Optimization of drying kiln operation

When timber is to be used in the form of furniture it must be dried. Green timber contains many times more water than wood and if it is placed indoors the water will slowly evaporate. When the fibre saturation point is reached the wooden parts start to shrink and the shape of the details will change. If the wood is dried before it is used for furniture parts this calamity is reduced because shrinking has occurred already in the drying kiln when the raw material was in the form of lumber. This drying process uses a lot of heat which is produced by electricity or by firing wood chips or oil in boilers. The cost for these energy sources varies during the season or, for electricity, also during the day. This paper describes how to optimize the use of energy in two drying kilns located at a small carpentry factory in the south of Sweden. Monitored values from the factory are used in order to describe the process in close detail. These values are then used as a basis for a mathematical model which is designed in the form of a mixed integer linear program. The method makes it possible to optimize the operating schemes for the two dryers. Copyright © 2000 John Wiley & Sons, Ltd.     

多级制冷系统超结构优化及其应用研究

在多级制冷系统超结构的基础上，以年操作费用与设备年折旧费用之和的年度总费用最低为目标函数，建立了多机制冷系统优化的混合整数非线性规划。利用该模型对乙烯裂解装置乙烯-丙烯复叠制冷系统进行了优化研究，优化后系统比原制冷系统年度总费用下降15%，经济效益明显。     

冰蓄冷空调系统的优化调度研究

为解决冰蓄冷空调系统的运行调度问题,提出两阶段优化调度的策略。第一阶段对机组能耗模型进行合理简化,以系统当日整体运行费用最低为优化目标,建立混合整型二次规划模型,并求出可接受的初解。第二阶段采用调度后处理的手段,以提升系统连续运行稳定性和经济性为目标,通过调整冷水机组的逐时运行数量和负载率对初解进行优化,使最终的调度结果符合现场实际运行需求。工程实例分析结果表明,采用此种调度策略,可实现降低系统当日整体运行费用的同时,减少设备启停次数,避免设备频繁启停导致系统波动,满足现场运行需求。     

基于MILP的PHEV入网效益评估模型求解及应用

插入式混合电动汽车(PHEV)已成为解决能源和环境问题的重要手段,为探讨未来大规模入网能否给电网与用户带来额外效益,以电力系统运行总成本最小化为目标,以区域电能供需平衡、电池电量平衡、机组爬坡率等条件为约束,建立了新的PHEV入网效益评估模型,并利用新的混合整数线性规划求解思路,使用分支和分割算法对建立的效益评估模型进行求解,通过算例对模型进行了模拟分析。结果表明,通过V2G技术,PHEV入网可为电网和PHEV用户带来显著效益。     

RDEA: A recursive DEA based algorithm for the optimal design of biomass supply chain networks

The optimal design of supply chain networks is often examined based on one or more economic or other criteria (e.g., cost, profit environmental impact, danger, time). However, the efficiency of the derived solutions is often ignored. In this work, a recursive DEA (RDEA) algorithm is presented, which introduces a different way of designing a supply chain network. The selection of possible installed facilities is based on minimum cost and maximum efficiency, through a MILP model. Optimal supply chain structure is obtained when the termination criterion is met, yielding only the efficient solutions, while simultaneously reducing the overall cost. An application of this RDEA algorithm to a biomass supply chain is examined. A comparative study is also presented, demonstrating the results obtained when solving the MILP without the proposed algorithm and with the use of an RDEA.     

基于If-Then-Else规则的热电联产系统能量调度方法

为了降低热电联产系统能量调度算法计算的复杂度,减少计算时间,提出了一种基于If-Then-Else规则的热电联产系统能量调度方法。通过引入逻辑变量来描述设备的启停状态和工作模式,建立混合逻辑动态模型,在模型预测控制的框架下,根据实时电价以及本地能源、电力负荷和热力负荷的预测结果,为模型中的二元决策变量赋值,从而将模型中的混合整数线性规划问题转化为线性规划问题。最后,通过仿真将本文提出的方法和混合整数线性规划方法进行比较,结果表明,本文所采用的方法在性能上几乎没有损失,平均计算时间降低65%。     

基于时序生产模拟的光伏接入容量研究

随着城市电网中光伏容量不断攀升,其容量规划问题的研究也迫在眉睫。该文考虑光伏出力与城市负荷的时序关系,结合火电机组的调频限制,利用混合整数线性规划法建立一种基于时序生产模拟的光伏容量规划模型。规划目标为在满足负荷需求下综合发电成本最低,包括火电机组调频成本和弃光成本。最后,以中国某地区实测数据为例,验证了该方法的有效性,同时分析了光伏接入容量与负荷类型的关系,为城市电网光伏容量规划提供了参考。     

偏差电量考核下风光储混合发电商的市场均衡博弈研究

为了更直观地分析风光储混合发电商对市场均衡博弈结果和市场力的影响,在偏差电量考核衡量风光储混合发电出力随机波动性的基础上,综合考虑各发电商的出力限制和储能系统的运行约束,建立以风光储混合发电商和传统发电商收益最大化为目标的市场均衡博弈模型,调用CPLEX软件求解利用非线性互补函数处理得到的混合整数规划模型,并对比分析了风光储混合发电商作为价格接受者和影响者参与电力市场竞争对均衡博弈电价和投标出力的影响。结果表明,风光储混合发电商参与电力市场竞争可抑制传统发电商的市场力,对电价有显著的\"削峰填谷\"作用;当风光储混合发电商作为价格影响者时,对电价的影响会减弱,但其收益有所增加。     

考虑抽水蓄能及电网运营成本的源荷储协调优化调度

将需求侧响应与抽水蓄能电站纳入系统优化调度,借助需求侧管理与抽水蓄能电站对负荷分布的调控能力以达到提高风电消纳水平和降低电网运营费用的目的。以弃风总量最小和电网购电费用最低为优化目标,并考虑系统功率平衡、机组启停时间、爬坡能力、机组出力界限、系统备用等约束条件,构建含大规模风电的源荷储协调优化调度模型,将模型转化为混合整数问题并应用MOSEK优化软件对其进行求解。算例结果表明,借助需求侧管理与抽水蓄能电站的协作效应,系统对风电消纳能力将有所提高,电网购电费用亦进一步降低。     

A multiple objective linear programming model for power generation expansion planning

The planning of new units for electrical power generation is a problem which involves different and conflicting aspects. Besides cost, security issues and environmental concerns must be explicitly incorporated into the models. In this way mathematical models become more realistic, and they enhance the decision maker's comprehension of the complex and conflicting nature of the distinct aspects of the problem. A multiple objective linear programming model for power generation expansion planning is presented. The model considers three objective functions (net present cost of the expansion plans, reliability of the supply system, and environmental impacts) and three categories of constraints (load requirements, operational restrictions and budget). Three generating technologies are considered for power system expansion: oil, nuclear and coal.     

基于混合整数线性规划模型的水电站日优化调度研究

利用分段线性模型描述水电机组出力特性曲线,通过设置最短运转时间与最短停机时间等机组启闭约束构建了水电站日优化调度的混合整数线性规划模型,采用GAMS编程调用CPLEX模块求解,并以隔河岩水电站为例对模型进行了验证。实例结果表明,该模型可在考虑水头变化影响、满足开停机约束等条件下,显著提高水电站的水能资源利用率。     

计及碳交易与需求响应的多典型日综合能源系统优化模型

系统负荷作为综合能源系统的约束条件,常以单个典型日加以表征,这难以描述实际负荷波动性与随机性的特点。本文构建了计及碳交易与需求响应的多典型日优化模型。通过引入谱聚类算法获得多个典型日数据,在表征原始负荷数据波动性与随机性的同时,也基于负荷数据构成实现了数据分类,并以负荷构成为基础分别建立优化模型,引入阶梯型碳交易机制与需求响应机制,在Python语言下调用Gurobi求解器完成模型求解仿真,在此基础上对阶梯型碳交易参数的变化开展研究。结果表明,本文提出的优化模型可很好地针对全年不同的负荷特征实现灵活调度,在兼顾经济性与环保性的同时有利于清洁机组出力。