基于热经济学会计模式亚临界600MW机组节能分析

以600 MW火力发电机组为例,利用热经济学会计模式建立机组热经济学成本模型。根据75%THA的设计和实验工况参数,进行热力学和热经济学指标计算,得出各子系统的火用效率和火用经济系数,并利用二者判别各子系统的节能潜力及是否进行改造。结果表明,6号低压加热器是节能改造的重点对象。     

基于热经济学的空调系统建模

为降低空调系统的运行成本,提高其运行的经济性,提出了一种新的用于空调系统热经济性分析的评价模型。该模型是在热力学的(火用)分析和经济学等理论的基础上形成的,并以能量费用和非能量费用计算的单位热经济学成本作为分析评价的依据。通过2因素3位级9个工况的正交实验,得到用该模型计算的单位热经济学成本曲线,并同热经济学矩阵模式分析方法的计算结果进行了比较,结果表明该模型是合理的,可为空调系统的经济运行状态诊断提供决策依据。     

热经济学结构理论在故障诊断中的应用

热经济学是热力学与经济学的交叉学科,它综合考虑能量的数量、质量以及经济因素因此更具有实用价值。通过在运行期间实际值与期望值之间的热经济学比较可以进行故障诊断并确定故障组元的位置。     

基于热经济学结构理论的燃气-蒸汽联合循环负熵分析

采用热经济学结构理论建立SGT5-4000F型燃气—蒸汽联合循环的生产结构图,根据"燃料—成本"概念阐述系统各个组件之间的生产关系。从机理上分析设备在三个典型工况下的负熵消耗及火用损产生的原因,采用比负熵、比火用损、火用损率等热经济学指标对系统进行评价。研究表明:燃烧室和余热锅炉在运行中存在较大的不可逆因素,使负熵消耗量较大,分别占系统全部负熵消耗的42. 37%和41. 81%,而余热锅炉和凝结水泵的火用损率较大;提升天然气的预热温度可以减少燃烧室的负熵消耗,提升系统整体的循环效率。     

基于结构理论的350MW超临界直接空冷机组的热经济学分析

应用结构理论建立了某超临界直接空冷机组的热经济学模型,通过量化各组件间的生产交互关系、计算各组件的单位成本,分析了系统生产成本的形成过程.简化合并直接空冷机组的凝汽组件,并近似计算其耗电量.根据该机组THA工况的计算结果,分析了影响组件产品单位成本的因素.结果表明:当消耗同一种燃料时,组件效率越低,其产品单位成本就越高;当消耗不同燃料时,要综合考虑燃料成本和效率对产品单位成本的影响,并指出7号低压加热器、给水泵、小汽轮机以及凝结水泵等组件的单位成本较大;直接空冷机组凝汽器的单位成本显著高于湿冷机组,应用结构理论能够准确评价空冷机组的生产性能.     

热电联产企业生产过程经济分析的热经济学方法

以[火用]分析为基础,分析了复杂能量系统的内部生产结构.按照经济分析的要求,利用数学求导的链式法则,建立了描述热力系统生产特性的热经济学模型,可分析在特定市场环境下企业利润最大化的边际条件、产品替代特性等经济性能指标.     

单耗分析的理论和实施

《单耗分析》是在(火用)和(火用)经济学的基础上所设计的能量系统分析的理论和方法,以产品单耗做为降耗节能的主要指标,分析单耗的构成及其分布和变化,为节能降耗技术提供实用的理论依据。     

Thermo‐economic‐environmental multiobjective optimization of a gas turbine power plant with preheater using evolutionary algorithm

In this study, the gas turbine power plant with preheater is modeled and the simulation results are compared with one of the gas turbine power plants in Iran namely Yazd Gas Turbine. Moreover, multiobjective optimization has been performed to find the best design variables. The design parameters of the present study are selected as: air compressor pressure ratio (r_AC), compressor isentropic efficiency (η_AC), gas turbine isentropic efficiency (η_GT), combustion chamber inlet temperature (T₃) and gas turbine inlet temperature. In the optimization approach, the exergetic, economic and environmental aspects have been considered. In multiobjective optimization, the three objective functions, including the gas turbine exergy efficiency, total cost rate of the system production including cost rate of environmental impact and CO₂ emission, have been considered. The thermoenvironomic objective function is minimized while power plant exergy efficiency is maximized using a genetic algorithm. To have a good insight into this study, a sensitivity analysis of the results to the interest rate as well as fuel cost has been performed. In addition, the results showed that at the lower exergetic efficiency in which the weight of thermoenvironomic objective is higher, the sensitivity of the optimal solutions to the fuel cost is much higher than the location of Pareto Frontier with the lower weight of thermoenvironomic objective. Copyright © 2010 John Wiley & Sons, Ltd.     

Exergo‐economic analysis of micro pin fin heat sinks

A parametric study of thermoeconomic performance over four micro pin fin heat sinks of different spacing and shapes was conducted. Unit cost per product exergy, relative cost difference, and exergo‐economic factor were utilized to evaluate the thermoeconomic performance. The effect of working fluid on the thermoeconomic performance was also investigated using R‐123 and water as working fluids. Unit costs per product exergy were obtained to evaluate the product costs (total exergy change between exit and inlet streams) in micro pin fin heat sinks at fixed mass flow rate and fixed pressure drop. The results of the thermoeconomic analysis were compared with the results of a past exergy performance study by the author. In the light of raw experimental data acquired from the past studies of the author, important differences between the results of exergy and exergo‐economic performances were observed. It was found that the unit cost of exergy change decreased as electrical power increased and the relative cost difference approached to unity at high electrical powers (greater than 20 W). Moreover, high exergo‐economic factor values (more than 0.5) were obtained at low electrical powers while exergo‐economic factors had a small value at high electrical powers. When looking at the effect of the working fluid, higher cost per Watts of the products (up to the double of R‐123) was obtained with water compared with R‐123 at both fixed mass flow rate and pressure drop. No significant effect of pin fin spacing on the unit cost of exergy change was observed at fixed mass flow rate, while higher unit costs (up to 102%) were recorded at fixed pressure drop for scarcely packed pin fin heat sinks. Finally, the unit cost of exergy change was found to be independent of pin fin shape at fixed mass flow rate, whereas at fixed pressure drop, the hydrofoil‐based pin fin heat sink had higher unit costs (up to 1.8 times as much) when compared with the unit costs of pin fin heat sinks having flow separation promoting pin fins. Copyright © 2010 John Wiley & Sons, Ltd.     

Thermoeconomics of seasonal latent heat storage system

A simple thermoeconomic analysis is performed for a seasonal latent heat storage system for heating a greenhouse. The system consists of three units that are a set of 18 packed‐bed solar air heaters, a latent heat storage tank with 6000 kg of technical grade paraffin wax as phase‐changing material, and a greenhouse of 180 m². The cost rate balance for the output of a unit is used to estimate the specific cost of exergy for a yearly operation. Based on the cost rate of exergy, fixed capital investment, operating cost, and economic data, approximate cash‐flow diagrams have been prepared. The systems feasibility depends on the cost rate of exergy, operating cost, internal interest rate, and rate of taxation strongly. A cash‐flow diagram based on exergy considerations may enhance the impact of thermoeconomic analysis in feasibility studies of thermal systems. Copyright © 2006 John Wiley & Sons, Ltd.