Research On Optimal Scheduling Of District Heating Network With Ring Topology And Multiple Heat Sources Based On Particle Swarm Optimization

In large-scale urban district heating network using water as heating medium,pumps are needed to continuously operate to provide power for the circulation of heating medium.In the quantity adjustment of district heating with multiple heat sources,the energy consumption of the pump occupies a large proportion.In order to reduce the energy consumption of heat source pump to the greatest extent,and ensure the hydraulic balance and heat demand of users in thermal power station.In this paper,particle swarm optimization(PSO)algorithm is combined with the optimization model of pipe network flow regulation.Through continuous optimization,the optimal matching scheme of pump speed and valve opening is finally found,which makes the pump consumption in pipe network lowest.Based on the basic formulas of heat supply regulation,the formulas for calculating the next relative flow ratio and return water temperature at different outdoor temperatures are derived,and the volume regulation curves are drawn.According to the graph theory and the law of conservation of mass and energy,the mathematical model of hydraulic condition of pipeline network is established,and the solution method is given.According to the analysis of accessibility theory,mathematical model of network accessibility analysis is established,and the way to determine the minimum required pump head is solved.For the district heating system with multiple heat sources,an optimal dispatching model of the district heating system is established.The model takes the sum of the heat pump consumption as the objective function,the speed ranges of the pumps,the opening ranges of the valve and the flow ranges of the heat sources as constraints,and the speeds of the pumps and the impedances of the pipe sections with the control valves as variables.In this paper,the particle swarm optimization algorithm is used to solve the optimal scheduling model.The applicability of particle swarm optimization(PSO)to solve this kind of problem is verified by the calculation of two examples with different sizes,which provides a reference for the calculation of quantity regulation of district heating network with multiple heat sources.Compared with the traditional heat source flow allocation,the total energy consumption of heat source circulating pump can be reduced by using particle swarm optimization(PSO)to solve the heat source flow allocation model when the operation volume of the district heating system with multiple heat sources is adjusted.A time-sharing heating method using primary pipe network volume regulation is proposed and verified by an example.The results show that the energy consumption of heat source circulating pump can be further reduced by time-sharing heating with primary central heating regulation compared with the traditional heating mode with primary central heating regulation.