Research On Dynamic Performance Of Centralized Heat-supply System

In China, there was a big embarrassment, it is that energy have been saved in buildings but heating energy consumption did not fall down. One of the important reasons is that the existing control strategy is extensive, it is mean that the centralized heat-supply system divided the supply water temperature only by outdoor temperature or experiences, what's more important is that the adjust only according to the return water temperature or didn't adjust either. This dissertation focuses on the most important theoretical basis of intensive control strategy, which is the dynamic performance of centralized heat-supply system, firstly a mechanism model, characteristic parameters and the evaluation model of the dynamic performance of heating pipes were proposed, and then a convenient method for the research of the dynamic performance in the construction was proposed. Theoretical foundation and calculation basis for intensive control strategy can be provided in the work, thereby it can guides the heating enterprises saving more energy and reducing more emissions, making the heat users more comfortable, and promoting the energy saving further development.The centralized heat-supply system dynamic performance were analysed using theoretical analysis and experimental analyses. The centralized heat-supply system has been divided into two parts. One is heat pipe, the other is in the construction. For the pipe, a theoretical model was established. For the part in the construction, a new system identification method was finded. Parameters of one centralized heat-supply system in Tianjin has been monitored for two years when the heating system works. In the meantime, based on the meteorological data divided by the Tianjin Meteorological Bureau, the dynamic characteristics of the research results are verified.The two most important thermal dynamic characteristic parameters for centralized heat-supply system are lag time and decay coefficient. In this paper, the expressions of the two characteristic parameters were proposed, and an important conclusion that the lag time of the centralized heat-supply system is equal to the time of fluid flowing in the pipeline was also finded. A system identification method which was applicable to the research of the dynamic characteristic of the part in the construction was proposed. Using the result of a project with climate compensator, the system identification method is proved to be a kind of quick and convenient analysis method, and what's more important is that its precision is ideal.