Urban Centralized Heating System Thermal Station Of The System Modeling And Studies Of The Heat Exchanger Unit

AbstractThe aim of the subject is to study the mathematic modeling and automatic control of the two-stage heat-exchange unit in central heating system heat station and to design its dynamic simulation and real-time monitor and control system.First, this paper looks back the development of the central heating and the importance of the heat station heat-exchange unit. It analyses the shortcoming of actual heat-exchange unit, such as the imperfect adjustment and the inefficient energy using. So, this subject is necessary and important to develop.According to the deficiency manifested in the running of traditional heat-exchange unit, this paper puts forward the two-stage structure. By the decompression valve and tube-heat-exchanger in the first stage, the inlet parameter of the plate-heat-exchanger in the second stage is permissible. The two-stage structure makes sure the normal and efficient running of the plate-heat-exchanger and improves the quality of the heat-exchanger unit. Moreover, the two-stage structure unit makes good use of the spare heat from the power plants, realizes the efficient co-generation and runs well in the project. The paper thinks about the fluid transfer and heat exchange and makes some reasonable simplicities and assumptions. So, it gives the dynamic mathematic model of the heat-exchange unit and brings forward the control algorithm which is combined by bang-bang and PID. The results via digital simulation indicate that the mathematic model can reflect the inherent mechanism and essence and that the algorithm has good performance in rapid response, robustness and control precision. The algorithm can control the process of the temperature adjustment in the heat-exchange unit that has great non-linearity, inertia and time lag. At the same time, because the algorithm is easy to be understood and to be applied in practice, it can be generalized to the industry processes, such as chemistry, medicine, central heating, etc.Besides, base on the practical applications, this paper adopts the configuration software produced by Beijing Kunlun generated automation software Co. Ltd. and designs a set of dynamic simulation and real-time monitor and control system of the two-stage heat-exchange unit in central heating system heat station by implanting the mathematic model and control algorithm which we have gained. This system has the following functions: dynamic simulate and real-time monitor the heat-exchange unit, look for data, analyze trend graph and help on-line, etc.. The running result is satisfied.