| The energy consumption of central heating system accounts for about 40%~60% of the total building energy consumption in cold regions.Energy conservation of heating system is of great significance for saving energy,reducing pollution and improving living environment.The paper focuses on the central heating system of a university in cold area.According to the composition and operation characteristics of the central heating system,exchange station—secondary pipe network — heating terminals multi-stage regulation and energy saving optimization operation methods are put forward.In addition,an optimal regulation method for dynamic hydraulic balance of pipe network,and digging energy saving potential of central heating system comprehensively are also explored in the paper.The above methods can provide theoretical and practical references for energy saving of building heating system.The main researches of this paper include the following contents:(1)Based on composition of common central heating system,the composition and operation characteristics of study subject is analyzed and the structure,hardware equipments and software platform of the remote energy saving monitoring system in a university are introduced.(2)According to different structures of central heating system,the dynamic adjustment methods and equipment operation quantity optimization strategies of heat transfer station are developed.The basic adjustment equation of heating is deduced by introducing the coefficient of flow optimization.On this basis,according to different structures and different testing conditions of central heating system,differential pressure mass dynamic regulation,minimum flow regulating indoor temperature feedback regulation,variable temperature difference variable differential pressure regulation and other types of regulation methods are proposed,which achieve heating on demand.(3)Based on pipeline heat loss,a new method to adjust the hydraulic balance of pipeline network is put foward.On this foundation,the genetic algorithm is used to optimize the dynamic hydraulic balance of pipe network.The effectiveness of the method is verified by simulation experiments.Firstly,the complex nonlinear hydraulic model is established based on power network graph theory.Because of the complexity of the model,Taylor series is used to linearize it.The energy consumption model of circulating pump is established by utilizing actual measurements.Aiming at the minimum energy consumption of circulating pump and the hydraulic stability of each branch,this method establishes dynamic hydraulic balance model based on genetic algorithm,which is used to optimize the running frequency of the circulating pump and the opening of the electric regulating valve of each branch.Comparing with differential pressure regulation,simulation results show that the dynamic adjustment method can reduce the operation energy consumption at rate of 12.27%.(4)Optimization methods of time division temperature control and fine operation adjustment control are developed for nonadjustable and adjustable terminals respectively.Meanwhile,a prediction model based on the equivalent heat capacity at room temperature can determine the mode conversion time of normal heating and short term low temperature heating precisely.(5)Process of engineering realization and effect analysis of operation are described for exchange station—secondary pipe network—heating end multi-stage regulation and energy saving optimization operation methods.Actual energy consumption datas show that the proposed optimal regulation methods can save about 17.4% heat consumption and 26.5% electricity consumption of heat transfer station while 15.4% heat consumption and 25.9% electricity consumption of air conditioning terminals. |
