Performance analysis of sloped solar chimney power plants in the southwestern region of Iran

The sloped solar chimney power plant (SSCPP) has significant capability to fulfil a part of the forthcoming energy requirements of villages located in the southwestern region of Iran. This paper presents the performance analysis of SSCPP which was expected to fulfil the urgent need for electric power in the southwestern region of Iran. However, to investigate the SSCPP performance and power generation throughout the southwestern region of Iran, five different regions across the Persian Gulf were considered. A mathematical model was developed to estimate the power output of solar chimneys. The performances, such as rate of air mass flow, system efficiency and solar collector efficiency, of the SSCPP were studied. The obtained results show that SSCPPs can produce from 2.98 to 5.91?MW of electricity power in the selected regions during different months of the year.     

Thermodynamical analysis of dry cooling tower and solar chimney power plant combination

Solar chimney power plant is one of the rather new technologies that can produce power from solar energy. Its high stack is one of the important parts of the system in which the differential density of air among its top and bottom sections causes air-flow. Dry cooling towers are used in industries for cooling condensing water by utilising this concept and generating air-flow. The structural and conceptual similarity between these two systems cause the feasibility of their combination and usage of waste energy in industries. In this article, a simple and useful analytical thermodynamic model is improved in order to estimate the thermodynamic flow properties for combining both systems. Results show that the stack height and diameter are effective parameters in recovery of power. Moreover, the results show that the collector area does not remarkably affect the system performance.     

太阳能强化烟囱技术在通风采光装置中的应用研究

通过对室外的通风采光装置的通风管改造成透明玻璃管,形成集热器式太阳能烟囱,测试了烟囱的通风速率和温度变化情况,根据其工作原理计算了从9:00-17:00时之间的室内外空气压力差,证实了太阳能烟囱可以提高室内外的通风速度。     

陶瓷太阳板及其应用的研究

陶瓷太阳板以普通瓷土、工业废弃物为原料,制造工艺简单、生产耗能少、成本低、寿命长、效率高建造的陶瓷太阳能房顶与原房顶共用结构层、保温层、防水层,结构简单、与建筑一体化、与建筑同寿命隔热、保温效果优于普通房顶,为建筑物提供热水、取暖、空调;用于沙漠太阳能发电、海水淡化、苦咸水淡化、改造沙漠成为耕地;可能实现太阳能使用成本低于常规能源。     

太阳能烟囱强化自然通风的数值模拟

太阳能烟囱的应用可以加强太阳能自然资源的利用,削减不可再生能源的耗费。本文通过使用数值模拟的方法对太阳能烟囱房间的气流流动进行了模拟分析,特别研究了太阳辐射量、环境温度以及太阳能烟囱截面宽度对房间通风量的影响。数值模拟计算结果与理论计算结果吻合很好,为加强房间通风效果提供了理论依据。     

火电厂烟囱烟道进口区域钢内筒温度应力分析

以某火电厂悬挂式钢内筒为例,利用有限元分析软件ABAQUS对烟囱烟道进口区域钢内筒温度应力进行了分析,针对分析结果提出了在烟道进口区域钢内筒及烟道内侧设置陶瓷玻化砖对钢结构实施隔热防护,从而减小烟道进口区域钢内筒及烟道的温度应力,起到保护钢内筒的作用。     

Enhancement of natural ventilation in buildings using a thermal chimney

A new module was developed for and implemented in the EnergyPlus program for the simulation and determination of the energy impact of thermal chimneys. This paper describes the basic concepts, assumptions, and algorithms implemented into the EnergyPlus program to predict the performance of a thermal chimney. Using the new module, the effects of the chimney height, solar absorptance of the absorber wall, solar transmittance of the glass cover and the air gap width are investigated under various conditions. Chimney height, solar absorptance and solar transmittance turned out to have more influence on the ventilation enhancement than the air gap width. The potential energy impacts of a thermal chimney under three different climate conditions are also investigated. It turned out that significant building cooling energy saving can be achieved by properly employing thermal chimneys and that they have more potential for cooling than for heating. In addition, the performance of a thermal chimney was heavily dependent on the climate of the location.     

基于性能的烟囱抗震设计

基于性能的抗震设计已成为当前抗震研究的热点问题。作为火力发电厂重要构筑物的烟囱,必须满足我国现行《建筑抗震设计规范》的总体抗震设防目标。但是,对于普通单筒钢筋混凝土烟囱主要非结构构件的内衬以及套筒式分段支撑砖内筒烟囱,烟囱规范对其抗震几乎没有要求。通过分析,提出了烟囱内衬和砖内筒的地震作用计算方法以及构造措施。     

陶瓷太阳板及其应用的研究

陶瓷太阳板以普通瓷土、工业废弃物为原料,具有制造工艺简单、生产耗能少、成本低、寿命长、效率高的优点。建造的陶瓷太阳能房顶与原房顸共用结构层、保温层、防水层,结构简单,可与建筑一体化,与建筑同寿命,且隔热、保温效果优于普通房顶,可为建筑物提供热水和取暖。陶瓷太阳板还可用于沙漠太阳能发电、海水淡化、苦成水淡化等。太阳能使用成本低于常规能源。     

Design,construction and performance prediction of integrated solar roof collectors using finite element analysis

An integrated roof solar collector was designed to achieve ease of construction, energy efficiency, functional integration, composite behavior, sustainability, reliability, flexibility, and cost effectiveness. A construction strategy was developed for the collector to ensure quality, ease and repeatability of manufacturing. Three-dimensional (3D) finite element models were then developed to evaluate the thermal performance of the integrated roof solar collector. The models were used to predict the optimum set of variables that can be used in buildings to achieve adequate thermal comfort. Coupled conduction, forced convection, and long wave thermal radiation modes of heat transfer were considered in the developed models. For demonstration purposes, a specific location (Blacksburg, VA) was modeled. Results showed that the integrated roof collector provides acceptable thermal performance by supplying approximately 85% of the building space heating and hot water requirements.     

Application of passive cooling systems in the hot and humid climate: The case study of solar chimney and wetted roof in Thailand

The thermal performance of two passive cooling systems under hot and humid climate condition is experimentally investigated. The experimental results were obtained from a test cell and a controlled cell with identical walls but different roof configurations. The passive cooling systems applied to the test cell are solar chimney and water spraying on roof. The experimental results obtained from the test cell are compared with the closed and no passive cooling controlled cell. In addition, the significant of solar-induced ventilation by using a solar chimney is realized by utilizing a wind shield to reduce the effect of wind-induced ventilation resulting in low measured air velocities to the solar chimney and low computed value of coefficient of discharge. The derived coefficient of discharge of 0.4 is used to compute Air Changes rates per Hour (ACH). The ACHs with application of solar chimney solely are found to be in the range of 0.16–1.98. The studies of air temperature differences between the room and the solar chimney suggest amount of air flow rates for different periods in a year. The derived relationships show that the air flow rate during February–March is higher than during June–October by 16.7–53.7%. The experimental results show that application of the solar chimney in the test cell could maintain the room temperature at 31.0–36.5 °C, accounting for 1.0–3.5 °C lower than the ambient air and 1.0–1.3 °C lower than the controlled cell. However, to make the test cell's room temperature much lower than the ambient temperature and increase the flow rate of air due to the buoyancy, the application of water spraying on roof is recommended together with solar chimney. The application of the two systems in the hot and humid climate are discovered to sustain the room temperature of the test cell to be lower than the ambient air by 2.0–6.2 °C and lower than the controlled cell by 1.4–3.0 °C.     

太阳能烟囱自然通风的一维稳态模型

太阳能烟囱是一种利用太阳能加热来强化自然通风的技术.在前人简化模型的基础上,考虑了玻璃盖板和集热墙的导热热阻的影响,建立了一个修正的太阳能烟囱自然通风的一维稳态数学模型.并利用此模型,对太阳能烟囱内的空气平均温度、集热墙温度、空气流量以及集热效率等进行了模拟计算和讨论.模型计算结果与相关实验数据及前人的简化模型进行了对...     

火力发电厂湿烟囱渗漏原因分析及防腐改造

结合忻州广宇煤电有限公司烟囱防腐的改造案例,对石灰石—石膏湿法脱硫烟囱渗漏的原因及改造方案进行了分析比较,并对烟囱钛—钢复合板内筒的设计进行了详细阐述,为火力发电厂旧烟囱防腐改造积累了经验。     

Effect of solar chimney inclination angle on space flow pattern and ventilation rate

The solar chimney is a simple and practical idea that is applied to enhance space natural ventilation. The chimney could be vertical or inclined. The chimney inclination angle is an important parameter that greatly affects space flow pattern and ventilation rate.In the present study, the effect of chimney inclination angle on air change per hour and indoor flow pattern was numerically and analytically investigated. A numerical simulation using Ansys, a FEM-based code, was used to predict flow pattern. Then the results were compared with published experimental measurements. A FORTRAN program was developed to iteratively solve the mathematical model that was obtained through an overall energy balance on the solar chimney.The analytical results showed that an optimum air flow rate value was achieved when the chimney inclination is between 45° and 70° for latitude of 28.4°. The numerically predicted flow pattern inside the space supports this finding. Moreover, in the present study a correlation to predict the air change per hour was developed. The correlation was tested within a solar intensity greater than or equal to 500 W/m², and chimney width from 0.1 m to 0.35 m for different inclination angles with acceptable values.     

火力发电厂建筑及结构探讨

结合自身工作经验,对大中型火力发电厂建(构)筑物的结构形式进行了分析,从经济技术角度进行方案对比优化,重点介绍了大中型火力发电厂主厂房、钢内筒烟囱的结构方案及施工做法等,以期指导实践。     

Studies on solar power satellites with down-converter solar cells

The Solar Power Satellite (SPS) is a renewable energy technology potentially capable of meeting the projected worldwide energy demand for future generations. Some general aspects of SPSs are discussed in this paper. It was calculated that a power output of 97.24?MW (almost double the power produced by a typical natural gas plant) could be generated using a theoretical system with solar photovoltaics with a total optimised dimension of 0.18?km². Among the potential problems discussed are the possible effect of microwaves on living organisms and the high capital costs involved in building and launching the satellite into a suitable orbit.     

Solar powered absorption air conditioning

The design of buildings to provide a suitable thermal environment is discussed and the reasons for artificial heating or cooling introduced. The problem of sizing a solar-powered cooling plant is investigated. An iterative method of estimating heat flow and resultant temperatures in buildings subject to fluctuating heat loads is described. A model is developed to allow investigation of the performance of a solar collector and thermal storage system and some of the basic relationships between performance and physical parameters are determined.

An iterative method of predicting the cooling output from a lithium bromide-water absorption refrigeration plant having variable heat input is described.

The design of a solar collector/thermal storage) absorption cooler system, its performance on a particular building and its fine tuning are examined.     

Mathematical modelling of solar radiation incident on tilted surface for photovoltaic application at Bhopal,M.P., India

In general, solar radiations are the combination of beam plus diffuse and ground-reflected radiation. The availability of recorded data on a tilted surface is very rare due to lack of measuring equipment and techniques involved. In this study, a standard procedure is adopted for estimation of solar radiation on a tilted surface for a location in Central region of India. Solar radiation is estimated for three tilted positions: First, solar collector tilt equal to latitude angle, second, solar collector tilt equal to latitude angle +15° and third, solar collector tilt at latitude ?15°. Total global solar radiation estimated on the inclined surface for various photovoltaic (PV) modules was used to obtain the annual energy yield based on the estimated value. It was found that on an average, 14?kWh/m² of annual energy output can be obtained for monocrystalline solar PV module corresponding to the inclination of 23.26° latitude at Bhopal.     

Analysis and design of a robust controller for a grid-connected photovoltaic power plant

ABSTRACT

Application of renewable energy systems has a drastic impact on the present power system. In particular, solar photovoltaic power generation is expanding exponentially. Hence, in this article analysis and design of a 1 Mega Watt (1?MW) solar power plant has been modelled. The obtained power is given as an input to the voltage source converter, which contently regulates the active and reactive power by controlling the pulse width modulation signals. In this article, robust control schemes were discussed to support the required active and reactive power. Further, a detailed analysis has been presented at various fault conditions and the results are explored.     

Energy and exergy analysis of a 747-MW combined cycle power plant Guddu

ABSTRACT

The paper presents a detailed study based on the energy and exergy analysis of a combined cycle power plant (CCPP) Guddu having triple pressure heat recovery steam generator (HRSG). The energy loss and the energy efficiency of each plant component with HRSG as a whole is calculated. The exergy destruction of these components and the sub-parts of the HRSG are also found out. All the three stages of the steam turbine are analysed individually. The combustion chamber is found to have the maximum share of exergy destruction while the condenser is having a maximum of energy loss. The total net power output, energy and exergy efficiency of the whole plant is calculated as 737.8?MW, 59.12% and 58.24%, respectively. The error in getting the designed power output of 747?MW is 3.16%. The thermal efficiency of the Brayton and Rankine cycle is 62.01% and 56.38%, respectively.