Dynamic Imitation And Real-Simulation Of Tree-Shaped Heat-Supply Network With Huge Difference In Height

With the continuous development of economy and the requirements on city environmental protection in China, city central heating has been developed rapidly. And because of the severe shortage of energy and the advocate of saving energy in China, the central heating is highly required .It becomes a focus that how to dispose central heating scientificly and reasonably is determinant of reducing consumption and saving energy in effect.Thanks to central heating features of tree-shaped network with simple arrangement, less investment and easy operation, it is adopted the most commonly in central heating network. Water pumps is one of main consumption of energy in central heating. Nowadays traditional tree-shaped network adopts the scheme setting up circulating pumps only in heat sources. When the operation is adjusted, to ensure the least favourable users heating in order, usually the pressure users near the network is higher than those far from network. When selecting users'diameter of the branches of the piple, due to limits of velocity of medium flow and standards of piple limited, the rest pressure is wasted by the valves of users'entrance. For the scheme that traditional tree-shaped network only adopting circulating pumps, leading to the waste of energy. The author of this article puts forward the scheme that tree-shaped network adopts circulating pumps and setting up backwater pumps at every users. In order to research feasible and energy-saving of the second scheme, it is adopted in the tree-shaped network with huge difference in height. Giving the design methology of the tree-shaped network with huge difference in height, on the basis of studying seriously theory foundation and basic regular of hydraulic power situation and heating power condition, building the mathmatic models of hydraulic power situation and heating power condition. Adopting dynamic simulation function of SIMULINK in MATLAB, the author himself develops the simulation models of the tree-shaped network with huge difference in height in design condition in view of SIMULINK. Plus, applying the measured data from the concrete examples of real projects to verify models. The verifying simulation data is a course continuously adjusting and verifying models, until the difference with the simulation and measured data falls into the acceptable range, the models is reasonable. And analyzing the cause of the difference and the backwater temperature rising. Afterwards, analysis of the hydraulic power condition and heating power condition of the reasonable simulation models in design condition. The results from analyzing hydraulic power condition indicate the being distributed situation of the pressure and flow, the result analyzing the heating power condition is that the network heat loss caused the temperatures of supplywater and backwater deviate from the ideal ones in design condition, the results bring about the unbalance of the heating power condition. To solute the unbalance of the heating power condition, the users'flow is adjusted. Pointing to the nature difference with firpst adjustment of the both schemes, showing the methologies of the initial adjustment and the operation adjustment.Finally, through analysis of the consumption of energy with pumps, the conclusion is the situation the less energy-consuming is. Through analysis of the consumption of energy with pumps of the both schemes in design conditions, the ratio of saving energy is 13.82%. giving the chart of consumption of pumps comparison. Analysing the pressure situation and the hydraulic pressure figure ,it is concluded that the pressure grade of the network and the equipments. Furthermore, the network is qualitatiuly analysed to be economic. The conclusion is the network is reasonable, energy-saving, economic and safe. It is worthy to apply in practice on large scale in central heating system.