The Research Of The Constant Pressure And Operation Adjustment Of Multi-heat Sources Loop-shaped Network

With the development of urban heat supply, multi-heat sources loop-shaped heat-supply network for its energy-saving,reliable heating and other advantages have become the trend. Because of the loop-shaped pipe network have different hydraulic characteristics with branch-shaped pipe network, in order to correctly design and adjust hydraulic conditions, and give full use of the advantages of loop-shaped heat-supply network. This paper presents several issues about multi-heat source loop-shaped heat-supply network'constant pressure and operational regulation, and we are to study it.This paper introduces the recent research and development of the multi-heat source loop-shaped heat-supply network at home and abroad. It also points out that in the application of this multi-heat source loop-shaped heat-supply network technology, there exist problems to be solved. The problems are mainly related to the numbers of the constant pressure points, hydraulic intersect position and multi-heat source loop-shaped heat-supply network'operation and adjustmentAs the particularity of the multi-heat source loop-shaped heat-supply network'hydraulic characteristics, the issue about using a single point constant pressure or multi-points constant pressure needs further study. The number of the constant pressure points directly affect the security, reliability and hydraulic stability of the multi-heat source loop-shaped heat-supply network. By using mathematical methods to deduce in this text,we solve this issue. Using graph theory to express the physical model of loop-shaped heat-supply network mathematically,we immediately establish the corresponding mathematical matrix model and use linear algebraic methods to theoretical derivation. At last? we find the conclusion that the network with multiple heat sources can only use the single point constant pressure.Multi-heat source loop-shaped network'hydraulic intersection points define the scope of the heat supply of each heat source. We try to correctly determine the intersection point of Multi-heat source loop-shaped network, it is of great significance to the design and operation of Multi-heat source loop-shaped network. By editing programs and using the MATLAB software to calculate multi-condition of the established network model, we come to the conclusion that the location of the hydraulic intersection point can be little affected with the impedance increases of the tabulations associated with the hydraulic intersection point,and it is also with the increases of the users' impedance.In the single-heat source branch-shaped network, the heat-supply scope will not change with the flow of the heating network, so the rotational speed of the circulating pump is directly proportional to the heat flow. However, for Multi-heat source loop-shaped network, the location of hydraulic intersection points may change with the change of the heat flow, the total resistance of the heat-supply scope of heat source will change, It may lead to the rotational speed of the circulating pump is no longer proportional to the heat flow. A number of hydraulic conditions are analyzed by using MATLAB software to prove this conclusion.Finally? aiming at the distribution of the heat source of Xi'an BeiLinOu, this text establishes a multi-heat source loop-shaped network model and by using this model,we calculate and analysis the above issues,reproduce the above conclusions which are from the theoretical analysis.Results of this study have a certain practical significance on the design and operation adjustment of the multi-heat source loop-shaped network.