蓄能型天然气分布式联供系统性能评价及设计研究

发布时间：2018-11-17 14:13

【摘要】：天然气分布式冷热电联供系统由于具有能源综合利用率高、环保性能好、安全可靠、削峰填谷、经济效益好等优点，近年来，其应用受到越来越多的关注。然而，由于冷热电联供系统靠近用户端，当建筑负荷波动时，联供系统供应也发生波动，从而出现部分负荷的工作状态，设备效率降低，不利于能源的充分利用，而蓄能有助于消除能量供需在时间与强度上的不匹配，使联供系统设备保持高效运行，从而提高综合能源利用效率。本文主要研究内容与学术贡献如下：总结了现有文献中冷热电联供系统组成部件模型，对于燃气轮机，结合热力学第一定律与产品样本，用拟合方法提出半经验解析模型，并将该模型用于建立联供系统解析模型。基于理想相变蓄能构建的联供系统解析模型，对传统以热定电及以电定热模式，研究蓄能对联供系统的性能改善评价，分析得到，①提出基于蓄能型联供系统性能的建筑负荷特征参数，包括：电热比、电(热)负荷波动因子、电热负荷相位差因子；②以热定电模式下，蓄能的作用在于减小燃气轮机供应的波动性，以电定热模式下，蓄能的作用在于减小热供需不匹配；③给出夏季工况最优相变温度的确定准则，即对于不带回热的燃气轮机，其最优相变温度应取燃气轮机出口烟气温度与环境温度的几何平均值，对于带回热的燃气轮机，其最优相变温度应取吸收机发生器温度。并将结论用于评价蓄能对各类型建筑性能改善效果，发现对于写字楼与商业设施效果最明显；对于医院冬季明显，夏季不明显；对于饭店，，效果最不明显。对于理想蓄能联供系统的优化设计，分别从定工况与变工况角度出发，得到系统的优化设计原则，对于定工况最优模式为以热定电；对于变工况，最优模式为以热负荷平均值确定的以热定电模式。然后，对于理想相变蓄能及实际相变蓄能冷热电联供系统，建立了蓄能型联供系统的数值模型，采用遗传算法与动态规划算法相结合的方法求得联供系统最优设计策略。对解析解进行验证，并对理想相变蓄能模型，得到其优化设计方法，对于实际相变蓄能，分析了蓄能器容量及蓄能器与环境散热对系统最优设计的影响。
[Abstract]:Due to the advantages of high comprehensive energy utilization, good environmental protection performance, safety and reliability, peak and valley cutting and good economic benefits, the application of distributed natural gas combined cooling and heat supply system has attracted more and more attention in recent years. However, because the combined cooling and heating power supply system is close to the user, when the construction load fluctuates, the supply of the joint supply system also fluctuates, which results in the partial load working state, and the equipment efficiency is reduced, which is not conducive to the full utilization of energy. Energy storage is helpful to eliminate the mismatch between energy supply and demand in time and intensity, and to keep the equipment running efficiently, so as to improve the efficiency of comprehensive energy utilization. The main contents and academic contributions of this paper are as follows: the model of the components of the combined cooling and heat supply system in the existing literature is summarized. For gas turbines, the first law of thermodynamics is combined with the product sample. The semi-empirical analytical model is proposed by fitting method, and the model is used to establish the analytical model of co-supply system. Based on the analytical model of cogeneration system constructed by ideal phase change energy storage, the performance improvement evaluation of energy storage system by thermal and electric heating modes is studied, and the results are obtained. 1. The characteristic parameters of building load based on the performance of energy storage system are put forward, including: electric heat ratio, electric (thermal) load fluctuation factor, electric heat load phase difference factor; (2) the function of energy storage is to reduce the fluctuation of gas turbine supply in thermal fixed mode, and the function of energy storage in electric fixed heat mode is to reduce the mismatch of heat supply and demand; (3) the criterion of determining the optimal phase change temperature in summer is given, that is, for the gas turbine with no heat, the optimum phase change temperature should be the geometric average of the gas turbine outlet flue gas temperature and the ambient temperature, and for the gas turbine with the return heat, the optimum phase change temperature should be taken as the geometric average of the gas turbine outlet gas temperature and the ambient temperature. The optimum phase change temperature should be taken as the temperature of absorber generator. The conclusion is used to evaluate the performance improvement effect of various types of buildings. It is found that the effect is the most obvious for office buildings and commercial facilities; for hospital winter, summer is not obvious; for hotels, the effect is the least obvious. For the optimal design of the ideal energy storage system, the optimum design principle of the system is obtained from the point of view of fixed working condition and variable working condition, and the optimal mode of fixed working condition is thermal fixed power. For off-condition, the optimal mode is the thermostatic mode determined by the average thermal load. Then, for the ideal phase change energy storage system and the actual phase change energy storage combined energy supply system, the numerical model of the energy storage system is established, and the optimal design strategy of the joint energy storage system is obtained by the combination of genetic algorithm and dynamic programming algorithm. The analytical solution is verified, and the optimal design method is obtained for the ideal phase change energy storage model. For the practical phase change energy storage, the influence of accumulator capacity and heat dissipation of accumulator and environment on the optimal design of the system is analyzed.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU996;TU8

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