强化传热、降低流阻是提升换热系统性能的重要途径。本文分别基于火积理论和流体力学分析构建了换热系统的整体传热和流动约束，结合帕累托优化思想，针对换热系统的优化问题，提出了传热与流动参数的协同优化方法。应用该方法，对中央空调冷冻水系统进行了优化设计。结果表明换热系统的传热和流动特性都会对系统的最优设计参数产生影响。给定系统中，房间换热量增大1倍时，最优热导将增大1.4倍；当流体管道长度增加1倍，最优热导也将增大20%。在此基础上，比较了上述协同优化方法与基于熵产等准则的优化方法的区别。基于熵产等准则的优化方法借助熵产和无量纲熵产等热力学评价准则将增强传热和降低流阻这两个目标转换为降低系统不可逆性这一单个目标；而本文提出协同优化方法是在不引入中间变量的前提下，建立系统结构和运行等设计参数与设计需求的整体约束关系。基于该整体约束关系，能够结合实际换热系统的具体优化目标或者熵产、火积耗散等优化准则对系统进行优化设计。因此，建立换热系统的整体约束是换热系统传热与流动特性协同优化的关键。基于换热系统的整体约束，针对换热系统的变工况运行优化问题，提出了系统结构参数的在线辨识和运行参数的优化设定方法，并将其分别应用于换热器热导、变频泵/管网特性参数的测量以及多回路换热系统和串/并联换热系统的运行参数优化。实验结果表明：对于多回路换热系统，优化变频泵的运行频率可以节能32%，优化阀门的开度可以节能9%；对于串联换热系统，优化变频泵的运行频率可以节能11%。针对负荷波动情况下换热系统的动态控制问题，基于动态性能分析，构建了多回路换热系统的状态空间，导出了相应的状态空间参数矩阵，以此分析了换热系统中各参数间的控制逻辑联系，提出了基于节点参数优化的换热系统整体优化控制策略。通过系统控制仿真，表明了节点温度优化的运行能耗比节点温度固定的运行能耗低20%。通过多回路换热系统的控制实验，阐述了运行参数的调节和变化过程，验证了该控制策略的可行性。最后，通过研究换热系统中部件优化和整体优化之间的关系，说明了部件优化准则应用于系统整体优化的局限性，并明确了应从换热系统的角度对换热器面积和流体流量进行整体优化，应在单个换热器面积和工质流量给定的前提下对换热器的传热系数进行优化。

Enhancing heat transfer and reducing flow resistance are important means to improve efficiencies of heat exchanger system. Combining the global heat transfer constraint based on entransy theory and the flow transportation constraint based on the analyses of dynamic and resistance of the fluid pipe network, the whole constraint of the heat transfer system is established. Based on the Pareto Optimality, the method of synergetic optimization considering both heat transfer characteristics and flow transportation characteristics of heat exchange system is proposed. Based on the the newly-built optimization method, this paper provides the optimization design of a central air conditioning system. The results show the influences of heat transfer characteristics and flow characteristics on the system optimization design, where 100% increasement of heat transfer rate requires 140% enlargement of thermal conductance, and 100% increasement of pipe length also requires 20% enlargement of thermal conductance.The difference between the method based on criterion parameter, such as entropy generation, and the newly-built optimization method, is illustrated, where the former turns the two goal of enhancing heat transfer and reducing flow resistance into one objective, i.e. the irrisibility, while the latter provides the global constraint among the operational, constructural and demand parameters. Based on the global constraint, extremums of actural requirement, entropy generation, entransy dissipation, and other criteria, can be achieved, which illustrates the global constraint is the key of synergetic optimization considering both heat transfer characteristics and flow transportation characteristics of heat exchange system.Based on the newly-built optimization method, the optimization operation method is proposed. With a multi-loop heat exchange experiment set and a complex pipe network heat exchange experiment set, an experimental method of parameter identification of the actual heat exchange system is put forward and applied. On the basis of the system structural parameters, the operating parameters of the multi-loop heat exchange system and the complex pipe network heat exchange system are optimized. The performances of the heat transfer systems bwtween the optimal operating conditions and other feasible conditions are compared, where the results show that rotation frequency optimization offers the obvious energy saving and the valve openness optimization can also help to save 32% and 9% energy consumption for the multi-loop system; the optimal condition exhibit 11% performance enhancement than tranditionally balanced flow working condition for the complex pipe network system with series structure. The influences of heat transfer characteristics and the flow characteristics on the system operating parameters are also illustrated. The optimization and experimental results show that, the increase of heat load will lead to the increase of pump speed or valve opening degree; the increase of flow resistance coefficient will result in a decrease in its flow rate. In addition, the experimental results also show that different heat load and resistance coefficient will affect the optimal value of set-point temperatures, which elucidates the limitations of the traditional operation methods with fixed set-point temperature.For the operation of heat transfer system with the heat load fluctuations in practical applications, the dynamic model of the heat exchange system is constructed based on entransy analysis. On this basis, the real-time optimal control strategy with load supervision of the heat exchange system is put forward. Through the simulation, the system energy consumption with real-time optimal set-point temperatures and set-point temperatures are compared, the results show that the former is about 20% less than the latter. With the control strategy, experiment and results illustrate the feasibility of the real-time optimal control strategy.The difference between the local optimization and global optimization is discussed with calculations of heat transfer area and heat flow capacity distribution. The results illustrate the limitation of applying local optimization results into the system. Thermal conductances or the heat capacity flow rates of each heat exchanger should be optimized in the global system level, and the heat transfer coefficient should be optimized in local level with given heat capacity rate and thermal conductance. Finally, this paper illustrates that the global heat transfer system contraint based on the entransy theory is the key to synergetic optimization for design and operation with considering both heat transfer characteristics and flow transportation characteristics.