SYSTEM
【作者】 明廷臻； 刘伟； 熊宴斌； 管绪虎；
【Author】 Ming Tingzhen
, Liu Wei, Xiong Yannbin, Guan Xuhu
(College of Energy and Power Department, Huazhong University of Science and Technology, Wuhan 430074, China)
【摘要】 建立了集热棚、烟囱以及多孔蓄热层的太阳能热气流发电系统传热与流动数学模型,分析了太阳辐射对蓄热介质的蓄热特性的影响。计算结果表明,在太阳辐射为200～800W/m2的范围内,随着太阳辐射的增强,蓄热介质的蓄热比例先减小后增大;烟囱底部的最小相对压力显著减小,流动速度增大;系统内空气的温升增大,蓄热介质表面的温度也显著升高。 更多还原
Mathematical models to describe the mechanism of heat transfer and flow in the collector, chimney and the energy storage medium of the solar chimney power generation system were established, and the effect of the solar insolation on the heat storage characteristic of the energy storage medium was analyzed. The numerical simulation results show that the heat storage radio of the energy storage medium decreases firstly and then increases alone with increase of the solar radiation from 200 W/m2 and 800W/m2. The minimum relative static pressure at the bottom of the chimney decreases significantly while the flow speed increases, the temperature difference between the system and the environment and the temperature of the surface of the enrgy storage medium increase notablely.
【关键词】 太阳能热气流发电系统； 集热棚； 蓄热层； 烟囱；
【Key words】 solar chimney power generation system； collector； energy storage medium； chimney；
【文献出处】 太阳能学报, Acta Energiae Solaris Sinica, 编辑部邮箱 , 2008年04期
Numerical analysis of flow and heat transfer characteristics in solar chimney power plants with energy storage layer
Energy Conversion and Management, Volume 49, Issue 10, October 2008, Pages 2872-2879
, Wei Liu, Yuan Pan, Guoliang Xu
Numerical simulations have been performed to analyze the characteristics of heat transfer and air flow in the solar chimney power plant system with an energy storage layer. Different mathematical models for the collector, the chimney and the energy storage layer have been established, and the effect of solar radiation on the heat storage characteristic of the energy storage layer has been analyzed. The numerical simulation results show that: (1) the heat storage ratio of the energy storage layer decreases firstly and then increases with the solar radiation increasing from 200 W/m2 to 800 W/m2; (2) the relative static pressure decreases while the velocity increases significantly inside the system with the increase of solar radiation; (3) the average temperature of the chimney outlet and the energy storage layer may increase significantly with the increase of solar radiation. In addition, the temperature gradient of the storage medium may increase, which results in an increase of energy loss from the bottom of the energy storage layer.
EXPERIMENTAL SIMULATION OF HEAT TRANSFER AND FLOW IN THE SOLAR CHIMNEY SYSTEM
【作者】 明廷臻； 刘伟； 熊宴斌； 管绪虎； 许国良； 潘垣；
【Author】 MING Ting-Zhen
, LIU Wei, XIONG Yan-Bin, GUAN Xu-Hu, XU Guo-Liang
School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
【机构】 华中科技大学能源与动力工程学院； 华中科技大学电气与电子工程学院 湖北 武汉 430074； 湖北 武汉 430074；
【摘要】 构建了小尺寸太阳能热气流发电的实验模型,测定了系统的温度随时间和空间的分布,测定了烟囱内的速度随时间的变化关系。实验结果表明:集热棚内温度分布和季节对系统传热与流动特性的影响符合理论分析结果,而由于烟囱较薄,散热较高,在烟囱内的温度降低显著。 更多还原
A small scale solar chimney system model has been set up, and the temperature distribution of the system with time and space, together with the velocity variation inside the chimney with time, has been measured. The experimental results show that the temperature distributions inside the collector and the effects of seasons on the heat transfer and flow characteristic of system show great agreement with the analysis, while the temperature decrease significantly inside the chimney as the chimney is very thin which causes very high heat loss.
【关键词】 太阳能热气流发电； 集热棚； 烟囱；
【Key words】 solar chimney power generation； collector； chimney；
【文献出处】 工程热物理学报, Journal of Engineering Thermophysics, 编辑部邮箱 , 2008年04期
Study on the performance influential factors of collector in the solar chimney power system
【作者】 张静敏； 张华； 刘红绍；
【Author】 ZHANG Jing-min, ZHANG Hua, LIU Shao-hong
(University of Shanghai for Science and Technology,Shanghai 200093,China)
【机构】 上海理工大学动力工程学院； 上海理工大学动力工程学院 上海200093； 上海200093；
【摘要】 太阳能集热器是太阳能热风发电系统的重要组成部分。进入集热器的空气流量、辐射强度、环境温度、集热器内的蓄热体和集热棚的高度等参数,对集热器性能都有一定的影响。通过试验对影响集热器性能的诸因素进行了研究,并分析了各因素对太阳能热风发电系统空气集热器性能的影响。 更多还原
The air collector is one of the most important parts in the solar chimney power plant system. Main factors that influence the performance of air collector are the solar radiation, the ambient temperature, the collector height, the volume flow of the air entering the collector, and the storage material in the collector. Experimental research has been done to reveal the influence laws of these factors on the performance of the air collector.
【关键词】 空气集热器； 进出口温差； 集热器效率；
【Key words】 air collector； temperature difference； collector efficiency；
【文献出处】 可再生能源, Renewable Energy Resources, 编辑部邮箱 , 2008年03期
TEMPERATURE RISE PERFORMANCE IN SOLAR CHIMNEYES WITH DIFFERENT HEAT STORAGES
【作者】 朱丽； 王一平； 胡彤宇； 王俊红；
【Author】 Zhu Li~1, Wang Yiping~2, Hu Tongyu~2, Wang Junhong~2
(1. School of Ardtitecture of Tianjin University, Tianjin 300072, China;
2. School of Chemical Engineering and Technology of Tianjin University, Tianjin 300072, China)
【机构】 天津大学建筑学院； 天津大学化工学院；
【摘要】 针对太阳能烟囱的不同应用背景,设计不同蓄热方式的实验系统,考察太阳能烟囱内部的温度分布及温升性能。实验结果表明,密闭水体的蓄热方式的温升最大,由于水分蒸发消耗了部分太阳热量,开放水体系统的温升效果最差,多孔材料的加入使集热后的空气温度进一步降低;非蒸发体系中的空气温度沿着主体流动方向存在最大值,蒸发体系中的空气温度分布总体呈上升趋势,但具体变化会因水分蒸发的强弱而不同。温度分布的结果表明为了避免出现集热棚下的热量散失段,需要对太阳能烟囱的结构参数进行优化设计。 更多还原
Aiming at different application fields, experimental solar chimney systems with different heat storage styles were set up. The results showed that the temperature difference in the sealed water system is the largest, while the open water system has the lowest one because of the latent heat consumed by water evaporation, the evaporation can be enhanced by porous materials with lower temperature increase, and there is a maximum data of temperature in non-evaporate systems with the air flow direction to the chimney. The temperature rises wholly with specific changes depending on the evaporation extent in the system having evaperation. The experimental results indicated there is the temperature distribution optimization of the system if the heat loss part of the collector to be avoided.
【关键词】 蓄热方式； 强化蒸发； 太阳能烟囱； 温度场； 湿度场；
【Key words】 storage style； evaporation enhancement； solar chimney； temperature field； humidity field；
【文献出处】 太阳能学报, Acta Energiae Solaris Sinica, 编辑部邮箱 , 2008年03期
Influence of Thermal Storage Materials on Thermal Performance of Heat Collector in Solar Chimney Power Generations
【作者】 黄惠兰； 张华； 安恩科； 姚秀平； 邬志敏；
【Author】 HUANG Hui-lan~(1,2), ZHANG Hua~1, AN En-ke~3, YAO Xiu-ping~4, WU Zhi-min~1
(1. College of Power Engineering, Shanghai University of Science and Technology, Shanghai 200093, China;
2. College of Mechanical Engineering, Guangxi University, Nanning 530004, China;
3. Department of Thermal Engineering, Tongji University, Shanghai 200092, China;
4. Department of Thermal Engineering, Shanghai University of Electric Power, Shanghai 200093, China)
【机构】 上海理工大学动力工程学院； 同济大学热能工程系； 上海电力学院热能工程系；
【摘要】 分别以沙子、石子以及石子与充水黑色密封管的组合作为蓄热介质,搭建了太阳能集热器试验装置并进行了相应的试验研究,得出了不同蓄热介质的吸放热特性及其对集热器内空气进出口温差、集热器效率的影响规律.结果表明:在相同的平均辐射强度下,石子与充水黑色密封管组合集热器的蓄热性能好,且集热器空气进出口温差及集热器效率最大,为太阳能热风发电系统集热器地面蓄热材料的选用提供了依据. 更多还原
A test rig of solar heat collector was set up and corresponding tests were carried out taking sands, pebbles and combination of pebbles and water-filled black sealed tubes as thermal storage material(TSM), respectively. Heat absorption and release characteristics of different TSMs and their influence on temperature differences between air inlet and outlet of heat collector are obtained. Results indicate that the combination of pebbles and water-filled black sealed tubes shows a higher heat storage capacity under the same average radiation intensity. Temperature difference between air inlet and outlet of heat collector, as well as heat efficiency, of the combination of pebble and waterfilled black sealed tubes are the highest among the three TSM heat collectors. Results provide a foundation for the selection of heat collector in solar chimney power generation system.
【关键词】 能源系统工程； 太阳能热风发电； 集热器； 蓄热介质； 热效率；
【Key words】 energy system engineering； solar chimney power generation； heat collector； thermal storage material； heat efficiency；
【基金】 国家自然科学基金资助项目(50476078); 上海市重点科建设基金资助项目(T0503)
【文献出处】 动力工程, Journal of Power Engineering, 编辑部邮箱 , 2008年04期
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