Research On Optimal Zero Pressure Difference Position Rule Of Power Distributed Secondary Pump Heating System Pipeline

The cooling and heating system is composed of three main links: cold and heat source,pipe network transmission and distribution,and users.At present,in the field of HVAC,building energy has achieved fruitful results in both cold and heat sources and users.As an important part of the system,the research on energy saving of pipe network transmission and distribution is rare in China.Strengthening the research on energy transmission and distribution is not only a pioneer in the improvement of power distribution theory,but also an important measure for HVAC energy conservation.It can be described as two birds with one stone.The distributed transmission and distribution system is relative to the centralized transmission and distribution system.The difference between the distributed transmission and distribution system and the centralized transmission and distribution system lies in the system composition,transportation mode,operating conditions,hydraulic balance,etc.,but the most essential The difference is zero pressure difference.The zero-pressure difference point is the point at which the pressure difference between the return and the water in the power distributed heat distribution system is zero,or the operating point when the pressure drop in the system balance pipe is zero.The energy saving rate of the pipe network transmission and distribution system is closely related to the position of the zero pressure difference point.When the zero pressure difference point is located at the separation point or the left side of the critical point X near the heat source,any connection network transmission and distribution system is supplied back.The balance pipe of the water main pipe can be regarded as the best zero pressure difference point,and the system energy saving rate reaches the maximum percentage.The research route of the optimal zero-pressure point distribution law in this paper is mainly composed of the following contents:Firstly,based on the theoretical analysis and the current research results,this paper determines the main factors affecting the energy saving rate and establishes the basic heat network model.The zero-pressure difference position is taken as the only variable to calculate the hydraulic and numerical simulation of the basic heat network model.The water pressure map analysis of each working condition shows that the separation point X under special working conditions includes the formula expression of the selected important influencing factors.Secondly,on the basis of the conclusion of the first step,by analyzing the law of the change of the hydraulic pressure map of the system and the essential causes of the phenomenon,the inference of the special working condition to the general working condition is obtained: under the general working condition,the dividing point X includes the selected important influence.The formula expression for the factor.Finally,the inference formula under the general working conditions is verified by the theoretical numerical calculation and engineering examples under the general working conditions.