Study On Energy Saving Of Operation Regulation And Prediction Of Hydraulic Conditions Of Metered Heating Supply System

In recent years, with the development of district heating, metered heating supply systems rely on its characteristics of high automation and user-adjustable of heat, which are widely used. After the adopting of metered heating, on one hand, the problems which produced by the area of cost-sharing in the past can be solved. On the other hand, due to heat users can adjust the heat according to their requirement, their energy-saving awareness and enthusiasm for energy conservation can be mobilized and the goal of demand-heating can be achieved. Although the system can achieve the purpose of energy-saving by users' adjustment, how to control heat network appropriately so that it can ensure the users' adjustable to the heat, meanwhile reducing energy consumption and improve the economy become an urgent problem.Based on the users' regulation of indirect connection metered heating system and considering the conservation of heat index and heat dissipation area in the design stage, this paper modifies the heat balance equation of the heating system with the steady-state heat transfer method. Then, based on the modified heat balance equation, this paper establishes and solves the secondary network adjustment model of active quality-quantity adjustment and passive quantity adjustment. According to the characteristics of high operation parameters of the primary net, the heat loss of boiler, pipeline heat loss and power consumption of circulating pumps consist the total consumption of the system, then regarding the consumption as the objective function. By using genetic algorithm, the supply and return water temperature and flow rate are optimized, then the optimized operating adjustment curve of primary network can be obtained. Due to the operation regulation is based on the hydraulic balance, this paper sets up a predicting model of hydraulic operating mode of metered heating systems. The model uses the Monte Carlo method to simulate the users' active adjustment, through the graph theory to calculate the parameters of hydraulic regime. Thus the probability of occurrence of hydraulic disorder in each position of the pipe network is obtained and the corresponding solutions are put forward. Finally, this paper chooses a central heating system of a certain area as the research object and its total energy consumption of the heating system in the heating season is calculated and compared.The research of metered heat supply systems shows that the established model of active quality-quantity adjustment and passive quantity adjustment not only meets the adjustment demand of users'heat adjustability, but also reduces the power consumption of pumps as a result of reduction of system flow. Based on the optimal operation regulation of primary network model, reasonable parameters can be obtained by using genetic algorithm. The parameter variation law shows that the best operating method which keeps the system's energy consumption lowest is the quality-quantity adjustment essentially. The variations of hydraulic condition of measurable heating system are closely related to the number and distribution of adjusted users and the operation adjustment method. The more adjusted users, the more unstable the hydraulic condition is. The position of the most disadvantaged position will change with the adjustment of users. The adjusted users locate in the end of pipe network has greater influence on hydraulic balance than in the front. The adjustment method of active quality-quantity adjustment and passive quantity adjustment only has a slightly effect on hydraulic balance. In the view of measurable heating system, compared with the comprehensive regulation which secondary network uses the traditional quality regulation and primary network uses the quality regulation of phase variable flow, the total regulation which secondary network uses active quality-quantity adjustment and passive quantity adjustment and primary network uses the optimized regulation will bring more energy-saving and economic benefits, which is suitable for popularization and application in metered heating supply system.